There are approximately 3,500 species of mosquito just a few rank among
the deadliest creatures on Earth. They include Anopheles gambiae, which
transmits the malaria parasite that kills hundreds of thousands of people each
year. Historians believe the mosquito arrived in the New World on slave ships
from Africa in the 17th century, bringing with it yellow fever, which has
killed millions of people. Today the mosquito also carries dengue fever, which
infects as many as 400 million people a year, as well as such increasingly
threatening pathogens as chikungunya, West Nile virus, and Zika.
Mosquitos, like all other life forms, are part of a complex food web.
Many fish feed on mosquito larvae, which are aquatic, and plenty of birds and
spiders and other insects feed on the adults. Dragonflies and damselflies love
mosquitoes. Frogs eat adult mosquitoes, tadpoles eat the larvae.
There isn't much love lost between people and mosquitoes. At the very
least, these bloodthirsty insects are major annoyances, biting us with a
persistence that can be maddening. If insects can be credited with evil intent,
mosquitoes seem determined to wipe the human race out. As carriers of deadly
diseases, mosquitoes are the deadliest insect on Earth. Each year, millions of
people die from malaria, dengue fever, and yellow fever after being bitten by a
disease-carrying mosquito. Mosquitoes also carry diseases that pose serious
threats to livestock and pets.
With all these strikes against them, it's hard to imagine that mosquitoes
fulfill any useful purpose. We forget that mosquitoes populated this planet
long before man; the oldest mosquito fossils date back some 200 million years,
to the Cretaceous period. Clearly, mosquitoes fill an important ecological
niche. So what good are mosquitoes?
Mosquito larvae are aquatic insects, and as such, play an important role
in the aquatic food chain. According to Dr. Gilbert Waldbauer in The Handy Bug
Answer Book, "mosquito larvae are filter feeders that strain tiny organic
particles such as unicellular algae from the water and convert them to the
tissues of their own bodies, which are, in turn, eaten by fish." Mosquito
larvae are, in essence, nutrient-packed snacks for fish and other aquatic
animals.
Their role on the bottom of the food chain doesn't end at the larval
stage, of course. As adults, mosquitoes serve as equally nutritious meals for
birds, bats, and spiders.
As much as we loathe them, mosquitoes represent a considerable biomass of
food for wildlife on the lower rungs of the food chain. Their extinction, were
it even achievable, would have an enormous adverse affect on the entire
ecosystem.
(Adapted from National Geographic magazine and www.insects.about.com)
