How to culture Drosophila melanogaster

 

INTRODUCTION

Drosophila melanogaster is a tiny, common insect that lives near rotten or unripe fruit. It is used for research in genetics and behavior for more than a century. Drosophila melanogaster goes through a complete metamorphosis, which comprises an egg, larva, pupa, and then emergence as a flying adult. Drosophila melanogaster eggs are not fertilized immediately after mating with male flies. During mating, female Drosophila melanogaster receive and store sperm in their sperm storage reservoirs, known as the seminal receptacle and spermatheca. Drosophila melanogaster sperm are "giant sperm," measuring 1.76 mm in length, 300 times longer than human sperm. Sperm can be stored for up to two weeks inside the bodies of female flies, with those stored in the seminal receptacle being used first, followed by those stored in the spermatheca. Sperm and egg fusion occurs only when the egg is going to be laid. The entire sperm penetrates the egg at the anterior pole, and the embryo's growth is seen in the gut area. The chorion is an opaque outer membrane that coats the egg's translucent and chitinous vitelline membrane. A pair of filaments protrude from the egg's anterodorsal surface. This pair of filaments keeps the egg from sinking into soft food where it might be placed. Drosophila melanogaster's lifespan changes based on its surroundings. When the conditions for survival are favorable, they can live for more than 100 days. Nonetheless, Drosophila melanogaster females have a life span of 26 days, and males have a life span of 33 days.

The temperature has a significant impact on the length of a Drosophila melanogaster's life cycle. The easiest way to grow flies is also at room temperature. However, the optimum rearing condition is a temperature of 25°C and 60% humidity. According to our experiment in room temperature generation time is 10 days from egg to adult.

MATERIALS REQUIRED FOR 11 FLY CULTURE BOTTLES:

2.9 grams Agar

4.8 grams Sugar

5 grams Corn flour

9.6 grams Dried killed yeast

515 ml Water

15.5 ml Nipagin solution

Beaker

11 dry McCartney Bottles

Cotton wool

PROCEDURE: 

1. Preparation of artificial diet to culture Drosophila melanogaster

Add Agar (2.9 g), Sugar (4.8 g), Cornflour (5 g), Dried killed yeast (9.6 g), and Water (515 ml) into a beaker and boil the mixture until it gets light yellowish colour. While boiling the mixture should stir well. After the mixture gets light yellowish colour, turn off the Bunsen burner. Then stir the mixture carefully and add Nipagin solution (15.5 ml) to it. After that pour the equal amounts of prepared media into 11 McCartney Bottles and allow to get cool and solidify. It should fill the culture bottles 1/5th to 2/5th full. (The culture bottles containing artificial diet should plug with non-absorbent cotton wool for future use.)

 

2. Culture Drosophila melanogaster in the artificial diet containing McCartney Bottles

Collect 6 to 8 Adult Drosophila flies (male and female) from the natural environment and introduce them into 3 to 4 culture bottles containing an artificial diet (2 flies for each culture bottle).  Close the bottles with flies and artificial diet with the use of muslin cloth. Then allow the flies to lay eggs inside these culture bottles. After the adults emerge from eggs you can transfer those adult flies to other artificial diet containing McCartney Bottles to avoid overcrowding in culture bottles. Observe the life stages and time taken for each life stage of Drosophila melanogaster

OBSERVATION:

At room temperature of 29°C, Drosophila melanogaster can complete its life cycle in this artificial diet within 10 days. More generations can be produced within this artificial diet very quickly. Therefore this artificial diet is suitable for Drosophila melanogaster culture. Small larvae can be seen in the culture media after the eggs hatch. In the larval stage, there are three instars. In addition, as the larvae feed they disrupt the smooth surface of the media and so by looking only at the surface one can tell if larvae are present. After the third instar, larvae move up the culture vial to pupate. All organs degenerate (histolysis) and reorganize into adult shapes throughout the pupal stage (metamorphosis). Adult flies emerge from pupal cases 10 days following egg-laying.

Two days after the introduction of flies to the culture bottle, female flies will lay eggs.

Two days after egg-laying- the eggs will hatch and produce the first instar larva

Three days after egg-laying - the second instar larva can be observed.

Four to five days after egg-laying- the third instar larva can be observed

Seven days after egg-laying- Pupa can be observed

Ten days after egg-laying- Eclosion (adults emerge from the pupa case).