MOSQUITO

 Body is small, fragile, 3-6mm long.  A slightly shorter spread of its narrow wings.  Its body, like that of other insects, consists of head, thorax, and abdomen.  The round head has a long proboscis (tubular mouth part) and antennae.

 In the male, long hairs on the antennae give these appendages a feathery appearance.  Hairs on the antennae of the female are shorter.  The mosquito's slender legs are attached to the triangular thorax.  The abdomen is long and narrow

antennae compound eyes palp Mouthparts (proboscis)

1.Antenna: plumose in male, pilose in female 2.Mouthparts: piercing and sucking type. 3.Proboscis and 6 needles. 4.palp 5.Feeding 6.External genitalia

With mandiblesWithout mandibles

 Mosquitoes have mouthparts which are adapted for piercing the skin of plants and animals.  They typically feed on nectar and plant juices.

 Piercing and sucking mouth-parts is that suited for piercing the tissues of plants and animals and sucking up their sap or blood.  The labium forms a long, cylindrical, 3-segmented

 The maxillae, each has 2 grooves on its inner surface. When they fit together, two tubes are formed between them.  The labrum is small and situated over the base of the proboscis.  The labium bears 2-terminal sensory labella.  The maxillary palps are well developed ( in male 5-segmened and in female 3-segmented).

 Single pair of membranous wings.  The other (hind pair) is modified into small knobbed sensory structures known as halteres.

Wings Anopheles with white and black spots Culex and Aedes without white and black spots

 Mosquitoes are aquatic in their early stages.  Mosquitoes go through four stages in their life cycle: egg, larva, pupa, and adult or imago.  Adult females lay their eggs in water.  5–14 days, depending on the species and the ambient temperature; eggs hatch to become larvae, then pupae.  The adult mosquito emerges from the pupa as it floats at the water surface.

The life cycle of mosquito The complete life cycle contains eggs, larva, pupa and adult. All mosquitoes require water for the development of the larvae and pupae, but the adults live in land.

Some recognition features ofAnopheles, Culex and Aedes AnophelesCulexAedes

Features AnophelesCulexAedes 1. color Dark-grayBrownBlack 2. wings With white and black spots Without white and black spots 3. legs With or without white rings Without white ringsWith white rings 4.sitting posture There is a angle between the body and the resting surface There is a parallel between the body and the resting surface Recognition features in the adults of Anopheles, Culex and Aedes

AnophelesCulex Aedes Adults Dark-gray Brown Black

Anopheles egg CulexAedes boat-shaped, have a pair of lateral floats, laid single and float on the water surface.. cylindrical or ovoid in shape and no float. They are laid stuck together in “ egg ’ s rafts ”. olive-shaped, no float. They are laid single on humid soil or the bottom of water (cans, contains)

 Morphologically has the three body parts common to insects: head, thorax, and abdomen.  As a fly, it has one pair of wings.  All types of mosquitoes must have water to complete their life cycles.  Culex mosquitoes prefer small bodies of still water full of organic matter, such as tin scans, bird baths or rain barrel

 Culex lays their eggs on the surface of fresh or stagnant water.  Mosquitoes prefer water sheltered from the wind by grass and weeds.  Culex egg is brown, long and cylindrical.  It may lay 300 eggs up-right on the water surface.  Culesx eggs are placed together to form an egg raft.  They are adhered to each other due to surface forces.

 It has long, narrow siphon. - There are more than one pair of sub-ventral tufts of hairs on the siphon, non of them near its base

 A Culex pupa floats on top of the water for one to four days while it transforms into an adult mosquito.  The pupal phase is a non-feeding, resting stage.

The adult females can live up to a month (or more in captivity) but most probably do not live more than 1-2 weeks in nature

floats on either side  Eggs are laid singly directly on water and are unique in having floats on either side.  Eggs are not resistant to drying and hatch within 2-3 days, although hatching may take up to 2-3 weeks in colder climates

do not have a siphon and they lay parallel to the water surface.  Anopheles larvae do not have a siphon and they lay parallel to the water surface.  The larva feed on micro-organisms and organic matter in the water.  On the fourth molt the larva changes into a pupa.

 As with the larvae, pupae must come to the surface frequently to breathe, which they do through a pair of respiratory trumpets on the cephalothorax.  The pupa is comma-shaped.  Pupae do not feed during this stage.  The pupa is less active than larvae

Anopheline mosquito resting on a net. The resting position of the adult Anopheles is typical in that the head, thorax and abdomen are kept in almost a straight line. The long axis of the body forms an angle of about 45 。 to the surface. “Hip”points to sky

Culicine mosquito taking a blood meal. Unlike Anopheline, these mosquitoes sit with a hunch. During the act of feeding the labium curls backwards allowing the biting fascicle to penetrate the tissues.

Ecology 1) Breeding habits Breeding sites: the place where the females lay eggs and breed larvae

Slowly flowing water type Jungle type Dirt water type Container type Paddy field type There are five type of breeding sites

Paddy field type of breeding- sites includes rice fields, marsh and pond, in which water is large, water clean and still. The breeding sites is suitable for Anopheles sinensis, anopheles anthrophagus, and culex triaeniorhynchus etc. Slowly flowing water type includes stream and irrigation raceway with clean and slowly flow water, which is the breeding site of Anopheles minimus commonly.

Jungle type includes mountain stream, stone cave and spring pond, in which Anipheles dirus is found usually. Dirt water type includes dirt water pit, sewer, fecal pit, which are the breeding sites of Culex pipiens pallens, C.p. quinquefasciatus. Container type includes water vats, jars, bamboo container, tree- hole etc, which are the breeding sites of Aedes albopictus and A. aegypti.

2) The behaviors of sucking blood 3) Resting sites of the adults 4) Flying and activity 5) hibernation In the winter, mosquitoes don’t suck blood and hide in warn place such as inside of house; the ovary don’t develop. The average month temperature is over 10 ℃, there is no hibernation for mosquitoes.

6) Seasonal fluctuation The phenomenon that population density of the mosquito varies with season is called seasonal fluctuation.

Mosquito and diseases 1) Direct harm to humans Biting by mosquitoes can cause irritation, or allergic reaction 2) Transmission of diseases 7) Longevity In tropical areas, the adult mosquitoes may live on average about two to 3 weeks; in temperature areas, the adult may live on four to five weeks or longer; the males have a shorter lifespan than the females.

Arbo-diseases MosquitoEpidemic area 1.malaria An.sinensisPlain areas An.anthropophagu s Mountain or hilly areas in South China An.minimusMountain or hilly areas in South China An.dirus Jungle areas of Hainan island 2. Japanese B encephalitis Culex tritaeniorhynchus Paddy field 3.Filariasis Culex pipiens pallens C.p. quinquefasciantus As a vector of Filariasis bancrofti in North areas of Yangtse river Anopheles sinensis A. anthropophagus As a vector of Filariasis malayi 4.Dengue fever Aedes aegypti A. albopicutus Tropical areas In China:Hainan, Guangdong etc

Mosquitoes as vectors Aedes: filaria, viruses (e.g. Aedes aegypti for dengue and yellow fever). Anopheles: malaria, filaria (Wuchereria bancrofti), viruses. Culex: filaria, viruses (e.g. Culex pipiens for SLE).

 The name comes from the Greek aēdēs meaning "unpleasant" or "odious", dengue fever filariasis  So called because of the diseases this type of mosquito transmits, including dengue fever and yellow fever. In Polynesia, the species Aedes polynesiensis is responsible for the transmission of human lymphatic filariasis

Aedes aegypti Worldwide within the 20°C isotherms. Vector of yellow fever and dengue. Urban mosquito. Daytime biting mosquito. Goddard J CRC Press

Aedes albopictus Asian Tiger Mosquito. Agressive, daytime biting mosquito. Associated with used automobile tires. Vector of yellow fever, dengue and Lacrosse encephalitis virus. Goddard J CRC Press

 3 famous culex species Culex tarsalis Culex pipiens Culex quinquefasciatus

1. Annoyance pest : A mosquito bite may induce local dermatitis or even systematic reaction in sensitive persons. 2. Disease Carrier: Often a carrier of diseases, such as Filariasis, encephalitis, yellow fever, dengue fever, dog heartworm, West Nile virus, and many others. The females, who drink blood, can carry disease from one animal to another as they feed

 Some species Anopheles acanthotorynus Anopheles albimanus Anopheles albitarsis

 Malaria  Malaria parasites are transmitted from one person to another by the female anopheline mosquito.  There are about 380 species of anopheline mosquito, but only 60 or so are able to transmit the parasite.

Anopheles labranchiae atroparvus Main malaria vector in the Low Countries. Lived in pig stables (Vapona strip) and attics (Sprays). The larvae are found in brackish water along the coast from the southern Baltic to Spain.

Anopheles gambiae Most important vector in Africa. 0 – 4 h maximal activity. Endophilic species.

Courtesy CDC

Control 1) Larva control 2) Adult control Chemical control, e.g., insecticide is placed in the water; biological control, e.g., predators, disease agents; source reduction or habitat management. Insecticides (direct action and residual action); Personal protection.

Malaria: Vector Control Source reduction (larval control) –Historically most effective campaign in Brazil and Egypt (1930s and 1940s). –Bacillus thurigiensis var. israelensis (Bti toxins). –Mosquito fish (Gambusia affinis): larger bodies of water.

DDT Dichloro-diphenyl-trichloroethane. Still an effective tool to control Anopheles fluviatilis – transmitted Plasmodium falciparum in India.