Rainfall decrease and red deer rutting behaviour: Weaker and delayed rutting activity though higher opportunity for sexual selection

• DOI: 10.1371/journal.pone.0244802
• Publication Date: 2021-01-20T19:40:14Z
• Authors: Marina F. Millán; Juan Carranza; Javier Pérez-Gonz...; Juliana Valencia; Jerónimo Torres-P...; Jose M. Seoane; Eva de la Peña; Susana Alarcos; Cristina B. Sánch...; Leticia Castillo; Antonio Flores; Alberto Membrillo
• Keywords: Male; 0106 biological sciences; Sexual Selection; 550; Science; Climate Change; Rain; 590; 01 natural sciences; Sexual Behavior, Animal; Climate change; Animals; Population Density; Deer; Q; R; Temperature; 15. Life on land; Sexual selection; 13. Climate action; Linear Models; Population density; Medicine; Female; Seasons; Research Article

In the last decades, climate change has caused an increase in mean temperatures and a reduction in average rainfall in southern Europe, which is expected to reduce resource availability for herbivores. Resource availability can influence animals' physical condition and population growth. However, much less is known on its effects on reproductive performance and sexual selection. In this study, we assessed the impact of three environmental factors related to climate change (rainfall, temperature and vegetation index) on Iberian red deerCervus elaphus hispanicusreproductive timing and sexual behaviour, and their effects on the opportunity for sexual selection in the population. We measured rutting phenology as rut peak date, the intensity of male rutting activity as roaring rate, and the opportunity for sexual selection from the distribution of females among harem holding males in Doñana Biological Reserve (Southwest Spain), from data of daily observations collected during the rut over a period of 25 years. For this study period, we found a trend for less raining and hence poorer environmental conditions, which associated with delayed rutting season and decreased rutting intensity, but that appeared to favour a higher degree of polygyny and opportunity for sexual selection, all these relationships being modulated by population density and sex ratio. This study highlights how climate change (mainly rainfall reduction in this area) can alter the conditions for mating and the opportunity for sexual selection in a large terrestrial mammal.