Multi-Male Mating and Female Choice Increase Offspring
Growth in the Spider Neriene litigiosa (Linyphiidae)
Abstract
The purpose of this controlled-breeding study was to investigate the viability consequences of
female choice and sequential polyandry for offspring in a way that would separate the influences of
these two aspects of female sexual behaviour. Female sierra dome spiders, Neriene litigiosa (=
Linyphia litigiosa) have many mating opportunities before their first oviposition. They typically mate
two to three times before production of their first batch of eggs, although some females (ca. 16%) mate
once. Strong fighters are preferred as first mates and principal sires of the offspring. Large males that
give a vigourous performance during copulatory courtship are preferred as sires from among a female's
secondary mates. In this study, the number of matings by free-living females was experimentally
controlled and the size and copulatory vigour of all the females' mates were recorded. At the end of
the breeding season, the females were collected and their broods were obtained in captivity. Randomly
chosen subsets of 28 female's offspring were reared under standard conditions during the following
spring. The spiderlings were reared for 27 days in the company of siblings under conditions that would
encourage the expression of genetic variation in viability. Spiderling growth and survivorship were
monitored. After controlling for maternal effects (i.e. female size and oviposition date) and variance in
feeding opportunities among rearing groups, both mate number and mate size were positively and
independently related to offspring growth rates and the size of offspring attained after emergence from
the natal cocoon. The results support the hypotheses that the preference for large males yields viability
benefits to offspring and that polyandry can augment the benefits of selective mating.