Frailty and Social Isolation of Elderly Prostate Cancer Patients: A Chain Mediating and Network Analysis of Illness Perception and Acceptance.

Mating strategies, whether sexual or asexual, have both costs and benefits to populations that allow for evolutionary processes to occur. The theoretical cost of sex and its disadvantages as a mode of reproduction are far higher than that of asexual reproduction (). Indeed, sexual reproduction has a 2-fold cost associated with the production of males due to having to share half of the offspring's genome with a mate (). In addition, sexual reproduction deprives individuals of reproductive assurance and increases the risk of predation (; ). Despite these disadvantages, most reproducing organisms utilize sexual reproduction to some degree. The main advantage that allowed sex to evolve and persist as the major mode of reproduction is meiotic recombination, which generates allelic diversity, allowing for the fixation of beneficial genetic variants and purging deleterious mutations (; ; ; ; ; ; ). Self-fertilization, a form of sexual reproduction, confers the benefits of meiosis and provides reproductive assurance while reducing the 2-fold cost of males (; ; ). Whether sexual reproduction, or outcrossing, is more favorable than self-fertilization depends largely on the interplay between the benefits and the costs of different reproductive modes in a particular environment. To capitalize on the benefits of multiple mating strategies (outcrossing, self-fertilization, asexual reproduction), some species evolved to use mixed-mating strategies. For instance, daphnids can switch from asexual to sexual reproduction in response to environmental stresses such as low temperature or starvation (). Similarly, pea aphids produce wingless females during favorable conditions, then switch to producing winged, sexual morphs in conditions of low food and high population density (). In addition, some plants can regulate their rate of self-fertilization based on environmental conditions, including temperature, light, nutrients, and water availability (; ; ). In nematodes, the species SB347 is trioecious and can reproduce via mating between males and females in favorable conditions, but develops as self-fertilizing hermaphrodite in unfavorable conditions (; ). However, the molecular mechanisms underlying these changes in mating strategies based on environmental conditions are not well understood. nematodes represent an excellent model to investigate such processes, as they exhibit changes in their mating strategies based on environmental experience. is an androdioecious species where the populations are composed primarily of self-fertilizing hermaphrodites, with rare males arising through either X-chromosome nondisjunction or through outcrossing (; ). In conditions favorable for growth, will develop continuously through 4 larval stages before becoming reproductive adults (control adults or CON). However, if animals experience unfavorable conditions such as starvation, high temperature, or crowding after hatching, they can enter the stress-resistant larval diapause state called dauer (). Once conditions improve, dauer larvae resume development to become reproductive adults (postdauers or PD) (; ). Passage through dauer over successive generations in wild isolates of , and , significantly increased the proportion of males in the population and the level of outcrossing between hermaphrodites and males (). Control and postdauer adults exhibit different transcriptional profiles that underlie altered behaviors and life history traits (; ; , , ; ; ). These altered behaviors could underlie the changes in mating strategies in postdauer animals and promote outcrossing in a typically self-fertilizing population.