Although injection of large volumes and amounts of dsRNA into insects is somewhat of a blunt instrument for performing reverse genetics, it has been used with great success in many systems while in others it has been less useful.
Stage and tissue limitations are commonly seen and these may be due to rapid degradation of dsRNA, inaccessibility of the dsRNA to the target cells, failure of the dsRNA to be taken up by the target cells etc.
Zhu et al. (2014) report successfully injecting dsRNA into the hemolymph of Culex quinqifaciatus and successfully silencing genes expressed in the antenna of the adult.
Zhu et al. make some estimates of the stability of their dsRNA in the hemolymph ex vivo, and found it to be stable after 3 hour incubations. Likewise the authors report decreases in transcription of their target odorant receptor genes in the antenna when sampled at 9 days post eclosion. Not surprisingly there was high variance associated with these measurements.
The authors’ technical approach is not entirely new but it does provide another useful example.
RNAi-based demonstration of direct link between specific odorant receptors and mosquito oviposition behavior.
Fen Zhu, Pingxi Xu, Rosângela M.R. Barbosa, Young-Moo Choo, Walter S. LealInsect Biochemistry and Molecular Biology
Volume 43, Issue 10, October 2013, Pages 916–923 DOI: 10.1016/j.ibmb.2013.07.008