Male aggressiveness in a polygynous ungulate varies with social and ecological context

ANTONELLA PANEBIANCO; GREGORIO PABLO; OVEJERO RAMIRO ; ANTONELA MAROZZI; RUIZ BLANCO M.; LEGGIERI, L. R.; TARABORELLI PAULA A; CARMANCHAHI P.

ETHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 p. 1 - 15

0179-1613

Aggression is a social behaviour which can be affected by numerous factors. Thequality and quantity of food resources may play an important role in the aggressivenessof territorial ungulates as the defence of these resources influences femalechoice and mating opportunities. However, the relationship between food resourcesand aggression remains poorly understood. We assessed the ecological and socialfactors that influence aggression in Lama guanicoe, a territorial ungulate exhibitingresource-defence polygyny, during three periods (group-formation, mating and postmating)in the reproductive seasons of 2014 and 2016. We recorded 460 focal observationsof territorial (family groups, solitary) and non-territorial (mixed and bachelorgroups) males. We performed analyses at the population level (including all focal observations)and at the group level (each social unit separately), to test whether thefactors that influence aggression differ at these different scales. We also identifiedproxies of vegetation quality as potential predictors of aggression. At the populationlevel, we found that the presence of aggressive behaviour peaked during the matingseason and that post-mating aggression may have been driven by inter-annual environmentalvariations. For family groups and solitary males, variables reflecting highvegetation quality/quantity were predictors of aggressive behaviour, reflecting theresource-defence strategy of this species. Conversely, for mixed-group males, aggressionmay be more associated with social instability and group size, although thishypothesis has yet to be tested. Our research reinforces the idea that aggression canoccur in multiple contexts depending on male status (e.g. territorial or non-territorial)and contributes to our understanding of how ecological (i.e. availability of food resources)and social factors influence aggression in a territorial ungulate.