Spider Males Adjust Mate Choice but Not Sperm Allocation to Cues of a Rival

Abstract

Spatial and temporal variation in ecological parameters selects for plastic responses to prevailing conditions. Males of web spiders have been shown to adjust developmental decisions to cues that relate to the degree of competition from other males. Here, we explore experimentally whether males of the spider Nephila senegalensis base behavioural decisions in the context of mate choice and sperm allocation to the presence of cues of a rival and to their own competitive dominance. Large and small males were offered a simultaneous choice between two penultimate instar females that varied in quality and in whether they were previously visited by a rival male. Large and small males avoided webs visited by a previous male, and this preference overrode differences in female quality. In a second experiment, males were assigned to copulate with a virgin female whose web was either previously visited by a rival male or not. We found substantial variation in male sperm allocation, but this variation was not related to our treatment. Our experiments demonstrate that males notice silk cues left behind by rival males on a female’s web and that they can utilize these cues in relation to decisions over whether to visit a web, but not in relation to sperm allocation.

Context‐ and State‐Dependent Male Mate Choice in a Sexually Cannibalistic Spider

“…This is unlike in Nephila senegalensis , another spider with a similar mating system, in which males have been found to avoid competition (Schneider et al. ) in a similar laboratory setting. Likewise, a study using the Australian N. plumipes found that males tend to avoid competitive situations when the context changes (Jordan et al.…”

Reproductive Foragers: Male Spiders Choose Mates by Selecting among Competitive Environments

“…In a mate-choice context, there is some evidence that individuals are able to assess competition for potential mates: when given a choice between females that are associated with other males and hence the subject of higher perceived sperm competition, males of some species prefer females subject to lower competition, for example, Poecilia reticulata (Dosen and Montgomerie 2004) and Gambusia holbrooki (Wong and McCarthy 2009). Further, previous studies of a closely related species to that used in this study, Nephila senegalensis, show that males avoid webs of females that have been previously visited by other males (Schneider et al 2011). However, in our experiments, males on average moved to places with more competitors than would be encountered under random movement.…”

Differential investment and size-related mating strategies facilitate extreme size variation in contesting male spiders

“…Males cease web building after reaching maturity and occasionally feed on prey caught by the female. Females are always receptive and accept several males for mating (Schneider, Lucass, Brandler, & Fromhage, 2011;Schneider & Michalik, 2011). Males transfer sperm to the females' paired sperm stores (spermathecae) and eggs are not fertilized until they are laid.…”