Influence of optical cues from conspecific females on escalation decisions during male-male interactions of jumping spiders.

An important prediction from game theory is that the value of a resource influences the level to which male-male conflict escalates. An earlier experimental study showed that males of Hypoblemum albovittatum, a common salticid in New Zealand, can discern by sight alone whether a female is in the vicinity and that, having detected a female's presence, males escalate (i.e., adopt behaviour that is likely to put them at greater risk of injury). Seeing a bare moving cork, a conspecific male or a prey item also elicits escalation, but not to the level elicited by seeing a conspecific female. Here the earlier study is extended by using non-conspecific females in control tests and by undertaking experiments with an additional six salticid species. Findings from these experiments suggest that the ability of interacting males to detect by sight alone that a conspecific, instead of a non-conspecific, female is present is widespread in the family Salticidae and that it may be routine for salticid males to use information about the presence of conspecific females when making strategic decisions related to escalation during encounters with other males.