Sperm regulates locomotor activity ofC. eleganshermaphrodites

Sex differences in sex-shared behavior are common across various species. During mating, males transfer sperm and seminal fluid to females, which can affect female behavior. Sperm can be stored in the female reproductive tract for extended periods of time. However, its role in regulating female behavior is poorly understood. In the androdioecious nematode C. elegans , hermaphrodites produce both egg cells and sperm, enabling them to self-fertilize or mate with males. Hermaphrodites exhibit less locomotor activity compared to males, indicating sex difference in behavioral regulation. In this study, sperm-deficient mutants were examined to investigate the role of sperm in the regulation of locomotor behavior. The results suggest that sperm plays a significant role in regulating sex-shared behavior in C. elegans , as sperm-deficient mutants exhibited increased locomotor activity. Additionally, females of closely related gonochoristic species, C. remanei and C. brenneri , exhibited reduced locomotor activity after mating. The regulation of locomotion by sperm may be an adaptive mechanism that enables sperm-less hermaphrodites to search for mates and allow females to cease their search for mates after mating.