They are mosquitoes but they ingest disease vector mosquito larvae. This type of ‘beneficial’ mosquitoes found in the premises of Raj Bhavan. The scientific name of those mosquitoes is Toxorhynchites. These mosquitoes are usually not found in city environment.
A couple of days ago, dengue infection occurred at staff quarters of Raj Bhawan. To find the source of the disease Mayor of Health department, Kolkata Municipal Corporation, Atin Ghosh led ‘Rapid Action Team’ including insect expert searches the Raj Bhavan. Raj Bhavan’s joint secretary-level officer was there with them.
Ghosh said that mosquito larvae were found in stagnant water in bamboo forest. Toxorhynchites eats 40-50 Adis Igyptai’s larvae daily. Usually, other mosquito larvae changed into pupa in two or three days but this ‘friend’ mosquito takes 25-28 days to change.