Species Diversity and Abundance of Tabanid Flies (Diptera: Tabanidae) and Its Potential Implications on Animal and Human Health in Osun State, Nigeria

Abstract

Tabanid flies (Diptera: Tabanidae) are important hematophagous vectors involved in the transmission of diseases affecting humans and animals, yet their diversity and distribution remain poorly documented in Osun State, southwestern Nigeria. This study investigated the species composition, abundance, and seasonal dynamics of tabanid flies across selected communities in the state. Entomological surveys were conducted from February 2025 to January 2026 in three local government areas namely Ife-South, Odo-Otin, and Ejigbo, using Nzi traps deployed in ecologically suitable habitats. Collected specimens were morphologically identified using standard taxonomic keys. Abundance was expressed as apparent density per trap per day (ADT), while spatial and seasonal variations were analyzed using descriptive statistics and the Kruskal–Wallis H test. A total of 135 female tabanid flies were collected, representing eight species across four genera: Chrysops, Tabanus, Ancala and Haematopota. Chrysops was the dominant genus (ADT: 0.340 flies/trap/day), with Chrysops distinctipennis constituting 63% of all captures. Ore recorded the highest abundance (ADT: 0.378 flies/trap/day), followed by Ifetedo (0.069) and Ife-Odan (0.021), although spatial differences were not statistically significant (p > 0.05). Tabanid abundance was strongly seasonal, with 89.6% of captures occurring during the wet season and peak densities observed in July and August (1.458 flies/trap/day). The predominance of Chrysops spp., recognized vectors of loiasis, indicates moderate to high transmission risk, particularly during the wet season, while the presence of multiple Tabanus species suggests potential implications for African animal trypanosomiasis. These findings provide baseline evidence for vector surveillance and integrated control strategies in Osun State.