All-in-One Mosquito Containers: From the Laboratory to the Release Sites

Abstract

Integrated vector control programs that use a Sterile Insect Technique approach require the production and release of large numbers of high quality, sterile male insects. In pilot projects conducted worldwide, sterile males are usually kept in containers at low densities until their manual release on the ground. Although the quality of the released insects is high, these containers are only suitable for small-scale projects, given the fact that the manual labor required for release is significant and therefore untenable in large-scale projects. This study will compare and contrast the quality of the males reared in the proposed "all-in-one" containers which considerably reduce both the handling of the insects and the manual labor required for release. As a result, project costs are lower. The design of these "all-in-one" containers incorporates two important features: ventilation and the density of the vertical resting surface. Having evaluated both features, it can be concluded that ventilation does not directly affect the quality of the insects, at least in the range of dimensions tested. However, the quality of the male insects is reduced in relation to an increase in the number of mosquitoes, with 500 being the optimum quantity of mosquitoes per "all-in-one" container.

Keywords: Sterile Insect Technique (SIT); automated; container; culicidae; genetic control of vectors; release.

Figure 1

Two-piece tube container featuring an external piece: pipe connection socket; and an internal piece: two methacrylate rings joined together by eight methacrylate strips.

Figure 2

Effect estimates and standard errors derived from the adjusted model of different densities of mosquitoes on two parameters: Probability of death during confinement (Pmort, left) and probability of survival under stress (Psurv, right). Four densities of mosquitoes (number of pupae loaded and resting density of vertical surface in mosquito/cm² between parentheses) evaluated against the control container. Table: parameter estimation for the effects of different densities of mosquitoes on two parameters with mixed model logistic regression. Asterisks indicate statistical significance compared with the control (α-level 0.05).

Figure 3

Kaplan–Meier plot to illustrate the survival of male mosquitoes in two different containers. Shaded areas show 95% confidence intervals. Crosses show censored individuals.