Understanding sand fly sampling methods: sticky traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

Autor: Bakri Elnur, Omran F. Osman, Jorge Alvar, Altayeb Khogali, Margriet den Boer, Osman Dakein, Tayseer Jibreel, Hassan H. Edries, Bashir Alsharif, Mohamed Hassan, Noteila M. Khalid, Dia-Eldin A. Elnaiem, Hanan Elhadi
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Parasites & Vectors, Vol 13, Iss 1, Pp 1-15 (2020)
Parasites & Vectors
ISSN: 1756-3305
DOI: 10.1186/s13071-020-04249-1
Popis: BackgroundSticky traps are generally viewed as interceptive sand fly sampling methods; although no previous experimental evidence has supported this assumption. In this study, we tested this assumption experimentally forPhlebotomus orientalis, the principal vector of visceral leishmaniasis in East Africa, and propose an explanation for the highly male-biased collection of sticky traps.MethodsA number of field experiments were carried out in March–June 2016–2019, in Gedarif state, eastern Sudan. In the first experiment, we compared numbers ofP. orientaliscaught on sticky traps made of black, red, transparent, white, yellow, green and blue A4 size papers set simultaneously at different lunar light conditions. In the second and third experiments, we compared numbers ofP. orientaliscaptured on sticky traps placed side-by-side horizontally or vertically on the ground, or horizontally on a 15 cm height stool. We also witnessed mating behaviour of sand flies following their landing on un-sticky papers placed on the ground.ResultsPhlebotomus orientalisshowed significant attraction to white, yellow and transparent traps, with negligible numbers caught on the black and the red traps. Similarly, significantly higher numbers ofP. orientaliswere attracted to the horizontal traps, resulting in an 8-fold increase in sand fly trapping efficacy as compared to the vertical traps. Placing the traps on the stools resulted in significant reduction in this attraction. In contrast to the sticky traps that captured only very few females; we found that when male sand flies land on un-sticky white paper they successfully lure females and copulate with them.ConclusionsWe demonstrate that, forP. orientalis, sticky traps are more attractant-based than interception-based sampling tools. Further, our findings support the notion that males of this sand fly species likely utilize the bright surface of the trap papers to perform mating rituals that attract the females for copulation. However, pre-mature death in the sticky oil hampers the completion of these rituals, and thus results in failure to attract the females. These findings inform our understanding ofP. orientalisbehaviour and have important implications for optimization of sticky trap design for vector surveillance purposes.
Databáze: OpenAIRE
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