1. Mosquito Biology & Control

2. Objective هدف
Name the biology of mosquitoes to appropriate control measures.

3. Overview مرور
Life Cycle
Behavior
Control Measures

4. Importance of Mosquitoes
Found worldwide except Antarctica
Adult female mosquitoes require a blood meal for successful reproduction
May transmit viruses, protozoa, and filarial disease agents
Can have devastating impact, especially during military campaigns

5. Mosquitoes Diseases
Mosquitoes are vectors of several important diseases:
Malaria
Dengue
Yellow Fever
Encephalitides (arboviruses)

6. Mosquito Growth and Development
Complete Metamorphosis
Egg, larva, pupa, adult
Water is required for larval development
BLOOD
WATER

7. Egg Raft (Culex species)

8. Single Eggs (Anopheles species)

9. Mosquito Habitats
Some require large bodies of still water with emergent vegetation (lake margins, rice fields)
Flooded rice field

10. Mosquito Habitats
Some require “dirty” water (lots of organic materials)

11. Mosquito Habitats
Salt marshes (brackish water)

12. Mosquito Habitats
Some require water in ditches, streams and other narrow vegetated watercourses (water does not move rapidly)

13. L - R: Bamboo, Pitcher Plant, Bromeliads
Mosquito Habitat
Water in certain plants
L - R: Bamboo, Pitcher Plant, Bromeliads

14. Mosquito Habitat
Water in tree holes

15. Mosquito Habitat
Some attach themselves to plants and get their oxygen through the plant

16. Mosquito Habitats
Water in artificial containers: cans, bottles, bird feeders, flower vases, and tires

17. Mosquito Habitat

18. Mosquito Growth and Development
A mosquito larva hatches from an egg…..

19. Mosquito Growth and Development
The larvae (“wigglers”) feed on microscopic plants and organic debris in the water; a few are predaceous (Toxorhynchites spp).
Using a respiratory tube, the larvae obtain oxygen from the surface of the water (Anopheles, Culex, and Aedes) or from aquatic vegetation (Mansonia).

20. Mosquito Larvae
Culex & Aedes
Anopheles

21. Mosquito Larvae
Mansonia species

22. Mosquito Larvae Mosquitoes have four larval stages
Development completed in 4 to 10 days

23. Mosquitoe Pupae The pupae are also known as tumblers:
quite active but do not feed
they breathe through two trumpet-like tubes located on the thorax
2 to 5 days as pupae

24. Mosquito Adult Emerging

25. And flying away…..

26. Mosquito Behavior
Defined: “The complex of mosquito actions and activities that meshes with, manipulates, and uses their environment”
Mosquitoes do not think or reason as humans do -- they act/react instinctively to certain stimulus.
We can use their behavior to facilitate surveying for them, trapping them, and killing them.

27. Break

28. Mosquito Behavior Feeding behavior Resting behavior Response to light
Flight behavior
Mating behavior

29. Feeding Behavior Males do not feed on blood.
Most mosquito species require a blood meal for the adult female to complete the reproduction cycle.
Males do not feed on blood.
Almost all mosquitoes need a blood meal to supply protein for each batch of eggs.
Some species can break down muscles for the protein to form one batch of eggs.

30. Feeding Behavior
Mosquito females are “pool feeders” when they take a blood meal.
They insert their straw-like proboscis into the host until it reaches capillary blood.
They salivate into the wound, injecting materials to keep the blood from clotting, causing a sub-dermal blood pool to form.
They pull the liquid blood pool through their proboscis to feed.

31. Culex species Aedes species
Blood-Fed “Engorged”
Culex species Aedes species

32. Feeding Behavior
Males and females feed on plant nectar to obtain carbohydrates necessary for their energy requirements.

33. Host Specificity Many mosquitoes are host specific:
Anthropophilic: feed exclusively on humans
Other animals
Domestic animals
Wild animals
Birds
Or any mixture of the above.
Domestic mosquitoes: found in close association with humans
Problems arise when pathogens are transferred between hosts
Mosquito feeding on bird now feeds on human

34. Host Attraction
Attractiveness for mosquito based on an identifiable attribute of the primary host
Carbon Dioxide (CO2): Attractive to many species; but all animals exhale CO2
L-lactic acid: Thought to be a human attractant; not considered to be important
Octenol: Attractive to some, but not all spp.
Other unidentified chemicals specific to host
Colors, shapes, sizes, temperatures

35. Feeding Periodicity Feed only during certain times of a 24-hour cycle
Knowing when they’re out feeding helps in targeting surveillance and control
Diurnal -- during the day
Crepuscular -- around sunrise and sunset
Nocturnal -- during the night

36. Feeding Location Endophagic: prefer to feed inside of structures
Rest in room corners, under beds, along roof, wait for host to come inside
Exophagic: prefer to feed outside of structures
Rest in shrubs, trees, pipes, feed on hosts when active outside

37. Resting Location Endophilic: prefer to rest inside after feeding
Rest inside closets, behind curtains, in animal stalls, etc.
Exophilic: prefer to rest outside after feeding
Rest in vegetation, tree canopy, leaf litter, etc.

38. Attraction to Light
Light attracts most mosquitoes, as it does most insects
Attractiveness is most pronounced during night hours
Some are so sensitive that they exhibit lunar periodicity
More active with certain phases of the moon
Increased activity w. full moon; decreased w. new moon
However, not all mosquitoes are attracted to lights

39. Flight Range Distance able to fly varies from species to species
Some tend to be weak flyers (</= 100 yds) -- Aedes aegypti and many peridomestic species
Some are strong flyers (Aedes dorsalis, and most salt marsh breeders)...

40. Mating Behavior
Adult males usually emerge from the pupal stage ~24 hours before females
Male genitalia must rotate 180 degrees before they become functional -- a slow process
A heavy emergence of males is often followed the next day by a heavy emergence of females

41. Mating Behavior
In some species, males form mating swarms near the emergence site to mate with females as they emerge
In some species, the adults mate singly, often near the blood host

42. Mosquito Control Control techniques vary with situation
Large area management
Limited recreational areas
Residential
Indoor
Outdoor
Field operational -- combinations of above

43. Control In/Around Buildings
Reduce vegetation to reduce mosquito resting sites
Outdoor residual pesticides applications in resting places
Screens, caulking, other barriers
Space spraying (“mosquito fogging”)

44. Wide Area Mosquito Management
Can be a complex problem
Involves separate sites and groups, and thus requires community involvement and administrative oversight needed
Uses several control strategies, such as…

45. Health Education Education of the public to gain
Understanding: People must understand the importance and process so they can and will contribute to it
Support: People must support the process so they will clean up their areas, make their property accessible, and take personal precautions to avoid disease

46. Survey for Breeding Places
Baseline survey must be made to locate the breeding sites of problem mosquitoes
Oviposition sites (where eggs are laid)
Larval habitats (where are they developing)
Adult surveys (where are they hanging out and when)

47. Source Reduction Channel stagnant water streams
Drain or fill if possible
Remove vegetation that forms harborage
Stock lakes and ponds with top-feeding minnows or mosquitofish (Gambusia)

48. Gambusia Mosquito fish

49. Chemical Management Larviciding
Control the larvae before they become mobile blood-feeders
Should be first line of attack
Adulticiding
Control the adults before they bite
Proper pesticide must be used in the proper way!

50. Larval Control
Use of an appropriate larvicide

51. Larval Control Biological Control:
Stock with predators like this Toxorhynchites mosquito species or Gambusia fish

52. Summary
Life Cycle
Behavior
Control Measures

53. Questions?
سوالات
Questions?