Adjustment of costly extra-group paternity according to inbreeding risk in a cooperative mammal

Females of many animal species seek mating opportunities with multiple males, despite being able to obtain sufficient sperm to father their offspring from a single male. In animals that live in stable social groups, females often choose to mate outside their group resulting in extra-group paternity. One reason proposed to explain female choice for extra-group males is to obtain compatible genes, for example in order to avoid inbreeding depression in offspring. The benefits of such extra-group paternities could be substantial if they result in fitter, outbred offspring. However, avoiding inbreeding in this way could be costly for females, for example through retaliation by cuckolded males or through receiving aggression whilst prospecting for extra-group mating opportunities. We investigate the costs and benefits of extra-group paternity in the banded mongoose Mungos mungo, a cooperatively breeding mammal in which within-group mates are sometimes close relatives. We find that pups born to females that mate with extra-group males are more genetically heterozygous, are heavier and are more likely to survive to independence than pups born to females that mate within their group. However, extra-group matings also involve substantial costs as they occur during violent encounters that sometimes result in injury and death. This appears to lead female banded mongooses to adaptively adjust extra-group paternity levels according to the current risk of inbreeding associated with mating within the group. For group-living animals, the costs of inter-group interactions may help to explain variation in both inbreeding rates and extra-group paternity within and between species

Indirect evidence of an early mating advantage in wild cooperatively breeding male banded mongooses

Promiscuous females reduce male reproductive control. Males can attempt to monopolise access to these females, but distractions and sneaky rivals mean extra copulations cannot always be blocked. By mating first, males can obtain a headstart in sperm competition, but this may be negated by sperm storage and cryptic female choice mechanisms. We carry out an indirect rare test of an early mating advantage in a population of free-living wild animals. Using Bayesian GLMM analysis of a long-term life history database spanning 17 years, we show that banded mongoose males who interacted with females in earlier days of oestrus had a higher chance of siring their offspring compared with later rivals. An early mating advantage would intensify initial male-male competition and hence selection for male choice, as any initial mistake identifying preferred mating partners could see paternity lost to rivals

Sex‐Dependent Influence of Major Histocompatibility Complex Diversity on Fitness in a Social Mammal

Parasite infections affect males and females differently across a wide range of species, often due to differences in immune responses. Generally, females tend to have stronger immune defences and lower parasite loads than males. The major histocompatibility complex (MHC) plays a crucial role in the adaptive immune response, and extensive research has explored how variation in this region influences infection and fitness outcomes. However, studies of sex‐specific relationships between MHC variation and infection are scarce, perhaps because MHC genes are located on the autosomes, which are shared by both sexes. Here, we provide evidence of sexually antagonistic selection in a wild, group‐living mammal—the banded mongoose. Using genetic and life history data collected from over 300 individuals across 25 years, we found that both MHC class I (MHC‐I) and MHC class II (MHC‐II) diversity influence lifetime reproductive success differently in males and females. Specifically, higher MHC diversity is linked to increased fitness in males but decreased fitness in females. Furthermore, MHC diversity did not differ between the sexes, indicating an unresolved genetic sexual conflict. Our findings demonstrate that sexually antagonistic selection acts on the MHC and may operate across both MHC classes but differently. This study contributes to the growing body of evidence that sex is a significant factor in shaping host immunity and fitness

Untangling the oxidative cost of reproduction: An analysis in wild banded mongooses

The cost of reproduction plays a central role in evolutionary theory, but the identity of the underlying mechanisms remains a puzzle. Oxidative stress has been hypothesized to be a proximate mechanism that may explain the cost of reproduction. We examine three pathways by which oxidative stress could shape reproduction. The “oxidative cost” hypothesis proposes that reproductive effort generates oxidative stress, while the “oxidative constraint” and “oxidative shielding” hypotheses suggest that mothers mitigate such costs through reducing reproductive effort or by pre‐emptively decreasing damage levels, respectively. We tested these three mechanisms using data from a long‐term food provisioning experiment on wild female banded mongooses (Mungos mungo). Our results show that maternal supplementation did not influence oxidative stress levels, or the production and survival of offspring. However, we found that two of the oxidative mechanisms co‐occur during reproduction. There was evidence of an oxidative challenge associated with reproduction that mothers attempted to mitigate by reducing damage levels during breeding. This mitigation is likely to be of crucial importance, as long‐term offspring survival was negatively impacted by maternal oxidative stress. This study demonstrates the value of longitudinal studies of wild animals in order to highlight the interconnected oxidative mechanisms that shape the cost of reproduction

Why don’t long-finned pilot whales have a widespread postreproductive lifespan? Insights from genetic data

In a handful of mammals, females show an extended post-reproductive lifespan (PRLS), leading to questions over why they spend a substantial portion of their lifespan non-reproductive. Theoretical and empirical studies suggest that PRLS may evolve when (1) demographic patterns lead to increasing local relatedness as females age, and (2) females come into reproductive competition with their daughters, as these conditions lead to high relative benefits of helping kin versus reproducing in later life. However, evolutionary pathways to PRLS are poorly understood and empirical studies are scarce. Here, we use a dataset of 1522 individuals comprising 22 pods to investigate patterns of reproduction and relatedness in long-finned pilot whales Globicephala melas; a toothed whale without species-wide PRLS. We find a similar relatedness structure to whales with PRLS: pods appear composed of related matrilines, and relatedness of females to their pod increases with age, suggesting that this species could benefit from late-life help. Furthermore, females with a large number of philopatric adult daughters (but not sons) are less likely to reproduce, implying intergenerational reproductive competition between females. This suggests that individuals may display a plastic cessation of reproduction, switching to investing in existing offspring when they come into competition with their daughters. To the best of our knowledge, this is the first time such a relationship has been described in relation to PRLS, and it raises questions about whether this represents a step towards evolving PRLS or is a stable alternative strategy to widespread post-reproductive periods

SRWC-PEAM: A Comprehensive Appraisal Tool for Short-Rotation Woody Crops in the Southeast

Short-rotation woody crops (SRWCs) are fast-growing trees grown for energy or paper production. The productivity and economic assessment model for short-rotation woody crops, or SRWC-PEAM, is a web-based tool for evaluating the potential to produce woody feedstock from SRWCs on marginal lands in the southeastern United States. Productivity and economic assessments are based on land history and conditions, species, economic factors and management, and an enterprise budget developed according to recent field research and published data. Extension professionals can use SRWC-PEAM to evaluate stand establishment and management options to find profitable SRWC project scenarios for landowners and improve producers\u27 economic risk management decisions for SRWCs

Oxidative stress in relation to diet and physical activity among premenopausal women

Abstract Higher levels of oxidative stress, as measured by F 2 -isoprostanes, have been associated with chronic diseases such as CVD and some cancers. Improvements in diet and physical activity may help reduce oxidative stress; however, previous studies regarding associations between lifestyle factors and F 2 -isoprostane concentrations have been inconsistent. The aim of this cross-sectional study was to investigate whether physical activity and intakes of fruits/vegetables, antioxidant nutrients, dietary fat subgroups and alcohol are associated with concentrations of F 2 -isoprostane and the major F 2 -isoprostane metabolite. Urinary F 2 -isoprostane and its metabolite were measured in urine samples collected at enrolment from 912 premenopausal women (aged 35–54 years) participating in the Sister Study. Physical activity, alcohol consumption and dietary intakes were self-reported via questionnaires. With adjustment for potential confounders, the geometric means of F 2 -isoprostane and its metabolite were calculated according to quartiles of dietary intakes, alcohol consumption and physical activity, and linear regression models were used to evaluate trends. Significant inverse associations were found between F 2 -isoprostane and/or its metabolite and physical activity, vegetables, fruits, vitamin C, α -carotene, vitamin E, β -carotene, vitamin A, Se, lutein+zeaxanthin and long-chain n -3 fatty acids. Although trans fats were positively associated with both F 2 -isoprostane and its metabolite, other dietary fat subgroups including SFA, n -6 fatty acids, n -3 fatty acids, MUFA, PUFA, short-chain n -3 fatty acids, long-chain n -3 fatty acids and total fat were not associated with either F 2 -isoprostane or its metabolite. Our findings suggest that lower intake of antioxidant nutrients and higher intake of trans fats may be associated with greater oxidative stress among premenopausal women

Costly sons do not lead to adaptive sex ratio adjustment in pilot whales, Globicephala melas

Maternal investment in reproduction and parental care is an important determinant of both offspring and maternal fitness. However, optimal investment strategies may differ depending on offspring sex, potentially resulting in a sex-biased distribution of maternal resources or adaptive variation in offspring sex-ratio. We used morphometric and genetic data collected from over 3400 long-finned pilot whales Globicephala melas in 40 pods to investigate whether females experience differential costs of producing sons and daughters and whether they differentially invest in male and female offspring. We found that male calves grow faster than female calves during the first five years of life, suggesting that sons may require greater investment from lactating mothers. This appears to result in mothers experiencing a higher cost to future reproductive opportunities when producing male offspring as the presence of dependent sons (but not daughters) reduced the probability that a female would be pregnant. Despite these costs, we found no evidence that mothers adaptively adjust their investment in sons and daughters according to their body condition or their social and physical environment. These results suggest that mothers may be constrained from biasing investment in the sexes, or that additional benefits may be masking such costs. KEY WORDS: cetacean, Globicephala melas, group size, maternal investment, reproductive costs, reproductive success, sex-rati