How To Get Rid Of Termites

Oplan Termites

Oplan Termites

You Might Start Missing Your Termites After Kickin'em Out. After All, They Have Been Your Roommates For Quite A While. Enraged With How The Termites Have Eaten Up Your Antique Furniture? Can't Wait To Have Them Exterminated Completely From The Face Of The Earth? Fret Not. We Will Tell You How To Get Rid Of Them From Your House At Least. If Not From The Face The Earth.

Get My Free Ebook


Termite Extermination Information

Termites create great damage to your home, which is why you should identify and eliminate them as quickly as they appear. This eBook Oplan Termites teaches you how to solve your termite problem once and for all. Learn how to identify termites, find out if your house is really infested, and eradicate them. Discover Some Of The Most Effective And Time-Proven Methods To Get Rid Of Termites! Learn Some Mean Ways To Really Get Rid Of These Pests From Every Nook And Corner Of Your Home.

Termite Extermination Information Summary

Rating:

4.6 stars out of 11 votes

Contents: Ebook
Author: Scott Harker
Price: $5.97

My Termite Extermination Information Review

Highly Recommended

This is one of the best ebooks I have read on this field. The writing style was simple and engaging. Content included was worth reading spending my precious time.

If you want to purchase this e-book, you are just a click away. Click below and buy Termite Extermination Information for a reduced price without any waste of time.

Download Now

WMWheeler The Termitodoxa of Biology and Society in the voice of a termite king

It has long been known that termites (Isoptera), cockroaches (Blattaria), and mantids (Mantodea) are closely related (Wheeler, 1904 Walker, 1922 Marks and Lawson, 1962) they are commonly grouped as suborders of the order Dictyoptera (Kristensen, 1991). Although there is a general agreement on the monophyly of the order, during the past two decades the sister group relationships of these three taxa and the position of woodfeeding cockroaches in the family Cryptocercidae in relation to termites have been lively points of debate (see Nalepa and Bandi, 2000 Deitz et al., 2003 Lo, 2003 for further discussion). A variety of factors contribute to obscuring the relationships. First, fossil and molecular evidence indicate that these taxa radiated within a short span of time (Lo et al. 2000 Nalepa and Bandi, 2000). A rapid proliferation and divergence of the early forms would obscure branching events via short internal branches separating clades, instability of branching order, and low...

HE Evans Life on a Little Known Planet

Estimate by Basset (2001) that cockroaches constitute approximately 24 of the arthropod biomass in tropical tree canopies worldwide, and hints from various studies suggesting that cockroaches may ecologically replace termites in some habitats (Chapter 10). We address previously unexplored aspects of their biology, such as the relationship with microbes that lies at the heart of their image as anathema to civilized households (Chapter 5). As our writing progressed, some chapters followed un-predicted paths, particularly evident in the one on mating strategies (Chapter 6). We became fascinated with drawings of male and female genitalia that are buried in the taxonomic literature and that suggest ongoing, internally waged battles to determine paternity of offspring. It is the accessibility of this kind of information that can have the most impact on students searching for a dissertation topic, and we cover it in detail at the expense of addressing more familiar aspects of cockroach...

Interaction Of Living Things With The Environment

It is not only chemical changes that are wrought, but also physical ones, from the temperature of Earth to the form of our landscape. The temperature of Earth's surface is strongly affected by plants' ability to remove carbon dioxide, a greenhouse gas that prevents radiation of heat energy from Earth into space. Bacteria in the gut of termites have been found to be responsible for the release of methane gas, another greenhouse gas, into our atmosphere. Trees, grasses, and other plants reduce soil erosion, affecting the shape of the landscape.

Oxymonadea phylum Metamonada

The oxymonads also lack both the Golgi and mitochondrion. These species are larger (mostly 50 m), strictly symbiotic anaerobes in the digestive tract of wood-eating insects (mostly known from termites and cockroaches). Typical genera include Monocercomoides, Oxymonas, Pyrsonympha and Saccinobacculus (Fig. 1.3). They lack a cytostome and ingest fragmented wood chips and microdetritus from the host gut, by phagocytosis from the posterior region of the cell. Pinocytosis occurs over the whole cell surface. There are two pairs of anterior basal bodies connected by a thick fibre. The cilia are trailing posteriorly and spiral-wrap around the cell body. From one basal body, a sheet of tightly cross-linked microtubules (the pelta) overlays the nucleus and supports the anterior region. A ribbon of cross-linked microtubules and other supporting cytoskeletal elements combine to form the axostyle. It is a characteristic organelle which runs the length of the cell and participates in locomotion. It...

Trichomonadea and Hypermastigea phylum Trichozoa

The trichomonads and hypermastigotes belong to the parabasalian protozoa, which are primarily endozoic symbionts or parasites. About half of the genera occur in wood-eating insects, such as the roach Crypotcercus, but two free-living species are known from water solutions rich in dissolved organic matter. Their internal structure has an elaborate fibrous cytoskeleton supporting the basal bodies, the nucleus and the anterior of the cell. They are amitochondriate anaerobes that feed by amoeboid phagocytosis on microdetritus in the digestive tract of host organisms. Their metabolism is enhanced by hydrogenosomes which carry out respiration of pyruvate to acetyl-Co A, CO2 and H2, producing ATE The storage material is glycogen. Mitosis is closed, with the chromosomes attached to the nuclear membrane, and an extranuclear spindle. The Earabasala derive their name from an elaborate system of fibrous cytoskeleton, that emanates from basal bodies to support the nucleus and the anterior of the...

Myrmecophiles Termitophiles

Coblatta wheeleri (Polyphagidae) run rapidly, and when disturbed withdraw their appendages under the body and adhere tightly to the substrate (Deyrup and Fisk, 1984). This behavior is similar to the defensive behavior of flattened Neotropical species (Fig. 1.11C) and suggests that although they appear integrated into colony life, a wariness of their predator hosts remains of selective value. Wheeler (1900) suggested that Att. fungicola is a truly cavernicolous form, living in caves constructed by its emmet hosts. It is the species of Nocticola taken from termite nests, however, that exhibit the delicate, elongate body, attenuated appendages, and pale cuticle typical of cave-adapted insects (and of most other Nocticolidae Roth, 1988,1991a Fig. 1.16C).

Community and Ecosystem Consequences

Mutualisms have also fostered dominance of certain mobile consumers. Leafcutter ants are the major herbivores of the New World tropics because their elaborate farming of fungi on harvested foliage allows them to use virtually any plant species as nourishment, in stark contrast to most herbivorous insects, which use one or a few closely related plant species as food. In lower termites,

Major Living Organisms of Ecosystems

Omnivores are consumers that eat both plants and animals, for example, pigs, rats, foxes, bears, cockroaches, and humans. These consumers typically hunt and kill live prey. On the contrary, the so-called scavengers feed on dead organisms that have either already been killed by other organisms or have died naturally, for example, vultures, flies, crows, hyenas, some species of shark, beetles, and ants. Detritivores (decomposers and detritus feeders) live off detritus, parts of dead organisms, and cast-off fragments and the waste of living organisms. Decomposers, mostly bacteria and fungi, are consumers that recycle organic matter in ecosystems by breaking down dead organic material (detritus) to get nutrients and release the resulting simpler inorganic compounds into the soil and water, where they can be taken up as nutrients by producers. This is also known as biodegradability. Detritus feeders, such as crabs, carpenter ants, termites, earthworms, and wood beetles,...

Comparison With Other Insects

With its axis more or less parallel to the channel (Schon, 1911 McIndoo, 1922 Debaisieux, 1938). The organ is connected with the cuticle at two points, as in a termite (Richard, 1950) and an ant (Menzel and Tautz, 1994), with two connections between a membrane bag surrounding the organ and the membrane lining the tracheal walls. Biophysics of the organ was investigated by Kilpinen and Storm (1997). When the leg is accelerated, inertia causes the haemolymph and the subgenual organ to lag behind the movement of the rest of the leg. The magnitude of this phase lag determines the displacement of the organ relative to the leg and to the proximal end of the organ fixed to the cuticle. The oscillating tube model suggests that the sensory cells respond to displacements of the organ relative to the leg.

Resource Requirements

Some species that exploit nutritionally poor resources require extended periods (several years to decades) of larval feeding in order to concentrate sufficient nutrients (especially N and P) to complete development. Arthropods that feed on nutrient-poor detrital resources usually have obligate associations with other organisms that provide, or increase access to, limiting nutrients. Microbes can be internal or external associates. For example, termites host mutualistic gut bacteria or protozoa that catabolize cellulose, fix nitrogen, and concentrate or synthesize other nutrients and vitamins needed by the insect. Termites and some other detritivores feed on feces (coprophagy) after sufficient incubation time for microbial digestion and enhancement of nutritive quality of egested material. If coprophagy is prevented, these organisms often compensate by increasing con

Recruitment pheromones

Recruitment can be defined as communication that directs members of a society to some point in space to perform certain tasks. This altruistic type of communication can be explained by kinship theories that predict a close relationship between the recruiter and the recruited individual. In fact, the distribution of recruitment pher-omones is limited to social organisms such as ants, bees, termites, naked mole rats, and social lepidopteran larvae. In these species, recruitment pheromones assemble nestor groupmates for joint efforts in food retrieval, nest construction, nest defense, or colony migration. Due to this multitude of tasks that is mediated by recruitment pheromones, this category cannot be clearly separated from others such as alarm or aggregation pheromones. Mass recruitment systems per definition can be induced and regulated by volatile chemicals that orient the recruits to the target site (e.g., food). The number of activated nestmates depends on the amount of recruitment...

Species Interactions in the Tropics

An important nutrition digestion mutualism in the tropics is the interaction between termites and fungi. Some species of termite carry material back to their nests where it is decomposed by fungus. The fungus is then used as a food source by the termite colony (Wood 1978). Leaf cutter ants also cultivate similar fungal gardens on leaf fragments (Stradling 1978). The mycorrhiza tree-root association is also extremely important in the tropics, as it contributes to high efficiency of nutrient cycling critical for tropical forests where there is a high potential for nutrient loss through leaching (Jordan 1985).

Case Study Panesthiinae

Uniquely among cockroaches, some macropterous members of this subfamily shed their wings. In some species of Panesthia, Salganea, and Ancaudellia only the basal region of the tegmina and wings remains intact. The wings are not cleanly snapped at a basal suture, as in termites, but have a raggedy, irregular border (Fig. 2.12B) (Roth, 1979c Maekawa et al., 1999b). Some early observers thought that dealation resulted from the chewing action of conspecifics (Caudell, 1906), that they solicit the assistance of their comrades to gnaw them off close to the base. Others, however, suggested that the wings were broken off against the sides of their wood galleries, because dealation occurs even in isolated individuals and because the proposed gnawing action was never observed (McKeown, 1945 Redheuil, 1973). The wings are most likely lost by a combination of both behaviors. In laboratory studies of Panesthia cribrata, Rugg (1987) saw adults moving rapidly backward, rubbing the wings against the...

Heterogeneity and Mosaic

(physical and chemical properties of the soil, microtopography, microclimate) as well as by organisms (plants via leaf deposit, exudate, root growth animals by grazing, trampling, burrowing). Some organisms, like termites, are real ecosystem engineers promoting heterogeneity and providing in such a way habitats for many other species that have a less direct relationship with the environment. Finally, another cause of heterogeneity is represented by stochastic events like earthquakes, hurricanes, fires, volcanic eruptions, flooding, etc.

Nesting and Brood Care

The complex eusociality characterizing termites and the social Hymenoptera has attracted considerable attention (e.g., Matthews and Matthews 1978, E. Wilson 1975). Eusociality is characterized by multiple adult generations and highly integrated cooperative behavior, with efficient division of labor, among all castes (Matthews and Matthews 1978, Michener 1969). Members of these insect societies cooperate in food location and acquisition, feeding of immatures, and defense of the nest. This cooperation is maintained through complex pheromon-al communication, including trail and alarm pheromones (Holldobler 1995, see Chapter 3), and reciprocal exchange of regurgitated liquid foods (trophallaxis) between colony members. Trophallaxis facilitates recognition of nest mates by maintaining a colony-specific odor, ensures exchange of important nutritional resources and (in the case of termites) of microbial symbionts that digest cellulose, and may be critical to colony survival during periods of...

Competitive Defensive and Mutualistic Behavior

Marking territorial boundaries takes a variety of forms among animal taxa. Male birds mark territories by calling from perches along the perimeter. Male deer rub scent glands and scrape trees with their antlers to advertise their territory. Social insects, including ants, bees, and termites, mark nest sites and foraging areas with trail pheromones that advertise their presence. These trail markers can be perceived by other insects at minute concentrations (see Chapter 3). Many orthopterans and some beetles advertise their territories by stridulating.

Resource Consumer Relationships Trophic Interactions

Microbial decomposition is often limited by low water availability, resulting in the accumulation of dry plant material and seeds. For that reason, animal detrivores are more important in deserts than in more mesic environments. Examples are darkling beetles, termites, and isopods. Termites are abundant in most of the warmer deserts and are often the dominant decomposers of dead plant material (above- and belowground) that play an extraordinarily important role in nutrient cycling. Since most termites live belowground, they are also important in the formation of soils. A similar phenomenon is displayed by scavenging animals, which are comparatively abundant among the desert fauna. Examples are large mammals (hyenas, coyotes, and jackals) and many birds (Old World and New World vultures, ravens, etc.). Like smaller detrivores in the desert fauna, many of these scavengers can switch to a predatory diet when needed.

In Existing Burrows and Nests

A number of cockroaches live in the nests of social insects, although these relationships are rather obscure. Some cockroach species collected in ant and termite colonies have been taken only in this habitat (Roth and Willis, 1960), and are presumably dependent on their hosts. In others, the relationship is more casual, with the cockroaches opportunistically capitalizing on the equable nest climate and kitchen middens of their benefactors. Several species of the genus Alloblatta, for example, scavenge the refuse piles of ants (Grandcolas, 1995b). Similar garbage-picking associations are found in Pyc. surinam-ensis with the ant Campanotus brutus (Deleporte et al., 2002), and in nymphs of Gyna with Dorylus driver ants (Grandcolas, 1997a). Occasional collections from insect nests include the Australian polyphagid Tivia australica, recorded from both litter and ant nests, and the blattellid Paratemnopteryx australis, collected from under bark, in litter, and from termite (Nasutitermes...

Importance Of The Macroarthropods

The macroarthropods are a significant component of soil ecosystems and their food webs. Macroarthropods differ from their smaller relatives in that they may have direct effects on soil structure. Termites and ants in particular are important movers of soil, depositing parts of lower strata on top of the litter layer (Fig. 7.8). Emerging nymphal stages of cicadas may be numerous enough to disturb soil structure. Larval stages of soil-dwelling scarabaeid beetles sometimes churn the soil in grasslands. These and other macroarthropods are part of the group that has been termed ecological engineers (Jones et al., 1994). Some macroarthropods participate in both above- and belowground parts of terrestrial ecosystems. Many macroarthropods are transient or temporary soil residents and thus form a connection between food chains in the green world of foliage and the brown world of the soil. Caterpillars descending to the soil to pupate or migrating armyworm caterpillars are prey to...

The contribution of native microbiota to immunity

A simple way in which the native microbiota support the immune response of an insect is by supporting the normal physiology of the host. In cases where there are mutalistic microbes living within an insect the disruption of these microbes can be anticipated to cause physiological changes that would alter the immune response of the animal. For example, in a termite that depends upon its native microbiota for the digestion of cellulose, it might be expected that a gut infection that altered the number and diversity of bacteria could adversely affect both the amount and quality of available nutrients, and thus alter the immune response. Changes in nutrient availability and insulin signalling could be described as a way of monitoring the health of a host's native microbiota.

Exposure to parasites nesting ecology foraging and food

Pathogenic fungi are mostly dispersed passively via wind, rain, etc. and enter hosts via the cuticle or openings such as the trachea (Andreadis, 1987). This implies that fungal spores will be spread out over relatively large areas and will often be associated with the soil, whereas propagules of the other disease categories will be deposited at sites visited by infected individuals. Ant and termite hosts usually start colonies by excavating galleries in the soil or in wood (Table 6.1). Some may erect nest mounds or paper nests when colonies mature, but as a rule the developing brood and foraging workers will remain associated with soil and wood (Brian, 1982). It thus seems obvious to expect that fungal diseases should be common in ants and termites. Most wasps build nests in the open, generally hanging freely from branches, so that they have minimal contact with soil or wood. Bees seem intermediate. Primitively eusocial bees (e.g. halictines) tend to excavate nests in the soil,...

The nature of tropical diversity

Another example comes from a classic data set, repeated in many textbooks, that shows increasing diversity towards the tropics in the numbers of breeding land bird species for Canada, the United States, and Mexico.14 Many similar examples are given in both introductory textbooks15,16 and more advanced texts,17,18 which provide long lists of taxa that show a gradient of declining species richness as one moves away from the tropics these include global tree species, freshwater fish in the rivers of the world, marine bivalves, termites, and African primates. Even aspects of human diversity have

Which microbes are symbionts

There are a range of other bacteria that are important in particular host groups. Chlamydia relatives have been found in symbiosis with the plant-sucking bug Bemisia tabaci and scale insects (Thao et al., 2003). Cockroaches, termites, and many scale insects require the presence of a Flavobacterium, specifically Blattabacterium in the case of cockroaches and termites (Bandi et al., 1995). Mealybugs carry a member of the beta division of proteobacte-ria, Tremblaya (Baumann and Baumann, 2005).

Effect Of Microbes On Human Health

Higher organisms evolved in a microbial world. From the perspective of microorganisms, plants and animals represent another environment to colonize. Thus, it is not surprising that humans, as well as other animals and plants, have a diverse community of microbes living on and in them. Some of these passengers are normal, beneficial, or even necessary (e.g., rhizobia in some plants cellulose degraders in animals such as termites and ruminants), whereas others are abnormal, harmful, or even fatal.

The differences in defence against parasites across the four groups of social insects

And transmission (Section 2) are normally not compensated by opposite differences in individual or collective defence (this section). The annual social bees and wasps face higher risks of introducing infections in their colonies when returning from foraging trips because they are more likely to ingest contaminated food away from the colony and have less effective filtering devices to prevent per os infections. Their individual antibiotic defences seem less general and elaborate, and their allogrooming, hygienic behaviour and waste management practices are generally less well developed or less frequent. Although task partitioning probably occurs in all major groups of social insects, physical worker castes that would help in defence against disease are restricted to the perennial ants and termites. In fact, the only factor that is not unambiguously pointing towards a significant advantage in disease defence for the long-lived, perennial societies of ants and termites is intracolonial...

An Update and Reappraisal of the Comparative Data

The database of Schmid-Hempel (1998), which was closed in 1996, has been updated with any new host-parasite interactions involving social insect hosts that were not already included in the Schmid-Hempel (1998) database. For the most part, updating was limited to literature that has appeared post-1996. Sampling effort varies dramatically between the social insect groups, with termites and wasps having received considerably less attention than have the ants and bees. More importantly, the distribution of the effort varies, most notably with a single bee species (Apis mellifera) having been studied with very great intensity whereas, for example, a very large number of ant species have been studied, but each relatively little. We used two methods to eliminate the confounding effects of sampling effort. The first method is the same as that applied by Schmid-Hempel (1998) and used the number of studies published on particular host species as an approximation of study effort. Residuals from...

Important issues for future work

Established single-species model systems will remain essential for further experimental studies. However, broader comparative studies will be valuable for uncovering general principles of social evolution and the ways in which parasitism affects social evolution (Schmid-Hempel, 1998 Schmid-Hempel and Crozier, 1999). Further insight into the overall patterns of disease pressure should probably also come from studying paired genera or higher taxonomic units that have much in common but differ in one or two of the key aspects affecting either the infection processes or defences (Fig. 6.1). An obvious case would be to compare disease diversity, prevalence, specificity and virulence in Apis honeybees and Melipona stingless bees. An advantage of this 'twin' model system would be that virtually all honeybee diseases are known and have been studied (Bailey and Ball, 1991), so that the organization of comparable studies in stingless bees will be straightforward. A difficulty will be to...

Additional Microbial Influences

Microbial products may act like pheromones. Because cockroach aggregation behavior is in part mediated by fecal attractants in several species, it is possible that gut microbes may be the source of at least some of the components. Such is the case in the aggregation pheromone of locusts (Dillon et al., 2000) and in the chemical cues that mediate nestmate recognition in the termite Reticuli-termes speratus (Matsuura, 2001).

Faunal Feedbacks On Microbial Community Composition And Diversity

Studies of microbial community similarity have been conducted comparing termite mounds and nearby tropical soils. Harry et al. (2001) used RAPD (random amplified polymorphic DNA) molecular markers to estimate the similarity of microbial communities in the mounds of several termite species and surrounding soils. They studied four species of soil-feeding termites and one species of fungal-feeding termite in a tropical rain forest area of the Nyong River basin in Southern Cameroon. They found that microbial communities of the mounds of the soil-feeding termite species were clustered in the same clade, whereas those of the mounds of the fungus-growing species were distinct like those of the control soils. The microbial changes were dependent upon the species' behavior, with the soil feeding species including feces in their mound building and the fungal-feeding species using saliva as particle cement in its mounds.

Towards a synthetic lifehistory theory of disease pressure in social insects

The question as to why ants and termites are obligatory iteroparous, whereas the social bees and social wasps (excepting a few derived lineages that originated and mostly remained in the tropics) have retained the ancestral semelparous life cycle is likely to be directly linked to the type of diseases that affect them and to the prevalence and virulence that these diseases achieve. Iteroparity is generally selected for when adult survival rates are high relative to juvenile survival rates (Stearns, 1977), whereas being parasitized selects for earlier reproduction (Forbes, 1993) and semelparity. Defences favouring colony resistance against, rather than colony tolerance of, parasites may have played a crucial role in this transition that took place early in the social evolution of both ants and termites. In organisms other than social insects, a high life expectancy after the first reproductive effort is generally associated with costly but efficient defences against natural enemies and...

Microbes As Pathogens

Sexual contact carries with it the risk of sexually transmitted diseases (e.g., Thrall et al., 1997), but no cockroaches were listed in an extensive literature survey on the topic (Lockhart et al., 1996). Wolbachia, a group of cyto-plasmically inherited bacteria that are widespread among insects (including termites Bandi et al., 1997) have not yet been detected in cockroaches, but few species have been studied to date (Werren, 1995 Jeyaprakash and Hoy, 2000). Further surveys of Blattaria may yet detect Wolbachia, but because they are transmitted through the cytoplasm of eggs, these rickettsiae may have trouble competing with transovariolly transmitted bacteroids (Nathan Lo, pers. comm. to CAN).

Invertebrate Effects On Fungal Community Structure

The mutualism between Macrotermitinae and Termitomyces species, in which the former cultivate the latter within their nests, is even more dramatic. Termitomyces species are poor competitors and are rapidly over-run if the termites abandon the nest, but are maintained in the fungus comb in active nests in more or less pure culture, despite continual inoculation with other fungi on plant material collected by the termites (Wood and Thomas, 1989 Shinzato et al., 2005). Passage through worker guts reduces germination of non-mutualistic symbiont spores, oral secretions are fungistatic, and nest microclimate (30 C and elevated CO2) is optimal for the fungal symbiont. There also seems to be genetic screening of Termitomyces strains, either directly via active selection by the termite or indirectly by intra-specific competition on the fungus comb, as evidenced by identical fungal molecular sequences in multiple samples from four different nests of species that have horizontal symbiont...

Improvement Of Nutritional Environment For Invertebrates

Ingested enzymes, from the fungus, also play an important role in the digestion of plant litter in siricid wood wasp, fungus-growing termite and fungus-growing ant mutualisms (Martin, 1992). Cellulose and hemicellulose are digested during passage through the alimentary tract, predominantly the midgut of Sirex spp. larvae, and by the termite and attine ant workers. These acquired enzymes survive gut passage and, in the case of the ants and termites, are concentrated in the faecal droplet which is deposited on fresh plant material (Martin, 1992 Ronhede et al., 2004). This prepares plant material for fungal colonization and increases the initial growth. Basidiomycota also render palatable wood and leaf litter that is initially repellent or unpalatable to invertebrates due to the presence of allelopathic compounds. Again there are well-documented examples for termites (see references in Swift and Boddy, 1984). There are several examples of trees whose central heartwood is resistant to...

Soil structure and microrelief

Micro-relief features created by physical processes include the frost polygons characteristic of the soils of polar regions. These structures may form extensive semi-regular patterns of low mounds defined by systems of polygonal cracks. In the cold desert of Antarctica, snow preferentially entrapped in such cracks melts to provide a locally-favourable micro-habitat for Acari, Collembola and their supporting microbial food base (Wise and Spain, 1967). Gilgai formations commonly comprise patterns of alternating low hollows and mounds at scales of a few metres and are common in soils containing expansive clays. Biotic micro-relief structures include such features as coppice mounds formed through the trapping of wind-borne soil materials around the bases of shrubs in desert regions, the mounds that form at the bases of trees through bole expansion and the termite and ant mounds abundant in many savanna, tropical forest and other landscapes (Chapter IV.5.2.2.1).

Terpenoid biosynthesis and use by animals

Other insects are known to synthesize terpenoids (Feld et al. 2001) or sequester them from their food sources (Codella and Raffa 1995 Wheeler et al. 2002), often for defensive purposes. Ants and termites, two unrelated groups of social insects, are known to possess a fairly complex array of ter-penoids in their glandular tissues (Lloyd et al. 1989 Billen et al. 2000) that may be used by the insects as components of trail pheromones (Janssen et al. 1997) or in defense (Val-terova et al. 1989 Roisin et al. 1990). Recent work has shown that the wood ants, Formica para-lugubris, which collect and store conifer resin in their nests, do not fare as well in artificial nests without resin due to increased growth of microorganisms (Christe et al. 2003). Presumably the terpenoids in the collected resin act to reduce the growth of pathogens. It can be hypothesized, then, that the various species of ants and termites that have evolved the capacity to secrete terpenoids (Lloyd et al. 1989...

Bo 100 Iso 300 260 300 3b0 400 Disturbance

Invertebrates such as ants and termites, vertebrates such as shore birds, and mammals such as beaver, buffalo, rodents and moles are building, burrowing, digging , trampling and moving soil and opening up the vegetation cover. Domestic livestock, when densely reared, can permanently modify the vegetation cover, producing a new landscape. An example is the terracettes produced on steep slopes on mountain pasture by sheep and goats trampling.

Components Of Soil Structure

Macropores are of particular importance in determining soil aeration and rapid water entry. In some soils (notably vertisols), large cracks form on drying and act in this regard at least during initial wetting. Large macropores created by the biota are known as biopores and functionally-effective, near-vertical pores are created in almost all soils by root growth and decay, earthworms, termites, ants and other burrowing invertebrates. Additionally, larger voids and horizontal galleries and chambers also occur that may not be continuous with the surface. In one particularly well-aggregated tropical inceptisol, Radulovich and Sollins (1991) showed that water flowed through the macropores at zero potential (and could be collected in zero potential lysimeters) even though the remaining soil was at less than field capacity (see definition in section I.2.2.2.2).

Effects Of Fauna On Litter Breakdown Rates

The association of soil fauna with litter decomposition is an ancient one. Labandeira et al. (1997) reviewed the evidence concerning associations of soil fauna in the geologic record. The incidence of oribatid mite feeding in coal deposits from Illinois and Appalachian sedimentary basins occurred in all major plant taxa in Pennsylvanian coal swamps. Virtually every type of plant litter tissue was used by the mites. Evidence for termites and holometabolous wood-boring insects dates to the early Mesozoic. The illustrations published by Labandeira et al. (1997) provide striking evidence of the importance of detritivores in these primitive forests.

Resource Availability and Distribution

Palmer (2003) explored the effect of termite-generated heterogeneity in resource availability on the competitive interactions of four ant species that reside on acacia, Acacia drepanolobium, in East Africa. Only one ant species occupied an individual tree at any given time, and violent interspecific competition for host trees by adjacent colonies was common. Acacia shoot production and densities of litter invertebrates increased with proximity to termite mounds. The competitively dominant ant, Crematogaster sjostedti, displaced other acacia ants, C. mimosae, C. nigriceps, and Tetraponera penzigi, near termite mounds, whereas the probability of subordinate species displacing C. sjostedti increased with distance from termite mounds. This variation in the outcome of competition for acacia hosts appeared to result from differential responses among the ant species to resource heterogeneity on the landscape.

Dynamics And Impairment Of Soil Structure

The important role of the macrofauna in aggregate formation in most soils (Bal, 1982 van Breemen, 1993) is due to their promotion of primary binding through their mechanical activities and intestinal mixing (Barois et al, 1993). They also produce macro-scale structures ranging from faecal pellets (250 m to several centimetres) to large subterranean structures such as termite and ant nests. Earthworm faecal pellets may accumulate to such an extent that certain soils have been called 'vermisols' (Pop and Postolache, 1987). Probably the two most important faunal groups in aggregate production are earthworms (Hopp and Hopkins, 1946 Marinissen, 1995 Blanchart et al., 1997) and termites (Eschenbrenner, 1986 Garnier-Sillam et al, 1988a Miklos, 1992) while such groups as enchytraeids (Didden, 1990 van Vliet et al, 1993) are probably of lesser importance.

Reduction and Loss of Genitalic Structures

Additional correlates of reduced male genitalia in cockroaches also must be considered. Among the Panes-thiinae species studied, the absence of an oothecal covering around the eggs is correlated with the absence or reduction of male genital structures (Walker and Rose, 1998). All of the species for which we have information also exhibit a burrowing lifestyle, tunneling in soil, rotted wood, or rotted palms. How all these threads connect (burrowing lifestyle, mating system, copulatory behavior, male genital morphology, and absence of egg case) awaits further study. It is of interest (Chapter 9), however, that termites are monogamous (Nalepa and Jones, 1991) and that isopteran males are largely unencumbered by genitalia (Roonwal, 1970). Termites also live in burrows, mate by backing into each other, and except for Mastotermes, have lost the casing around their eggs. Species in the Cryptocercidae, the sister group of termites, live in burrows and are apparently monandrous, but male...

Symbionts Symbiosis with animals

Among the Collembola, Lepidosinella armata (Entomobryinae) and Cyphoderidae are specialized symbionts in the nests of ants and termites, where they feed on detritus (Hopkins, 1997). Calobatinus rhadinopus are associated with termites (Bellicositermes netalensis and B. bellicosus) in the sawdust imbibed with saliva or on the termite mouth parts (Denis, 1949). Numerous species of mites are ectosymbionts on a variety of animals (Evans, 1992) (Table 4.12). Some form close associations with soil and litter organisms. For example, the majority of species in the suborder Antennophorina are found living alongside insects, but primarily ants. Antennophorus species will stroke the mouth parts of the ant Lasius which disgorges liquefied food for the mite (Donisthorpe, 1927). Soil mites themselves harbour internal and external symbionts. In a study of five species of Oribatida and Acaridida, the culturable bacterial population between the surface and the digestive tract of the mites was found to...

Reduction and Loss of the Egg Case

Oviparous cockroaches in protected environments, like social insect nests, also may exhibit reduction or loss of the egg case. The ootheca of Attaphila fungicola, for example, lacks a keel (Roth, 1971a), and several species of Nocticolidae have thin, transparent oothecal cases. Nocti-cola termitophila apparently lays its eggs singly, without any external covering (Roth, 1988). Termites, the social cockroaches (Chapter 9), exhibit a parallel loss of protective egg cases. The basal termite Mastotermes dar-winiensis packages its eggs within a thin, flexible outer covering that lacks keel. The site and mode of production, associated morphological structures in the female, parallel arrangement of eggs, and discrete, tanned outer covering together indicate that the ootheca of Mastotermes is homologous with those of cockroaches (Nalepa and Lenz, 2000). All other termites lay their eggs singly, without a covering. Both the heart of a social insect colony and the brood sacs of live bearing...

Focus on acetogenesis A process that competes with methanogenesis in anaerobic habitats

The study of acetogenesis is important because of the role that acetogens play in carbon cycling in many anaerobic communities. Acetate is a trophically important metabolite for microbial communities in many ecosystems. The flux of organic carbon into the acetate pool and its metabolic turnover can be enormous in some natural habitats. Approximately 1013 kg of acetate are formed and metabolized annually in anaerobic habitats globally. Of this amount, 10 is derived from CO2 fixation through the Wood-Ljungdahl pathway, and 1.22 x 1012 kg of acetate per year is estimated to be produced microbiologically in the hindgut of termites alone. This mass of acetate greatly exceeds the amount of methane produced annually through microbial reduction of CO2. Acetogenesis also occurs in the human gastrointestinal tract. Reports have estimated that 90 of the carbohydrates ingested by the human population are processed anaerobically through the homoacetate fermentation biochemical pathway....

Box 82 The benefits of symbiotic nitrogen fixation

Finally in this section, it should be remembered that animals can make a large difference to nitrogen gains and losses. Animals such as salmon, birds and termites that travel long distances can bring in significant amounts of nitrogen and other nutrients. Although salmon die in streams once spawned, their nutrients are available to those plants with roots in or near the water (such as those of willows or alders). Animals can also significantly reduce nitrogen input by eating nitrogen-fixing plants such as legumes. Moreover, ruminants that hold microbes in their stomachs can speed up nitrogen cycling by acting as living decomposition vessels.

Aggregation and Group Effects

Group effects refer to morphological, physiological, or behavioral differences between animals that are grouped versus those of the same species that are bereft of social contact. The prolongation of the juvenile growth period in isolated nymphs is the best-studied group effect in cockroaches, occurs in a wide range of species (Table 8.3), and is discussed in Chapter 9 in relation to its evolutionary connection to caste control in termites. One benefit of accelerated development in grouped nymphs is that it moves them quickly through one of the riskiest stages of their lifecycle. The number of cockroach species examined for group effects is extremely limited relative to the number of species available for study especially interesting would be a study of those in which nymphs seem to disperse shortly after hatch, like Than. akinetum (Grandcolas, 1993a). Altered juvenile growth rates, however, are not the only effect of social interaction. Like some other insects that aggregate...

Parental Care in a Nest or Burrow

Cryptocercus is the only known oviparous cockroach with well-developed parental care, and is discussed in Chapter 9 in the context of its sister group relationship to termites. A recent study found that adult presence has a significant effect on offspring growth in families of C. kyebangensis (Park and Choe, 2003a), but the relative influence of parental care and group effects are yet to be determined. In gregarious Periplaneta, for example, single nymphs raised with adults grow and develop as rapidly as grouped nymphs (Wharton et al., 1968). All studied species in the wood-feeding blaberid genus Salganea live in biparental families (Matsumoto, 1987 Maekawa et al., 1999b, 2005). In Sal. taiwanensis, nymphs cling to the mouthparts of their parents and take liquids via sto-modeal feeding (Fig. 8.3B). Removal of neonates from parental care results in high mortality removed nymphs that live have a significantly longer duration of the first instar (T. Matsumoto and Y. Obata, pers. comm. to...

Escape from predation

Life cycles have evolved so as to minimize predation or (for plants) herbivory. Usually one part of the life cycle is highly vulnerable to predation, such as newly produced offspring or adult stages involved in reproductive behavior. Examples include mast-fruiting in oaks, periodical cicadas (Williams et al. 1993, Karban 1997), bamboos that reproduce once a century (Janzen 1976), century plants, mayflies, and the mating flights of ants and termites. In all of these cases reproduction is synchronized in a local population or in many populations over a large geographical area. So many potential prey organisms are produced in such a short time period, or in such an unpredictable manner (e.g. periodical cicadas reproduce once every 13 or 17 years), that potential predators can eat their fill (satiation) without seriously reducing the prey population. Since predator populations cannot build up due to the brevity of the vulnerable stage and or the unreliability of the prey population, the...

Toll and Imd signalling pathways

Domain, the dFADD death domain, and the IKKp kinase domain (Figure 13.3 Begun and Whitley, 2000 Schlenke and Begun, 2003 Jiggins and Kim, 2007 Sackton et al, 2007). Adaptive evolution of the Relish complex is not universal among Drosophila, but is restricted to certain species in the mela-nogaster group (Levine and Begun, 2007 Sackton et al., 2007). In an interesting parallel, the Relish gene of Nasutitermes termites also evolves adap-tively, again with positively selected mutations localized in and around the caspase cleavage site and linker (Bulmer and Crozier, 2006), suggesting convergence of selective pressures in these distantly related insects. Nor is adaptive evolution in Drosophila restricted to the Relish complex. Many other signal transduction genes in the Imd and Toll pathways (imd, spirit, persephone, Toll, dorsal, necrotic) also show evidence of rapid evolution in Drosophila (Schlenke and Begun, 2003 Jiggins and Kim, 2007 Sackton et al., 2007).

Soils And Gaia Possible Mechanisms For Evolution Of The Fitness Of The Soil Environment

In the areas of soil texture and structure, as well as soil chemical properties, there are numerous examples of soil biotic interactions having a generally beneficial effect in the top meter of soil material. One example of this is provided by Gill and Abrol (1986), who described how planting Eucalyptus teretocornis and Acacia nilotica on an alkali soil (pH 10.5) markedly decreased pH and salinity within 3 to 6 years. These changes were probably caused by a suite of factors including increased water permeability, which followed the development of root channels and the accumulation of organic matter in the upper 20-50cm of the soil profile. Other biota, notably termites, can promote higher salt content in soils, as detected by measurements in inhabited and abandoned termite hills compared to the surrounding soil (de Wit, 1978). Many of these processes tend to increase the amounts of heterogeneity within soil profiles, which has been well reviewed recently by Stark (1994).

Recognition molecules in the humoral response

T urnover on the lineages that separate Drosophila from mosquitoes, honey bees, and Tribolium (see section 6.4.4 in this volume Evans et al, 2006 Waterhouse et al, 2007 Zou et al, 2007). Most GNBPs and PGRPs do not appear to have experienced recent adaptive evolution in Drosophila (Jiggins and Hurst, 2003 Schlenke and Begun, 2003 Jiggins and Kim, 2006 Sackton et al, 2007), mosquitoes (Little and Cobbe, 2005), or the crustacean Daphnia (Little et al., 2004). A notable exception, however, is a Drosophila PGRP which shows strong indications of adaptive evolution. PGRP-LC, an alternatively spliced gene that sits atop the Imd signalling cascade, has sustained a two amino acid insertion in the PGRP-LCa isoform in species of the melanogaster subgroup. This insertion is predicted to alter the binding specificity of that isoform, and appears to have been positively selected in conjunction with several additional adaptive substitutions (Sackton et al., 2007). Interestingly, the alternatively...

Cost of Parental Care

Typically low in nitrogenous materials. The high cost of parental care in Cryptocercus may account for their functional semelparity (Nalepa, 1988b), and has been proposed as a key precondition allowing for the evolution of eusociality in an ancestor they share with termites (Chapter 9). It is of interest then, that, another wood-feeding cockroach (Salganea matsumotoi) that lives in biparental groups and is thought to exhibit extensive parental care appears to have more than one reproductive episode (field data) (Maekawa et al., 2005).

The Behavioral Continuum

Striking ethological similarities in cockroaches and termites have been recognized since the early 1900s (Wheeler, 1904). These behavioral patterns probably arose in the stem group that gave rise to both taxa (Rau, 1941 Cornwell, 1968) and may therefore serve as points of departure when hypothesizing a behavioral profile of a termite ancestor. The most frequently cited behaviors shared by cockroaches and termites are those that regulate response to the physical environment. Both taxa are, in general, strongly thigmotactic (Fig. 3.7), adverse to light, and associated with warm temperatures and high humidity (Wheeler, 1904 Pettit, 1940 Ledoux, 1945). Additional shared behaviors include the use of con-specifics as food sources (Tables 4.6 and 8.4), the ability to transport food (Chapter 4), aggregation behavior, elaborate brood care (Chapter 8), hygienic behavior, al-logrooming (Chapter 5), and antennal cropping, discussed below. The remaining behaviors common to Blat-taria and Isoptera...

Vibrational Communication

Termites use vibratory signals in several functional contexts. Drywood termites, for example, assess the size of wood pieces by using the resonant frequency of the substrate (Evans et al., 2005). When alarmed, many termite species exhibit vertical (head banging) or horizontal oscillatory movements that catalyze increased activity throughout the colony (Howse, 1965 Stuart, 1969). While cockroaches are known to produce a variety of acoustic stimuli in several functional contexts (Roth and Hartman, 1967), a recent review of vibrational communication included no examples of Blattaria (Virant-Doberlet and Cokl, 2004). It is known, however, that Peri-planeta americana is capable of detecting substrate-borne vibration via receptors in the subgenual organ of the tibiae (Shaw, 1994b), and that male cockroaches use a variety of airborne and substrate-borne vibratory signals when courting females, including striking the abdomen on the substrate. Tropical cockroaches that perch on leaves during...

Organochlorine Pesticides

Chlordane, banned since 1988, was used in 24 million United States homes, usually as a termiti-cide, and it has been detected in the home environment as long as thirty-five years after use (Wright, Leidy, and Dupree, 1994). Chlordane concentrations in the Hudson River estuary have been found to exceed regulatory criteria for human health protection for several specimens of American eel, white perch, and the hepatopancreas of blue crab (Skinner et al., 1996). However, only blue crab hepatopancreas showed average concentrations that exceeded the regulatory criterion of 300 ng g. Greatest concentrations were found in samples taken from the East River and the Newark Bay complex and are possibly due to residential applications for termite control.

Developmental Foundations

The influence of hemimetabolous development in the evolution of termite societies has long been recognized (Kennedy, 1947 Noirot and Pasteels, 1987). Unlike the holometabolous Hymenoptera, termite juveniles do not have to mature before they are capable of work. Hemi-metabolous insects also tend to grow less between molts and molt more often over the course of development (Cole, 1980). This is due, at least in part, to differences in nutritional efficiency between the two groups. The conversion of digested food to body mass can be 50 greater in holometabolous insects, possibly because they do not need to produce and maintain a large mass of cuticle during the juvenile stage (Bernays, 1986).

Control of Development

An examination of conditions known to modify cockroach development may provide insight into the origins of termite polyphenism, the proximate causes of which are still little understood (Bordereau, 1985 Roisin, 2000). Here we focus on three extrinsic factors that may have influenced development as the termite lineage evolved minor injuries, nourishment, and group effects. Each of

Injury and Development

There is a large body of literature indicating that minor wounds in cockroach juveniles delay development. Injuries to legs, cerci, and antennae result in an increased number of instars, in the prolonged duration of an instar, or both (Zabinski, 1936 Stock and O'Farrell, 1954 Willis et al., 1958 Tanaka et al., 1987). The developmental delay may be attributed to the allocation of limited resources, because energy and nutrients directed into wound repair and somatic regeneration are unavailable for progressive development (Kirkwood, 1981). This relationship between injury and development may be relevant to termites in two contexts. First, in a variety of lower termites, mutilation of the wing pads and occasionally other body parts is common (e.g., Myles, 1986). These injuries are hypothesized to result from the bites of nest mates, and they determine which individuals fly from the nest and which remain to contribute to colony labor. Injured individuals do not proceed to the alate stage,...

Nutrition and Development

Cockroach development is closely attuned to nutritional status (Gordon, 1959 Mullins and Cochran, 1987). Poor food quality or deficient quantity results in a prolongation of juvenile development via additional molts and or prolonged intermolts (Hafez and Afifi, 1956 Kunkel, 1966 Hintze-Podufal and Nierling, 1986 Cooper and Schal, 1992). Diets relatively high in protein produce the most rapid growth (Melampy and Maynard, 1937), and on diets lacking protein, nymphs survive for up to 8 mon, but eventually die without growing (Zabinski, 1929). The effect of nutrition on development is most apparent in early instars, corresponding to what is normally their period of maximum growth (Woodruff, 1938 Seamans and Woodruff, 1939).A nutrient deficiency in a juvenile cockroach results in a growth stasis, in which a semi-starved nymph idles until a more adequate diet is available. This plasticity in response to the nutritional environment is suggestive of the arrested development exhibited by...

Group Effects and Development

From both decreased weight gain per stadium and increased stadium length (Griffiths and Tauber, 1942b Willis et al., 1958 Wharton et al., 1968 Izutsu et al., 1970 Woodhead and Paulson, 1983). In P. americana, nymphs isolated at day 0 are one-half to one-third the size of grouped nymphs after 40 days (Wharton et al., 1968).The effect is cumulative, with no critical period. It occurs at any stage of development and is reversible at any stage (Wharton et al., 1967 Izutsu et al., 1970). Respiration of isolates may increase, and new proteins, expressed as electrophoretic bands, may appear in the hemolymph (Brossut, 1975 pers. comm. to CAN). The physiological consequences seem to be caused by a lack of physical contact (Pettit, 1940 Izutsu et al., 1970) and the presence of even one other individual can ameliorate the effects (Izutsu et al., 1970 Woodhead and Paulson, 1983). The means by which tactile stimuli orchestrate the physiological changes characteristic of the group effect in...

Heterochrony Evolutionary Shifts in Development

Termites are essentially the Peter Pans of the insect world many individuals never grow up. Most colony members are juveniles whose progressive development has been suspended. Even mature adult termites exhibit numerous juvenile traits when compared to adult cockroaches, the phylogenetically appropriate reference group (Nalepa and Bandi, 2000). Termites therefore may be described as paedomorphic, a term denoting descendent species that resemble earlier ontogenetic stages of ancestral species (Reilly, 1994). The physical resemblance of termites and young cockroaches is indisputable, and is most obvious in the bodily proportions, the thin cuticle, and a short pronotum that leaves the head exposed. Cleveland et al. (1934) and Huber (1976) both noted the resemblance of early instars of Cryptocercus to larger termite species, with the major difference being the more rapid movement and longer antennae of Cryptocercus (Fig. 9.5). One advantage that termites gain by remaining suspended in...

Types And Patterns Of Detritivory And Burrowing A Detritivore and Burrower Functional Groups

General functional groupings for detritivores are based on their effect on decomposition processes. Coarse and fine comminuters are instrumental in the fragmentation of litter material. Major taxa in terrestrial ecosystems include millipedes, earthworms, termites, and beetles (coarse) and mites, collembolans, and various other small arthropods (fine). Many species are primarily fungivores or bacteriovores that fragment substrates while feeding on the surface microflora. Many fungivores and bacteriovores, including nematodes and protozoa, as well as arthropods, feed exclusively on microflora and affect the abundance and distribution of these decomposers (e.g., Santos et al. 1981). A number of species, including dung beetles, millipedes, and termites, are coprophages, either feeding on feces of larger species or reingesting their own feces following microbial decay and enrichment (Cambefort 1991, Coe 1977, Dangerfield 1994, Holter 1979, Kohlmann 1991, McBrayer 1975). Xylophages are a...

Selfgrooming and allogrooming

In many social insects, self-grooming and allogrooming are extremely prevalent and may be an effective strategy for removing the spores of entomopathogenic fungi or the infective stages of entomopathogenic nematodes (Schmid-Hempel, 1998). In the dampwood termite, Zootermopsis angusticollis, allogrooming increases in frequency during and after exposure to the spores of the fungus Metarhizium anisopliae (Rosengaus et al., 1998b). This appears to be effective in removing potentially infectious spores from the cuticle, so increasing termite survival. Thus, allogrooming plays a crucial role in the control of disease in termites, and Rosengaus and colleagues speculate that this advantage of group living may have been significant in the evolution of social behaviour in the Isoptera. Across ant species, the frequency of allogrooming tends to increase with colony size (Schmid-Hempel, 1998), whilst the frequency of self-grooming tends to do the opposite (Schmid-Hempel, 1990). In some ways,...

Dependence on Flagellates for Cellulase

All termites and all cockroaches examined to date produce their own cellulases, which are distinct from and unrelated to those produced by the hindgut flagellates (Watanabe et al., 1998 Lo et al., 2000 Slaytor, 2000 Tokuda et al., 2004). The common possession of a certain family of cellulase genes (GHF9) in termites, cockroaches, and crayfish suggest that these enzymes were established in the Dictyopteran lineage long before flagellates took up permanent residence in the hindguts of an ancestor of the termite- Cryptocercus clade (references in Lo et al., 2003b). At present, Cryptocercus and lower termites are considered to have a dual composting system (Nakashima et al., 2002 Ohkuma, 2003) cellulose is degraded by the combined enzymes of the host and the hindgut flagellates. Nonetheless, these hosts are dependent on the staggeringly complex communities of mutually interdependent co-evolved organisms from the Ar-chaea, Eubacteria, and Eucarya in their digestive systems. The...

Flagellates Cause Eusociality

Hindgut protozoans were crucial in the evolution of eu-sociality in their termite hosts, but not for the reasons usually cited. In termites, the hindgut flagellates die just prior to host ecdysis. A newly molted individual must reestablish its symbiosis by proctodeal trophallaxis from a donor nestmate, making group living mandatory. In the classic literature, this codependence of colony members was thought to be the main precondition for the evolution of eusociality in termites the idea can be traced to the work of L.R. Cleveland (1934). While loss of flagellates at molt may enforce proximity, it provides no explanation for the defining characteristics of termite eusociality, namely, brood care, overlapping worker generations, and non-reproductive castes (Starr, 1979 Anders-son, 1984). Moreover, the bulk of evidence suggests that protozoan loss at molt in termites did not precede euso-ciality. It is a secondary condition derived from eusocial-ity of the hosts, and is associated with...

Immunity and sociality in insects

Throughout this chapter, many examples pointing to insect immunity having specificity and greater functional complexity than previously assumed come from social insects. Social insects will also be particularly sensitive to issues relating to the existence of specific immune responses (e.g. Table 14.2). Therefore, time will be taken here to briefly outline further related aspects of the evolution of social insects and their immune defences.

Definition and Occurrence

Given their wide biogeographic range, savannas occur on a number of soils types, typically oxisols, ultisols, entisols, and alfisols (using US soil taxonomy). In general, these soils are ancient and highly weathered, low in organic matter and cation exchange capacity (CEC). Oxisols occur in tropical savanna regions of South America and central and eastern African savanna and consist of highly weathered, transported, and deposited material occurring on fluvial terraces. Extensive weathering of primary minerals has occurred and they are dominated by clay minerals such as kaolinite and gibbsite which have low CEC. Also present in the soil are acidic Fe and Al sesqui-oxides, which limits nutrient availability, especially phosphorus. Savanna soils tend to be sands to sandy loams, deep and well drained but with low soil moisture-holding capacity. Entisols that occur in Australian savanna also feature the occurrence of ferruginous gravels, further reducing water- and nutrient-holding...

Spacing and movement patterns

Whether species feed in individual territories or gregariously seems to depend on the consistency of the food supply, and whether it is defendable (Newton 1998b). The same species can behave territorially on one type of food and gregariously on another. For example, Steppe Eagles Aquila nipalensis in Africa are mostly territorial when feeding on mammals, and gregarious when exploiting local abundances created by emerging termites or Quelea colonies. In addition, dominant individuals of a species may behave territorially, while subordinate ones, unable to get territories, feed solitarily or in flocks, sometimes on different foods (for White Wagtail Motacilla alba see Zahavi 1971, for Yellow Wagtail M. flava see Wood

Available Moisture and Nutrients

Two common images of savannas are herbivory by large, native ungulates, particularly in Africa and the widespread grazing by domestic herds, particularly cattle. A more neglected group of savanna herbivores are the invertebrates, particularly grasshoppers, caterpillars, ants, and termites. Mammal herbivores are typically categorized as grazers, browsers, or mixed feeders, who can vary their diet depending on food availability. Mammal and insect herbivores impact on savanna structure and function via consumption of biomass, seed predation, trampling of understory, and the pushing over and killing of trees and shrubs. The importance of herbivory as a determinant varies between savanna regions, and appears to largely reflect the abundance of large herbivores present. Large herbivore diversity and abundance are much higher in Africa than in Australia, Asia, or South America. More than 40 large wild herbivore species have been described in African savanna. In contrast, only six species of...

Double Symbiosis The Role Of Bacteroids

A hindgut filled to capacity with a huge complex of interacting microbiota was not the only symbiotic association influential in the evolution of termite eusociality. Grasse and Noirot (1959) noted nearly a half-century ago that the two taxa bracketing the transition from cockroaches to termites share a unique double symbiosis an association with cellulolytic flagellates in the hindgut, and endosymbiotic bacteria housed in the visceral fat body. Cryptocercus is the only cockroach that has the former symbiosis, which it shares with all lower termites, and The bacteroid-uric acid circulation system was in place when termites evolved eusociality (Fig. 9.1), possibly allowing for the mobilization of urate-derived nitrogen from the fat body and its transfer among conspecifics via coprophagy and trophallaxis (Chapter 5). The endosym-biosis was subsequently lost in other termite lineages when these diverged from the Mastotermitidae (Bandi and Sacchi, 2000). Other termites sequester uric acid...

Development Of The Concept

This model does not apply to termites. Husseneder et al. (1999) and Thorne (1997) suggested that developmental and ecological factors, such as slow development, iteroparity, overlap of generations, food-rich environment, high risk of dispersal, and group defense, may be more important than genetics in the maintenance of termite eusociality, whatever factors may have favored its original development.

Evolution Of Eusociality 1 Baseline

A detailed examination of the biology of colony initiation in Cryptocercus lends itself to a logical, stepping-stone conceptual model of the evolution of the earliest stages of termite eusociality, with a clear directionality in the sequence of events. Female C. punctulatus lay a clutch of from one to four oothecae. Unlike other oviparous cockroaches (Fig. 7.1), nymphs do not hatch from the ootheca simultaneously. The majority of egg cases require 2-3 days for all neonates to exit (Nalepa 1988a). Laboratory studies further suggest that there is a lag of from 2-6 days between deposition of successive oothecae (Nalepa, 1988a, unpubl. data). Consequently, there can be an age differential of 2 or more weeks between the first and last hatched nymphs in large broods. These age differentials are corroborated by field studies. Families collected during autumn of their reproductive year can include second, third, and fourth instars (Nalepa, 1990), at which point development is suspended prior...

Evolution Of Eusociality 2 Transition

It is reasonable to assume that a termite ancestor packaged its eggs in oothecae, since the basal termite Mas-totermes does so (Nalepa and Lenz, 2000). If the timing of oviposition in this ancestor was similar to that of Crypto-cercus a reproductive burst, with several oothecae laid within a relatively short time frame nymphs in the family also exhibited age differentials. It is likely that repro duction was suspended as adults fed and otherwise cared for their dependent neonates, as reproductive stasis occurs in extant young termite families when adults are nurturing their first set of offspring (reviewed by Nalepa, 1994). This suggests that, as in Cryptocercus, parental care during colony initiation in the termite ancestor was costly. The crucial step, and one that occurs during the ontogeny of extant termite colonies, is that older nymphs assume responsibility for feeding and maintaining younger siblings, relieving their parents of the cost of brood care and allowing them to invest...

Heterochrony Revisited

The recognition that heterochronic processes play a fundamental role in social adaptations is increasingly recognized in birds and mammals (see references in Gariepy et al., 2001 Lawton and Lawton, 1986) but to date changes in developmental timing have not received the attention they deserve in studies of social insect evolution. Hete-rochrony is pervasive in termite evolution, and most aspects of isopteran biology can be examined within that framework (Nalepa and Bandi, 2000). The evolution of the initial stages of termite eusociality from subsocial ancestors described above is predicated on a behavioral het-erochrony, an alteration in the timing of the expression of parental care (Nalepa, 1988b, 1994). Recently, behavioral heterochrony has been recognized as a key mechanism in hymenopteran social evolution as well (Linksvayer and Wade, 2005). Behavioral heterochronies often precede physiological changes, with the latter playing a subsequent supportive role (e.g., Gariepy et al.,...

Conceptual Organization of Soil Organisms

A third approach integrates spatial scale and trophic perspectives, linking specific spatial scales to soil processes. Ecosystem engineers, such as earthworms and termites, can indirectly influence the cycling of nutrients through direct impacts on soil structure. A second group is considered the litter transformers (micro- and macro-arthropods) and fragments or comminutes litter into smaller pieces, thereby increasing the surface area available to microbial decomposition. Members of a third group are part of a 'micro-food web', and include microbes and microfaunal predators (primarily nema-todes and protozoa). Each level in this conceptual scheme influences ecosystem properties through actions at different size, space, and timescales.

Movement of Food Resources

Spatial subsidies through the movement of prey items are, however, not confined to those that cross the aquatic-terrestrial boundary as in the examples above, but are commonplace in many environments and at many spatial scales. In particular, organisms which undergo 'ontogenetic shifts' in foraging or habitat-use patterns often mediate these subsidies. Cicadas, termites, and other emerging insects provide a subsidy from below-ground to aboveground ecosystems ontogenetic shifts in foraging and movement patterns of California killifish (Fundulus parvipinnis, a small wetland resident fish) subsidize predators in subtidal ecosystems with energy these fish derived from foraging as juveniles in high intertidal pools migrations of potential prey items, from Monarch butterflies to caribou, provide consumers in distant habitats with substantial trophic subsidies. Taken as a whole, subsidies resulting from the movement of prey (or detritus) can range in distance from a few centimeters to many...

Management of Crop Forest and Urban Pests

Management of crop, forest, and urban pests has been a major application of insect ecology. Insect roles in ecosystems may conflict with crop and livestock production and human health and habitation when conditions favor insect population growth. For example, densely planted monocultures of crop species, often bred to reduce bitter (defensive) flavors, provide ideal conditions for population growth of herbivorous species (see Chapter 6). Similarly, buildings provide protected habitats for ants, termites, cockroaches, and other species, especially when moisture and unsealed food create ideal conditions. Insects become viewed as pests when their activities conflict with human values. chemicals, including insect growth regulators (IGRs) and chitin sythesis inhibitors (CSIs), with shorter half-lives in the environment. Research results also have led to greater use of microbial pathogens, including nuclear polyhedrosis viruses (NPV) and Bacillus thuringiensis (Bt). Effectiveness of these...

Mutualisms involving gut inhabitants

Foregut Fermentation Rabbits

13.5.4 Termite guts Termites are social insects of the order Isoptera, many of which depend on mutualists for the digestion of wood. Primitive termites feed directly on wood, and most of the cellulose, hemicelluloses and possibly lignins are digested by mutualists in the gut (Figure 13.11), where the paunch (part of the segmented hindgut) forms a microbial fermentation chamber. However, the advanced termites (75 of all the species) rely much more heavily on their own cellulase (Hogan et al., 1988), while a third group (the Macrotermitinae) cultivate wood-digesting fungi that the termites eat along with the wood itself, which the fungal cellulases assist in digesting. Termites refecate, so that food material passes at least twice through the gut, and microbes that have reproduced during the first passage may be digested the second time round. The major group of microorganisms in the paunch of primitive termites are anaerobic flagellate protozoans. Bacteria are also present, but cannot...

Box 76 Colonial insects and wood decomposition

A number of termites, beetles and ants attack undecayed wood. Of these, termites account for the very rapid (and to us, potentially devastating) disappearance of wood in warm temperate and tropical forests. There are more than 2500 species of termites worldwide and the genus Coptotermes has 28 pest species, of which the Formosan subterranean termite or FST C. formosanus is the most widely distributed and economically important. Although probably endemic to southern China it was apparently transported to Japan prior to the 1600s and is now found in many other countries, having spread widely in the USA since the 1960s. As with other termites the FST has three primary castes the reproductives, soldiers and workers. New colonies are each founded by two 'alates', one male and one female, from the huge swarms which fly on calm and humid evenings in early summer. The colony establishes on moist wood and takes 3-5 years to become large enough to cause severe damage. This termite attacks...

Marla B Sokolowski and Joel D Levine

Insects, honeybees, ants and termites (Wilson 1971). By contrast, the term eusocial is used specifically to describe a society that has a reproductive division of labour (with or without sterile castes), overlapping generations and cooperative care of young (Wilson 1971). This chapteris notaliterature review, but it includes examples from social and eusocial animals, as both offer important insight into nature-nurture interdependencies. Although many of the examples used here come from model genetic organisms, the available resources (genetic tools, genome sequences, high-throughput behavioural analyses, sophisticated monitoring of animals in nature) are rapidly expanding. Thus, we are poised to expand our research from quantitative genetic analysis to investigations of how specific genes, genomes and environments affect behaviour.

Detritivores and specialist microbivores

Images Detritivores

The microbivores are a group of animals that operate alongside the detritivores, and which can be difficult to distinguish from them. The name microbivore is reserved for the minute animals that specialize at feeding on microflora, and are able to ingest bacteria or fungi but exclude detritus from their guts. Exploitation of the two major groups of microflora requires quite different feeding techniques, principally because of differences in growth form. Bacteria (and yeasts) show a colonial growth form arising by the division of unicells, usually on the surface of small particles. Specialist consumers of bacteria are inevitably very small they include free-living protozoans such as amoebae, in both soil and aquatic environments, and the terrestrial nematode Pelodera, which does not consume whole sediment particles but grazes among them consuming the bacteria on their surfaces. The majority of fungi, in contrast to most bacteria, are filamentous, producing extensively branching hyphae,...

Effects On Invertebrate Behaviour

Effects on termites are particularly well documented (see references in Swift and Boddy, 1984 Su, 2005). Mycelium of brown-rot fungi (Chapter 2), wood decomposed by them and extractives from such wood are often attractive to termites, and VOCs can stimulate termites to eat more sound wood and build more galleries. White-rot fungi and white-rotted wood are often unattractive and even toxic to termites, though P. ostreatus was attractive. White-rot fungal mycelia are, however, attractive to other arthropods. For example, fungus gnats (Bradysia Sciaridae) are highly attracted to and oviposit in interaction zones of mating incompatible mycelia of Stereum spp. and Phlebia spp. (Boddy et al., 1983 Figure 2a). Collembola are also attracted to and preferentially graze in interaction zones between mycelia growing from woody resources into soil (Figure 2b). These regions are presumably more palatable and leak nutrients, and VOCs are upregulated (Hynes et al., 2007). Sciarids and phorids...

Intercolony interactions infections and the maintenance of diseases

The intercolony transmission rate is a direct function of the encounter rate of infected and uninfected individuals from different colonies, where encounters are defined as either direct physical contact or indirect contact with an object or patch that contains viable disease propagules. The likelihood of intercolony disease transmission in the four groups of social insects depends to a large degree on how the foraging areas are used. Bees and wasps may cover up to several kilometres on the wing (Spradbery, 1973 Roubik, 1989 Beekman and Ratnieks, 2000 Goulson and Stout, 2001 Dramsted et al., 2003) and typically exploit food sources that are accessible to all colonies in the area. Bees from many different colonies are thus likely to visit the same flowers for nectar and pollen, and wasps from many different colonies may scrape fibres for nest building from the same pieces of dry wood, forage for insect prey in the same patches, or cut pieces of meat from the same carrion. As a...

Forest types and classification

Terrestrial Biomes

The Miombo savanna, which lies to the south of the East African plains, the nyika thornbush, and the Congo forest is one of the most extensive African biomes. Measuring 2575 km (1600 miles) from east to west, and over 1287 km (800 miles) from north to south, it covers southern Tanzania, most of the southern Congo, Angola, Zambia, Zimbabwe and Malawi. It is largely found on the elevated inland plateaus of southern central Africa on deep, semi-podzolic sandy soils of little use to cultivation. Typically it rains for one half of the year while the other is dry and dusty. The miombo is sparsely populated, and is in a part of Africa where sleeping sickness, caused by the protozoan Trypanosoma, continues to spread despite all attempts to eliminate its vector, the tsetse fly. This savanna is effectively a woodland with a field layer dominated by grass, though in many places the trees are tall and may form contiguous forest. At the onset of the dry season tree leaves wither and fall, the...

Feeding on vertebrate feces

Bison Excrament Fungi

Herbivore dung is also sufficiently thickly spread in the environment to support its own characteristic fauna, consisting of many occasional visitors but with several specific dung-feeders. Dung removal varies both seasonally and spatially. In tropical and in warm temperate regions most activity occurs during summer rainfall, whereas in Mediterranean-type climates dung removal is highest during spring after the winter rainfall and again in mid-summer when temperatures are high (Davis, 1996). Dung removal also occurs at greater rates in unshaded situations and is faster on sand than on harder, more compacted clay soils (Davis, 1996). A wide range of animals are involved, including earthworms, termites and, in particular, beetles. The full range of tropical dung beetles in the family Scarabeidae vary in size from a few millimeters in length up to the 6 cm long Heliocopris. Not all remove dung and bury it at a distance from the dung pile. Some excavate their nests at various depths...

Consumption of plant detritus

Two of the major organic components of dead leaves and wood are cellulose and lignin. These pose considerable digestive problems for animal consumers, most of which are not capable of manufacturing the enzymatic machinery to deal with them. Cellulose catabolism (cellulolysis) requires cellulase enzymes. Without these, detritivores are unable to digest the cellulose component of detritus, and so cannot derive from it either energy to do work or the simpler chemical modules to use in their own tissue synthesis. Cellulases of animal origin have been definitely identified in remarkably few species, including a cockroach and some higher termites in the subfamily Nasutitermitinae (Martin, 1991) and the shipworm Teledo navalis, a marine bivalve mollusc A wide range of detritivores appear to have to rely on the exogenous microbial organisms to digest cellulose. The invertebrates then consume the partially digested plant detritus along with its associated bacteria and fungi, no doubt obtaining...

Box 83 Nutrient dynamics at Hubbard Brook

Molde Ramos Arvore

Above-ground biomass of tropical forests on extremely nutrient-poor soils to be so high. Nutrient recovery by tree roots is very efficient, aided by mats of roots above the soil surface. In an experiment in an Amazonian forest more than 99 of radioactivity applied as calcium-45 and phosphorus-35 isotopes to the ground surface was retained in the root mat. Termites and fungi, especially decomposer basidiomycetes, destroy dead wood above ground, while root absorption is often assisted by mycorrhizas.

Discontinuous gas exchange cycles

Gaseous Exchange Cycle

Schechter 1966) that resulted in a comprehensive understanding both of the pattern and the mechanisms underlying it. Subsequently, discontinuous gas exchange has been documented in a wide variety of both adult and pupal insects, although the patterns and control thereof show considerable variation among species. To date, discontinuous gas exchange has been found in cockroaches (Kestler 1985 Marais and Chown 2003), grasshoppers (Harrison 1997 Rourke 2000), hemipterans (Punt 1950), beetles of several families (Lighton 1991a Davis et al. 1999 Bosch et al. 2000 Chappell and Rogowitz 2000), lepidopterans (Levy and Schneiderman 1966b), robber flies (Lighton 1998), wasps (Lighton 1998), and ants (Lighton 1996 Vogt and Appel 2000). Similar patterns have been found in a variety of other insects including thy-sanurans, termites (Shelton and Appel 2001a,b) and Drosophila (Williams et al. 1997), but these patterns are not considered DGCs because they deviate somewhat from the standard,...

Metabolism and gas exchange

Because flight is such an energetically demanding activity, and because so many insect species use flight as a major method of locomotion, much of the work done on substrate catabolism has been concerned with the aerobic provision of ATP for flight. Nonetheless, it is worth noting that only adult insects are capable of flight, that in ants and termites only the alates fly and then usually for just

Influence of herbivores

Insect Groups

Whose forewings are modified to form protective elytra that meet along the mid-dorsal line and protect the membranous hind wings which fold beneath them. They have biting mouth parts and many of them, especially the death-watch beetle Xestobium rufovillosum, cause considerable damage to timber. The weevils (Curculionoidea), of which there are 11 families, are by far the largest major group of Coleoptera. One species, the spruce bark beetle Ips typographus, has killed millions of Norway spruce Picea abies trees. Next numerous are the Lepidoptera with less than half the number of species. Many of these four-winged moths and butterflies are extremely beautiful, but their larval stages often cause severe damage to plant populations. The hornets, wasps, bees, and ants of the Hymenoptera follow with 13 of species, while the two-winged flies of the Diptera have 12 . Various members of the Hemiptera (true bugs), whose mouth parts are used for piercing and sucking, attack both flowering plants...

Saprotrophic Channels of Food Webs in the

Saprotrophic

Detritus in the sea is the nutritional base of some large animals and important fisheries, while on land only a limited number of species of small arthropods are detriti-vores, and fungi are the major consumers of wood detritus. Termites are one animal group that thrives on wood. Termites have invited themselves to this exclusive feast by evolving mutualistic interactions with bacterial and other symbionts, which live in the termite gut. These

Commensals in Animals

Whether or not the gut bacteria are considered commensals or mutualists depends on how strictly the definitions are applied. Besides synthesizing vitamins, the bacteria in the human gut, like those in animal rumens or termite guts, break down plant polysaccharides into simple sugars that are utilized by their host. However, human gut bacteria cannot break down the larger and more complex plant polymers such as cellulose, which can be utilized by herbivores with a rumen, such as cattle, or by termites with a diverse gut flora. Complex carbohydrates pass through the human intestine relatively unaltered. Nevertheless, the efficiency of plant polysaccharide breakdown exhibited by human gut microbes is significant.

Species Interactions

Some insect species could be considered to be keystone species to the extent that their abundance greatly alters diversity, productivity, rates of energy or nutrient flux, etc. Many herbivorous insects increase the diversity of plant species by selectively reducing the density of abundant host species and providing space and resources for nonhost plants (Lawton and Brown 1993, Schowalter and Lowman 1999). The southern pine beetle, Dendroctonus frontalis, is capable, at high population densities, of killing pine trees and increasing the availability of woody resources that maintain populations of other xylophagous species (Flamm et al. 1993). Naiads of the large dragonfly, Tramea lacerata, prey on other dragonflies as well as on various other taxa that also are prey of other dragonfly and dam-selfly naiads. Wissinger and McGrady (1993) found that addition of T. lacerata to wetland communities had a direct negative effect on damselfly prey but also an indirect positive effect through...

Factors Affecting Succession

Rapidly growing and expanding populations are more likely to colonize even marginally suitable sites than are declining populations. For example, trees dying during a period of minimal bark beetle abundance would undergo a delay in initiation of heterotrophic succession, dominated by a different assemblage of insect species associated with different microorganisms (e.g., Schowalter et al. 1992). Wood initially colonized by decay fungi, such as inoculated by wood-boring beetles, wasps, and termites, decays more rapidly, thereby affecting subsequent colonization, than does wood initially colonized by mold fungi, such as inoculated by bark and ambrosia beetles (Kaarik 1974, Schowalter et al. 1992). Animals that construct burrows or mounds or that wallow or compact soils can kill all vegetation in small (several m2) patches or provide suitable germination habitat and other resources for ruderal plant species (D. Andersen and MacMahon 1985, MacMahon 1981 see also...

Soil Aggregation Models

That result in the formation of biological macroaggregates (Fig. 3.12) (Six et al., 2002b). These include the following three processes (1) Fresh plant- and root-derived residues form the nucleation sites for the growth of fungi and bacteria. Macroaggregate formation is initiated by fungal hyphae enmeshing fine particles into macroaggregates. Exudates from both bacteria and fungi, produced as a consequence of decomposition of fresh residues, form binding agents that further stabilize macroaggre-gates (tl> A). (2) Biological macroaggregates also form around growing roots in soils, with roots and their exudates enmeshing soil particles, thereby stimulating microbial activity (t0 B to ti)B). (3) A third principal mechanism of biological macroaggregate formation in soils in all climates is via the action of soil fauna, particularly earthworms, termites, and ants. For example, earthworms often produce casts that are rich in organic matter (tl,C) and are not stable when freshly formed and...

Decomposition and Mineralization

Termites have received considerable attention because of their substantial ecological and economic importance in forest, grassland, and desert ecosystems. Based on laboratory feeding rates, K. E. Lee and Butler (1977) estimated wood consumption by termites in dry sclerophyll forest in South Australia. They reported that wood consumption by termites was equivalent to about 25 of annual woody litter increment and 5 of total annual litterfall. Based on termite exclusion plots,Whitford et al. (1982) reported that termites consumed up to 40 of surficial leaf litter in a warm desert ecosystem in the southwestern United States (Fig. 14.3). Overall, termites in this ecosystem consumed at least 50 of estimated annual litterfall (K. Johnson and Whitford 1975, Silva et al. 1985). N. M. Collins (1981) reported that termites in tropical savannas in West Africa consumed 60 of annual wood fall and 3 of annual leaf fall (24 of total litter production), but fire removed 0.2 of annual wood fall and 49...

Xenarthrans Edentates

Living anteaters range from southern Mexico through Central America and into South America as far as Paraguay and northern Argentina. Habitat includes savannas, pampas, and tropical forests. The specializations of these xenarthrans reflect their ability to capture and eat social insects, primarily ants, termites, and bees. The skull consists of an elongate cranium, long and tapered rostrum, and a long, delicate mandible. The mouth is tubular. All anteaters lack teeth. Jaw musculature is reduced, but muscles controlling the tongue are well developed and strong. The highly specialized tongue is long, slender, covered with backward-directed, spinelike papillae, protrusible, and attaches by muscles to the sternum (breastbone), rather than to the hyoid bones in the throat (the site in almost all other mammals). Salivary glands secrete a sticky saliva that covers the tongue. Powerful Tamanduas (Tamandua) and silky anteaters (Cyclopes) walk on the side of the front foot, with the digits and...

Positive Interactions

Positive interactions vary in their strength and importance (Morin, 1999 Stiling, 1999). Some interactions are obligate mutualisms, in which species cannot survive without the assistance of their partners. These dependent situations often involve symbiosis, in which species live intimately associated with one another. Living close together facilitates energy transfer and protection. For example, microscopic animals and bacteria living in the guts of most vertebrates and termites are needed for

Lemurs and Other Lower Primates

Pottos are the African version of the Asian lorises. Nocturnal creatures of habit, they are generally found in a closed canopy environment. Unlike their Asian kin, pottos eat mostly fruit, leaving a very small percentage of their diet to animal protein (insects, ants, termites). Like the Asian lorises, the pottos also have a specialized hand in which the thumb is rotated 180 degrees in divergence from the other digits. This specialization allows them powerful grasping capabilities. In addition to the thumb specialization, the index finger has been reduced to a nub. Pottos have one unique specialization not found in any other primate their lower cervical vertebra and first

Regulation of Net Primary Productivity by Insects

Despite the obvious influence of animals on key ecosystem processes, their regulatory role has remained controversial and largely untested. Herbivorous insects possess the characteristics of cybernetic regulators (i.e., low maintenance cost and rapidly amplified effects, sensitivity to deviation in ecosystem parameters, and capacity to dramatically alter primary production through positive and negative feedback) and appear, in many cases, to stabilize NPP. For example, inconsequential biomass of phytophagous insects, even at outbreak densities, is capable of removing virtually all foliage from host plants and altering plant species composition (see Chapter 12). Virtually undetectable biomass of termites accounts for substantial decomposition, soil redistribution, and gas fluxes that could affect global climate (see Chapter 14).The following model for insect effect on ecosystem stability focuses on herbivores, but detritivores, pollinators, and seed dispersers also are capable of...