This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
In 1922, a scientist named F.W. Edwards published a paper describing a remarkable thing: a flying, biting midge collected from the Malay Peninsula in southeast Asia that he named Culicoides anophelis. What made the midge was remarkable was the thing it bit: mosquitoes.
Yet in the years since, relatively little work has been done on these potentially important blood-sucking midges, even though their geographic range encompasses the mosquito hotbeds of India, China, and southeast Asia. Recently, however, a team of scientists in China managed to capture one of them on film.
Using a tasty cow as bait, the Chinese scientists trapped mosquitoes and took them back to the laboratory. Among their catch was a single mosquito with a midge clinging tenaciously to its backside. The next day, they repeated the procedure and again netted a midge-bearing skeeter. This time they chloroformed the pair "lightly" and placed them under a dissecting microscope and appear to have recorded a video by sticking a camera up to the lens.
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After about three minutes, the midge decided it had had enough and attempted to de-deploy -- with somewhat comical results -- at about 1:30. In order to uncork itself, it has to do a 180 and pull like hell, bracing itself against its victim for leverage. After nearly a minute of struggle, it finally pops free. The midge's mouthparts seem designed to keep it securely harpooned to their new bestest friend whether they're feeding, flying, or silently cursing evolution's ironies. Some midges have been observed attached to their mosquitoes for up to 56 hours. One poor mosquito was found flying like a drunkard on the southeast Asian island of New Britain in 1945. The mosquito was ornamented by an engorged midge and was apparently woozy from blood loss. Both were preserved, and even in death the midge remained steadfastly attached to its host. Culicoid midges, apparently, have to decide they've really had enough blood, thank you, to leave.
Although it's oh-so-satisfying to hear mosquitoes have their own blood-sucking winged pests (though ponder for a moment that, scaled to our size, their parasites would be about the size of dinner plates, and unlike us, mosquitoes have nothing to whack them with), we may ultimately be losers in the business as well. The host range of C. anophelis, like its geographic range, is enormous. It has been found to parasitize at least 19 species of mosquito, but it has also been collected sucking blood directly from buffaloes and cattle.
Culicoides midges are known carriers of bluetongue virus, Oropouche virus and Schmallenburg virus while mosquitoes they parasitize carry Dengue, West Nile, and Japanese encephalitis viruses. If mosquitoes are flying dirty syringes that spread disease among humans, parasitic midges may further scramble the disease load, introduce new viruses to new vectors, and generally add another order of magnitude to disease transmission calculus. But no one really knows. The studies, as authors of this paper point out, have yet to be done.
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The idea for this post came from an excellent post written by student Sarah Prammer over at the Parasite of the Day blog. Thanks guys!
Reference
Ma Y., Zhenzhou Yang, Xiaohua Wang, Zhongling Lin, Wei Zhao, Yan Wang, Xiangyu Li & Hua Shi (2013). A video clip of the biting midge Culicoides anophelis ingesting blood from an engorged Anopheles mosquito in Hainan, China, Parasites , 6 (1) 326. DOI: http://dx.doi.org/10.1186/1756-3305-6-326
