Résumé
Innovative control tools are needed against Aedes mosquitoes. The boosted sterile insect technique (bSIT) consists of treating sterile males with a biocide prior to their release to contaminate larval habitats. We compared the efficacy of SIT and boosted SIT to prevent the emergence of adult Aedes albopictus in large cages. We tested two sterile-to-fertile male ratios: 5:1 (SIT5) and 1:1 (SIT1), with and without pyriproxyfen enhancement (bSIT or SIT). The eggs were collected in ovitraps and the immature stages were monitored until adult emergence or up to 15 days after hatching to estimate the relative risk (RR) of adult emergence compared to the control category. The concentration of pyriproxyfen in the ovitrap water did not change when sterile males were released with females or alone (chi 2 = 0.99, df = 1, p = 0.547). This concentration was higher when the sterile-to-fertile male ratio was increased from 1:1 to 5:1: chi 2 = 18.8, df = 1, p = 0.006. All four treatment categories were effective in suppressing mosquito populations. With a relative risk RR = 0.194 95% CI [0.128; 0.275], SIT5 was the most effective. Boosted SIT was not as effective as SIT. However, bSIT1 (RR = 0.418 [0.351; 0.492]) and bSIT5 (RR = 0.512 [0.431; 0.596]) were equally effective. Boosted males directly vectored pyriproxyfen to breeding sites. Boosted SIT was more effective than SIT alone with a low sterile-to-fertile male ratio. Under operational conditions, it could be initially deployed to suppress the target population and then switched to standard SIT.
Des outils innovants sont n & eacute;cessaires pour lutter contre les moustiques Aedes. La technique de l'insecte st & eacute;rile renforc & eacute;e (TIS-R) consiste & agrave; traiter les m & acirc;les st & eacute;riles avec un biocide avant leur l & acirc;cher afin de contaminer les g & icirc;tes larvaires. Nous avons compar & eacute; l'efficacit & eacute; de la TIS et de la TIS-R pour pr & eacute;venir l'& eacute;mergence d'Aedes albopictus adultes dans de grandes cages. Nous avons utilis & eacute; deux ratios entre m & acirc;les st & eacute;riles et fertiles : 5:1 (TIS5) ou 1:1 (TIS1), trait & eacute;s ou non par du pyriproxyf & egrave;ne (TIS-R5 et TIS-R1). Les oe ufs ont & eacute;t & eacute; collect & eacute;s dans des pi & egrave;ges & agrave; oviposition et les stades immatures ont & eacute;t & eacute; surveill & eacute;s jusqu'& agrave; l'& eacute;mergence des adultes ou jusqu'& agrave; 15 jours apr & egrave;s l'& eacute;closion afin d'estimer le risque relatif (RR) d'& eacute;mergence des adultes par rapport & agrave; la cat & eacute;gorie t & eacute;moin. La concentration de pyriproxyf & egrave;ne dans l'eau des pi & egrave;ges & agrave; oviposition n'a pas chang & eacute; lorsque les m & acirc;les st & eacute;riles & eacute;taient l & acirc;ch & eacute;s avec les femelles, ou seuls (chi 2 = 0,99, df = 1, p = 0,547). Cette concentration & eacute;tait plus & eacute;lev & eacute;e lorsque le rapport entre m & acirc;les st & eacute;riles et fertiles passait de 1 & agrave; 5 : chi 2 = 18.8, df = 1, p = 0,006. Les quatre traitements ont permis de supprimer les populations de moustiques. La TIS-R5 s'est av & eacute;r & eacute;e la plus efficace : RR = 0,194 [0,128; 0,275]. La TIS-R n'& eacute;tait pas aussi efficace que la TIS. Cependant, la TIS-R1 (RR = 0,418 [0,351; 0,492]) et la TIS-R5 (RR = 0,512 [0,431; 0,596]) & eacute;taient d'efficacit & eacute; similaire. Les m & acirc;les trait & eacute;s ont directement transmis le pyriproxyf & egrave;ne aux g & icirc;tes larvaires. La TIS renforc & eacute;e s'est av & eacute;r & eacute;e plus efficace que la TIS standard avec un ratio entre m & acirc;les st & eacute;riles et fertiles peu & eacute;lev & eacute;. En conditions op & eacute;rationnelles, elle pourrait & ecirc;tre utilis & eacute;e en d & eacute;but de lutte pour supprimer la population cible, puis remplac & eacute;e par la TIS standard.