UNDERSTANDING HOW SEX MODULATES THE FEMALE NERVOUS SYSTEM TO DRIVE DISTINCT REPRODUCTIVE BEHAVIOR STATES
Layla Nassar, Addys Bode, Kevin Collins.
University of Miami, Coral Gables, FL.
We are interested in understanding how mating and reproductive behaviors are coordinated in the female nervous system. Specifically, we are identifying the neural signaling systems that drive two mutually exclusive C. elegans vulval motor behaviors: mating with males or the release of progeny during egg laying. We hypothesize that 1) female vulval muscle twitching contractions facilitate male spicule insertion during mating, 2) specific mechanical and chemical signals report successful copulation and insemination, and 3) mating initiates reproductive behaviors including oocyte production and egg release. To investigate these hypotheses, we are using calcium imaging techniques to record vulval signaling events during mating with males, after successful insemination, and during the resumption of normal egg laying behavior. We have found that hermaphrodites with sperm have reduced vulval muscle twitching behaviors resulting in inefficient mating. In contrast, hermaphrodites depleted of sperm have increased vulval muscle twitching that facilitates male spicule insertion and mating. After mating is complete, hermaphrodites display distinct and sustained vulval muscle contractions. Sharp vulval muscle contractions during mating have been shown to result in release of sperm from the uterus. This behavior may act as a mechanism for competition with self-sperm. We are now examining how the other cells in the egg-laying circuit, including the HSN and VC neurons and uv1 neuroendocrine cells, respond during steps of male mating. Together, these results will explain how internal and external signals modulate activity in the same neural circuit to drive distinct behavior states.