The sensory trap hypothesis describes an evolutionary idea that revolves around mating behavior and female mate choice. It is a model of female preference and male sexual trait evolution through what is known as sensory exploitation.[1][2] Sensory exploitation, or a sensory trap is an event that occurs in nature where male members of a species perform behaviors or display visual traits that resemble a non-sexual stimulus which females are responsive to. This tricks females into engaging with the males, thus creating more mating opportunities for males.[2][3] What makes it a sensory trap is that these female responses evolved in a non-sexual context, and the male produced stimulus exploits the female response which would not otherwise occur without the mimicked stimulus.[2][4]
The term "trap" indicates that these sensory trap events may be detrimental to female mating success, but they may not always be costly. In fact, there are circumstances where not responding to the stimulus itself can be costly, as females may ignore the actual stimulus in the correct context, and lose the fitness benefits that come with it.[2] There are also circumstances where these traps can actually be beneficial in the context of mate choice, where the females who are responding to the trap end up gaining high-quality males to mate with.[2][3]
While these sensory traps can be quite successful when they appropriately mimic the non-sexual stimulus, they often become exaggerated as a result of excessive selection to the point where they are no longer useful.[2] This is due to the trait or behavior becoming imperceptible or no longer resembling the original stimulus.[2]