ABSTRACT

Cockroaches show the entire range of reproductive modes: oviparous, ovoviviparous, viviparous, and intermediate stages. Postparturition parental care is likewise diverse, ranging from species in which females remain with neonates for a few hours, to biparental care that lasts several years and includes feeding the offspring on bodily fluids in a nest. Both ovoviviparity and parental care arose a number of times in the taxon. Evolution of reproductive mode seems most influenced by predators, parasites and cannibalism. Ovoviviparity, aggregation behavior of young nymphs, and diet are suggested as factors influential in the evolution of postparturition parental care. Females regulate parental investment via absorption of oocytes, abortion, cannibalism and brood reduction. The developmental status of cockroaches at hatching ranges along an altricial–precocial spectrum and is correlated with the presence and type of parental care. In several subsocial species neonates are blind, poorly sclerotized, and dependent for food, while in the sole viviparous cockroach nymphs hatch in an advanced state of development and require fewer molts to adulthood than any known cockroach. Association with microorganisms in both the digestive system and the fat body is suggested as one factor influential in the repro – ductive versatility of cockroaches. In particular, the endosymbiont flavobacteria which mediate the storage and recycling of nitrogenous waste products may allow for the variety of modes of postovulation provisioning of offspring.