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

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, Habronattus trimaculatus and Phidippus regius. Based on several
anecdotal observations and other aspects of their biology, we hypothesized
a priori that H. trimaculatus would be (1) less willing to feed on
unpalatable prey and (2) more susceptible to toxins that are consumed
compared with P. regius. In Experiment 1, we presented spiders of both
species with size-matched quinine-dipped crickets. Consistent
with our hypothesis, all H. trimaculatus attacked and rejected them while
all P. regius 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, Folsomia candida) 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 H. trimaculatus. Habronattus has a unique red
retinal filter pigment (not found in Phidippus) 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.