Epigenetics: Sexually Selected Traits and Behaviors

Differences between females and males has always intrigued scientists. Pre and post-natally, individuals are subjected to hormones that greatly affect development. Geary et al. published an article in 2012 examining epigenetic influences on sexually selected traits and behaviors. The researchers discovered that many sexually dimorphic traits are due to epigenetic mechanisms. These mechanisms are induced by sex steroids and are more dynamic than other naturally selected traits.

This dynamism allows for fluctuation in hormones such as testosterone. Male animals often invest significant energy in expressing sexually selected traits to attract female partners both anatomical and behavioral. For example bright plumage in birds or male-male aggression in deer which helps various species achieve the reward of a female mate. Although these features or behaviors could potentially increase predation risk (Geary et al. 2012).

Geary et al. discovered that epigenetic regulation of sex-traits vary due to factors such as season. Regulating these characteristics evolutionarily can improve the survival and success of an animal so that the animal can spend energy elsewhere rather than always on their sexual traits or behavior. 

Geary et al. explains, "Serum testosterone concentrations in such males declines after the breeding season, and these traits are thus confined only prior to and at the time the animals seek out mates, suggesting again that sexually selected traits are tightly regulated by environmental cues, including daylight and other factors, operating through the endocrine system." This plasticity would not be possible if not for epigenetic mechanisms. Sex traits and behaviors have evolved to improve likelihood of achieving a mate, and epigenetics has allowed animals to continue extravagance in order to achieve this goal. 


All pictures accessed 10/05/15 and referenced from top to bottom of articlehttp://www.clker.com/cliparts/4/K/G/V/J/7/boy-and-girl-stick-figure-red-md.pnghttp://www.uecthai.com/wp-content/uploads/boy-girl-sterotypes.jpg
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Reference:
Geary, D., Jašarević, E., Rosenfeld, C.,  (2012). Sexually Selected Traits: A Fundamental Framework for Studies on Behavioral Epigenetics. ILAR J,  53 (3-4), 253-269. doi: 10.1093/ilar.53.3-4.253