Drosophila melanogaster

Its biology links two very different stages: a feeding, worm-like larva and a flying adult that finds food and egg-laying sites through chemical cues.

Adult males are generally smaller than females and have a darker, more rounded abdomen.

Males also carry dark sex combs on the front legs, visible under magnification.

Small larvae have dark mouth hooks at the head.

Body colour is also a genetic trait: the yellow gene contributes to cuticle pigmentation, and its disruption can alter the normal dark pattern.

Females lay fertilised eggs after mating and can retain sperm from an earlier mating.

Development proceeds through egg, larva and pupa before the adult emerges, a sequence called complete metamorphosis.

The larval period has three instars, during which feeding and growth precede the transition to a pupa.

Before pupation, mature larvae move away from the food.

Development time varies with temperature.

The future wing develops from an imaginal disc, a growing group of cells present during larval life.

These cells increase their biomass as well as divide; making more cells and making a larger tissue are related but distinct processes.

Ecdysone, an insect hormone, helps coordinate disc growth with the transition into metamorphosis.

In a controlled study of larvae with reduced endogenous ecdysone production, restoring hormone signalling allowed wing discs to resume proliferation.

At a maintained hormone level, the discs eventually stopped growing, showing that continued exposure did not cause unlimited growth.

Fermenting fruit is more than a sugary surface: it contains yeasts that provide food for developing larvae.

Adults respond to volatile chemicals associated with yeast fermentation, connecting smell with the search for suitable resources.

Experiments with winery-derived D. melanogaster lines found that several yeast species supported development.

One tested yeast, Pichia kluyveri, delayed development in those lines, even though it attracted adults and encouraged egg laying.

Attraction and nutritional performance therefore need not point to the same preferred partner.

Drosophila is useful for studying inheritance because researchers can compare recognisable traits across controlled crosses and successive generations.

Pigmentation provides one such connection between a visible feature and a named gene, while wing-disc experiments connect organ growth to hormonal signalling.

The fly also offers a way to study how an animal’s development depends on the microbes in its food, not just on its own genes.

The organism is NCBI Taxonomy 7227, a species-level Drosophila record; the pigmentation example is the separate FlyBase gene record FBgn0004034, named yellow.

The inspected FlyBase report displays FB2026_02 and a Gene Snapshot review date of 28 May 2026.

Its pigmentation annotations include mutant-phenotype evidence, whereas the suggested structural role of Yellow is expressed as a possibility rather than a demonstrated enzymatic activity.

Quan and Eisen profiled fungi on winery flies and tested D. melanogaster lines.

The field analysis included D. simulans, so its pooled fungal frequencies are not D. melanogaster-only estimates.

Strassburger and colleagues reduced ecdysone synthesis by targeting spookier and then restored signalling experimentally in third-instar larvae.

They distinguished DNA-synthesis-associated proliferation from protein-synthesis-associated growth using different readouts.

The experiment supports a conditional relationship between hormone signalling and wing-disc growth, not a rule that increasing a hormone always increases an intact adult’s size.