Some time back I reported on an effort to use sterile male releases to control disease spread by tsetse fly in Ethiopia–and why it probably was a doomed effort.

Another bit of evidence in today’s Science: a letter pointing out that flies reared in colonies are inadvertently selected to be most successful in the laboratory, not the wild:

“The compatibility and competitiveness of laboratory-reared tsetse for release into wild populations are concerns that have been raised previously in behavioral (1) and physiological work (2, 3). Substantial differences are typically found between natural populations and colony-reared flies, ranging from physiological tolerance of lethal temperatures to mating compatibility. Moreover, feeding behavior in tsetse appears to be a learned response obtained during early adult development (4), suggesting that laboratory-reared flies raised on artificial membranes may not feed on wild animals. Thus, they would not survive for more than a few days in the wild. Similarly, caged rearing conditions are known to be deleterious to flight and locomotor performance because flight muscle development is restricted, which in turn may limit mating success in the wild (5). Other work on insects has shown that laboratory adaptation substantially alters animal performance (6). “

–Factory Flies Are Not Equal to Wild Flies. John S. Terblanche and Steven L. Chown. Science 21 September 2007: 1678.

This has always been a problem with species reared in captivity, and not just those with 6 legs.

(I’m in love with Google Books right now, so I expect I’ll keep referencing some of my favorites that I can now get online.)