Habitat Associations Shape Phlebotomine Sand Fly Assemblages at the Andes–Amazon Interface in Southeastern Peru

Phlebotomine sand flies, vectors of Leishmania parasites, remain poorly studied in southeastern Peru, a region with a high burden of cutaneous leishmaniasis (CL). Using modified UV light traps, we surveyed sand fly assemblages across four habitat types at Manu Biological Station during the wet season (March–May 2023): secondary forest, Guadua bamboo forest, fruit crop plots, and peridomicile habitats. A total of 2,641 sand flies representing 32 species were collected, with females comprising 74.5% of captures. Habitat type was the primary driver of assemblage composition, with minimum nightly temperature as the strongest environmental correlate. Sand fly abundance was highest in secondary forest (n = 921) and peridomicile habitats (n = 836), where assemblages were dominated by Nyssomyia shawi, a generalist species also captured indoors. Although Guadua bamboo forests harbored lower total abundance (n = 386), potential vector species comprised 92% of the assemblage compared to 42–86% in other habitats, and communities exhibited greater evenness. These findings suggest that expanding bamboo forests may pose an underrecognized risk for CL transmission. Additionally, peridomicile assemblages consisted largely of generalist species overlapping with adjacent forested habitats, indicating potential pathways for sylvatic-to-peridomestic spillover. Our findings underscore the importance of habitat-specific assemblage structure and vector dominance in shaping spatially heterogeneous transmission risk and highlight the need for habitat-targeted surveillance strategies in dynamic Amazonian landscapes.