The C. elegans male exercises directional control during mating through cholinergic regulation of sex-shared command interneurons.

Background: Mating behaviors in simple invertebrate model organisms represent tractable paradigms for understanding the neural bases of sex-specific behaviors, decision-making and sensorimotor integration. However, there are few examples where such neural circuits have been defined at high resolution or interrogated.

Methodology/principal Findings: Here we exploit the simplicity of the nematode Caenorhabditis elegans to define the neural circuits underlying the male's decision to initiate mating in response to contact with a mate.

Multiple doublesex-related genes specify critical cell fates in a C. elegans male neural circuit.

Background: In most animal species, males and females exhibit differences in behavior and morphology that relate to their respective roles in reproduction. DM (Doublesex/MAB-3) domain transcription factors are phylogenetically conserved regulators of sexual development. They are thought to establish sexual traits by sex-specifically modifying the activity of general developmental programs.

The robustness of Caenorhabditis elegans male mating behavior depends on the distributed properties of ray sensory neurons and their output through core and male-specific targets.

Many evolutionarily significant behaviors, such as mating, involve dynamic interactions with animate targets. This raises the question of what features of neural circuit design are essential to support these complex types of behavior. The Caenorhabditis elegans male uses 18 ray sensilla of the tail to coordinate mate apposition behavior, which facilitates a systematic search of the hermaphrodite surface for the vulva.