Female gray treefrogs, Hyla versicolor, are responsive to visual stimuli but unselective of stimulus characteristics

Abstract

The visual ecology of nocturnal anurans is poorly understood, but there is growing evidence that vision plays a role in important behaviors such as mate choice. While several recent studies have demonstrated that females are responsive to visual cues when selecting mates, the forces responsible for these preferences are unknown. We investigated the responsiveness of female gray treefrogs, Hyla versicolor, to video playbacks of calling conspecific males in which we varied attributes of the vocal sac, a conspicuous visual characteristic of calling males and a target of female choice in other species. Females responded surprisingly strongly to the video playbacks, but did so indiscriminately with respect to variation in vocal sac characteristics. We followed up on these results with a series of additional tests that examined female responses to abstract stimuli. Females continued to respond to such stimuli, leading us to conclude that their behavior was related to a generalized phototactic response. Because of this, we were unable to make conclusions regarding female preferences for vocal sac characteristics. Nonetheless, our results are significant in two respects. First, we illustrate that despite much effort into improving video playback methodologies, challenges remain, and we offer our experimental design as a method to ensure that appropriate conclusions can be drawn from such studies. Second, we argue that the female phototactic response has potentially significant behavioral implications and in general the consequences of anuran visual preferences deserve further investigation.

Mate choice behavior of female Eastern Gray Treefrogs (Hyla versicolor) is robust to anthropogenic light pollution

“…This suggests that mate choice, at least in the Gray Treefrogs tested here, is mediated predominantly by acoustic cues. This is in line with previous studies on multimodal communication in this species, that showed that although females are not indifferent to visual cues colocalized with an acoustic signal (Reichert & Höbel, 2015), there is no evidence for visual mate choice (Reichert et al, 2014).…”

“…However, there is substantial between‐species variation in the use of visual cues, as well as the relative reliance on visual versus acoustic signal components. In H. versicolor , visual mate choice is weak (Reichert, Galante, & Höbel, ; Reichert & Höbel, ), and we therefore expect that females would not attend more to visual cues under increased light levels. Nevertheless, there are species that do attend to visual cues (Gomez et al., ; Taylor et al., ), and for them increased nocturnal light should facilitate the use of inter‐ or intrasexual displays.…”

Modality interactions alter the shape of acoustic mate preference functions in gray treefrogs

“…Details of video stimulus preparation can be found in Reichert et al. (). Briefly, the animated frog stimuli consisted of a still image of a male H. versicolor with an appended image of a vocal sac that was animated to mimic the inflation and deflation that takes place during the production of a natural advertisement call (see Supporting Information Movie S1 in Reichert et al.…”

“…In addition, in a video playback experiment, females showed phototaxis to a variety of visual stimuli presented on a computer monitor (Reichert et al. ).…”

Frequency-channel dependent selectivity for temporal call characteristics in gray treefrogs, Hyla versicolor

“…All experiments were performed in a darkened semi-anechoic chamber (for further details of the testing arena, see Reichert et al, 2014). Females were placed in an acoustically transparent release cage in a circular arena 1 m from each of the playback speakers.…”