Dim-light vision in jumping spiders (Araneae, Salticidae): identification of prey and rivals

Jumping spiders (family Salticidae) are known for their intricate vision-based behavior during encounters with prey and conspecific individuals. This is achieved using eyes specialized for discerning fine detail, but there has been minimal research on the capacities that salticids might have for visual performance under low ambient light levels. Here we investigate the capacity of two salticid species, Cyrba algerina from Portugal and C . ocellata from Kenya, to perform two specific visual tasks under low ambient light levels. We used lures made from spiders and midges in prey-identification experiments and mirror images (virtual conspecifics) in rival-identification experiments. These experiments were implemented under a range of ambient light levels (234 cd m −2 , 1.35 cd m −2 , 0.54 cd m −2 , 0.24 cd m −2 ). In most instances, C . algerina and C . ocellata were proficient at performing both of these visual tasks when ambient light was 234 cd m −2 and 1.35 cd m −2 , and a minority performed these tasks at 0.54 cd m −2 , but none succeeded when light level was 0.24 cd m −2 . C. algerina and C. ocellata made vision-based discriminations under low ambient light levels previously associated with nocturnal species.