Mosquito Biology & Control

1. MosquitoBiology & 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)

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

14. Mosquito Habitat • Water in tree holes

15. Mosquito Habitat • Some attach themselvesto 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 (Toxorhynchitesspp). • 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 • 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. 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) -- Aedesaegypti and many peridomestic species • Some are strong flyers (Aedesdorsalis, 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