Alternative responses by two species of jumping spiders to unpalatability and toxicity in prey

Abstract

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Conspicuous stripes on prey capture attention and reduce attacks by foraging jumping spiders

“…The fact that there seems to be subtle variation in responses to striped prey across salticids makes this group particularly well suited for phylogenetic comparative studies that test broad hypotheses about how and why predators respond to different components of aposematic displays. For example, an interesting next step would be to replicate the tests done here across a phylogenetic scale that includes multiple closely related species pairs with and without colour vision [40] and with different sensitivities to prey toxins [47]. This would allow us to test ideas about how a species' degree of colour vision (and ability to rely on long-wavelength warning colours like red and orange) and the relative costs of ingesting prey toxins might influence their attention to and avoidance of aposematic patterns that contain only achromatic (black and white) elements.…”

“…If species only have dichromatic vision (like P. regius ), we might expect them to rely more heavily on achromatic cues compared with trichromats (like H. trimaculatus ) that can also rely on reds and oranges in warning displays. And species that are most susceptible to prey toxins might be more attentive to aposematic colour schemes broadly compared with those that can ingest prey toxins with little cost [47]. Because of their multiple evolutionary origins of tri- and tetra-chromacy [40,41], the salticids offer a unique opportunity to test such ideas that is not possible in many other taxa [90].…”

“…Phidippus regius is a presumed dichromat [41] with a robust ability to withstand prey toxins: while they sometimes avoid chemically defended prey [45,46], they have also been documented to sometimes consume chemically defended prey in the field and laboratory and often suffer only minor consequences from the ingestion of prey toxins [46,47]. By contrast, H. trimaculatus has trichromatic vision [41] and a higher sensitivity to unpalatability and toxicity in prey, meaning that they are more easily deterred by unpalatability and suffer more severe consequences if they consume toxic prey [47]. A second way that the present study builds on previous work is that our experiments were designed to disentangle the effect of internal body pattern from contrast with the background.…”

“…However, despite the clear biological differences between the two species we chose for the present study, we had no clear a priori predictions about if and how any patterns might differ between the species. On the one hand, we might expect P. regius, with its increased ability to withstand prey toxins [47], to be less discriminating when foraging and less likely to be deterred by a common aposematic signal like stripes compared with H. trimaculatus . On the other hand, the fact that P. regius has a limited ability to see and discriminate long-wavelength colours might mean that they must be more attentive to achromatic warning signals like stripes compared with H. trimaculatus that can rely on red and other long-wavelength coloration as well.…”

“…First, by asking how these two additional species respond to striped prey, we can begin to assess whether heightened attention to and/or aversion to stripes is likely to be a general feature of jumping spider foraging, and to what extent it varies across species with and without colour vision and with different sensitivities to prey toxins. Phidippus regius is a presumed dichromat [41] with a robust ability to withstand prey toxins: while they sometimes avoid chemically defended prey [45,46], they have also been documented to sometimes consume chemically defended prey in the field and laboratory and often suffer only minor consequences from the ingestion of prey toxins [46,47]. By contrast, H. trimaculatus has trichromatic vision [41] and a higher sensitivity to unpalatability and toxicity in prey, meaning that they are more easily deterred by unpalatability and suffer more severe consequences if they consume toxic prey [47].…”