In biological research, transgenic fruit flies (Drosophila melanogaster) are model organisms used to study the effects of genetic changes on development. Fruit flies are often preferred over other animals due to their short life cycle, low maintenance requirements, and relatively simple genome compared to many vertebrates.
The first release of modified mosquitoes were performed in the 1970s. It was mosquitoes of the species that transmit the dengue virus, that were sterilised by irradiation (sterile insect technique).
The British company Oxitec use a technique called RIDL (Release of Insects with Dominant Lethality), that can produce fertile male adults that induce a high mortality of the descendants. The adults generated with this technique and released in the environment are not sterile but their descendants have a survival rate of 0% (this lethality can be switched off by introducing tetracycline into their diet). This company is currently(written 3/23/15) working on releasing these insects into Florida Keys, reducing the amount of wild insects that carry disease.
^Wise De Valdez, M. R.; Nimmo, D.; Betz, J.; Gong, H. -F.; James, A. A.; Alphey, L.; Black, W. C. (2011). "Genetic elimination of dengue vector mosquitoes". Proceedings of the National Academy of Sciences108 (12): 4772. doi:10.1073/pnas.1019295108.edit