The highly arborized PVD neuron has male-specific function and structure in C. elegans
The link between sensory neuron morphology and function remains difficult to ascertain, particularly in complex organisms. The nematode Caenorhabditis elegans provides a simpler model to investigate the morphogenesis and function of dendritic arbors. I focus on the bilateral neuron pair PVD, which has been extensively studied in hermaphrodites, but not in males. My results reveal PVD develops a male-specific dendritic structure into the copulatory organ and plays a new role during the complex mating behavior of the male. The morphological sexual dimorphism seems to stem from a male-specific expression pattern of a sex-shared guidance pathway controlled by the Menorin complex. In particular, the epidermally expressed SAX-7/L1 Cell Adhesion Molecule (L1CAM) guides PVD branches into the male copulatory organ during adulthood, while the behavioral aspect likely involves several sensory circuits and depends on animal age.