Species‐specific communication systems in an introduced toad compared with native frogs in Australia

Abstract

Abstract Lineage‐specific communication systems may offer innovative ways of targeting control measures at invasive species. Recent work has identified such a scenario in invasive cane toads (Bufo marinus) in Australia: toad tadpoles flee from chemical cues derived from crushed conspecifics, and this ‘alarm pheromone’ reduces tadpole survival rates and reduces body size at metamorphosis. Before this method can be applied in the field, however, the signal's specificity needs to be tested against a wide range of Australian frog taxa, especially tropical species sympatric with cane toads. A signal that affected native frogs as well as toads clearly would be of little use for toad control. Laboratory studies on cane toads and nine native frog taxa from the wet–dry tropics of the Northern Territory (Cyclorana australis, C. longipes, Limnodynastes convexiusculus, Litoria caerulea, L. dahlii, L. nasuta, L. rothii, L. rubella, Opisthodon ornatus) show that toad tadpoles rarely react to chemical cues from crushed frog tadpoles, and that frog tadpoles rarely react to chemical cues from crushed toad tadpoles. Crushed toad tadpoles occasionally elicited low‐level attraction (to a potential food source) by frog tadpoles. Overall, frog tadpoles were less responsive to chemical cues (either from crushed conspecifics or crushed toads) than were toad tadpoles. The low level of cross‐lineage reactivity is encouraging for the feasibility of using cane toad alarm pheromones to control this invasive species in Australia; the risk of collateral damage to sympatric native frogs appears to be minimal. Copyright © 2009 John Wiley & Sons, Ltd.