Abstract
Successful reproduction in mammals depends on coordinated interactions between mating, maternal physiology, immune tolerance, and offspring development. While seminal fluid exposure at conception is known to influence implantation and placental development, the long-term effects of preconceptual mating on future reproductive success remain unclear. This thesis investigated whether repeated exposure to mating-related stimuli prior to conception, including seminal fluid, mechanical stimulation, olfactory cues, and partner-specific interactions, could shape subsequent fertility and pregnancy outcomes in mice. Female mice were exposed before conception to vasectomized males, vasectomized males lacking seminal vesicles, or female-only housing conditions, allowing specific components of mating to be experimentally isolated. Across experiments, preconceptual mating experience influenced implantation success, fetal viability, placental morphology, maternal body composition, offspring growth, and litter survival. Females exposed to prolonged preconceptual mating generally showed improved reproductive outcomes, particularly when later mated with males of the same genetic and major histocompatibility complex (MHC) background as the previous males. In contrast, females switched to genetically different males than their previous partners, experienced reduced offspring survival and growth, suggesting that females retain partner-specific information that influences maternal reproductive investment. Unexpectedly, exposure to mechanical, olfactory, and social cues without seminal fluid often produced equal or greater benefits than exposure including seminal fluid, indicating that physical stimulation and associated neuroendocrine changes may play a central role in reproductive priming. Together, these findings demonstrate that preconceptual mating has lasting effects on female reproductive physiology and pregnancy success, and that behavioural, sensory, and social components of mating may be as important as seminal fluid-mediated immune interactions in shaping reproductive outcomes.