Data from: From forest to city: Urbanization modulates relative abundance of anti-predator coloration

Increased urbanization has resulted in community changes including
alteration of predator communities. Little is known, however, about how
such changes affect morphological anti-predator traits. Given the
importance of coloration in predator avoidance, this trait in particular
is expected to be susceptible to novel selective environments in urban
areas. Here we investigate the coloration pattern of a Neotropical anuran
species, the túngara frog (Engystomops pustulosus), along an urbanization
gradient. Túngara frogs have two distinct color patterns (unstriped and
striped) which we found to occur at different frequencies along an
urbanization gradient. Striped individuals increased in frequency with
urbanization. To assess the strength of selection imposed by predators on
the two color morphs, we deployed clay models of túngara frogs in forest
and semi-urban populations. In addition, we examined microhabitat
selection by individuals of the different morphs. We found higher
predation rates associated with urbanization than forested areas. In
particular, frogs from forested habitats had lower number of attacks by
avian predators. Contrary to our predictions, however, predation rates
were similar for both color morphs independent of urbanization. Also,
coloration of the frogs did not affect their microhabitat preference.
Overall, túngara frogs are more likely to have a striped coloration
pattern in semi-urban areas where predation by birds is higher than in the
forest. Our findings suggest that factors other than predation pressure
shape the coloration pattern of urban frogs and emphasize the complex
nature of effects that anthropogenic changes in habitat and predator
communities may have on prey morphology.