Alternative mating strategies in fish species often involve a social dominance hierarchy with dominant males and secondary ones, also known as sneaker males. Dominant males tend to assume a much higher cost during reproduction as they are responsible for guarding the nest, attracting a female, and defending their territory. Sneaker males often obtain reproductive success by sneaking, as their name implies, into the nest or mimicking female behaviors.

In a recent collaboration, Steve Vollmer studied the differential gene expression between the brains of territorial males, sneaker males, and reproductive females in the non-model species black-faced blenny, Tripterugion delaisi. The research, recently published in BMC Genomics, suggests that more genes were differentially expressed among the two males phenotypes than between males and females.

Phenotypic plasticity is an important part of selection and evolution, and the research of Vollmer and his colleagues illustrates how social interactions can trigger behavioral and physical changes.