Are you scared of great white sharks? Or maybe grizzly bears, or saltwater crocs, or tigers?

If you are I can understand. I am too. But it turns out that what we should really be worried about are mosquitos which are, by a very large margin, the most dangerous animals on earth. Every year more than 2 million people die from illnesses transmitted by these little devils and they transmit diseases like malaria and yellow fever to some 70 million.


In the autumn I often bring some mosquito larvae into the lab for the kids to look at under the microscope. They are vigorous little swimmers but, when undisturbed, they tend to hang suspended in the surface film where they feed on bacteria and algae. They are able to survive in poorly oxygenated water and take oxygen diretcly from the surface through a siphon located in their posteriors. I imagine them breathing through their arses, although technically, this is not quite true. Don´t believe anyone who tells you that mosquito larvae breathe through their arses. They will be talking through theirs!

Not all mosquito species feed on blood, although many of them do. The blood is needed by the female to provide the proteins necessary for egg production. The males leave us alone and, like the females when they are not in the business of making eggs, they normally feed on sugary foods like nectar. It is unusual for the adults to live more than a couple of weeks, although some can survive in a kind of semi dormant state for much longer. I was surprised to have a mosquito land on my hand only a week ago, well into our winter.

Despite their disease-spreading activities for which they are well-known, mozzies are important sources of food for birds and spiders and dragonflies and, no doubt the larval stage in the life cycle is an important source of food for fish.

Here in Spain we have our fair share of mosquitos and, in many waters, mosquito fish have been introduced to help control their numbers. Even though it seems hard to believe now, malaria has been present in Spain in the past. Mosquito fish, which come originally from North America, have been very widely distributed not only in Spain, but worldwide for the purpose of controlling mosquitos and they are now among the most commonly distributed freshwater fish.

Mosquitos make up an important part of the diet of birds like ouse martins

Mosquitos make up an important part of the diet of birds like house martins

Mosquito fish - widely stocked to feed on mosquito larvae

Mosquito fish – widely stocked to feed on mosquito larvae like the ones in the picture