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

<p>A key challenge for generalist predators is avoiding toxins in prey. Species-specific strategies range from total avoidance of distasteful (and potentially toxic) prey to the use of physiological mechanisms to metabolize toxins after consumption. We compare two species of jumping spiders, <i>Habronattus trimaculatus</i> and <i>Phidippus regius.</i> Based on several anecdotal observations and other aspects of their biology, we hypothesized <i>a priori </i>that <i>H. trimaculatus</i> would be (1) less willing to feed on unpalatable prey and (2) more susceptible to toxins that are consumed compared with <i>P. regius.</i> In Experiment 1, we presented spiders of both species with size-matched quinine-dipped crickets. Consistent with our hypothesis, all <i>H. trimaculatus</i> attacked and rejected them while all <i>P. regius</i> attacked and consumed them. In Experiments 2 and 3 we assigned spiders of both species to experimental feeding treatments with varying levels of toxicity (using toxic springtails, <i>Folsomia candida</i>) and assessed effects on their growth. Spiders of both species readily fed on the springtails. Collectively, results from these two experiments suggest that springtails have negative effects on both species, but that these effects are stronger in <i>H. trimaculatus</i>. <i>Habronattus </i>has a unique red retinal filter pigment (not found in <i>Phidippus) </i>that likely improves their ability to discriminate reds and oranges. The evolution of this unique visual system may have been driven by their heightened susceptibility to prey toxins, and thus the benefits of avoiding prey that advertise toxins with long-wavelength colors.  </p>