Treehole mosquitoes

ROLE OF TREE-HOLES AS IMPORTANT BREEDING SITES OF MOSQUITOES (DIPTERA: CULICIDAE) INCLUDING DISEASE VECTORS IN NORTH KERALA, INDIA

Sumodan, P.K and Jaseela, P.

P.G. Department of Zoology, Government College, Madappally, Vadakara- 673102

INTRODUCTION

Mosquitoes are the most important insect disease vectors responsible for about 2 million deaths annually

Of the 3000 known species about 100 are vectors

Mosquitoes breed in variety of breeding sites Aedes mosquitoes are container breeders Tree-holes are natural container breeding sites The present study was carried out to reveal the

significance of tree-holes as mosquito breeding sites

The study was conducted from June-December 2009

STUDY AREA

Vadakara Taluk (Kozhikode district)

METHODOLOGY

Trees were surveyed randomly for holes in three localities in Vadakara Taluk (Madappally, Mukkali and Chekkiad)

Tree-holes up to a height of 6 feet were surveyed for mosquito breeding

Water from the hole siphoned out using a plastic tube into containers

Samples transferred to the laboratory for mosquito emergence and identification

Identified under stereomicroscope using standard keys (Barraud, 1934)

COLLECTON

TREE HOLES

REARING

OBSERVATIONS & RESULTS

Total tree-holes surveyed: 100 Tree-hole with mosquito breeding : 100

(100%)

SPECIES DIVERSITY

Aedes albopictus -100% Heizmannia chandi- 90% Culex brevipalpis- 10% Armigeres subalbatus-10% Toxorhynchites splendens-15%

AEDES ALBOPICTUS

Vector of Chikungunya and Dengue Described as Culex albopictus by Skuse

(1894) from Calcutta

HEIZMANNIA CHANDI

Vectorial status- not known Described from Puthuppadi, Kozhikode

district in 1922 by Edwards

CULEX BREVIPALPIS

Vectorial status- not known Described as Stegomyia brevipalpis by Giles

in 1902 from Shajahanpur

ARMIGERES SUBALBATUS

Suspected vector of Wuchhereria bancrofti, Japanese Encephalitis and dog heart worm Dirofilaria immitis

Described as Culex obturbans by Walker (1860)

TOXORHYNCHITES SPLENDENS

Non-blood feeding species Larvae are predators of other mosquito

larvae Described as Culex splendens by Wiedemann

from Java in 1819

BREEDING PERCENTAGE

Aede

s al

bopi

ctus

Heizm

anni

a ch

andi

i

Arm

iger

es sub

alab

atus

Culex

bre

vipa

lpis

Toxo

rhyn

chite

s sp

lend

ens

0

30

60

90

BREEDING ABUNDANCE BASED ON EMERGENCE

Aedes albopictus – 56.5% Heizmannia chandi-35.8% Culex brevipalpis- 2.8% Armigeres subalbatus-3.2% Toxorhynchites splendens-1.8%

SPECIES ABUNDANCE

Aedes albopicusHeizmannia chandiCulex brevipalpisArmigeres sub-albatusToxorhynchites splendens

DISCUSSION 100% of tree-holes were positive for mosquito-

breeding. Hence it is an important category of breeding sites

Aedes albopictus, the vector for Dengue and Chikungunya was found breeding in all tree-holes surveyed. They were also the most abundant species.

Toxorhynchites splendens, the predator mosquito was also found breeding in 15% of the tree-holes, which may be used as a control agent

The study emphasizes the need of including tree-holes in the anti-mosquito strategy of public health authorities

More research is needed to formulate effective control strategies in these neglected breeding sites.

Any questions?

Thank you