Male fish copy and mislead their rivals

Posted on December 13, 2016

Because the numbers of sexually receptive females are relatively low in wild guppy populations, male fish incur a high cost in searching for suitable mates. However, such costs can be reduced if males are able to collect information on females by observing their sexual interactions with other males. To assess this possibility, preference experiments were conducted in a test aquarium with a clear container at either end. In each trial a focal male fish was placed into a transparent cylinder in the middle of the central tank and a stimulus female was placed in each end compartment. The male was released and its sexual preference determined by recording the amount of time it spent close to each female. The male was then replaced in its cylinder and allowed to watch as a model of a male guppy made “display” movements close to the compartment with the less-preferred female. This was followed by a second mating preference trial. There was a significant positive shift in male preference between the first and second trials, showing that males were more inclined to mate with a female that had apparently received attention from another male. In a second experiment, where focal males were allowed to choose between females, first in the absence of an audience and then while being watched by one or two other males, the focal males reduced their female preference when in the presence of an audience. These results show that males can use public information quite flexibly: they lowered their costs by copying other males, but also reduced the risk of being copied themselves (and thus the risk of sexual competition) by shifting their sexual attention away from a preferred female in the presence of rivals.

Reference: Auld, H.L. & Godin, J.-G. 2015. Sexual voyeurs and copiers: social copying and the audience effect on male mate choice in the guppy. Behavioral Ecology & Sociobiology 69, 1795–1807.