Ontogeny Of Habitat

Although nymphs generally live in the same habitats as adults (Mackerras, 1970), there are several cockroach species that exhibit ontogenetic niche shifts. The most common pattern is that of females, female-nymph combinations, and groups of young nymphs reported from burrows, shelters, and other protected sites, often in or near a food source. These sheltered sites serve as nurseries, with the habitat of youngest nymphs determined by the partition3 behavior of the mother; subsequently, nymphs may or may not disperse from their natal area. In all species of Gyna, for example, adults are found primarily in the canopy, while nymphs are found at ground level, often burrowing in the dust of treeholes, abandoned insect nests, and caves (Corbet, 1961;Grandcolas, 1997a). Juveniles of Capucina patula are restricted to the habitat beneath loose bark of live or fallen trees; adults are occasionally seen on nearby foliage (WJB, pers. obs.). Nymphs of Car. lutea, and females and nymphs of Parcoblatta ful-vescens have been recorded from the burrows of pocket gophers (Geomys sp.) (Hubbell and Goff, 1939). Adults of both these species are found in a variety of above-ground habitats. Adults of Parcoblatta bolliana are found in grass-

3. Partition is defined as the expulsion by the female of the reproductive product, whether it is an egg or a neonate (Blackburn, 1999).

Table 3.1. New World distribution and microhabitats of Latiblattella (Blattellidae). From Willis (1969).

Species

Habitat

Country

Latiblattella inornata

Decaying leaf mold and litter under palms

Canal Zone

Lat. chichimeca

In bromeliads

Mexico

Lat.zapoteca

Under stones at the edge of rivers

Costa Rica

Lat. rehni

In Spanish moss (Tillandsia usueoides), under bark of dead pines

Florida

Lat. lucifrons

On Yucca elata

Arizona

Lat.angustifrons

On Inga spp. trees

Costa Rica

Lat. azteca

On grapefruit trees

Mexico

Lat. vitrea

In dry, curled leaves of corn plants (Zea zea)

Mexico, Costa Rica, Honduras

1996a). In wood-feeding cockroaches, juvenile food and habitat is set when the parent chooses a log to colonize. The horizontal distribution of cockroaches in caves is often related to the resting positions of bats, which determine the placement of guano and other organic matter. Gautier (1974a, 1974b) calculated the spatial distribution of burrowing Blaberus nymphs in caves by counting the number of individuals in 50 cm2 samples to a depth of 15 cm. He found that nymphs were concentrated in zones where bat guano, fruit, and twigs dropped by the bats accumulated, and were absent from zones of dry soil, stones, or pebbles. In many cave cockroaches, females descend from their normal perches on the cave walls to oviposit or give birth on the cave floor in or near guano (e.g., Blaberus, Eublaberus, Periplaneta—Crawford and Cloudsley-Thompson, 1971; Gautier, 1974b; Deleporte, 1976), where the nymphs remain until they are at least half grown. They then climb onto the cave walls, where they complete their development.

lands, shrub communities, and woods, where they are associated with leaf litter and loose bark. Early instars, however, are consistently found living in nests of Cre-matogaster lineolata, an ant that inhabits the soil beneath large rocks (Lawson, 1967). Females, nymphs, and oothe-cae of Escala insignis have been collected from ant colonies in Australia, but males live in leaf litter (Roth, 1991b; Roach and Rentz, 1998). In Florida, densities of Blattella asahinai nymphs and females bearing oothecae are highest in leaf litter of wooded areas; all other adults are more diffusely distributed (Brenner et al., 1988).

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