Relatedness and age reduce aggressive male interactions over mating in domestic fowl

Altruistic behaviour represents a fundamental challenge in evolutionary biology. It is often best understood through kin selection, where favourable behaviour is directed towards relatives. Kin selection can take place when males cooperate to enhance the reproductive success of relatives. Here, we focus on reduced male–male competition over mating as a case of cooperation, by examining male tolerance of matings by related and unrelated competitors. A suitable model for exploring whether relatedness affects male–male interactions over mating is the domestic fowl, Gallus gallus domesticus. In this species, males form social hierarchies and dominant males commonly interrupt subdominant males’ copulation attempts. We investigated whether dominant male fowl differentially direct aggressive interactions towards unrelated and related subordinate males during mating attempts. Dominant male fowl were found to interrupt mating attempts of male relatives less often than those of unrelated males. We further tested whether male age mediates the magnitude of kin tolerance behaviour. However, we found no support for this as both young and old dominant males were less likely to interrupt related, compared to unrelated, subdominant males’ copulations during male–male interactions. Our results, consistent with kin selection, provide a rare experimental demonstration of relatedness relaxing male–male competition over mating

Relatedness and age reduce aggressive male interactions over mating in domestic fowl

Altruistic behaviour represents a fundamental challenge in evolutionary biology. It is often best understood through kin selection, where favourable behaviour is directed towards relatives. Kin selection can take place when males cooperate to enhance the reproductive success of relatives. Here, we focus on reduced male–male competition over mating as a case of cooperation, by examining male tolerance of matings by related and unrelated competitors. A suitable model for exploring whether relatedness affects male–male interactions over mating is the domestic fowl, Gallus gallus domesticus. In this species, males form social hierarchies and dominant males commonly interrupt subdominant males’ copulation attempts. We investigated whether dominant male fowl differentially direct aggressive interactions towards unrelated and related subordinate males during mating attempts. Dominant male fowl were found to interrupt mating attempts of male relatives less often than those of unrelated males. We further tested whether male age mediates the magnitude of kin tolerance behaviour. However, we found no support for this as both young and old dominant males were less likely to interrupt related, compared to unrelated, subdominant males’ copulations during male–male interactions. Our results, consistent with kin selection, provide a rare experimental demonstration of relatedness relaxing male–male competition over mating

Relatedness and age reduce aggressive male interactions over mating in domestic fowl

Altruistic behaviour represents a fundamental challenge in evolutionary biology. It is often best understood through kin selection, where favourable behaviour is directed towards relatives. Kin selection can take place when males cooperate to enhance the reproductive success of relatives. Here, we focus on reduced male–male competition over mating as a case of cooperation, by examining male tolerance of matings by related and unrelated competitors. A suitable model for exploring whether relatedness affects male–male interactions over mating is the domestic fowl, Gallus gallus domesticus. In this species, males form social hierarchies and dominant males commonly interrupt subdominant males’ copulation attempts. We investigated whether dominant male fowl differentially direct aggressive interactions towards unrelated and related subordinate males during mating attempts. Dominant male fowl were found to interrupt mating attempts of male relatives less often than those of unrelated males. We further tested whether male age mediates the magnitude of kin tolerance behaviour. However, we found no support for this as both young and old dominant males were less likely to interrupt related, compared to unrelated, subdominant males’ copulations during male–male interactions. Our results, consistent with kin selection, provide a rare experimental demonstration of relatedness relaxing male–male competition over mating

Harnessing global fisheries to tackle micronutrient deficiencies

Micronutrient deficiencies account for an estimated one million premature deaths annually, and for some nations can reduce gross domestic product1,2 by up to 11%, highlighting the need for food policies that focus on improving nutrition rather than simply increasing the volume of food produced3. People gain nutrients from a varied diet, although fish—which are a rich source of bioavailable micronutrients that are essential to human health4—are often overlooked. A lack of understanding of the nutrient composition of most fish5 and how nutrient yields vary among fisheries has hindered the policy shifts that are needed to effectively harness the potential of fisheries for food and nutrition security6. Here, using the concentration of 7 nutrients in more than 350 species of marine fish, we estimate how environmental and ecological traits predict nutrient content of marine finfish species. We use this predictive model to quantify the global spatial patterns of the concentrations of nutrients in marine fisheries and compare nutrient yields to the prevalence of micronutrient deficiencies in human populations. We find that species from tropical thermal regimes contain higher concentrations of calcium, iron and zinc; smaller species contain higher concentrations of calcium, iron and omega-3 fatty acids; and species from cold thermal regimes or those with a pelagic feeding pathway contain higher concentrations of omega-3 fatty acids. There is no relationship between nutrient concentrations and total fishery yield, highlighting that the nutrient quality of a fishery is determined by the species composition. For a number of countries in which nutrient intakes are inadequate, nutrients available in marine finfish catches exceed the dietary requirements for populations that live within 100 km of the coast, and a fraction of current landings could be particularly impactful for children under 5 years of age. Our analyses suggest that fish-based food strategies have the potential to substantially contribute to global food and nutrition security