Cross‐Modality Effects of Prey Odour During the Intraspecific Interactions of a Mosquito‐Specialist Predator

Abstract

One of the predictions from evolutionary game theory is that individuals will increase their willingness (i.e., become primed) to escalate aggression when they detect the presence of a limiting resource. Here we test this prediction in the context of prey odour priming escalation decisions during vision-based encounters by Evarcha culicivora. This East African jumping spider (Salticidae) feeds indirectly on vertebrate blood by actively choosing blood-carrying female mosquitoes as preferred prey. Unlike many salticid species, it also expresses pronounced mutual mate choice. As predicted, we show here that, in the presence of odour from their preferred prey, both sexes of E. culicivora escalate during vision-based same-sex encounters. This is further evidence that the odour of blood-carrying mosquitoes is salient to this salticid. For both sexes of E. culicivora, this particular prey may be a resource that matters in the context of intrasexual selection.

Discrimination of draglines from potential mates byEvarcha culicivora, an East African jumping spider

“…Experiment 2, males escalated conflict with a same-sex rival significantly more often when in the presence of draglines from virgin females instead of when in the presence of draglines from previously mated females. Earlier studies on intraspecific interactions using E. culicivora had focused on using rank (Cross & Jackson 2009b) or interaction duration (Cross & Jackson 2014) as a measure of conflict escalation. Here, I have shown that both rank and interaction duration increased when E. culicivora males were presented with draglines from virgin conspecific females, suggesting that these females are a more valuable resource than previously mated females.…”

Influence of seeing a red face during the male–male encounters of mosquito-specialist spiders

“…The test spiders in our experiments were adult males of E. culicivora collected from our field site (see Cross et al, 2008) in western Kenya 2-3 weeks before use. Basic methods for maintaining and handling test spiders were as in earlier studies (for details, see Cross & Jackson, 2014).…”

Rapid nectar-meal effects on a predator's capacity to kill mosquitoes

“…[33]). The role of olfaction in the biology of E. culicivora is especially complex [34][35][36][37][38] and includes odour-mediated responses to plants [39]. In the field, E. culicivora is frequently found on Lantana camara and Ricinus communis [40], two of the most common plant species in its habitat [41][42][43] and E. culicivora is attracted to the odour of both of these plant species in olfactometer experiments [39].…”