The Sterile Insect Technique for Controlling Populations of Aedes albopictus (Diptera: Culicidae) on Reunion Island: Mating Vigour of Sterilized Males

Abstract

Reunion Island suffers from high densities of the chikungunya and dengue vector Aedes albopictus. The sterile insect technique (SIT) offers a promising strategy for mosquito-borne diseases prevention and control. For such a strategy to be effective, sterile males need to be competitive enough to fulfil their intended function by reducing wild mosquito populations in natura. We studied the effect of irradiation on sexual maturation and mating success of males, and compared the sexual competitiveness of sterile versus wild males in the presence of wild females in semi-field conditions. For all untreated or sterile males, sexual maturation was completed within 13 to 20 h post-emergence and some males were able to inseminate females when 15 h old. In the absence of competition, untreated and sterile males were able to inseminate the same number of virgin females during 48 h, in small laboratory cages: an average of 93% of females was inseminated no matter the treatment, the age of males, and the sex ratio. Daily mating success of single sterile males followed the same pattern as for untreated ones, although they inseminated significantly fewer females after the ninth day. The competitiveness index of sterile males in semi-field conditions was only 0.14 when they were released at 1-day old, but improved to 0.53 when the release occurred after a 5-day period in laboratory conditions. In SIT simulation experiments, a 5∶1 sterile to wild male ratio allowed a two-fold reduction of the wild population’s fertility. This suggests that sterile males could be sufficiently competitive to mate with wild females within the framework of an SIT component as part of an AW-IPM programme for suppressing a wild population of Ae. albopictus in Reunion Island. It will be of interest to minimise the pre-release period in controlled conditions to ensure a good competitiveness without increasing mass rearing costs.

Declining malaria, rising of dengue and Zika virus: insights for mosquito vector control

“…Besides radiation, transgenic and symbiont-based control approaches (e.g. Wiwatanaratanabutr et al 2010;Oliva et al 2012;Moretti and Calvitti 2013;see Bourtzis et al 2016 for a dedicated review), an effective option readily available in tropical and subtropical areas worldwide may be the employ of biological control agents of Culicidae young instars, in the presence of ultra-low quantities of nanoformulated botanicals, which boost their predation rates (e.g. Murugan et al 2015b, c;Subramaniam et al 2016).…”

“…In particular, the majority of the studies focused on the sexual behaviour of medically important Aedes species focused on comparisons of insemination ability in sterilized and wild males (e.g. Balestrino et al 2010;Wiwatanaratanabutr et al 2010;Boyer et al 2011;Oliva et al 2012;Bellini et al 2013;Hamady et al 2013;Moretti and Calvitti 2013;Madakacherry et al 2014), without behavioural quantification of courtship and mating events (but see Oliva et al 2013;Benelli 2015c;Benelli et al 2015). Notably, limited information is also available on the potential molecules mediating aggregation and mating dynamics in mosquitoes (Cabrera and Jaffe 2007;Fawaz et al 2014;Pitts et al 2014).…”

Seasonal variation in size estimates of Aedes albopictus population based on standard mark–release–recapture experiments in an urban area on Reunion Island

“…It has been applied worldwide to effectively control a variety of insect species of veterinary, human health, and agricultural importance (Klassen and Curtis, 2005;Vreysen et al, 2007). Currently, several SIT feasibility studies are being developed for the release of irradiated males to effectively reduce vector activity and limit insecticide applications in Europe (Bellini et al, 2007), African continent (Malcolm et al, 2009) and in the Islands of the southwest of the Indian Ocean (Oliva et al, 2012). The geographical isolation makes Reunion Island a suitable testing ground for demonstrating the efficacy of SIT against Ae.…”

Impact of environmental factors on mosquito dispersal in the prospect of sterile insect technique control

“…When ρ s is close to 0, the release is not appropriate, whereas an optimal release corresponds to ρ s = 1. Finally, parameter f s represents the sexual competitivity of sterile males [40]. Thus, ρ s Λ s may represent the release of "efficient" sterile males.…”