Page 154 - Engineering in Nature

Engineering in Nature

the blood moves, because they are all resistant to its speed and pres-
sure. Thanks to this system, the insect is able to ingest up to 300
micro-liters of blood in 15 minutes—the equivalent of a human being
drinking 200 liters (52 gallons) of water. 44
These insects are similar to mosquitoes, in that they're able to ex-
pand their bodies considerably as they drink. For example, a mos-
quito that ingests 4 micro-liters of blood consumes a great deal more
than the volume of its own body. So what is it that prevents the mos-
quito from bursting as a result of such enormous consumption?
As with other blood-suckers, working in tandem with the mosqui-
to's digestive system are tension sensors that tell them when to drink
blood and when to stop. Human be-
ings use similar systems to those in
the mosquito and the assassin bug in
water- storage facilities. The water
drawn up by pumps is transferred
into tanks, where special sensors con-
trol the water level. When water in the
tanks reaches the maximum level, the
pump shuts down automatically.
To make a crude comparison of the
two systems, water pumps usually
weigh tens of kilos or more, are very
loud, and require large amounts of en-
ergy. In time, the pipes and the gaskets
wear out, and water begins to escape,
unless they are maintained to prevent
corrosion and rust.
The sucking system in the mosqui-
3
to's head is less than 1mm in size. It

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