The Evolution of Sexual Mimicry in Cuttlefish

 

Sexual Selection

The mechanism for the majority of mating and courtship behaviors arises through sexual selection. A direction of mating system whether it is sperm competition, a garish display, or a female impersonation is usually determined by which of the competing interests dominatesunder any given set of ecological variables. Often in order to evade this competition males are able to utilize the females bias and manipulate them into considering them an apparopriate mate choice or to trick them into not being aware of the male as a potential mate such as in the case of female impersonation.

Female Impersonation

Two large Australian cuttlefish mate. (Source: cuttlefishsepiida.weebly.com)

While larger males may fight or perform color displays in order to court females, smaller males have little to no chance of mating success when utilizing these courtship methods. Due to cephalods ability to change the appearance of their body female impersonation is an easy mating strategy for small competitive male cuttlefish to be able to mate with females who prefer larger males. This ability likely evolved due to the preference many females have for larger males. A small male is often able to move close enough to a female in order to successfully mate due to their ability to rapidly assume a female appearance. The difficulty that arises when small males attempt to mate with females may have led to the evolution of cephalopods ability to alter their color and shape. This is an example of males are able to exploit a females bias through trickery such as sexual mimicry and mate with her when her typical mate choice preference is not similar to the male who is attempting to mate with her.

Sexual mimicry in Cuttlefish

a) A male cuttlefish (m) disguises itself as a female and approachesthe female (f) while another male (c) displays to an approaching male in order to compete for the female.

b)The female cuttlefish mates with the disguised male as the other male continues to display to approaching males.

c)The larger male (m) finishes its display and waits for the disguised male (m) to finish mating while another disguised male (m) approaches in the hopes of mating with the female. (Source: nature.com Transient sexual mimicry leads to fertilization)