Copulatory behaviour increases sperm viability in female spiders

CARGNELUTTI, FRANCO; COSTA-SCHMIDT, LUIZ ERNESTO; CALBACHO-ROSA, LUCIA; CÓRDOBA-AGUILAR, ALEX; UÑATES, DIEGO; PERETTI, ALFREDO V

Indiana

Congreso; 57th Annual Conference of the Animal Behavior Society (Virtual Meeting); 2020

Animal Behavior Society

One occasional feature of internal fertilization animals is a reduction in sperm viability in females. Whether such reduction is driven by a sperm competition or cryptic female choice is unclear. From a CFC perspective, sperm viability may be affected by male copulatory behaviors. Here, we investigated the following: a) sperm viability in mated females vs. males; b) If sperm viability varies temporally after mating; and, c) if male copulatory behavior varies positively with sperm viability in females. We used the spider, Holocnemus pluchei, males of which use several copulatory behaviors to court females. We found that females that stored sperm for 4 or 15 days showed no difference in sperm viability but had lower sperm viability compared to males, while males that had longer post-insemination behavior had higher viability of sperm inside the female. It is unclear how sperm viability is reduced and how male post-insemination behavior affects this. Possibly, the extension of copulation allows males to induce females to keep sperm alive for longer. This result echo the theory that males induce females to facilitate sperm to reach and fertilize eggs based on male copulatory behavior.