RT Journal Article
SR Electronic
T1 Multilevel and sex-specific selection on competitive traits in North American red squirrels
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 104240
DO 10.1101/104240
A1 David N. Fisher
A1 Stan Boutin
A1 Ben Dantzer
A1 Murray M. Humphries
A1 Jeffrey E. Lane
A1 Andrew G. McAdam
YR 2017
UL http://biorxiv.org/content/early/2017/05/04/104240.abstract
AB Individuals often interact more closely with some members of the population (e.g. offspring, siblings or group members) than they do with other individuals. This structuring of interactions can lead to multilevel natural selection, where traits expressed at the group-level influence fitness alongside individual-level traits. Such multilevel selection can alter evolutionary trajectories, yet is rarely quantified in the wild, especially for species that do not interact in clearly demarcated groups. We quantified multilevel natural selection on two traits, postnatal growth rate and birth date, in a population of North American red squirrels (Tamiasciurus hudsonicus). The strongest level of selection was typically within-acoustic social neighbourhoods (within 130m of the nest), where growing faster and being born earlier than nearby litters was key, while selection on growth rate was also apparent both within-litters and within-study areas. Higher population densities increased the strength of selection for earlier breeding, but did not influence selection on growth rates. Females experienced especially strong selection on growth rate at the within-litter level, possibly linked to the biased bequeathal of the maternal territory to daughters. Our results demonstrate the importance of considering multilevel and sex-specific selection in wild species, including those that are territorial and sexually monomorphic.Data archival: the data set is archived on Dryad (info XXX), with a five-year embargo from the date of publication.