Cytoplasmic Incompatibility as a Means of Controlling Culex pipiens quinquefasciatus Mosquito in the Islands of the South-Western Indian Ocean

Abstract

The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands.

Tsetse-Wolbachia symbiosis: Comes of age and has great potential for pest and disease control

“…Second, Wolbachia -induced CI could also be used as a spreading/replacement mechanism for desired phenotypes, because infected females have a reproductive advantage over uninfected females, since they can mate with both uninfected and infected males thus invading populations in nature (Bourtzis, 2008; Bourtzis and Robinson, 2006; Bourtzis and O’Neill, 1998; Brelsfoard and Dobson, 2009; Dobson et al, 2002; Hoffmann et al, 1998; Rasgon, 2008, 2007; Sinkins and Gould, 2006). Wolbachia -based suppression and/or replacement approaches have been documented with insect vector species (the mosquito species: Culex pipiens species complex, Aedes aegypti , Aedes albopictus ) under laboratory, semi-field or field conditions (Atyame et al, 2011; Chambers et al, 2011; Hoffmann et al, 2011; Laven, 1967; Ruang-Areerate and Kittayapong, 2006; Walker et al, 2011; Xi et al, 2005). Most of the above-mentioned examples were based on host transinfection via embryonic cytoplasmic injections.…”

Symbiotic control of mosquito borne disease

“…IIT has been successfully developed for some major agricultural pests 48,49 and recently has also been explored for its effectiveness in the control of mosquito populations in the field. Recently, Atyame and collaborators 50 showed that the wPip(Is) Wolbachia strain, naturally infecting Culex pipiens pipiens from Turkey, can be used in the context of IIT to sterilize Cx. p. quinquefasciatus females from several islands of the southwestern Indian Ocean, confirming the feasibility of IIT in mosquito control.…”

Naturally Occurring Incompatibilities between Different Culex pipiens pallens Populations as the Basis of Potential Mosquito Control Measures

“…Infection with Wolbachia has been reported in many species, including some disease vectors such as Aedes albopictus and Culex quinquefasciatus ( =  Cx. pipiens fatigans ) [15], [21], [30]. For naturally uninfected insects, artificial Wolbachia infection would generate an incompatible strain that could be used to suppress target populations [28].…”

“…Wolbachia -infected mosquito strains that display novel patterns of CI for population suppression are usually created by introgression or transinfection [30]–[32]. The preparation of incompatible mosquitoes using such methods is often laborious and time-consuming.…”