Parental Feeding of Offspring

Like other subsocial insects, the defense of offspring is a component of the behavioral repertoire of all cockroach species that exhibit parental care. Parents protect offspring in a nest, beneath the body, under wing covers, or directly attached to the body. A large number of cockroach species produce defensive secretions (Roth and Al-sop, 1978) and females with young may be the most likely to employ them (e.g., Thorax porcellana—Reuben, 1988). More unique among subsocial insects is the variety of mechanisms by which cockroach parents are a direct source of food to their nymphs. Many species for which we have evidence of advanced parental care, as well as viviparous and possible ovoviviparous females, see to the nutritional needs of their offspring by feeding them on bodily fluids (Table 8.4). Parental food may be produced internally in a brood sac, expelled in a mass after hatch, secreted externally either dorsally or ventrally on the abdomen, or produced from either end of the digestive system. The materials transferred from parent to post-hatch offspring have not been analyzed in any cockroach species. The basis of the stomodeal feeding exhibited by Salganea (Fig. 8.3B) would be of particular interest, as Periplaneta is known to secrete at least two different types of saliva in response to stimulation from different neurotransmitters. One type of saliva has a dramatically higher proteinaceous component than the other (Just and Walz, 1994).

Maternal provisioning likely occurs in taxa additional to those listed in Table 8.4. Like Gromphadorhina, the blaberids Byr. fumigata, Blaberus sp., and R. maderae all have glandular cells in the brood sac that may secrete a post-hatch meal for neonates (references in Perry and Nalepa, 2003). The lateral abdominal tergites in most female Perisphaeriinae and in many Panesthiinae of both sexes have rows of glandular orifices of unknown function (Anisyutkin, 2003). The vast majority of ovovivipa-rous females have yet to be studied while alive. Even if a female does not provide bodily exudates, she may facilitate offspring feeding in other ways. There are two reports that young nymphs of R. maderae accompany their mother on nocturnal foraging trips (Sein, 1923; Wolcott, 1950).

If the standard diet of a species is one that can be handled more efficiently by adults than by juveniles (e.g., physically difficult food), then the most efficient way to convert it to a form usable by young nymphs may be via exudates from a parent. The young are offered a reliable,

Table 8.4. Parental care in cockroaches where post-hatch offspring are fed on the bodily secretions of adults (modified from Nalepa and Bell, 1997).

Offspring

Table 8.4. Parental care in cockroaches where post-hatch offspring are fed on the bodily secretions of adults (modified from Nalepa and Bell, 1997).

Offspring

Species

Subfamily

Location

Food source

Perisphaerus sp.

Perisphaeriinae

Cling ventrally

Hemolymph?4

Trichoblatta sericea

Perisphaeriinae

Cling ventrally

Sternal exudate5

Pseudophoraspis nebulosa

Epilamprinae

Cling ventrally

?6

Phlebonotus pallens

Epilamprinae

Under tegmina

?6,7

Thorax porcellana

Epilamprinae

Under tegmina

Tergal exudate5

Gromphadorhina

Oxyhaloinae

Abdominal tip

Secretion from

portentosa

of female

brood sac?8

Salganea taiwanensis1

Panesthiinae

Mouthparts of

Stomodeal fluids9

adult

Cryptocercus punctulatus,

Cryptocercinae

Abdominal tip

Hindgut fluids10,11,12

C.kyebangensis1,2

of adult

Blattella vaga2,3

Blattellinae

Under tegmina

Tergal exudate13

1Biparental families. 2Oviparous. 3Brief association. 4Roth (1981b). 5Reuben (1988). 6Shelford (1906a). 7Pruthi (1933).

8Perry and Nalepa (2003).

9T. Matsumoto and Y.Obata (pers. comm.to CAN).

10Seelinger and Seelinger (1983).

"Nalepa (1984).

12Park et al.(2002).

13Roth and Willis (1954).

1Biparental families. 2Oviparous. 3Brief association. 4Roth (1981b). 5Reuben (1988). 6Shelford (1906a). 7Pruthi (1933).

8Perry and Nalepa (2003).

9T. Matsumoto and Y.Obata (pers. comm.to CAN).

10Seelinger and Seelinger (1983).

"Nalepa (1984).

12Park et al.(2002).

13Roth and Willis (1954).

easy-to-digest diet, thereby relieving them of the necessity of finding and processing their own food. Because the mother can meet at least part of the metabolic demands of "lactation" from her own bodily reserves, these cockroach juveniles are unaffected by temporary shortages of food items in the habitat during their phase of most rapid growth (Pond, 1983). The cockroach ability to store and mobilize nitrogenous materials via symbiotic fat body flavobacteria may be the basis for the variety of different food materials offered in parental provisioning (Nalepa and Bell, 1997, Chapter 5).

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