Population differences and domestication effects on mating and remating frequencies in Queensland fruit fly

Females of many insect species are unreceptive to remating for a period following their first mating. This inhibitory effect may be mediated by either the female or her first mate, or both, and often reflects the complex interplay of reproductive strategies between the sexes. Natural variation in remating inhibition and how this phenotype responds to captive breeding are largely unexplored in insects, including many pest species. We investigated genetic variation in remating propensity in the Queensland fruit fly, Bactrocera tryoni, using strains differing in source locality and degree of domestication. We found up to threefold inherited variation between strains from different localities in the level of intra-strain remating inhibition. The level of inhibition also declined significantly during domestication, which implied the existence of genetic variation for this trait within the starting populations as well. Inter-strain mating and remating trials showed that the strain differences were mainly due to the genotypes of the female and, to a lesser extent, the second male, with little effect of the initial male genotype. Implications for our understanding of fruit fly reproductive biology and population genetics and the design of Sterile Insect Technique pest management programs are discussed.

Bigger Is Better, Sometimes: The Interaction between Body Size and Carcass Size Determines Fitness, Reproductive Strategies, and Senescence in Two Species of Burying Beetles

The cost of reproduction hypothesis suggests that allocation to current reproduction constrains future reproduction. How organisms accrue reproductive costs and allocate energy across their lifetime may differ among species adapted to different resource types. We test this by comparing lifetime reproductive output, patterns of reproductive allocation, and senescence between two species of burying beetles, Nicrophorus marginatus and N. guttula, that differ in body size, across a range of carcass sizes. These two species of burying beetles maximized lifetime reproductive output on somewhat different–sized resources. The larger N. marginatus did better on large and medium carcasses while the smaller N. guttula did best on small and medium carcasses. For both species, reproduction is costly and reproduction on larger carcasses reduced lifespan more than reproduction on smaller carcasses. Carcass size also affected lifetime reproductive strategies. Each species’ parental investment patterns were consistent with terminal investment on carcasses on which they performed best (optimal carcass sizes). However, they exhibited reproductive restraint on carcass sizes on which they did not perform as well. Reproductive senescence occurred largely in response to carcass size. For both species, reproduction on larger carcasses resulted in more rapid senescence. These data suggest that whether organisms exhibit terminal investment or reproductive restraint may depend on type and amount of resources for reproduction.

Life Strategies in Placozoa

Placozoans are essential reference species for understanding the origins and evolution of the animal organization. However, little is known about their life strategies in natural habitats. Here, by establishing long-term culturing for four species of Trichoplax and Hoilungia, we extend our knowledge about feeding and reproductive adaptations relevant to their ecology and immune mechanisms. Three modes of population growth depended upon feeding sources, including induction of social behaviors and different reproductive strategies. In addition to fission, representatives of all haplotypes produced swarmers, which could be formed from the lower epithelium (with greater cell-type diversity) as a separate asexual reproduction stage. In aging culture, we reported the formation of specialized structures (spheres) from the upper cell layer as a part of the innate immune defense response with the involvement of fiber cells. Finally, we showed that regeneration could be a part of the adaptive reproductive strategies in placozoans and a unique model for regenerative biology in general.

The Spiny Mouse—A Menstruating Rodent to Build a Bridge From Bench to Bedside

Menstruation, the cyclical breakdown of the uterine lining, is arguably one of evolution's most mysterious reproductive strategies. The complexity and rarity of menstruation within the animal kingdom is undoubtedly a leading contributor to our current lack of understanding about menstrual function and disorders. In particular, the molecular and environmental mechanisms that drive menstrual and fertility dysregulation remain ambiguous, owing to the restricted opportunities to study menstruation and model menstrual disorders in species outside the primates. The recent discovery of naturally occurring menstruation in the Egyptian spiny mouse (Acomys cahirinus) offers a new laboratory model with significant benefits for prospective research in women's health. This review summarises current knowledge of spiny mouse menstruation, with an emphasis on spiral artery formation, inflammation and endocrinology. We offer a new perspective on cycle variation in menstrual bleeding between individual animals, and propose that this is indicative of fertility success. We discuss how we can harness our knowledge of the unique physiology of the spiny mouse to better understand vascular remodelling and its implications for successful implantation, placentation, and foetal development. Our research suggests that the spiny mouse has the potential as a translational research model to bridge the gap between bench to bedside and provide improved reproductive health outcomes for women.

REPRODUCTIVE ASPECTS OF JAGUAR (PANTHERA ONCA): FEMALE

Objective: Describe the reproductive characteristics of the female jaguar as well as assisted reproduction techniques. Design/methodology/approach: A literature review about reproductive characteristics and assisted reproduction techniques was done to documented information about it. Results: The Jaguar is considered the largest feline in America, females are 1.57 to 2.19 m of length and weigh 45 to 82 kg. The jaguar female is ready for mating when it is about 2 years old. Regarding the estrous cycle, it is divided into: proestrus, estrus, diestrous, interestrous and anestrus. Environment influence on the reproductive behavior of the jaguar, being the steroids those that stimulate the production of pheromones to attract the male; in the female the secretion is cyclical. The gestation lasts approximately between 90 and 110 days and they usually give birth to 1 or up to 4 young. In the case of assisted reproduction, artificial insemination could be useful to preserve genetic material from animals with outstanding characteristics. Limitations on study/implications: The destruction of forests and jungles, the fragmentation of habitat, indiscriminate hunting, the lack of prey as a food source and the conflict with ranchers has put the Jaguar on the brink of extinction, in addition there is little information about its reproductive characteristics, which is why in Mexico, it is imperative to generate this information, mainly in free-living jaguar. Findings/conclusions: Reproductive characteristics of jaguar female were documented from a literature review as well as assisted reproduction techniques. Knowledge of these will allow developed reproductive strategies to work on a national conservation and reproduction strategy to preserve the species.