Entomology (Insect) Cuelex spp.

3. More than 3000 species of mosquitoes have
been described on a world-wide basis.
Scientists group species by genus on the basis of
the physical characteristics they share.
These species are divided among 28 differentThese species are divided among 28 different
genera, one of them is Culex genus, that has
approximately 1216 species.
commonly has in Asia and Australia.
Culex known as vectors of the pathogens causing
human diseases.

4. Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Culicidae
Species: Culex spp.

5. Culex body: small, fragile, 3-6mm long.
Piercing-sucking mouthpart, Proboscis and 6 needles.
External genitalia.
Adult abdomen, thorax, legs, Halters, and one pair
wings are uniformly covered with brown scales.wings are uniformly covered with brown scales.
Adult is terrestrial, but Larva and Pupa are Aquatic.
Distinguishing of sexes:
1. Female : Plumose antenna, Male : Pilose antenna.
2. Only female Culex bites and drinks animals blood,
Male does not bite and drink blood.
Both sexes feed on flower nectar for water and sugars.
They have been known to fly up to two miles

9. EggAdult
Eggs
Adult
LarvaPupa
Larva
Pupa

12. (Common house mosquito)

13. Female Male
Female Mouth part

14. CulexCulex antennaantenna
Female : Plumose antenna Male: Pilose antenna

15. Culex lay their eggs on the surface of water.
lay their eggs one at a time usually at night.
may lay a raft of eggs every third night during its life span.
It is sticking them together to form a raft of from 200-300
eggs. A raft of eggs looks like a speck of soot floating on
the water and is little—only about (6mm) long andthe water and is little—only about (6mm) long and
(3mm) wide.
The eggs hatch in 14–18 hours.
Tiny Culex larvae emerge from the eggs within 1-4 days.
Culex egg is brown, long and cylindrical.

17. Larva :The larva (larvae - plural) called: wigglers
live in the water and come to the surface to
breathe.They shed their skin four times growing
larger after each molting. Most larvae have long,
narrow siphon tubes for breathing and hang from
the water surface.the water surface.
Larval instars (4).
In 5–9 days, larvae are fully developed.
Aquatic, Filter feeders. eats algae and small
organisms which live in the water.
Respiration.

20. Some times the Culex larvae become fishes
and other insects food.

21. Pupa: commonly called ;tumblers;, The pupal stage is a
resting, non-feeding stage.
Like a;,; divided into cephalothorax and abdomen.
It moves actively but takes no more food.It moves actively but takes no more food.
This is the time the Culex mosquito turns into an adult.
When development is complete, the pupal skin splits and
the Culex emerges as an adult.
It takes about 2-3 days before the adult is fully developed.
Respiration.

22. Culex Pupa

23. The pupal skin splits and the Culex
emerges as an adult

24. Pupa

25. Adult:The newly emerged adult rests on the
surface of the water for a short time to allow itself
to dry and all its parts to harden. Also, the wings
have to spread out and dry properly before it can
fly.
After 3–5 days of emergence, adult flies are ready
Culex adult
After 3–5 days of emergence, adult flies are ready
to mate.
Feeding .

28. Surface water, the wings
spread out and Dry
Ready for flying Completed adult Culex

31. Culex mosquitoes are night biters, and they commonly
rest indoors before and after biting.
Both male and female mosquitoes feed on plant nectar,
fruit juices and liquids that ooze from plants as their
main source of energy, by burning it as fuel for flight
and is replenished on a daily basic and help in the
pollination of many flowers.pollination of many flowers.
Blood is reserved for imbibing less frequently and
mostly for egg production, because female Culex lay
multiple hatches of eggs, thus require a blood meal as
a source of protein for every hatch they lay.
Hibernation Culex, like all insects, are cold blooded
creatures. As a result, they are incapable of regulating
body heat and their temperature is essentially the
same as their surroundings.

32. • Culex usually live only a few weeks during the warm
summer months. Those females which emerge in late
summer search for sheltered areas where
they ;hibernate; until spring. Warm weather brings
her out in search of water on which to lay her eggs. in
spite of ; some species survive bad conditions.
• Culex are generally distributed in urban• Culex are generally distributed in urban
environments around the world, and towns with
poor or inadequate drainage and sanitation support
large populations, but they are not common or
absent in extreme northern parts of temperate zones.
• Most species breed in ground pools, puddles, and
agricultural fields, breeds in waters polluted with
organic debris, such as household refuse and excreta.

34. 1. Annoyance pest: A mosquito bite may induce local
dermatitis or even systematic reaction in sensitive persons.
2. Arboviruses diseases : such as:
A-West Nile (WN) virus belongs to the Japanese
encephalitis virus complex, preferentially transmitted by
Culex species, with wild birds.Culex species, with wild birds.
B- Encephalitis viruses (of different types with different
vector species of Culex):
•Japanese encephalitis (JE) virus.
•Venezuelan Equine Encephalitis (VEE) virus, U.S.

35. Scientists have found Culex mosquitoes may fly as far as 2 miles
(3.22 kilometers),This lets them carry encephalitis to whole new
areas .
Every year, there are cases of encephalitis reported around
the world, Most are in Asia and Australia.
3. Parasitic diseases: filariasis:Two worms, Wuchereria
bancrofti and Brugia malayi,are responsible for over a hundred
million active cases of filariasis worldwide.The worms live inmillion active cases of filariasis worldwide.The worms live in
the lymphatic system Cx. uinquefasciatus its vector.
4. In 1924 M. Hertig and S. B. Wolbach observed bacteria in
the cells of a mosquito (Culex pipiens). Hertig formally
described them in 1936 as Wolbachia pipientis in honor of his
collaborator in the earlier work.
Wolbachia, an intracellular bacterium discovered first
infecting the ovaries of Culex pipiens mosquitoes.

39. A mosquito can "smell" its human blood dinner from a distance
of up to 50 kilometers (30 miles) away.
A female mosquito begins locating prey by detecting carbon
dioxide, which is emitted by animals when they exhale and
through their skin.
The mosquito uses an antenna-like structure called a maxillary
pulp to detect carbon dioxide from as far as (50 m) away. Atpulp to detect carbon dioxide from as far as (50 m) away. At
closer distances, it uses a feathery antenna to identify certain
chemicals, and its nose is perforated with many tiny holes that
the odors in the air can penetrate.
After the mosquito has found a concentration of carbon dioxide
being emitted by a person, the mosquito's sensory receptors tell
it whether the combination of chemicals and odors being
emitted by that person make him or her suitable prey.

40. Scientists are still investigating the complexities involved
with mosquito host acceptance and rejection.
Most mosquitoes are attracted to the odor of carbon
dioxide (C02). All humans exhale C02 with every breath.
Yet this fact hardly helps explain why some people are
"bitten" more than others.
Very large people and pregnant women generally breathe
Why are some people more attractive to mosquitoes
than others?
Very large people and pregnant women generally breathe
out more carbon dioxide, so they tend to be bitten more
often.
Although it was once believed that blood types were an
important factor in varying attraction rates, this theory
has been discredited.
There are over 400 such "magnetic compounds". It
appears that some compounds come from within the
body and some from without.

41. Research suggests that, in addition to carbon
dioxide, some of the substances that people
produce and that attract mosquitoes are sweat,
lactic acid, uric acid and a chemical called octenol.
Lactic acid is emitted through the skin, especially
during exercise. Uric acid is a product of the body
metabolizing certain proteins, and most of it ismetabolizing certain proteins, and most of it is
excreted in urine, but excess uric acid can build up
under the skin. Octenol is present in a person's
sweat and breath.
Some people produce greater quantities of these
substances, so mosquitoes bite some people more
than others.

42. People who exercise outdoors produce more lactic
acid, sweat more and breathe more heavily, so
they also tend to suffer more mosquito bites.
Many perfumes and deodorants that people to
mask their natural body odors also are believed to
be attractive to Mosquitoes.
Gender does not now seem to be the all-importantGender does not now seem to be the all-important
factor in mosquito "bite" susceptibility.
In most cases, only the mosquito knows why one
person is more attractive than another.
Although till correctly only mosquito now why
some people most attract than others!

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larvicidal activity of leucas aspera, vitex negundo and eucalyptus against culex quinquefasciatus
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