Effects of λ-cyhalothrin on the behavior and physiology of Leschenault's rousette bat (Rousettus leschenaultii)

In addition to exerting direct toxic effects, pesticides disrupt the complex physiology and behavioral patterns of bats. Previous studies have focused on quantifying pesticide residues in bats. However, limited studies have examined the effects of pesticides on acoustic behavior, auditory health, and gene expression in bats. This study examined the effects of λ-cyhalothrin on vocalization, auditory health, and gene expression in Rousettus leschenaultii by integrating behavioral, cochlear pathological, and transcriptomic analyses. Exposure to low and high concentrations of λ-cyhalothrin increased the frequencies of social calls in R. leschenaultii. Histological analysis revealed that λ-cyhalothrin induced tympanic canal bleeding, Reissner's membrane rupture, and cell shedding in the tectorial membrane and the organ of Corti. Transcriptomic analysis revealed that λ-cyhalothrin significantly altered the enrichment of genes in Gene Ontology entries, especially those related to actin, transport protein for sodium-potassium ion channel, and the calcium pathway. These results suggest that λ-cyhalothrin exposure alters social calls in R. leschenaultii by inducing pathological damage and dysregulating gene expression in the cochlea. Thus, there is an urgent need to develop sustainable agricultural practices to mitigate pesticide impacts on bats and their ecological roles.