Within-morning dynamics of filarial infection in breeding village weavers ( Ploceus cucullatus ): Sex-biased patterns and implications for host condition

Microfilariae are blood parasites transmitted by hematophagous vectors, yet short-term, within-morning dynamics of the infection in wild passerines are poorly understood. This study aimed to (i) assess within-morning fluctuations in microfilariae prevalence and intensity in breeding adult village weavers ( Ploceus cucullatus ), and (ii) evaluate the influence of infection on host body condition (reflected in their body mass). A total of 124 birds (72 males, 52 females) were trapped in the Amurum Forest Reserve, Nigeria, using mist nets during early, mid-, and late-morning intervals. Microfilariae were detected via the buffy coat method, and body condition was estimated from body mass. Overall, 94.4% of males and 30.8% of females were infected. Contrary to our hypothesis that early-morning captures would predominantly sample filaria-free birds, prevalence and intensity peaked in mid-morning, especially in males (P < 0.05). Infected males were consistently in better condition than uninfected males, indicating trade-offs favoring reproductive investment over immune defense, whereas infected females exhibited a mid-morning reduction in body mass, likely reflecting the energetic costs of infection. These results reveal pronounced sex-biased infection patterns and highlight temporal variation in host activity and condition, with implications for sampling and understanding host-parasite interactions in wild passerines.