THE EDITOR, Sir:AFTER READING Martin Henry's interesting piece about malaria and mosquitoes, I was prompted to write a brief follow-up on mosquitoes.
In a piece written over 50 years ago by Marston Bates, he gave a fascinating account of the lives of mosquitoes. To begin, it is the blood-sucking female mosquito that bites. Up to the time of Bates' report not much was known about the food habits of the males but that they had been seen frequently on flowers or sucking juices from fruits or manure. After using several devices to entice mosquitoes, Bates discovered that he could catch a few by moistening absorbent cotton with his wife's perfume. According to Bates, there had been a few scientific articles on the blood-sucking habits of the male mosquitoes. However, when these peculiar males were examined, they turned out to be hermaphrodites i.e., one side of the body may be male and the other side a female.
The female anopheles is the blood-sucking nuisance!
In 1932 a world list of mosquitoes was published; it estimated to be 1,400. Assuming that an average of 40 new species would evolve each year, Bates estimated that the count would multiply to well over 2,000 at the time (1950) when he wrote his article.
It was reported that, South America and the Orient had over 500 species, about 400 species in Africa and 200 species in Australia. North America had 121 species and Europe had 125 species.
The French scientist, Emile Roubaud discovered that one variety of the common house mosquito, culec pipiens, could develop eggs without blood. Research showed that this species of mosquito didn't really need blood, yet were among the most viscious bloodthirsty of all mosquitoes. When they did get a blood meal, they produced more eggs. Interestingly, these mosquitoes can survive for generations in the laboratory without blood, living only on apples and raisins.
Any species of the anapholes mosquito can transmit malaria. When a mosquito has had enough blood, she goes off somewhere to digest the meal. Depending on the temperature of the environment and type of mosquito, digestion may take from two days to a week. So, when we hear the buzzing of the mosquito, it's not the same one that just bit you; it's another female who is trying to suck your blood.
The anopheles mosquitoes breed in ponds, marshes, quiet waters, stagnant water found in plant containers, empty cans and containers laying around with water.
I am, etc.,
F.L. SPENCER-STRACHAN
Medical anthropologist
55a Lady Musgrave Road
