Research
Since I no longer work on this subject, this page is no longer maintained and thus outdated.
The fruitfly, Drosophila, is a widely used organism for biological research. It is readily caught in the wild, occurs at almost any place on earth in diverse habitats, and is easily bred in the laboratory. Especially the latter character has stimulated the interest in the use of Drosophila for research, due to the easy breeding conditions, short generation cycle (approx. two weeks at 25°C for D. melanogaster), and high offspring numbers. Therefore, a lot of the genetics, ecology, and molecular properties of this organism is known. (see Flybase for more information on Drosophila).
Stress is usually considered to have a negative effect on an organism. What this effect is and how it acts on the organism is generally not known or only in rather vague terms. Recently, interest in the molecular and evolutionary mechanisms of stress has increased. The most widely researched stress type is heat stress, although other stresses as starvation and contamination receive a lot of attention as well. A large amount of data on heat-stress resistance in Drosophila is available. At this time, most attention is directed towards the molecular mechanisms of stress resistance, in particular the regulation and expression of the heat-shock proteins
When applying heat stress to an organism, a pretreatment with shorter and/or colder treatment almost always has beneficial effects on the resistance to heat stress later on. The beneficial effects of this process, termed heat hardening or heat acclimation are widely known and accepted. Less is known about the negative effects of such a pretreatment. A small amount of data is available showing that a pretreatment that increased resistance at the same time reduces fecundity and growth.
Recently, it has been shown that the assumption, that stress always has negative effects on the organism, is wrong. A small amount of heat stress applied on Drosophila actually increased the life-span of these organisms. This leaves open many questions about the evolution of many life history characters in almost all living organisms.
