Repeated Copulation in the Wood-feeding Cockroach Cryptocercus punctulatus Does Not Influence Number or Development of Offspring

Wood-feeding cockroaches in the genus Crytocercus live in biparental family groups in the interior of rotten logs and are considered socially monogamous. They typically produce a single brood of altricial offspring, with parental care then lasting until the death of adults 2 or 3 years later. Field and laboratory evidence suggests that copulation occurs repeatedly in C. punctulatus, with sexual activity occurring during non-fertile periods. We carried out a long-term field study to explore the significance of repeated copulation in C. punctulatus. The presence of a male positively affected the onset of female reproduction, but neither the male’s physical presence nor his ability to mate influenced the number or early development of nymphs. Sperm are viable in the spermathecae for at least 3 years. We conclude that it is unlikely that male-derived material benefits have driven the evolution of repeated copulation in C. punctulatus. Accumulating evidence suggests that prior to oviposition, repeated copulation may be rooted in sperm competition, but after the eggs are laid it may secure the continued paternal contribution of the male social partner.