Adaptation and Identification
Hover flies carry a
variety of adaptations that make them unique and allow them to
fit into their ecological niche. Many of these adaptations are
in regards to appearance and can be used to help identify
members of each individual species.
One main adaptation unique to the genus
Eristalis is that all
members display some sort of batesian mimcry- an otherwise
defenseless organism posing as another that is undesirable to
predators. (Microscopy-UK 2007) In the case of
Eristalis transversa
the organism being mimicked is a honey bee; the threat of a
nasty sting will keep most predators at bay.
While this seems like a fool proof
mechanism, there is one flaw that allows hover flies to be
easily distinguished. Bees and wasps have four wings (two pairs)
where hover flies only have two (one pair). The reason for this
is because the hover flies second pair of wings has been
modified, over time, into a small structure used for in-flight
balancing known as a halter. (Kaufman 2007) Upon further
examination of the wing, another identifying feature becomes
evident: hover flies have a false vein on each wing about midway
up the wing that just tapers of and does not actually connect to
anything. If one of these false veins is observed, the specimen
is surely a hover fly. (Microscopy-UK 2007)
One very interesting and unique adaptation
of hover flies is their ability to actively digest pollen and
use its proteins in their own body, something not many insects
or animals are capable of due to the exterior of a pollen
particle which is very resistant to digestive enzymes.
(Microscopy UK 2007)
For more detailed diagrams and photos of hover fly anatomy please visit: All about Hover Flies
How and what hover flies feed on: Nutrition