Demography of the Gambian Epauletted Fruit Bat (Epomophorus gambianus) in Ghana.

Abstract

We provide the first estimates of survival and reproductive rates for a population of the Gambian Epauletted Fruit Bat Epomophorus gambianus in Ghana. We focused on a large colony of ca. 5,000 bats over 3 years to estimate population parameters including population size, birth rates, survival, and sex ratios for this species. Reproduction chronology was confirmed as seasonal bimodal polyestry, with births occurring in March/April and August/September each year. The estimated birth rate was 0.89 (95% CI = 0.85 to 0.92) per reproductive season. The overall sex ratio (female to male ratio) of the study population was male-dominated (0.69, 95% CI = 0.64 to 0.75), but female-biased for adults (62% female, χ² ₁ = 42, P < 0.0001), and showed temporal and age-specific variations. By radiotracking 60 bats for 10 months, we obtained the first estimates of minimum monthly survival for this species as 0.81 (95% CI = 0.74 to 0.86), but this could be an underestimate due to possible undetected emigration of tagged bats.