Recent research published in Biology Letters revealed that female cane toads (Bufo marinus) can inflate themselves to prevent them from passionate males. This unusual behaviour suggests that female frogs and toads may have more power to select their mate than usually thought.
Female toads are typically the choosier sex and discriminate among potential mates by approaching the toad with the best call. However, on their way to the best performed ribbit, small ‘satellite’ males grasp any female that comes within their reach and retain their hold unless displaced by a rival male.
By inflating herself, the female can loosen the grip of the male so that only the strongest males have a chance to mate.
It was already known that frogs and toads inflate themselves for defence against predators, therefore the inflation of the female was assumed to be a response to the physical stress of the male. However, the Australian researchers hypothesized that inflation may have evolved both as a defensive mechanism and for mate choice.
To test this, they inflated a model female toad and experimentally prevented females from inflating their bodies. It was revealed that also the model toad strongly reduced a male’s ability to hold on and furthermore that the toads that undergone surgery where unable to shake off even the smalles males.
Thus, by inflating itself at the right moment, a female can manipulate the outcome of male-male competition, which helps her to mate with the biggest and strongest male that is likely to produce the healthiest offspring.
Bruning, B., Philips, B. L., Shine, R. 2010. Turgid female toads give males the slip: A new mechanism of female mate choice in the Anura. Biology letters, published online before print January 6, 2010