Abstract

Background: The development and implementation of innovative vector control strategies for
malaria control in Africa requires in-depth ecological studies in contained semi-field environments.
This particularly applies to the development and release of genetically-engineered vectors that are
refractory to Plasmodium infection. Here we describe a modified greenhouse, designed to simulate
a natural Anopheles gambiae Giles ecosystem, and the first successful trials to complete the life-cycle
of this mosquito vector therein.

Methods: We constructed a local house, planted crops and created breeding sites to simulate the
natural ecosystem of this vector in a screen-walled greenhouse, exposed to ambient climate
conditions, in western Kenya. Using three different starting points for release (blood-fed females,
virgin females and males, or eggs), we allowed subsequent stages of the life-cycle to proceed under
close observation until one cycle was completed.

Results: Completion of the life-cycle was observed in all three trials, indicating that the major lifehistory behaviours (mating, sugar feeding, oviposition and host seeking) occurred successfully.
Conclusion: The system described can be used to study the behavioural ecology of laboratoryreared and wild mosquitoes, and lends itself to contained studies on the stability of transgenes,
fitness effects and phenotypic characteristics of genetically-engineered disease vectors. The
extension of this approach, to enable continuous maintenance of successive and overlapping insect
generations, should be prioritised. Semi-field systems represent a promising means to significantly
enhance our understanding of the behavioural and evolutionary ecology of African malaria vectors
and our ability to develop and evaluate innovative control strategies. With regard to geneticallymodified mosquitoes, development of such systems is an essential prerequisite to full field releases.