Temporal Bet-Hedging in Sand Fly Oviposition: Pharate Phlebotomus papatasi Sand Fly Neonates Regulate Hatching Time in Response to Organic Matter and Proximity to Conspecific Eggs.

In phlebotomine sand fly, the topic of the factors stimulating or inhibiting egg hatching has been largely ignored. In this study, we evaluated the hypothesis that pharate neonate sand flies are able to regulate their hatching time adaptively in response to cues indicative of the presence of food or potential competitors. In this study, we evaluated the independent and combined effects of organic matter (OM) extract and proximity to conspecific eggs on the hatching proportion of Phlebotomus papatasi eggs. In one set of larval rearing jars, we introduced 16 eggs into a small hole in the center of a plaster base of the jar. In another set, we introduced a single egg into each small hole of a 4-by-4 symmetrical array. To one set, we added an aqueous OM extract, and to the other, we added deionized water (DI). OM stimulated egg hatching while egg clustering slightly inhibited egg hatching. Results of this experiment are biologically important because they show, for the first time, that pharate sand fly neonates are able to adaptively regulate their hatching time in response to external cues.