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Previous research on Cyrba algerina (Araneae, Salticidae) has shown this jumping spider expresses predatory specialisation with respect to spiders as prey as well as inter-population variation in responsiveness to prey-spider odour. However, this earlier research pertained to a single prey species (Oecobius machadoi) and only field-collected C. algerina individuals were tested. Here we extend the previous research by using laboratory-reared, as well as field-collected, individuals of C. algerina and also by using another prey-spider species, Zelotes thorelli, as well as O. machadoi. Two localities in Portugal are considered, Sintra where C. algerina and both prey species are abundant and Tavira where C. algerina is present but neither prey species has been found. In olfactometer experiments, field-collected C. algerina individuals from Sintra, but not Tavira, were attracted to the odour of both prey species. Next, we tested the response of laboratory-reared Sintra C. algerina individuals that had been maintained with no prior experience with the odour of either prey species. We found no evidence of laboratory-reared individuals being attracted to the odour of either prey species in the olfactometer. These findings suggest that prior experience mediates responsiveness of C. algerina to the odour of local prey. [ABSTRACT FROM AUTHOR]

Geographic variation in a predator's reliance on kairomones from prey was investigated. The predator studied, Cyrba algerina, is an araneophagic (spider-eating) jumping spider (Salticidae) and the prey were oecobiid spiders (Oecobiidae). There were two study sites (Sintra and Tavira), both in Portugal. Oecobius machadoi was a common oecobiid in Sintra, but no oecobiids were found in Tavira. Staged encounters showed that oecobiid-specific prey-capture behaviour was adopted by the C. algerina in Sintra but not in Tavira. In experiments using a Y-shaped olfactometer, significantly more Sintra C. algerina individuals chose the side with oecobiid odour instead of the blank side when the odour came from females of a sympatric species ( O. machadoi), but not when the odour came from O. machadoi males or from females of an allopatric species ( O. amboseli). Regardless of whether the odour came from O. machadoi or O. amboseli, the Tavira C. algerina did not choose the odour side significantly more often than the blank side. These findings suggest that, in Sintra, C. algerina is locally adapted to a locally abundant oecobiid species. Whether this example of geographic variation in kairomone use is a behavioural ecotype or instead an instance of phenotypic plasticity is currently unknown. [ABSTRACT FROM AUTHOR]

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 capacity that salticids might have for visual performance under low ambient light levels. Here, we investigated the capacity of two salticid species, Cyrba algerina from Portugal and Cyrba 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, 1.35, 0.54, 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 and 1.35 cd m -2 , and a minority performed these tasks at 0.54 cd m -2 , but none succeeded when the light level was 0.24 cd m -2 Cyrba algerina and C. ocellata showed vision-based discrimination under low ambient light levels previously associated with nocturnal species., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)