Paper: Social and Genetic Effects on Fitness

A recent paper by Frere et al. published in PNAS examines the interaction between social and genetic factors that affect fitness in dolphins. This is the first study to go beyond the social relations themselves, combining genetic data to form a more comprehensive perspective. The authors used data from a population of bottlenose dolphins in Shark Bay, Western Australia, that has been studied for more than 20 years. There are separate groups for females and males in this population.

The results show that genetic and social factors interact to influence female fitness, in terms of calving success. Although pairs of females that are closely related have similar fitness, and also pairs of females that are socially close, there is weak correlation between relatedness and social preference. Other factors, like time spent in a social group and home range size, were not found to correlate with calving success.
To summarize, this study shows the combined influence of relatedness and sociality on fitness. It is interesting that sociality seems to be more important here than genetic relatedness. Females with more strong associations with other females succeed more as mothers, although it's not clear if socializing contributes to maternal care or maybe better mothers tend to socialize more with one another.

Methodological highlights:
- The addition of genetic relatedness to social relations.
- The use of the pedigree-free animal model to quantify the effect of social relations.