This week (1-5 Feb, 2010), scientists are meeting at the International Atomic Energy Agency (IAEA) in Vienna, Austria to present recent developments and plan future research in male mosquito biology.
This is a critical topic for developing genetic control of mosquito vectors since all genetic programs require mating between wild mosquitoes and some type of modified mosquito that will be released. Competitiveness among males for mating with wild virgin females is an – perhaps THE most - important characteristic, but little has been known about what characteristics promote male competitiveness.
Furthermore, how does con-specific mate recognition occur between closely related forms such as the An. gambiae M and S molecular forms.
These two forms are known to segregate based on genetic data, but the means was not clear: is recognition olfactory, swarm timing, location, auditory?
Insight has been provided by two studies particularly: one on a possible mechanism by which individuals recognize similar molecular forms and another regarding the locations of swarms in natural settings .
Pennetier et al. recently reported that wingbeat matching between M and S types occurred less frequently than among M and S types: matching types sing the same song. Because tone matching reflects mating propensity, this provides a possible mechanism by which at least near-range mate recognition can occur. Great! We can imagine that as a female or male approaches a swarm, at some distance they can recognize whether or not it is their form.
Separate studies by Diabaté et al. have demonstrated that spatial swarm segregation occurs between the M and S forms. Previous studies had not clearly observed this phenomenon, but this two year study of mating swarms clearly established spatial segregation, if not the mechanism. At least part of the segregation may be due to the fact that swarm markers were important for the M form, but were not apparent for S forms.
Between these two lines of evidence, the challenges for genetic control of An. gambiae and the way forward are both clarified. It is clear that explicit targeting of the M and S types will require mosquitoes customized for each and is a complicating programmatic factor. It could be prohibitive if we had no knowledge of the characteristics that defined mating related behavior of each form to measure. Now we do.
The advantages of vector area-wide control make understanding mating biology an essential investment. The question of how M and S forms segregate that once seemed so formidable has become less daunting.
One yellow traffic signal on the road to genetic control of this species has just turned green.