Data from: Hormonal and behavioural correlates of reproductive seasonality in a polygynous territorial ungulate
Description
Dataset corresponding to the article: Seasonal hormonal dynamics and aggression in wild male guanacos: the role of cortisol and testosterone Panebianco, A.1; Ovejero, R.2; Palme, R.3; Gregorio, P.1; Marozzi, A.4; Peña Lodis, F.1, 5; Pomponio, V.1; Taraborelli, P.6; Carmanchahi, P.1 1 Grupo de Investigación de Eco-Fisiología de Fauna Silvestre (GIEFAS), Centro Regional Universitario San Martín de los Andes (CRUSMA), Universidad Nacional del Comahue (INIBIOMA - CONICET - CRUSMA - UNCO), Neuquén, Argentina. 2 Instituto de Biodiversidad Neotropical, IBN-CONICET-UNT; CCT NOA SUR, Tucumán, Argentina. 3 Department of Biological Sciences and Pathobiology, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria 4 Instituto de Investigaciones Biológicas y Tecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas- Universidad Nacional de Córdoba, Av. Vélez Sarsfield 1611 (5000) Córdoba, Argentina 5 Witral. Red de Investigaciones en conservación y manejo de vida silvestre en sistemas socio-ecológicos, Instituto Argentino de Investigaciones de las Zonas Áridas (IADIZA), CONICET, Mendoza, Argentina 6 CONICET-UDEA- CIAP - IFRGV, Córdoba, Argentina *Corresponding author: Antonella Panebianco e-mail: apanebianco@comahue-conicet.gob.ar Using the guanaco (Lama guanicoe), a territorial ungulate exhibiting resource-defence polygyny, we 1) analysed faecal cortisol (FCMs) and testosterone (FTMs) metabolites in males during the reproductive season; and 2) assessed the relationship between these hormones and aggressive interactions, often associated with territoriality and competition for resources. During the 2014 and 2016 reproductive seasons, we recorded 227 focal observations of males from different social units across three periods (group-formation, mating, and post-mating) and collected fresh faecal samples for hormone analysis via group-specific enzyme immunoassays. FCMs and FTMs increased during the mating period, with significant inter-annual differences, likely reflecting variations in forage quality and availability. We found no relationship between aggressive behaviour and FCMs potentially due to the predominance of low-aggression level displays that require low energetic demands. The relationship between FTMs and aggressive interactions supports the predictions of the challenge hypothesis for polygynous species, indicating a low androgen responsiveness to male-male interactions due to already elevated baseline testosterone during mating. Our findings highlight how seasonal reproductive demands and environmental variability shape hormone secretion, emphasizing the interplay between social and ecological factors in regulating endocrine responses in wild mammals.