COS 143-5 - CANCELLED - Benefits of living closer to kin vary by genealogical relationship in a territorial mammal

Background/Question/Methods

While cooperative interactions among kin are a key building block in the societies of group-living mammals, their prevalence in species lacking stable social units is less clear. For example, mammals in less predictable social environments may instead invest in mutualistic relationships regardless of relatedness as a form of social bet-hedging. North American red squirrels (Tamiasciurus hudsonicus) defend individual territories in dynamic neighbourhoods and are known to benefit from living among familiar conspecifics, but not relatives. However, kin-directed behaviours may be restricted to specific genealogical relationships, or strongly mediated by geographic distance, potentially masking their influence at larger scales. Using distance between territories as a proxy for the ability to interact, we estimated the influence of primary kin (parents, offspring, full siblings) on the annual survival and reproductive success of red squirrels.

Results/Conclusions

Controlling for effects of age and resource pulses, we found that females had enhanced survival when they lived closer to their daughters, but no evidence that the reverse was true. Surprisingly, males had higher annual reproductive success when living closer to their father, raising new questions about father-son interactions. Thus, rather than reflecting indiscriminate cooperation among relatives, kin-directed benefits in red squirrels only emerged in certain genealogical relationships and fitness components. These findings point to an unexpected level of nuance in the consequences of kinship dynamics for a species that is territorial and largely solitary.