Oviposition Preferences of Culex Restuans and Culex Pipiens (Diptera: Culicidae) for Selected Infusions in Oviposition Traps and Gravid Traps

Abstract

Field studies were conducted in southwestern Virginia to determine the ovipositional preferences of Culex restuans and Culex pipiens by using ovitraps and gravid traps baited with selected infusions. For the ovitrap collections, 4 different infusions (manure, hay, grass, and rabbit chow) were used. Significant differences among infusions were detected on most sample dates for both species. For 3 of the first 4 wk of collections, the manure infusion collected significantly more Cx. restuans than all the other infusions. The hay and grass infusions collected the majority of the egg rafts during weeks 5-9. Cx. pipiens egg rafts were absent from the first 3 wk of collections. Of the remaining 6 wk, 4 showed significant differences in attractiveness of infusions, with the hay and grass infusions preferred by Cx. pipiens. Two infusions, manure and hay, were used for the gravid trap experiment and both Cx. restuans and Cx. pipiens data were combined for analysis. Only the first 2 wk showed significance, with manure being preferred over hay in both weeks. In later collections, the relative attractiveness of the hay infusion increased. A seasonal shift in infusion preference may be related to incubation temperature during preparation of the infusions. New infusions were prepared each week and incubation was done outside. Increased attractiveness of the hay infusion coincided with higher average temperatures in July and August. Hay infusion was very effective for trapping both Cx. pipiens and Cx. restuans in southwestern Virginia and is more convenient to use than manure. However, cool outside temperatures in the early season may interfere with the fermentation process and thus incubation should be done for a longer time or brought indoors.

Unexpected spatiotemporal abundance of infected Culex restuans suggest a greater role as a West Nile virus vector for this native species

“…restuans to Cx. pipiens, which has been shown to be related to increased WNV activity (Jackson et al, 2005;Kunkel et al, 2006;Lampman and Novak, 1996), is strongly dependent upon habitat type since it was only observed in the more developed sites. The lack of a seasonal crossover in the wetland sites is likely driven by the cooler and wetter conditions in these areas that are more favorable to Cx.…”

“…pipiens and has been shown to also effectively attract Cx. restuans (Jackson et al, 2005). One trap was used per location and traps were rotated weekly to avoid trap bias.…”

Overlap in the Seasonal Infection Patterns of Avian Malaria Parasites and West Nile Virus in Vectors and Hosts

“…restuans oviposition activity typically occurs earlier than Cx. pipiens, [52][53][54] although the two species may overlap extensively in some areas 55 ). Differences in the mosquito infection dynamics between CHI03PL and CHI06PL could be associated with seasonal changes in Culex composition if these Culex mosquitoes differ in their vector competence for these two Plasmodium species.…”

La Crosse Virus Field Detection and Vector Competence of Culex Mosquitoes

“…Mosquito collection and rearing for vector competence study. Culex egg rafts were collected using oviposition traps on the campus of Virginia Tech, Blacksburg, VA. 32 Aedes triseriatus eggs were collected using ovitraps placed in forested areas near the road at the entrance to Jefferson National Forest in Montgomery County, VA.…”