Aphids are sap-sucking insects of great economic importance, and recently the pea aphid Acyrthosiphon pisum had its genome sequenced and annotated. Insect genetic technologies are in high demand for this insect but it is proving to be a real challenge.
Perhaps the simplest insect genetic technology is the wholesale injection of specific dsRNA into the hemocoel of insects resulting in silencing of target genes in at least some tissues. This is a rather blunt but effective tool for probing functional genomic questions.
This approach has been met with considerable frustration by scientists working on aphids. RNAi-based silencing was not particularly effective in some cases.
Christiaens et al. report that both the hemolymph and midgut contain dsRNA degrading activities.
Christiaens O, Swevers L, Smagghe G: DsRNA degradation in the pea aphid (Acyrthosiphon pisum) associated with lack of response in RNAi feeding and injection assay. Peptides 2014, 53:307-314. DOI: 10.1016/j.peptides.2013.12.014