Testando o princípio de fisher em quatro espécies de mamíferos do Parque Nacional de Maputo, sul de Moçambique

Abstract

The principle formulated by Fisher proposes that, in natural environments, species with sexual reproduction tend to exhibit balanced sex ratios, approaching 1:1 (Fisher, 1930). However, this relationship can be influenced by multiple ecological and social factors, such as resource availability, predation pressure, and the social structure of organisms (West et al., 2002). These influences can generate deviations in the sex ratio and reflect evolutionary adaptations that favor population persistence and the reproductive success of species in their respective habitats. Based on this theoretical framework, the present study tested the hypothesis of conformity to Fisher's principle in populations of four species of wild herbivores from Maputo National Park. Through direct observation and photographic analysis, 1031 individuals were identified, distributed among Connochaetes taurinus (n = 323), Redunca arundinum (n = 236), Tragelaphus angasii (n = 223), and Kobus ellipsiprymnus (n = 249). The observed sex ratios were 1.4:1 for C. taurinus and 0.6:1 for the other species. Statistical analysis using the chi-square test (χ²) revealed significant differences between the sexes (p < 0.05), with a predominance of males in the C. taurinus population and females in the other species. These findings highlight a relevant deviation from the theoretical sex ratio of 1:1, reinforcing the need for complementary studies that support environmental management decisions in the park through scientific evidence.(TRADUÇÃO NOSSA)