Common mosquitoes of Thailand

Department of Entomology, Faculty of Agriculture, Kasetsart University

Chris Daeyun Kim, Ph.D.

Lecturer, Department of Entomology

Mosquitoes were present in Thailand long before humans. They are a problem for humans and animals because of the pain experienced when the females feed on blood, and also, when they are blood feeding, they can transmit disease-causing pathogens. It is important to understand the biology of the various mosquito species and to be able to identify them. For public health and mosquito control operations, surveillance which includes mosquito identification is the basis of an effective, efficient, and environmentally sound program.

There are some mosquito species that do not feed on humans, preferring birds, reptiles, and other organisms. Toxorhynchites species never feed on blood. Primarily because of their blood feeding preferences, some will never be a pest or disease vector for humans. But there are a few species that are dangerous. For example, Culex quinquefasciatus, Aedes aegypti, and Anopheles dirus. Photos and descriptions in this page will guide you to identify of adult mosquitoes commonly encountered in Thailand. However, it does not include every species collected in Thailand. One of two characters of the adult mosquito that may be useful for quick identification in the field, without the need for a microscope. A hand lens is helpful, but most of the key characters can be seen without magnification. Field-collected adult mosquitoes may be missing key characters if the mosquito is old or has been damaged.

Glossary

Abdomen: The posterior of the three main body divisions

Antenna (pl. antennae): Sensory appendage on the head above the mouthparts; adult mosquitoes have one pair of antennae

Apical: At the end, tip, or outermost part

Asynchronous: Adult mosquitoes emerge sporadically, not all at the same time

Basal: At the base; near the point of attachment (of an appendage)

Cercus (pl. cerci): Appendage at the posterior end of the abdomen; adult mosquitoes have one pair of cerci

Coxa (pl. coxae): The basal segment of the leg

Dorsal: Top or uppermost; pertaining to the back or upper side

Flagellum (pl. flagella): The whiplike part of the antenna beyond the second segment

Flight range: Distance the adult mosquito flies from its larval habitat: Short = not far from larval habitat; Medium = may move several km from larval habitat; Long = over 20 km from larval habitat

Palp (pl. palpi): Elongated, segmented appendages found near the mosquito’s mouth; adult mosquitoes have one pair of palpi

Posterior: Hind or rear

Proboscis: The extended beak-like mouthparts

Pronotum: Dorsal plate on the thorax

Scales: Minute, platelike appendages covering some parts of a mosquito

Segment: A subdivision of the body or of an appendage; sometimes identified by number

Seta (pl. setae): A bristle

Synchronous: Adult mosquitoes emerge all at the same time, or very close together in time

Tarsal: On the tarsus

Tarsomere: A segment of the tarsus

Thorax: The body region posterior to the head; the thorax bears the legs and wings

Tibia (pl. tibiae): The fourth segment of the leg, between the femur and tarsus

Wing: Membranous flight appendage; adult mosquitoes have on pair of wings

Species Identification

1. Aedes aegypti

2. Aedes albopictus

3. Culex quinquefsciatus

4. Anopheles dirus

5. Toxorhynchites sp.

1) Aedes aegypti

Figure 1. Aedes aegypti

Scientific Name: Aedes aegypti

Common Name: Yellow fever mosquito

Key Characters: Silver-white scales forming shape of a lyre on the dorsal surface of thorax; basal bands of white scales on each tarsal segment of the hind legs

Larval Habitat: Containers

Medical Importance: Yellow fever, Dengue fever

Common hosts: Humans

Feeding Time: Daytime, in the shade; will feed at night in well-lit rooms

Flight Range: Short

Notes: May occur throughout the year in Thailand, Asynchronous

2) Aedes albopictus

Fig. 2 Aedes albopictus

Scientific Name: Aedes albopictus

Common Name: Asian tiger mosquito

Key Characters: Stripe of silver-white scales along the midline of the dorsal surface of the thorax; basal bands of white scales on each tarsal segment of the hind legs

Larval Habitat: Containers

Medical Importance: Dog heartowrm

Common hosts: Humans, dogs, other mammals

Feeding Time: Daytime, early evening

Flight Range: Short

Notes: May occur throughout the year in Thailand, Asynchronous

3) Culex quinquefasciatus

Fig. 3 Culex quinquefasciatus

Scientific Name: Culex quinquefasciatus

Common Name: Southern house mosquito

Key Characters: Half-moon pattern of golden scales on basal areas of abdominal segments

Larval Habitat: Highly organic, polluted, foul water in containers, catch basins, ground pools, effluent from sewage treatment areas, abandoned swimming pools, dairy lagoons, ditches, animal watering tanks

Medical Importance: Dog heartowrm

Common hosts: Birds; mammals

Feeding Time: Evening

Flight Range: Short

Notes: May occur throughout the year in Thailand, asynchronous

4) Anopheles dirus

Fig. 4 Anopheles dirus

Scientific Name: Anpheles dirus

5) Toxorhynchites sp (larva)

6) Armigeres sp.

Urban and Medical Entomology / Bed bugs