Speaker
Description
The ecological constraint hypothesis proposes that ecological conditions, e.g. limited breeding resources, constrain dispersal and solitary breeding, promoting cooperative breeding. The impact of climate and weather variables on cooperative plural breeding, where all females in a group can reproduce, are unclear. Female grey mouse lemurs, Microcebus murinus, forage solitarily at night, and sleep either solitarily or socially with kin; hence, they breed solitarily or cooperatively during breeding seasons. We used sleeping nest data to assess the effects of density, El Niño-Southern Oscillation, temperature and precipitation on cooperative and solitary breeding in a wild grey mouse lemur population from 2017 to 2021 in Kirindy, Madagascar. We recorded 2192 social and 2107 solitary sleeping observations of 169 females. As density increased, the likelihood of breeding cooperatively and the number of females per nest increased. These results did not support the ecological constraint hypothesis, since most nests were unoccupied. An increase in density may have increased the number of kin in the population, facilitating cooperative breeding. The likelihood of cooperative breeding and the number of females per nest increased with el Niño and la Niña events compared to normal phases, and there was no significant difference between el Niño and la Niña events. Temperature and precipitation did not significantly influence the likelihood of breeding cooperatively and the number of females per nest. These results suggest that female grey mouse lemurs breed cooperatively when environmental uncertainty increases. Our research shows that breeding strategies and social dynamics in grey mouse lemurs adapt to environmental factors.
