Experimental host preference of diapause and non-diapause induced Culex pipiens pipiens (Diptera: Culicidae).

Ary Faraji,Randy Gaugler

doi:10.1186/s13071-015-1012-1

Abstract

BackgroundCulex pipiens pipiens plays an important role in the transmission of several vector-borne pathogens such as West Nile virus (WNV) in North America. Laboratory and field studies suggest that this species is ornithophilic but because of genetic hybridization with sibling species during the active mosquito season, it may occasionally feed on mammals. Adult female Cx. p. pipiens undergo a facultative diapause and may serve as an overwintering mechanism for WNV. To determine the effect of diapause on the innate host preference of Cx. p. pipiens emerging from winter hibernation, we conducted host-choice experiments using bird and mammal hosts.MethodsMosquitoes were reared under non-diapause induced (NDI), diapause induced (DI), and field collected from overwintering (OW) hibernaculae. They were released into a large mesh enclosure housing two lard can traps, and given a choice between feeding on a dove or a rat.ResultsHost seeking Cx. p. pipiens were four times more likely to feed on the dove than the rat, regardless of experimental conditions. Under NDI conditions, Cx. p. pipiens were (p < 0.001) more attracted to the bird (79.9 % [75.6-84.1]) than the rat (20.1 [15.9-24.4]). Overwintering mosquitoes and those exposed to DI conditions were also significantly (p < 0.001) more attracted to birds (81.6 % [75.9-87.3]) than to rats (18.5 [12.7-24.2]).ConclusionsWe provide new information about the innate host preference of Cx. p. pipiens emerging from diapause in temperate habitats where winter survival is crucial for disease transmission cycles. Although we showed that Cx. p. pipiens prefers an avian to a mammalian host, nearly 20 % of emerging mosquitoes in the spring could feed on mammals. Changes in host preferences may also contain valuable clues about transmission dynamics and subsequent timely interventions by vector control and public health practitioners.

Highlights

Culex pipiens pipiens plays an important role in the transmission of several vector-borne pathogens such as West Nile virus (WNV) in North America
Host-choice experiments Host seeking Cx. p. pipiens were four times more likely to feed on rock doves than rats, regardless of experimental conditions (Table 1)
Our study shows that when offered a choice, Cx. p. pipiens strongly prefers an avian over a mammalian host

Summary

Introduction

Culex pipiens pipiens plays an important role in the transmission of several vector-borne pathogens such as West Nile virus (WNV) in North America. Louis encephalitis (SLE) are serious public and veterinary health concerns These viruses are primarily maintained in an enzootic cycle involving ornithophilic Culex mosquitoes and avian amplification hosts [1,2,3]. Culex pipiens pipiens L. has been incriminated as the primary enzootic vector of WNV and SLE throughout its geographic range [1, 2, 5, 6] This mosquito belongs to a complex of evolutionarily and morphologically closely related species which differ dramatically in biology, ecology, and vectorial capacity [2, 7]. Pipiens form pipiens develops in above ground larval habitats, mates in swarms within open areas, undergoes a facultative winter diapause, requires a blood meal to develop eggs, and primarily feeds on birds [2, 7, 9] Culex p. pipiens form pipiens develops in above ground larval habitats, mates in swarms within open areas, undergoes a facultative winter diapause, requires a blood meal to develop eggs, and primarily feeds on birds [2, 7, 9]

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