Fruit flies have found themselves in biology classes and genetics lab because fruit flies have well-understood genetics and short generational spans. This makes them ideal for research and demonstrations on hereditary traits. Several obvious characteristics of fruit flies follow traditional or Mendelian genetics. The apterous fruit flies has just such a trait.
Apterous Versus Vestigial
Apterous fruit flies' defining characteristic is their lack of wings. This contrasts with the wildtype fruit flies, which have fully functional wings. Additionally, apterous fruit flies are different from other flightless fruit flies. For example, vestigial-winged fruit flies possess stunted, deformed wings that don't allow for flight. Apterous flies have no wings whatsoever.
In traditional or Mendelian genetics, the gene for apterous flies is a recessive trait. This means that a fruit fly must get the gene for aptery from both parents. If the fly has a single copy of the gene for normal wings, it will mask the presence of the gene for aptery and the fly will develop normal wings. The apterous gene occurs on the flies' second chromosome, near the genes that control pigmentation.
The apterous gene has several other effects on the fly. The gene affects adipose or fatty tissue. Initially, it was believed that flies with the apterous gene would be short-lived and females would be sterile. However, several variations of the apterous gene exist, with differing effects. Still, most flies with this gene are short-lived, and most females are usually sterile. Most flies with this gene are more sluggish than their winged counterparts, or even vestigial-winged fruit flies.
The sluggish behavior of apterous fruit flies makes them unlikely to survive in the wild. Even active fruit flies find themselves at a grave disadvantage in the wild and often wind up as food. These flies can pretty much survive only in a biology lab or other captive situation since they cannot compete with other fruit flies for food. However, their sluggish, flightless behavior does make them, along with vestigial-winged flies, popular live food for reptiles and other pets.