Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called “fruit flies”. One species of Drosophila in particular D.melanogaster, has been heavily used in research in genetics and is a common model organism in developmental biology. The entire genus, however, contains about 1,500 species and is very diverse in appearance, behavior, and breeding habitat. Scientists who study Drosophila attribute the species’ diversity to its ability to be competitive in almost every habitat, including deserts. (Ref to Book of Deepa Parvathi Va, Akshaya Amritha Sa, Solomon FD Paul).
Life cycle of Drosophila
Stages and duration:
Embryonic development, which follows fertilization and the formation of the zygote, occurs within the egg membrane. The egg produces larva, which eats and grows and at length becomes pupa. The pupa, in turn develops into an imago or adult. (Fig. 1) The duration of these stages
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A female drosophila can lay upto 500 eggs.
Drosophila is a holometabolous insect—that is, an insect that has a larval and a pupal stage prior to the adult stage. (Hemimetabolous insects, on the other hand, have nymph stages preceding the adult.) The adult Drosophila may live for more than 10 weeks. During this time, mating takes place. Fertilization is internal, and sperm are stored within the female’s body in a seminal receptacle and the paired spermathecae. Females reach the peak of their egg production between the fourth and seventh day after their emergence. During this time, they lay eggs almost continuously at a rate of 50–70 eggs per day.
The pupal stage lasts for 3–4 days, after which the adult fly, or imago, emerges from the pupal case (eclosion). Adult male flies are sexually active within hours of emerging, females don’t have ripe eggs until two days after eclosion, and the cycle begins