The mixed-species chorus as public information: túngara frogs eavesdrop on a heterospecific

Abstract

Multispecies choruses represent a promising but uninvestigated forum for public information. Although frogs exposed to a potential predator call more readily in the presence of conspecifrc calls than in their absence, none are known to make comparable use of heterospecific calls. To test for heterospecific eavesdropping, we isolated calling male tungara frogs (Physalaemus pustulosus), presented them with a potential predator, and recorded their responses to playbacks of 1 of 4 stimuli: calls of a conspecifrc, a sympatric heterospecific (Leptodactylus labialis), an allopatric congener (Physalaemus enesefae), or silence. We found that males called more in response to the L. labialis call than to either the silent stimulus or the P. enesefae call. In contrast, the P. enesefae call did not result in significantly more calling than the silent stimulus. The conspecifrc call was the most effective at promoting calling. The data indicate that tungara frogs selectively attend to the call of a heterospecific. We hypothesize that such heterospecific eavesdropping contributes to the emergent behavior of mixed-species choruses.

Mate choice in response to dynamic presentation of male advertisement signals in túngara frogs

“…Our study shows that this preference hinges critically on the timing of complex call production: females prefer males that produce a complex call. All males are capable of producing complex calls but choose to do so depending on the social environment, with complex calls more commonly produced (1) during bouts of vocal competition between neighbouring males (Bernal et al 2009), (2) in the presence of females (K. L. Akre, personal communication), (3) when predation risk is perceived to be lower (Tuttle et al 1982;Jennions & Backwell 1992;Phelps et al 2007) and (4) when injected with arginine vasotocin (Kime et al 2007), a neuropeptide that modulates social behaviour in many species (Moore & Miller 1983;Boyd 1994;Chu et al 1998;Marler et al 1999;Sanantgelo & Bass 2006). We show that the continued production of complex calls is critical when females are assessing and approaching potential mates, and therefore, males should be under selection to maintain complexity during peak female attendance at the chorus or when females are detected directly.…”

“…For other females nearby, continuing an approach after cessation would be of no value. Males also tend to cease calling when they detect predators (Tuttle et al 1982;Jennions & Backwell 1992;Phelps et al 2007), and therefore, it would be beneficial for females to restrict movement following call cessation. For many anuran species, including tú ngara frogs (Ryan 1983), a strong predictor of male mating success is chorus tenure (reviewed in Wells 2007); males that attend choruses and call more achieve more matings, thereby generating both important benefits and costs (e.g.…”

Anuran assemblage composition and distribution at a modified environment in Três Marias reservoir, south-eastern Brazil

“…Considering that higher densities of anurans in preferred habitats may attract more predators and/or facilitate disease transmission, thus being potentially detrimental to anurans, it is reasonable to consider that biotic interactions in general are less likely to influence anuran distribution than environmental features. However, in the case of increased predation risk, species can use both conspecific and heterospecific signals as cues to detect predator presence (Phelps et al 2006), in which case large aggregations might bring benefits at the individual level (Downes and Hoefer 2004).…”

The effect of signal complexity on localization performance in bats that localize frog calls

“…Calling frogs detect approaching bats using their vision and respond with evasive behaviour (Tuttle et al 1982;Jennions & Backwell 1992;Phelps et al 2007). A frog that detects an approaching bat stops calling, deflates its vocal sac, submerges such that only the top of its head protrudes above the water surface and, if the threat continues, ultimately dives under water.…”