Biology subjects

Cant, M.

Publications and source records attributed to Cant, M..

3 recordsLinked to original sources

bioRxiv2024

Fitness incentives to male fighters undermine fighting performance in intergroup contests

In humans and other animal societies, groups engage in intergroup conflicts over resources. The success of groups in these conflicts depends on individual contributions to collective fighting, yet individuals may have personal fitness incentives to defect rather than fight, which could undermine group performance. Here we test the hypothesis that personal fitness incentives affect intergroup conflict success in wild banded mongooses (Mungos mungo). In this species, intergroup fights are sometimes initiated by estrous females, who gain outgroup matings while their male group-mates contribute most of the fighting effort. We found that group fighting success was highest when a groups females were in estrus, suggesting that, although females may initiate fights, their male group-mates seem motivated to chase away rival groups to defend their paternity. Surprisingly, we found that groups that won fights conceded more paternity to their rivals than groups that lost. In other words, behavioral "wins" did not always result in fitness "wins". Younger males were more successful at attaining paternity between groups compared to within their own groups, suggesting that they may forego intergroup fighting to focus on intergroup mating. Overall, our results suggest that personal fitness incentives--here, in the form of paternity--vary widely among group members and can undermine rather than promote collective fighting performance. Such conflicts of interest are likely inherent in group combat and can contribute to variation in the frequency and costliness of intergroup violence.

animal behavior and cognition↗

bioRxiv2024

Strategic use of male alternative reproductive tactics in cooperatively breeding banded mongoose groups

Alternative reproductive tactics (ARTs) allow smaller or less competitive individuals to reproduce by avoiding direct fights through sneaky strategies. Within cooperatively breeding groups ARTs are rarely reported, potentially due to difficulties observing male reproductive behaviour in the wild, or reproductive suppression by fellow group members. In societies where all mating opportunities cannot be monopolised by one male, young males could use sneaky tactics as a stepping-stone to gain limited reproductive success while they grow in resource holding potential (RHP). Using 20 years of pedigree, weight, group demography, and behavioural data, we investigated the use of sneaky pesterer ARTs in wild banded mongooses. Instead of a stepping stone, pestering tactics were typically a rare back-up used by males displaced from mate guarding tactics by higher RHP rivals. Additionally, pesterers have lower siring success compared to mate guards, despite similar weight loss costs, which may explain why most males settle for reproductive inactivity rather than use pestering tactics. However, pestering allows younger males to gain access to older, higher fecundity females in the group and may even facilitate inbreeding avoidance. Overall, ARTs provide a viable option for reproductive fitness for some males that lose out on reproductive positions in highly male-skewed groups.

animal behavior and cognition↗

bioRxiv2024

Reproductive restraint to avoid the costs of reproductive conflict in a cooperatively breeding mammal

The costs of reproductive conflict can be an important factor shaping the evolution of life histories in animal societies. These costs may change as individuals age and grow, and with within-group competition. Social costs of reproductive conflict have been invoked to explain why females might gain from delaying maturity or ceasing reproduction midway through life, but not in males. Here we analyze more than 20 years of data to understand how individual male banded mongooses adjust their reproductive activity in response to the costs of reproductive conflict. In banded mongooses groups multiple female breeders enter oestrus synchronously and males compete to mate guard the females. The oldest and heaviest males in the group gained the greatest share of paternity, while younger and lighter males obtained little or no paternity. Those lighter males that are reproductively active paid disproportionate survival costs. Our results suggest that by delaying or suppressing reproduction early in life, males may reduce their mortality. Males may also avoid inflicting costs on their male kin by queuing. These results from an egalitarian cooperative breeding mammal may provide a rare example of voluntary reproductive restraint, although we cannot discount reproductive suppression by rival males.

animal behavior and cognition↗