We know very little about the natural biology of the transposable elements we use to transform these species yet are challenged to predict, with little or no data, how these elements will behave in their new host species so that sensible assessments of risk associated with transgenesis can be formulated.
Furthermore, one of the pivotal questions concerning the use of transposable elements as gene vectors in insects—their ability to spread beneficial genes through insect populations—still remains unanswered.
These questions are large, but tractable to experimental analysis, and the next few years should witness considerable progress being made toward their resolution.