Effects Of Mate Choice And Carrying Spiderings On Female Fitness In The Wolf Spider Pardosa Astrigera

In the present study,we aimed to investigate the adaptive consequences of female mate choice and carrying the offsprings of the female wolf spiders Pardosa astrigera,and further determine the seasonal variation of their phenotypes.In order to shed some insights on the mechanism underlying female mate choice,we determined the differences in female reproductive output and offspring fitness between the preferred mated and non-preferred mated females.Our results showed that there were no significant differences in female mating duration,latency to egg laying,eggsac cannibalizing rate,latency to egg hatching,fecundity and egg hatching rate between the preferred mated and non-preferred mated females.Developing duration of the female offsprings from the preferred mated females was markedly shortened and carapace width of the female offsprings from the preferred mated females was significantly larger than those of the non-preferred females,respectively.There were no significant differences in developing duration and carapace width of the male offsprings between the preferred and non-preferred mated females.In addition,the surviving rate from egg hatching to adult of the offsprings of the preferred females was apparently higher than that of the non-preferred females.Our results provided compelling evidence that the mate choice of monandrous P.astrigera females is attributed to genetic,rather than material benefits.Secondly,we collected female wolf spiders with eggsacs in field.We first took off their egg sacs and then determined whether females can discriminate between the two egg sacs.The results showed that female wolf spiders of the overwintering generation and the first generation can not identify their own egg sac.We conducted two groups: female spiders carrying their own egg sac or females carrying the egg sac from other females.Once the spiderlings hatched,we record the duration of the spiderlings left on the back of the females between the two groups.To shed some light on the mechanism of female wolf spider carrying their eggs and spiderlings,we also compared their survival between the spiderlings that left their mother naturally and those that were separated artificially.We found that the duration of spiderlings staying on their own mothers was significantly longer than the others.The spiderlings left from their mother naturally had a significantly higher survival.It indicated that female wolf spiders had some mechanism underlying to recognize their own offsprings and the behavior of carrying spiderings greatly improve offsprings' fitness.We collected P.astrigera adults of the overwintering generation in March and the first generation in July,in 2010 and 2016 year,respectively.Their seasonal variations in body size,fecundity,egg size and lipid content were compared between the two generations.The results showed that the spider carapace width,fecundity and egg size of the overwintering generation were significantly greater than those of the first generation,respectively.However,there was no significant difference in lipid content between the two generations.Our study therefore suggests that seasonal variations in phenotype of the wolf spider P.astrigera are adaptive to environment conditions.