Data from: Female chorus frogs delay mate choice under suboptimal environmental conditions

Many traits important for reproductive isolation are environmentally
responsive. However, most studies examining reproductive isolation do not
explicitly take into consideration environmental variation. Temperature
can have a particularly large effect on reproductive behaviors, especially
in ectotherms. Here, we tested whether temperature affects the degree of
reproductive isolation between the Upland chorus frog (Pseudacris
feriarum) and its congener P. nigrita. These two species engage
in costly hybridization in nature, leading to reinforcement of male
signals and female preferences in sympatry. However, male advertisement
calls vary with temperature such that the difference between the
advertisement calls of the two species is narrower at cold than at warm
temperatures. To examine the effect of temperature on reproductive
isolation in this system, we performed six binary choice preference trials
using sympatric female P. feriarum. In these experiments, we
acclimated females to either warm (20°C) or cool (10°C) temperatures and
gave them a choice between heterospecific and conspecific advertisement
calls appropriate for the temperature. We also conducted experiments where
we gave females a choice between more similar stimuli at warm temperatures
to test whether females have more specific preferences at cold
temperatures. We found that females always preferred the conspecific
advertisement call, though they tended to make more mistakes when given a
choice between more similar stimuli at warm temperatures. However, females
took twice as long to make a choice in sub-optimal conditions. This time
delay may lead to increased risk of hybridization, despite female ability
to discriminate between calls. Our results highlight the importance of
considering environmental context when examining traits involved in
reproductive isolation.