Intriguing compensation by adult female spiders for food limitation experienced as juveniles

Abstract

We conducted a field experiment to test for food limitation in immature stages, and its consequences for mature females, in the territorial, cannibalistic spider Lycosa tarentula (L.). Randomly selected antepenultimate juveniles were provided supplemental prey until they matured, at which time supplemental feeding ceased. Immature stages of L. tarentula are food‐limited. Supplemented juvenile spiders decreased foraging activity, disappeared at a lower rate and grew faster than the control spiders, which had been exposed only to ambient prey levels. Fed juvenile females were less hungry at maturity, as judged by an index of body condition, and showed higher mating success as adults, as judged by cohabitation rates with mature males. Foraging theory predicts that in order to compensate for residual effects of food limitation, adult female spiders that had experienced a shortage of prey as juveniles – the controls – would have to exhibit a greater increase in foraging activity upon maturing than the prey‐supplemented group. Contrary to expectation, the control females did not increase their foraging activity, but the previously fed females did forage more actively as adults. Furthermore, the difference in mass gain during the mating period between the two groups was opposite from what the difference in change in foraging activity would predict. Control females, the spiders that had not changed their foraging activity, gained mass more rapidly than the previously fed females, with the result that the two groups were similar in mass by the end of the mating period. We hypothesize that an increased rate of sexual cannibalism may have been one mechanism by which control females compensated for the food limitation that they had experienced as immatures.

Dangerous mating systems: Signal complexity, signal content and neural capacity in spiders

“…Sexual cannibalism before copulation clearly entails a large cost for the male, but also for the female if she remains unmated (see Kralj-Fišer et al, 2013). Nevertheless, a male may constitute a substantial meal for a female, which may increase her survival and future reproductive prospects (Moya-Laraño et al, 2003). The risk of cannibalism for a courting male varies with the state and the personality of a female (Rabaneda-Bueno et al, 2008;Berning et al, 2012) as well as with the relative size differences between the sexes (Johnson, 2005;Wilder and Rypstra, 2008).…”

Feeding regime, adult age and sexual size dimorphism as determinants of pre-copulatory sexual cannibalism in virgin wolf spiders

“…Pre-copulatory sexual cannibalism may play particularly important role in the ecology of lycosids. For example, in a congeneric, L. hispanica, female's diet in the field largely consists of conspecific males in situations in which heterospecific prey is limiting (Moya-Laraño 2002;Moya-Laraño et al 2003a;Rabaneda-Bueno et al 2008). Thus, in this gender, Pre-SC may be an adaptive and flexible behaviour strongly dependent on the females' feeding history and the ecological conditions that they face during the mating season.…”

“…The 'adaptive foraging hypothesis' (AFH; Newman and Elgar 1991) posits that females benefit from consuming males, obtaining energy and nutrients which enhance their body condition (Moya-Laraño et al 2003a, 2003bBarry et al 2008) and subsequently their fecundity (Birkhead et al 1988;Johnson 2001Johnson , 2005Rabaneda-Bueno et al 2008;Berning et al 2012;Welke and Schneider 2012;Pruitt et al 2014). An economic model associated to the AFH (Newman and Elgar 1991) explains the probability of SC depending on the trade-off between the female chances of mating and foraging.…”

Contributions of juvenile and adult diet to the lifetime reproductive success and lifespan of a spider

“…Some spiders have been hypothesized to compensate for juvenile food limitation by increasing adult voracity or mass gain (Schneider and Elgar , Moya‐Laraño et al ). In the wolf spider Lycosa tarantula , individuals that were food‐limited as juveniles matured at a smaller mass than food‐supplemented females but gained mass more rapidly as adults, such that the mass of both treatments was similar two weeks post‐maturation (Moya‐Laraño et al ). Yet, in our study of bridge spiders, juvenile food limitation had lasting effects on fecundity even when adults had ad libitum food availability.…”