Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

Eliningaya J Kweka,Mramba Nyindo,Andrew K Githeko,Stephen Munga,Leila B Beilhe,Thomas M Gilbreath,Amruta Dixit,Guiyun Yan,Yaw Afrane,Goufa Zhou

doi:10.1186/1756-3305-5-33

Abstract

BackgroundThe effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between An. gambiae s.s. and Cx. quinquefasciatus on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions.MethodsExperiments were set up with three combinations; Cx. quinquefasciatus alone (single species treatment), An. gambiae s.s. alone (single species treatment); and An. gambiae s.s. with Cx. quiquefasciatus (co-habitation treatment) in different densities in semi field situation.ResultsThe effect of co-habitation of An. gambiae s.s. and Cx. quinquefasciatus was found to principally affect three parameters. The wing-lengths (a proxy measure of body size) of An. gambiae s.s. in co-habitation treatments were significantly shorter in both females and males than in An. gambiae s.s single species treatments. In Cx. quinquefasciatus, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both An. gambiae s.s. and Cx. quinquefasciatus. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co-habitation treatments more females emerged than males. In this study, there was no significant competitive survival advantage in co-habitation.ConclusionThese results suggest that co-habitation of An. gambiae s.s. and Cx. quinquefasciatus in semi-natural conditions affect mostly An. gambiae s.s. body size. Hence, more has to be understood on the effects of co-habitation of An. gambiae s.s. and Cx. quinquefasciatus in a natural ecology and its possible consequences in malaria and filariasis epidemiology.

Highlights

The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat
In African mosquito ecology, immature stages of Anopheles gambiae s.s. and Culex quinquefasciatus are frequently found to co-occur in diverse habitats such as drainage ditches, swamps and abandoned goldmines [7,8,9,10,11]
At a density of 60 was there more Cx. quinquefasciatus that survived in a single species treatment than in co-occurrence treatment (Figure 1)

Summary

Introduction

The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. In African mosquito ecology, immature stages of Anopheles gambiae s.s. and Culex quinquefasciatus are frequently found to co-occur in diverse habitats such as drainage ditches, swamps and abandoned goldmines [7,8,9,10,11] In mosquito species, such as An. gambiae, An. stephensi, Aedes aegypti, and Cx. pipiens, the effects of both abiotic and biotic factors on immatures have been documented to have an influence on life history traits and subsequent adult fitness [12,13]. Interspecific competition that can be investigated with co-habitation species could lead in some cases to competitive displacement of local population [20,21]; based upon certain ecological principles that state that different species cannot simultaneously occupy the same niche

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