The
Dark Fly
The
dark fly, Anopheles caligatus,
does not get its name from its color, which is, in fact, a light
grey. Rather,
it is due to
its preferred habitat. Just as the
dark fly is not a fly, but a
mosquito.
The
dark fly lives mainly in the caves of Southern Europe, although some
colonies have been found as far north as Bergen, in Norway, and
others as far south as the Atlas mountains in Morocco. Although many
mosquito species fly in swarms during the mating season to improve
chances of reproduction and as a defense mechanism against predators,
the behavior is more pronounced in dark flies, and for good
(evolutionary) reasons.
Living
in caves, they often share their habitat with bats. Dark flies emit a
strong odour that repels the nightly mammals, but only if they can
gather in big enough swarms for the smell to reach a certain
threshold. Otherwise, the bats will trade off the slight dipleasure
for a juicy
meal. However, it has been observed on mutlitple occasions that,
whenever a swarm of dark flies manages to settle in a cave, it will
soon drive out the bats. Indeed, Dr. Hugo Forsher, from the German
Institute of Reverse Displacement (DIVV, Deutsches Institut der
Verkehrten Verscheuchung), believes that dark flies are one of the
main causes for dwindling bat populations in Europe today.
The
fact that dark flies ar drawn to darkness, and not light, is an
as-of-yet unexplained curiosity. This
behavior has driven the mosquitoes into caves, where the low
visibility and intense echoes make communications through sound and
sight impractical. Because of this, dark flies have a very pronounced
olfactive sense. It is believed that there is not a place in Europe
from where a dark fly would not be able to find the nearest colony of
its fellows.
Although
they rarely come into contact with humans due to their living
preferences, a few cases have been reported where people venturing
into caves inhabited by dark flies have had so much of their blood
sucked that their lives where in jeopardy. What the mosquitoes eat
when no humans are present is not yet know, altough scientists
believe their diet must consist mainly of small mammals that wander
into their territory. None of them went to check, though.
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