Analysis of COI gene, prevalence, and intensity of the bat fly on roosting straw-coloured fruit bat in Southwest Nigeria.

We investigated ectoparasite diversity, interspecific infestation rates and host preference in roosting fruit bats, , from Bowen University, Southwest Nigeria. Fur of captured were sampled monthly for ectoparasites from January 2021 to June 2022. We examined a total of 231  and observed a significant female to male adult sex ratio (0.22:1); with 53.9% ectoparasitic infestation rate. We identified and enumerated the ectoparasite; and subjected its Cytochrome oxidase subunit I (COI) gene to phylogenetic analysis with other nycteribiids. COI gene sequences obtained formed a distinct clade with other sequences. We recovered a total of 319 (149 female and 170 male) ectoparasites and observed a balanced female to male adult sex ratio of 0.88:1. Ectoparasitic sex distribution had no association with host sex and season. Prevalence was significantly higher during the wet season, but not between sexes of . The intensity of infestation, 3.7 ± 0.4 individuals per fruit bat, was significantly higher during the wet season with a bimodal seasonal distribution. The strongly male-biased host adult sex ratio had no significant influence on metapopulation adult sex ratio.