Evolution of sexual motivation circuits

Evolution of female sexual motivation

How new behaviors evolve in the nervous system remains a fundamental question in neuroscience. Within the Caenorhabditis genus, some species reproduce through self-fertilizing hermaphrodites, while others maintain separate males and females. This natural diversity provides a powerful opportunity to investigate how neural circuits evolve to generate different reproductive behaviors.

We study the species C. afra, in which females display strong sexual motivation toward males, actively seeking and initiating mating. In contrast, C. elegans hermaphrodites typically show little interest in males. By comparing neural activity, gene expression, and circuit organization between these species, we aim to uncover how evolutionary changes reshape neural circuits controlling mating behavior.

Our work suggests that the neural circuits underlying sexual motivation may already exist in hermaphroditic species but remain latent. Evolutionary changes in neuromodulation and gene expression may unlock these hidden circuit states, revealing how new behaviors emerge without major rewiring of the nervous system.