Timing of maturation and the mating system of the spider,Stegodyphus lineatus(Eresidae): how important is body size?

Abstract

Selection on life history traits such as the timing of maturation and the size at maturity strongly depends on the mating system. In spiders, the mating system is hypothesized to be determined by spermathecal morphology and the related sperm precedence pattern. In a natural population of the eresid spiderStegodyphus lineatus, predictions concerning the timing of maturation, male mating behaviour and success were tested. Eresid spiders are supposed to show protandry, prematuration mate guarding and strong male–male competition resulting in selection for large body size and early maturation. In contrast to these predictions, male and female maturation overlapped largely. Males did not guard premature females nor was there evidence for male–male competition. Among mating pairs, male size did not relate to female size, nor to duration of cohabitation. Evidence for an advantage of first over second or large over small males is weak. In males, body size at maturity and the time of maturation were negatively correlated although a trade off between timing of maturation and the body size reached by then should result in a positive correlation. Possible causes are discussed.