The Drosophila life cycle

Egg/Embryo

Prepupa

~ 1 day

1 day

1 day2 days

5 days

Adult (Imago)

Modes of Insect Development

20-H

ydro

xyec

dyso

neThe life cycle of Drosophila melanogaster

Embryo 1st instarlarva

2nd instarlarva

3rd instar larva Pre-pupa

Pupa

modified after Riddiford, 19931 2 3 54 6 7 8 9 10

Adultfemale

days

.......

..

.

.

.

....

.......

..

.

.

.

...........

..

.

.

.

....

.......

..

.

.

.

....

.......

..

.

.

.

....

.......

..

.

.

.

....

1 2 3 4 5 6 7 8 109 days

Regulation of Insect Metamorphosis

(Prothoracicotropic hormone)

20E (fat body)

OH

(20E)

EcR Usp

20E

20E20E

20E

EcR Usp

Transcription

20E

20E

Nucleus

Cytoplasm

Hormone ResponseElement

Tissue- and stage-specific responses to a systemic signal

Third instar larva Prepupa Pupa

0 hrspupariation 10 hrs

Histolysis:

Differentiation:

Remodeling:

Larval midgut Salivary gland

Anterior muscles Post. muscles

Imaginal discs

Central nervous system

Head eversion

20E 20E

Locations and Developmental Fates of Imaginal Discs and Imaginal Tissues in the ThirdInstar Larva of Drosophila

engrailed

Compartments in the wing imaginal disc

boundary

compartment HedgehogEngrailed

Compartmentalization and Anterior-Posterior Patterning in the Wing Disc

Dpp: Decapentaplegic

Determining the Dorsal-Ventral Axis

Compartments in the wing imaginal disc