This document describes the process of culturing and studying the development of Drosophila melanogaster flies. It notes that Drosophila are commonly used in genetic and behavioral research due to their small size, short lifecycle, and fully sequenced genome. The document outlines the requirements and life cycle of Drosophila, including how to culture them, collect eggs, and observe embryonic development from fertilization to hatching as a larva over the course of 24 hours. Key stages of embryonic development are described in detail. The larval and pupal stages are also summarized. In conclusion, the power of Drosophila for modeling human genetic diseases is highlighted.

1. Aim of experiment:- To the study of drosophila culture.
• INTRODUCTION:- Drosophila melanogaster is a small, common fly found near
unripe and rotted fruit .It has been use for over a century to study genetics and
behaviour. Thomas Hunt Morgan was the preeminent biologist studying
Drosophila early in the 1900’s.He was the first to discover sex-linkage and genetic
recombination, which placed the small fly in the forefront of genetic research.
• REQUIREMENT
1.Small size (Adults 3mm and eggs -0.5mm in length).
2.Easy to handle.
3. One female can lay about 100 eggs.
4.Short generatic time (9-100)
5.Sexual dimorphism ( different male and female).
6.4 pairs of chromosomes and the whole genome is sequenced.
7. Low culture and maintenance cost (requires maize food, culturing in small bottle, and relesser
lab space).

2. Culturing drosophila melanogaster:- Drosophila their on fermenting
Soft lemon fruits. A very suitable culture medium, therefore, is crushed lemon. It provides
all the necessary nutrient for both the larval and adult stages. The lemon can kept along
with the flies in sterile pint Jars with cotton or foam rubber plugs.
Collecting Eggs:- When a female is laying rapidly, however, the uterus is being cleared fast ,
and eggs in their early stages of development can be obtained. To achieve this, it is best to
use culture of flies that are 5 days old. A female is within her peak laying period at this time
and is laying eggs as quickly as one every 3 minutes.
Collecting chamber:- Use plastic spoons whose handles have been cut so they fit in the
culture chamber without touching the plug. Put culture medium on the spoon, score it to
make grooves, paint a light coating of baker’s yeast suspension on the surface of the scored
medium, and place one or two of these spoons in the collectin chamber with the flies.
Mating behaviour of adult flies:- To remove flies easily , first place the bottle in the
refrigerator or keep it on ice for at least 20 minutes. This number the flies, you can remove them
without their escaping into the room. It can be distinguishing males from females by looking for the
black pigmentation on the posterior abdominal segment of the males, it is absent from females.

3. Courtship behaviour:- A female is very much in control of whether She is inseminated being
larger and stronger then a male. She must give an acceptance signal by slowing down extruding her
ovipositor, and spreading her wings, in order for mating to occur .There is no known incidence of rape
among these organisms. A female rejecte a male by kicking with her hind legs, fending with her middle
legs, flicking her wings, producing a rejection buzzing sound by fluttering her wings, or moving away
rapidly. If she has already mated , she also will extrude her genitalia to reject the male.
Later in the courtship, the male extends his proboscis to touch the female’s genitalia
If all the active courtship of the male has stimulated the female enough to accept the male, the two mate
with the male on top of the female.
Observation of the Eggs:- fine forceps to remove the eggs to a small petrudish containing containing
insect Ringer’s Solutions.
Insect Ringer’s Solution:- Nacl 7.6 gm make up to 1 liter with distilled water.
Kcl 0.35 gm
Cacl2 0.21 gm.
Embryogensis:-
1.Early Cleavage (15 minutes-1.5 hours).
2.Magration of cleavage nuclei(1.5 hours)
3. Formation of syncytial blastoderm( 2 hours)
4. Cellular blastoderm (2.5 hours).
5.Early gastrulation (3.5 hours)
6.Might invagination(3.4-5 hours)

4. 7. Germ band extension (4-5 hours)
8.Stomodeal invagination (5-7 hours)
9.Shortening of the germ band (9-10 hours)
10. Shortened embryo (10-10 hours)
11.Condensation of ventral nervous system(15 hours hatching).
Lateral development:- By 16 hours of development, muscular movement will be apparent. Just
before the embryo hatches as the first instar larva at 22-24 hours , you will be able to see air-filled
tracheae and other internal organs.
Embryonic Staging Series:- The staging series shown in Table to stage your embryo, it is one of the
more widely used series for drosophila embryonic develophila.

5. Embryonic stage of Drosophila:-
Stage Time Developmental event
1 0,0:25 First two nuclear division. Eggs
uniformly dark in center and light
at periphery.
2 0:25-1:05 Nuclear division 3-8. Egg
cytoplasm retracts considerably
from vitelline envelope, leaving
empty space at anterior and
posterior poles
3 1:05-1:20 At posterior end, three polar buds
form and divide once. Nuclear
division 9.
4 1:20-2:10 Nuclear division 10-13
5 2:10-2:50 Cellularization of the blastoderm

6. Embryonic stage of Drosophila:-
15 11:20-13 Head involution continuous.
Dorsal closure and closure of
midgut .
16 13:00-16:00 Intersegmental grooves
distinguishable mid-dorsally .
Dorsal ridge overgrows tip of
clypeolabrum .
17 16-24 Tracheal tree contains air .
Retraction of ventral cord
continues . Embryo hatches as first
instar larva .

7. Larval stage of drosophila time after fertilization
Hour Days Development event (at 25 ‘ c)
24 1 Hatching from egg ; first larval
instar begins.
49 2 First molt , second instar begins.
72 3 Second molt , third instar begins.
120 5 Puparium formation , puparium
white.
120 5.1 Paparium fully colored
124 5.2 “Prepupal” molt .
132 5.5 Pupation , cephalic complex wings ,
legs everted
169 7 Eye pigmentation begins.
189 7.9 Bristle pigmentation begins
216 9 Adult ready to emerge from
pupacase.

8. CONCLUSION:-
Drosophila is a powerful sytem for studying human trinucleotide repeat
Diseases and RNA- based toxicity diseases. Genetic modifiers identified
using forward genetics screens or candidate gene approaches have
provided valuable insight into pathogenic mechanisms.
REFERENCE:-
1. Robert.E.K,Lords of the fly “Drosophila Genetics and the
experimental life”. Universcity of Chicago press; 1999;29
2. Demerec M, Kaufman P, Drosophila Guide: Introduction to the
genetics and cytology of Drosophila melanogaster. Cold Spring
Harbour Laboratory;1996;4-8.