by Irene Moon
Far from expected it was. Hot summer months, third floor apartment in the city, a vase of flowers near an open window. The video my friend sent me said it all and how lovely it told the entire store of the life cycle of this common summer affliction. The flowers are rotten; they have simply been there too long. Did you go away for the weekend? Too busy with work or school to notice that metropolis gunk had begun to change the fresh water that once nourished the blossoms into a nutrient soup perfect for visitors?
One of our most notable pestest pals, the mosquito.
In his email he likened them to a sea monkey invasion, which conjured up visions of Von Leeuwenhoek and the wee beasties. Spontaneous generation of life? Not possible in reality but in perception these creatures were not there one day and there the next. It has to do with the very rapid life cycle of the mosquito, from hardly visible egg mass laid on the water surface, to adult, often in just a few days, it can seem they come out of nowhere.
They flicked fast, breaking the water tension above in order to breathe, then quickly swimming to the safety of the bottom of the vase. They were pupa and late instar larvae both moving around in the vase. Fascinating fact, as the pupa of the mosquito is one of the few insects with such a mobile transformative state. Far from living a sedentary lifestyle, they move from under the murky water to the top of their water pool home for a breath. That is right, they do not have gills and, even as a pupa, need a periodic breath from the water surface. The big question than is, how do they make the metamorphosis from larva to pupa when they must keep moving? Have to keep moving or die! All of their tissues are rearranging from a larval-form creature that is dependent on water to one that has the ability to fly in the air; if you look quickly at the larva of a mosquito and then the adult. The transformation is miraculous.
Their presence does shake a curious chord immediately as the mosquito is one of the members of the insect order Diptera that commands our respect. Flies, from the common housefly to the mosquito, all have one characteristic in common: they all have a characteristically reduced second pair of wings, termed "halteres". Halteres are used as steering mechanisms during flight and are regarded as the classic anatomical feature that distinguishes all flies.
It was difficult to judge from the video exactly what species of mosquito we were dealing with but it was likely an Aedes aegypti or some species in the genus Culex. Even though there are 170 or so mosquito species described from North America and 62 species that live in New York State alone (and perhaps a new variety of mosquito that exists only in the New York Subways. (see http://tinyurl.com/9y3g4jp)
Mosquitoes are flying hypodermic needles that regurgitate saliva into the bite wound. The saliva has a purpose, to maintain the flow of blood despite our vertebrate clotting mechanisms. It is those that bite and then vomit inside you that one should be concerned with (this includes those pesky ticks). This is exactly the perfect mechanism to transmit disease. Don't get me wrong, disease transmission is not personal between mosquitoes and humans; there is no intent here, but the mechanism involved has allowed for the evolution of some of the most devastating human diseases known, ever. The World Heath Organization estimates that there were 216 million cases of malaria in 2010 alone resulting in 655,000 deaths, with 65% of these being children under 15 years old. The numbers are not improving. It is a very complex disease, when properly treated people can recover, but in areas where malaria is high it is the repeat exposure, along with less medical care, that takes a very serious toll on human life. About 1500 cases of Malaria are reported in the United States every year and it once was more common, especially in the Southern United States, before we started spraying DDT absolutely everywhere. Birds suffered but we managed to push back some of the tides of pests at least in this country. Of course, there is an ongoing effort to eradicate the disease elsewhere, however the parasite has been with us now for more than 50,000 years and perhaps it is not in the news as much as it should be, since nearly half a million children will die this year from the protist.
It is not the point of this article to despise the mosquito, but to inform and encourage a healthy respect and awareness. They are amazing organisms that even find their way into our homes, keeping us up at night looking for a blood meal to deliver their eggs the best of health. But it has been to our devastation that the mosquito, a fly with a highly specialized lifestyle, became one of the most efficient vectors for human disease. A fact we seem so often to ignore.
Many thanks to Raphael Lyon for the video, email, and story inspiration.