23 species of blood-sucking flies recorded in Andaman & Nicobar Islands

Newly recorded blood-sucking flies from the Andaman and Nicobar Islands
| Photo Credit: Special Arrangement

Researchers from the Zoological Survey of India (ZSI) have identified 23 species of blood-sucking flies, 13 of them recorded for the first time in the country, in the Andaman and Nicobar Islands.

These tiny insects, also called midges, are similar in appearance to flies but are more closely related to mosquitoes in their feeding habits. Belonging to the Culicoides genus, they are locally called bhusi files.

The findings were published in the latest issue of the international journal Parasites and Vectors, marking the first comprehensive survey of these insects in the archipelago. The authors of the study are Koustav Mukherjee, Surajit Kar, Atanu Naskar, Chandrakasan Sivaperuman, and ZSI Director Dhriti Banerjee.

According to the study, these flies feed on the blood of livestock such as sheep, goats, and cattle, as well as wild animals like deer. Of particular concern are five species known to transmit the bluetongue disease virus, a condition that can be fatal to livestock.

Bluetongue disease manifests through symptoms including blue discolouration of the tongue, fever, facial swelling, and excessive salivation. It can potentially lead to death in affected animals and poses a significant threat to livestock farming and the agricultural economy.

“The presence of multiple Culicoides species, particularly those responsible for the bluetongue virus transmission, necessitates regular surveillance and appropriate control measures in the Andaman and Nicobar Islands. This is especially crucial given the region’s importance as a major tourist destination,” Dr Banerjee said.

The study, conducted in 2022 and 2023, revealed that 17 of the 23 species identified are known to bite humans, although no human disease transmission has been reported. “A systematic survey of the entire archipelago is needed to understand the role of these insects in disease transmission,” said Dr Naskar, the officer in charge of ZSI’s Diptera section.

The researchers did not rule out the possibility of recording more Culicoides species as many areas in the archipelago remain unexplored. “Apart from continuing our survey, we are conducting population and genetic studies of these flies,” Mr Mukherjee, a senior research fellow said.

A total of 3,529 adult Culicoides were trapped during the survey, representing five subgenera and three unplaced species groups. The 13 new species recorded for India are C. barnetti, C. gouldi, C. flaviscutellaris, C. flavipunctatus, C. hui, C. histrio, C. guttifer, C. perornatus, C. okinawensis, C. quatei, C. obscurus, C. coronalis, and C. kusaiensis.

The Indian Culicoides fauna now includes 93 valid species, many of which are recognised as confirmed or potential vectors of important pathogens of animal health.

Culicoides, a large genus of the family Ceratopogonidae with cosmopolitan distribution excluding New Zealand and Antarctica, includes species that are among the smallest haematophagous members of the order Diptera.

The midges of this family are gaining significant attention due to their role as vectors of almost 60 viruses, 40 protozoans, and 24 filarial nematodes, impacting not only livestock and wildlife but also humans.