Co-Designing a Care Coordination Intervention for People With Motor Neuron Disease: Protocol for a Mixed Methods Study.

The evolution of internal fertilization in animals introduced unique challenges in the process of sexual reproduction. Following this transition in reproductive mode, the female body shapes the physical and chemical environment that sperm must survive and traverse before fertilization (; ; ). In turn, mating can physically harm the female () and introduce pathogens from the environment or in the ejaculate (), and transferred seminal fluid proteins may alter female physiology in ways which can be costly to females (). The outcome of these interactions between the sexes entails both cooperation and conflict, shaping the evolution of morphological and physiological reproductive traits (; ; ). There has been a growing appreciation for the role that females play in mediating postmating interactions and the evolution of reproductive traits in both sexes (; ; ; ; ; ). For instance, female reproductive tissues and secretions support sperm viability after insemination (; ; ), from hours or days in some mammals () to months or even years in some eusocial Hymenoptera (). However, conflict between the sexes also shapes postmating physiological traits (; ; ). In the cabbage white butterfly (), females break down the hard spermatophore envelope with teeth-like signum in the bursa and have co-opted digestive enzymes from the gut to process the ejaculate (; ). The combination of selection pressures arising from, or constrained by, the multiple intersecting roles of the female reproductive system thus differentially influences the evolution of these tissues across species. These functions include (i) mitigating the costs of mating and intromission, including infection (), (ii) processing the ejaculate, (iii) aiding and potentially modulating sperm transport, storage, and survival (; ; ), and (iv) preparing for egg production, maturation, and ovulation (; ; ; ). To accommodate these various functions, females across many species undergo a series of changes in morphology, physiology, and behavior after mating (; ; ). These postmating responses are accompanied by dynamic changes in gene expression in the female reproductive tract (; ; ; ; ; ; ; ; ; ). For instance, the immune challenge associated with mating coincides with an increase in immune gene expression in the female reproductive tract, a pattern found from insects to mammals (; ; ; ; ; ; ). In , the earliest transcriptional changes in the reproductive tract occur within minutes after courtship and mating, with a peak in differential gene expression 6 h after the start of mating (; ; ). The female reproductive tract is hypothesized to start in a “poised” state and, after mating, undergo terminal differentiation to support subsequent reproductive events (e.g. ovulation and oviposition) (; ). However, our limited knowledge of the molecular and physiological adaptations that underpin postmating female responses impedes understanding of basic insect physiology and sexual selection as well as the development of tools to control insect reproduction ().