Chemical Communication in Archaic New Zealand Frogs (#193)
Studies of the social behaviour of anuran amphibians traditionally have centred on the role of bioacoustic signalling in mate choice. However, the abilities of amphibians to use chemical cues for detecting prey and predators, homing and navigation, and territorial defence have been well documented. In recent years researchers have begun to realise that frogs and toads communicate through multimodal channels. The most archaic lineages of frogs, represented by the New Zealand family Leiopelmatidae, communicate by chemical rather than bioacoustic signals. In the wild, Hamilton’s frogs, Leiopelma hamiltoni, live 40 years or more, rarely moving outside small (< 25 m2), well-defined home ranges. At night, individuals travel slowly above ground throughout their home ranges and return to diurnal refuges as morning approaches. Frogs were collected in the field, held in containers for 72 hours, and then tested for their discrimination between substrates that they themselves had marked and those marked by conspecifics. Individuals showed evidence of self-recognition as they spent more time on their own substrates than on those marked by frogs collected from other home ranges. This social discrimination was strongest when subjects were presented chemical cues of conspecifics from home ranges that did not overlap with their own. Using the same protocol, subjects were exposed just to samples of skin secretions, urine, or faeces that were collected from conspecifics or themselves. Skin secretions were most effective in eliciting self-recognition, as subjects readily discriminated between their own odours and those of conspecifics when exposed only to swabs taken from the skin. Subjects also discriminated between substrates marked by self and non-self urine. However, subjects did not consistently discriminate between their own faeces and those of conspecifics. These findings raise the possibility that chemical communication may complement bioacoustical signalling abilities to serve a variety of social functions in anuran amphibians.
- Waldman, B. in press. Chemical communication in archaic New Zealand frogs. In: Schulte BA, Ferkin MH, Goodwin TE (eds) Chemical Signals in Vertebrates 13. Springer, New York.