Thread subject: Diptera.info :: Fly bubble blowing
Posted by Kahis on 05-04-2007 21:13
I suspect that the regurgitation is simply a mechanism to concentrate the fluid food by evaporation. Because nutrients are dilute in many fluid foods, this behavior relieves the excretory system of some of its work. Honey Bees extend tongues and develop a film of nectar, and the fanning of wings in the hive increases evaporation due to increased heat and air circulation--result: honey.
The problem I have with this idea is that it makes little sense from a physicist point of view. A spherical droplet is the worst possible geometry for evaporation; it has the smaller surface area for the volume. A thin film is much better for this purpose. Absorbing water and allowing it to evaporate from the tracheal system would be probably much more efficient. For most insects retaining enough water is a problem, not having too much of it :)