Tuesday, April 9, 2019

Male‐mediated prenatal loss can provide greater reproductive benefits to males than infanticide; compared to infanticide, male‐mediated prenatal loss may be more prevalent and of greater role in mammalian species than thought

Male‐mediated prenatal loss: Functions and mechanisms. Matthew N. Zipple et al. Evolutionary Anthropology: Issues, News, and Reviews, April 6 2019. https://doi.org/10.1002/evan.21776

ABSTRACT: Sexually selected infanticide has been the subject of intense empirical and theoretical study for decades; a related phenomenon, male‐mediated prenatal loss, has received much less attention in evolutionary studies. Male‐mediated prenatal loss occurs when inseminated or pregnant females terminate reproductive effort following exposure to a nonsire male, either through implantation failure or pregnancy termination. Male‐mediated prenatal loss encompasses two sub‐phenomena: sexually selected feticide and the Bruce effect. In this review, we provide a framework that explains the relationship between feticide and the Bruce effect and describes what is known about the proximate and ultimate mechanisms involved in each. Using a simple model, we demonstrate that male‐mediated prenatal loss can provide greater reproductive benefits to males than infanticide. We therefore suggest that, compared to infanticide, male‐mediated prenatal loss may be more prevalent in mammalian species and may have played a greater role in their social evolution than has previously been documented.

---
Bruce Effect in Wikipedia:

Evolutionary benefits

Males

When given the opportunity, male mice tend to direct their urine in the female’s direction.[23] This allows males to improve their fitness success by “sabotaging” the pregnancy of a male competitor,[3] and more quickly returning the female to estrus.[24] The Bruce effect can also aid in maintaining social status, with dominant males leaving more urinal scent markings,[25] and so blocking the pregnancies initiated by subordinate males.

Females

Females can control their likelihood of terminating pregnancy by pursuing or avoiding novel male contact during their most susceptible periods.[26] In this way, females can exert a post-copulatory mate choice, reserving their reproductive resources for the highest-quality male. Certainly, females are more likely to seek proximity to dominant males.[26] In many rodent species, males kill unrelated young; pregnancy block may avoid the wasted investment of gestating offspring likely to be killed at birth.[5][27] The Bruce effect is most common in polygynous rodent species, for which the risk of infanticide is highest.[28]

No comments:

Post a Comment