Department of Entomology and Plath Pathology, North Carolina State University, Raleigh, NC.
Department of Biology, University of North Carolina at Greensboro, Greensboro, NC.
J Med Entomol. 2021 Mar 12;58(2):518-527. doi: 10.1093/jme/tjaa198.
Phlebotomine sand flies are worldwide vectors of Leishmania parasites as well as other bacterial and viral pathogens. Due to the variable impact of traditional vector control practices, a more ecologically based approach is needed. The goal of this study was to isolate bacteria from the most attractive substrate to gravid Phlebotomus papatasi Scopoli sand flies and determine the role of bacterial volatiles in the oviposition attractancy of P. papatasi using behavioral assays. We hypothesized that gravid sand flies are attracted to bacterially derived semiochemical cues associated with breeding sites. Bacteria were isolated from a larvae-conditioned rearing medium, previously shown to be highly attractive to sand flies. The isolated bacteria were identified by amplifying and sequencing 16S rDNA gene fragments, and 12 distinct bacterial species were selected for two-choice olfactometer bioassays. The mix of 12 bacterial isolates elicited strong attraction at the lower concentration of 107 cells per ml and significant repellence at a high concentration of 109 cells per ml. Three individual isolates (SSI-2, SSI-9, and SSI-11) were particularly attractive at low doses. In general, we observed dose-related effects, with some bacterial isolates stimulating negative and some positive dose-response curves in sand fly attraction. Our study confirms the important role of saprophytic bacteria, gut bacteria, or both, in guiding the oviposition-site selection behavior of sand flies. Identifying the specific attractive semiochemical cues that they produce could lead to development of an attractive lure for surveillance and control of sand flies.
白蛉是一种世界性的利什曼原虫寄生虫以及其他细菌和病毒病原体的传播媒介。由于传统的病媒控制措施效果不一，因此需要一种更具生态学基础的方法。本研究的目的是从对致倦库蚊最具吸引力的基质中分离细菌，并通过行为测定来确定细菌挥发物在致倦库蚊产卵吸引力中的作用。我们假设，致倦库蚊会被与繁殖地有关的细菌来源的半化学物质线索所吸引。从先前已被证明对致倦库蚊具有高度吸引力的幼虫饲养条件培养基中分离细菌。通过扩增和测序 16S rDNA 基因片段对分离出的细菌进行鉴定，并选择 12 种不同的细菌用于双选择嗅觉计生物测定。12 种分离菌的混合物在较低浓度 107 个细胞/毫升时引起强烈的吸引力，而在较高浓度 109 个细胞/毫升时则产生显著的驱避作用。三个单独的分离物（SSI-2、SSI-9 和 SSI-11）在低剂量时特别有吸引力。总的来说，我们观察到剂量相关的效应，一些细菌分离物在致倦库蚊吸引力方面刺激了负的和一些正的剂量反应曲线。我们的研究证实了腐生细菌、肠道细菌或两者都在指导白蛉产卵地选择行为方面的重要作用。确定它们产生的特定有吸引力的半化学物质线索可能会导致开发出一种有吸引力的诱饵，用于监测和控制白蛉。
