What’s in a name? What’s a Sandfly?

Life cycle of the parasites from the genus Lei...

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When people talk about sand flies it can be very confusing because there are several different bloodsucking insects around the world called sand flies. This is why scientists use latin names for species to avoid confusion.

My work on sand flies that spread Leishmania parasites is on the group of phlebotomine sand flies. The English name of “sand fly” is very confusing for phlebotomines since they dont all live in sand; Brazilian ones may live in the rainforest, no sand in sight and they don’t all live on the beach. In Middle East deserts it may be appropriate.  Both black flies (Simuliidae) and biting midges (Ceratopogonidae) are also known as “sand flies” in various parts of the world. The latter are the ones most likely to be biting people on beaches, particularly members of the genus Culicoides.

All phlebotomine sand flies can be distinguished by the lay person by the following characteristics:

1. Size

Sand flies are smaller than mosquitoes but larger than midges, with a body length of 2-3mm.

2. Colour

All sand flies are brownish in daylight but their bodies are densely covered in oily hairs which give the insects a whitish appearance when illuminated. This explains some of their common names, e.g. “manta blanca” (white mantle) in Ecuador, “palomilla” (little dove) in Colombia and “asa branca” (white wing) in Brazil.

3. V-shaped wings

This is perhaps the most distinctive feature of the group. Phlebotomines at rest hold their wings in a raised “V” . The wings are never closed or laid flat across the body. This feature explains another vernacular name in Brazil, “cangalinha” or “little yoke”.

4. Flight

Phlebotomines have a weak, direct flight and once on the host progress by a series of small hops. They do not hover round a host and as such are often not recognised as a biting nuisance.

5. Noise

The wingbeat frequency of phlebotomines is inaudible to the human ear. They thus do not produce a buzzing or whining noise before biting, which again reduces the perceived nuisance to man.

6. Nocturnal habit

Phlebotomines are crepuscular or nocturnal biters, although they may bite during the day if disturbed from their resting sites or when deep shade or clouds produce low light levels.

7. Painful bitePhlebotomines are pool feeders or “telmophages” which suck blood from a small wound they make in the skin of the host. Their bite is therefore relatively painful, and has been likened to a drop of hot oil or a cigarette burn. In Colombia the insects are sometimes known as “quemadores” (burners) or “pringadores” (stingers).

I am indebted to Dr Bruce Alexander who told me about the S. American names.

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