Species composition of mosquito breeding in bamboo stumps in Sikkim, India

Sikkim is a part of Eastern Himalayan biodiversity hotspot of India rich in bamboo flora harbouring over 30 different bamboo species. The present study was aimed to investigate the larval mosquito diversity in the bamboo stumps of Gangtok, Sikkim. Besides, efforts were also made to evaluate the propensity of particular species of mosquito towards specific bamboo species (if any).

A total of 75 bamboo stumps of four genera were surveyed and screened at five different sampling sites of Gangtok from July to October 2017. Mosquito species similarity between the five sampling sites and the four varieties of bamboo species was calculated using the Bray-Curtis similarity index.

A total of 216 larvae were collected from 25 different bamboo stumps studied. The species identified were Aedes albopictus, Ae. atlanticus, Ae. aegypti, Orthopodomyia signifera, Oclerotatus japonicus, Oc. taeniorhynchus, Armigeres subalbatus, and Toxorhynchites splendens. The Oc. japonicus (34.5%) was found to be the most abundant species having distribution in Phyllostachys assamica, Dendrocalamus hamiltonii and Bambusa nutans. On the other hand, genus Armigeres subalbatus and Tx. splendens were found to breed only in the stumps of P. assamica. Based on Bray-Curtis similarity index highest species similarity was recorded between D. hamiltonii and P. assamica bamboo species.

The study may help to understand the bioecology of the mosquito larvae which may help to devise suitable mosquito control programmes. Future studies including the survey of large number of bamboo stumps both in urban and rural areas of Sikkim may provide better insight into the mosquito diversity in the bamboo stumps of Sikkim.