February 02, 2019

The Sandfly – The Mosquito’s Cousin We Dread Of

The Sandfly – The Mosquito’s Cousin We Dread Of

The Sandfly – The Mosquito’s Cousin We Dread Of

No matter where we go to enjoy the sun and tropical breeze, we have biting insects everywhere. There are mosquitoes, and then there are sandflies. The bane of our picnics, fishing trips, bike trails and BBQ pits along Singapore’scoastlines.

The sandflies attack swiftly and deftly, either singly or in small swarms. A sandfly can approach a human, bite an exposed part of skin, and leave stealthily. It is only until the bite itches, that a human will then notice that he or she has just got bitten by a sandfly. Due to this nature of sandflies and lack of information online, Singaporesandflies tend to be confused with either blackflies or New Zealand sandflies. The Entomologist Loungeexplains the confusion in detailhere.

According to the Singapore Biodiversity encyclopaedia, the species in Singapore is Culicoides spp. also known as biting midge. Just like their mosquito cousins, only female sandflies feed on blood as protein source for egg development.

A close-up image of a Culicoides example during blood feed. Source: Agricultural Research Service (public domain).

A sandfly looks like a cross between a mosquito and a fly with spotted wings. Much smaller than mosquitoes, sandflies are only 1 to 4 mm in length, making it very hard for us to notice an individual sandfly unless they come in small swarms.

A photo speaks a thousand words, so we will let this photo illustratethe size comparison.

A sandfly/biting midge (left) and a mosquito (right) feeding on a human skin. Source: Wikimedia (Author: Dunpharlain)

Here are four important questions you should ask about Singapore sandflies/biting midges:

  1. Do sandflies carry disease in Singapore?

At time of publication, there is no official records of sandflies or biting midges carrying any disease in Singapore. In other parts of world, Phlebotomus and Lutzomyiasandflies are known vectors of leishmaniasis (also known as kala azar) but these two species are not recorded in Singapore.

  1. When are sandflies active in Singapore?

Sandflies are active all year round. They bite mostlyduring the day, especially when the wind is calm as they are weak fliers.

  1. Where do sandflies breed in Singapore?

Female sandflies lay their eggs in damp locations, such as wet sandy beaches, lake/river banks and wetlands. Larvae of sandflies can also be found under bark, in rotten wood, compost, mud, tree holes, or water-holding plants.Unlike mosquitoes, sandflies are not known to breed around buildings in Singapore unless one lives close to nature or coastlines. Since sandflies do not have ability to travel far, their biting activity is also close to their breeding ground.

  1. What can I do to protect myself and my family?

Sandflies/biting midges bite humans just like mosquitoes, so you should use the same principles when it comes to self-protection. Apply recommended insect repellents on exposed skin and on clothing. Re-apply at regular intervals, and more frequently after sweating and towelling as these two will remove the layer of repellent. Wear long clothing to cover exposed skin if possible. Pay extra attention to babies and young children. If you use tents, check if the netting used for entrance is made of extra-fine mesh as sandflies are much smaller than mosquitoes and may pass through larger mesh size.


© Jo-Lynn Teh, BCE

 Jo-Lynn Teh is ESA Board Certified Entomologist based in Singapore. While her specialisation is on tropical insects that affect public health and agriculture, Jo-Lynn’s passion is also to help people understand insects. Find her on LinkedIn.



  1. Ng, P. K., Corlett, R., & Tan, H. (2011). Singapore Biodiversity: An Encyclopaedia of the Natural Environment and Sustainable Development. Singapore: Editions Didier Millet in association with Raffles Museum of Biodiversity Research.

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