Diptera, or true flies, are an order of insects with over 125,000 species. They are distinguished by having only one pair of wings, while their hind wings are reduced to club-like structures called halteres. Flies undergo complete metamorphosis and have specialized mouthparts adapted for sucking or piercing. Some economically important flies transmit diseases like malaria and dengue fever, while others play beneficial roles in ecosystems as pollinators or through waste decomposition. Despite a few pest species, flies as a whole are very successful due to their short lifecycles, high reproduction rates, and diverse specializations.

1. ORDER: DIPTERA
General organization and economic importance
MD SHADAB KHAN
M.Sc 3rd sem.

2. DIPTERA (Two wings)
 ~ 125,000 species
 "Diptera, the name being derived from
the Greek δι- di- "two", and πτερόν
pteron "wing"“
 They are known as true flies.
 Members of this order of insect are found
in almost all type of terrestrial and
freshwater habitats with forest and the
margin of water bodies having the
greatest diversity of species.

3. Characteristics of Diptera
 One pair of membranous wings.
 Hind wing are reduced to small club like
structures called halteres. The halteres
are used as stabilisers during flight.
 Mobile head with large compound eyes .
 Sucking mouthparts, sometimes adapted
for piercing e.g mosquitoes .
 Highly modified thorax, with a reduced
prothorax and metathorax and a greatly
enlarged mesothorax.

4.  Short simple antennae, frilled or bushy in
mosquitoes and crane flies.
 Complete metamorphosis, they go through
at least 4 stages which include egg, larva,
pupa and adult .
Feeding
 Adult flies are only able to ingest liquid
foods due to their sucking / piercing
mouthparts.
 In most species digestion is partially
external and salivary secretion are
introduced to liquefy the food and then the
softened product is mopped up.

5. Life cycle of Diptera
 Flies have a complete life cycle
and will mate while flying.
 The eggs are usually laid into
suitable substrate or close by an
appropriate food source.
 The larvae complete their
development and pupate in the
substrate where they were laid ,
which may be soil, organic
matter, water , plant tissue or
animal tissue .

6. Order diptera is divided into two
suborders
Nematocera
 Many primitive suborders includes craneflies,
mosquitoes, midges and fungus gnats , Thread
like antennae.
Brachycera
 More robust with short stout antennae of less than
six segments and include the orthorrhapan groups,
fruit flies hover flies flesh flies etc

7. Why diptera are successful insects ?
 Due to its short life cycle there is enough time for
selection and evolution to take place .
 The high reproduction ability of them has paved a way
for a large variation for selection.
 The increased interaction with other organisms has led
to diverse specialisation in order to minimise
competition thus increasing chance of survival.
 Mouth parts has become highly specialised.

8. Economic Importance
 Most of the species that make up
this huge and diverse order are
beneficial to ecosystem as
pollinators, parasites, predators
and are vital to the process of
decomposition and nutrient
recycling.
 However the activities of
relatively few species have a
greater impact on man and other
animals than any other insect
group. They causes malaria,
yellow fever, Dengue fever,
leishmaniasis.

9. Uses
 Drosophila melanogaster a fruit
fly has long been used as model
in genetic research.
 Maggots formed on corpses are
useful to forensic entomologist
 Some species of maggots such
as blow fly larvae are bait in
angling and as food for
carnivorous animals in
Zoological parks.

10. THANK YOU