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1. Life history, mating dynamics and the origin of parental care

   https://doi.org/10.1111/jeb.13959  

   Azad, Tamjeed; Alonzo, Suzanne H.; Bonsall, Michael B.; Klug, Hope (November 2021, Journal of Evolutionary Biology)

   Abstract Parental care, mating dynamics and life history co‐evolve. Understanding the diversity of reproductive patterns found in nature is a major focus of evolutionary ecology research. Previous research suggests that the origin of parental care of eggs will be favoured when egg and adult death rates and juvenile survival are relatively high. However, the previous research that explored the link between care and life history did not account for among‐species variation in mating dynamics. As mating dynamics are generally expected to influence care, we explore, theoretically, the life‐history conditions (stage‐specific rates of maturation and survival) that favour parental care across three mating scenarios: reproductive rate (1) is unaffected by males (assuming that some males are present), (2) increases as male abundance increases or (3) decreases as male abundance increases. Across scenarios, all forms of care were most strongly favoured when egg and adult death rates, juvenile survival and female egg maturation rates were relatively high. When reproductive rate was unaffected by male abundance or increased as male abundance increased, as we might expect in systems in which females are mate‐limited, all forms of care were most strongly favoured when male egg maturation rate (i.e. the rate at which male eggs develop, mature and hatch) was moderate or high. When greater male abundance inhibited reproduction, which might occur in systems with intense male–male competition, all forms of care were most strongly favoured when male egg maturation rate was low‐to‐moderate. These results suggest that life history affects the evolution of parental care, and sex‐specific life history can interact with mating dynamics to influence the origin of care. 

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2. The impact of gender on individual perceptions and team psychological safety in engineering design teams

   https://doi.org/10.1115/DETC2022-89910  

   Cole, C.; Jablokow, K.; Simkins, S.; Miller, S. (August 2022, International Design Engineering Technical Conferences and Computers and Information in Engineering Conference)

   Improving team interactions in engineering to model gender inclusivity has been at the forefront of many initiatives in both academia and industry. However, there has been limited evidence on the impact of gender-diverse teams on psychological safety. This is important because psychological safety has been shown to be a key facet for the development of innovative ideas, and has also been shown to be a cornerstone of effective teamwork. But how does the gender diversity of a team impact the development of psychological safety? The current study was developed to explore just this through an empirical study with 38 engineering design student teams over the course of an 8-week design project. These teams were designed to be half heterogeneous (either half-male and half-female, or majority male) or other half homogeneous (all male). We captured psychological safety at five time points between the homogenous and heterogenous teams and also explored individual dichotomous (peer-review) ratings of psychological safety at the end of the project. Results indicated that there was no difference in psychological safety between gender homogenous and heterogenous teams. However, females perceived themselves as more psychologically safe with other female team members compared to their ratings of male team members. Females also perceived themselves to be less psychologically safe with male team members compared to male ratings of female team members, indicating a discrepancy in perceptions between genders. These results point to the need to further explore the role of minoritized groups in psychological safety research and to explore how this effect presents itself (or is covered up) at the team level. 

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3. Relative rates of evolution of male-beneficial nuclear compensatory mutations and male-harming Mother’s Curse mitochondrial alleles

   https://doi.org/10.1093/evolut/qpad087  

   Dapper, Amy L.; Diegel, Amanda E.; Wade, Michael J. (May 2023, Evolution)

   Abstract Mother’s Curse alleles represent a significant source of potential male fitness defects. The maternal inheritance of mutations with the pattern of sex-specific fitness effects, s♀>0>s♂, allows Mother’s Curse alleles to spread through a population even though they reduce male fitness. Although the mitochondrial genomes of animals contain only a handful of protein-coding genes, mutations in many of these genes have been shown to have a direct effect on male fertility. The evolutionary process of nuclear compensation is hypothesized to counteract the male-limited mitochondrial defects that spread via Mother’s Curse. Here we use population genetic models to investigate the evolution of compensatory autosomal nuclear mutations that act to restore the loss of fitness caused by mitochondrial mutation pressures. We derive the rate of male fitness deterioration by Mother’s Curse and the rate of restoration by nuclear compensatory evolution. We find that the rate of nuclear gene compensation is many times slower than that of its deterioration by cytoplasmic mutation pressure, resulting in a significant lag in the recovery of male fitness. Thus, the numbers of nuclear genes capable of restoring male mitochondrial fitness defects must be large in order to sustain male fitness in the face of mutation pressures. 

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4. The Context of Food Sharing and Tolerance in Wild Bornean Orangutans (Pongo pygmaeus wurmbii)

   Kane, Erin E; Susanto, Tri Wahyu; Knott, Cheryl D (August 2020, 42nd Annual Meeting of the American Society of Primatologists)

   When female chimpanzees, orangutans, and callitrichids share challenging‐to‐process resources with their offspring, they improve offspring access to foods and calories which would otherwise be unavailable. Adult chimpanzees share foods rarely, but when they do, sharing valuable resources solidifies inter‐individual bonds (e.g., when building coalitions or eliciting copulations). While maternal‐offspring food sharing has been studied in wild orangutans, the context in which adult orangutans share food and feed in proximity is poorly known. We use 27 years of research on orangutans in West Kalimantan, Indonesia, to examine this behavior. Food sharing and tolerance were observed during 2,131 follows between 1994‐2019. Mother‐infant food sharing occurred in 78%, of these follows, female‐female sharing in 22%, male‐female sharing in 32%, and male‐male in just 1%. Adult females shared foods at different rates with adult males than with offspring (Chi‐square = 49.27,p< .01,N= 589 events). Eighty‐one percent of mother‐offspring food sharing/tolerance was fruit, compared to only 71% of male‐female food sharing/tolerance. Durio, Lithocarpus, and Willughbeia (hard‐to‐process fruits) were most frequently shared by mothers. Twenty‐three percent of male‐female food sharing/tolerance occurred while eating termites; only 3% of mother‐infant sharing did. Only two of 350 mouth‐to‐mouth or hand‐to‐mouth transfers involved adult males and females. Mothers increase their offspring’s access to challenging resources, while food sharing/tolerance among adult males and females is not limited to valuable resources, but may indicate strong social tolerance or affiliation in generally solitary adults 

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5. Temperature-Sensitive Reproduction and the Physiological and Evolutionary Potential for Mother’s Curse

   https://doi.org/10.1093/icb/icz091  

   Montooth, Kristi L; Dhawanjewar, Abhilesh S; Meiklejohn, Colin D (June 2019, Integrative and Comparative Biology)

   Abstract Strict maternal transmission of mitochondrial DNA (mtDNA) is hypothesized to permit the accumulation of mitochondrial variants that are deleterious to males but not females, a phenomenon called mother’s curse. However, direct evidence that mtDNA mutations exhibit such sexually antagonistic fitness effects is sparse. Male-specific mutational effects can occur when the physiological requirements of the mitochondria differ between the sexes. Such male-specific effects could potentially occur if sex-specific cell types or tissues have energy requirements that are differentially impacted by mutations affecting energy metabolism. Here we summarize findings from a model mitochondrial–nuclear incompatibility in the fruit fly Drosophila that demonstrates sex-biased effects, but with deleterious effects that are generally larger in females. We present new results showing that the mitochondrial–nuclear incompatibility does negatively affect male fertility, but only when males are developed at high temperatures. The temperature-dependent male sterility can be partially rescued by diet, suggesting an energetic basis. Finally, we discuss fruitful paths forward in understanding the physiological scope for sex-specific effects of mitochondrial mutations in the context of the recent discovery that many aspects of metabolism are sexually dimorphic and downstream of sex-determination pathways in Drosophila. A key parameter of these models that remains to be quantified is the fraction of mitochondrial mutations with truly male-limited fitness effects across extrinsic and intrinsic environments. Given the energy demands of reproduction in females, only a small fraction of the mitochondrial mutational spectrum may have the potential to contribute to mother’s curse in natural populations. 

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