Influence of Food Distribution and Relatedness on Social Interactions in a Colony of Free-Ranging Domestic Cats (Felis catus)

Behavioral interactions form the basis of social structure within populations. Ecological, demographic, and social factors may affect types of interactions or which individuals spend time near each other. For example, food resource distribution can affect social interactions and, if food resources are clumped, may result in interindividual competition. Social interactions also may be influenced by relatedness since close relatives may engage in more affiliative behaviors with one another because these behaviors may increase their inclusive fitness. We examined the influence of food distribution and relatedness on behavioral interactions in a colony of free-roaming domestic cats (Felis catus). Supplemental cat food was presented in a dispersed or clumped manner, and individuals were genotyped at 10 polymorphic microsatellite loci to determine relatedness. We observed the frequency of affiliative, agonistic, and investigatory behaviors and the number of times that individuals were in proximity to each other for 20 adults. We calculated three network metrics to quantify network structure: mean weighted degree, mean eigenvector centrality, and network density. Mean weighted degree and mean eigenvalue centrality were significantly non-random in both the dispersed and clumped food treatments for affiliative behavior. Network metrics for agonistic and investigative behaviors did not differ from random expectations in dispersed or clumped treatments. Network metrics increased between dispersed and clumped food treatments for affiliative but not agonistic or investigative behaviors. All three network metrics for proximity were significantly non-random in the dispersed and clumped treatments and increased between clumped and dispersed food treatments. There was no effect of genetic relatedness on any behavior or proximity, but sex was more important. Same-sex individuals were less likely to have agonistic behaviors when food was dispersed. These results suggest that some cats displayed affiliative behavior toward a subset of conspecific colony members as well as being in closer proximity to some individuals than others.