Whispers on the wind: male cane toads modify mate searching and amplexus tactics based on calls from other males

Abstract

In many species of anurans, males produce advertisement calls that function to attract reproductively active females. Rival males may use the public information in these calls to optimize their own tactics for acquiring mates. To see whether male cane toads, Rhinella marina, modify their mate-searching and amplexus behaviours in response to conspecific calls, we monitored toads in outdoor enclosures while playing recordings of advertisement calls, a biologically irrelevant stimulus with similar acoustic properties or silence. Male toads were seven times more likely to engage in amplexus and moved twice as much during a toad chorus than during the control sound or silence. Nonacoustic cues also influenced propensity to initiate amplexus, with males five to 16 times more likely to amplect a moving target than a stationary one (regardless of the sex of the animal being amplexed). Our study shows that male toads dramatically alter their behaviour in response to acoustic and visual information from conspecifics, suggesting that this public information holds substantial value to them as they seek to fine-tune their own reproductive tactics.