On how trap positioning affects phlebotomine sand fly density estimations

There is a need for standardizing sand fly sampling methodology and guidance on trap positioning for quantitative sand fly studies. We investigated differences in sand fly density with 'sticky' interception and CO₂ -light attraction traps, in relation to trap distance to the ground and the presence or absence of a continuous or discontinuous (wire mesh) vertical surface adjacent to the trap. The study, conducted in a dog kennel in southeast Spain, lasted 48 days and collected 692 Phlebotomus papatasi, P. perniciosus, P. ariasi and Sergentomyia minuta specimens. There were no significant differences between species with respect to trap position. Overall, density in sticky traps was highest closest to the ground and next to the continuous vertical surface, followed sequentially by traps similarly placed adjacent to the wire mesh and those hanging from a rope across the kennel yard. In contrast, density in CO₂ -light traps was highest in traps hanging from the rope near the ground, followed by those next to the continuous vertical surface. The overall negative relationship between sand fly density and ground distance was not significant for CO₂ -light traps next to the continuous vertical surface. Modelling also suggested that sand flies do not use the wire mesh to move vertically.