Male performance and associated costs in successive sexual encounters in a polygynous web wolf spider

Abstract

Polygynous males increase their reproductive success by fertilizing as many females as possible. However, this strategy can lead to costs for the males. This study focused on an atypical wolf spider that lives in webs, Aglaoctenus lagotis. Previous studies report polyandrous females, but little is known about the mating strategy of males and its potential associated costs. Our goals were to determine the potential polygyny and the changes in sexual behaviour, body condition and physiology of males throughout successive matings. Males were expected to mate with multiple females; males’ body condition was expected to decrease and male mating performance, including sperm transfer, was expected to decrease over successive matings. Males were exposed to successive virgin females every 3 days until the male did not court, was cannibalized or died of natural causes. Agreeing with our predictions, males were capable of multiple matings, showing an average of 5 ± 2 matings (range 3–11). Their mating performance decreased in successive matings and, although no changes were found in the behavioural patterns during the courtship over successive matings, the number of palpal insertions decreased. Unexpectedly, overall body condition did not decrease and males did not deplete their sperm supply. We found that 44% of the males were victims of sexual cannibalism after their third mating. The females that attacked or cannibalized males had less sperm stored in their spermathecae than those that did not. We discuss hypotheses that may clarify this scenario and the role of the cryptic female choice mechanism.