Midge Taxonomy
The taxonomy for midges is quite complicated. They are insects of Order Diptera, Suborder Nematocera, and Infraorder Culicomorpha. Within the parks of Rome, we have typically found two Families of midges: Chironomidae and Ceratopogonidae. The stereo microscope enables us to determine sex of the midge as well as the family. Male midges have very distinct looking antennae: many flagellomeres (segments) with whorls of long setae leading to its plumose appearance, while females have antennae composed of fewer shorter flagellomeres with more sparse setae. To distinguish between the two Families, we examine midge’s flagellomeres . Chironomidae have rod-like flagellomeres while Ceratopogonidae have ball-shaped flagellomeres. The difference between the two types can be seen in a comparison of Figs. 7 & 10. Further classification into Subfamilies, Genus and Species can also be accomplished using the stereo microscope to scrutinize other morphological characteristics of the midge, namely the wings and legs. The primary aspect to examine in the wings is the veins, especially their distribution pattern. The legs of a midge have five segments and the ratio between the lengths of various segments can be a classifier. To truly identify a midge to the Species level requires looking at the “hypopygium” i.e. the male sexual organ in midges. This process involves dissecting the midge to remove the hypopygium and mounting it on a slide to be examined under the compound microscope. Unfortunately, this means that it is not possible to identify precisely female midges.
For further information on midge identification (and the resource we currently use), see: P.H.Langton and L.C.V.Pinder, Key to the adult male chironomidae of Britain and Ireland, Volumes 1 and 2, Freshwater Biology Association, 2007.
Chironomidae
This is a Family of nematoceran flies that can be found around the world. Known informally as chironomids or non-biting midges, they are also closely related to Ceratopogonidae. As can be seen the figures below, Chironomidae resemble mosquitoes and are frequently misidentified as the latter. The difference between the two is that former lacks the wing scales and mouthparts of the latter. The following figures show a sample of the different specimens that we have collected throughout Rome.
Figs. 1 – 4 are Subfamily: Orthocladiinae, Genus: Cricotopus, Species: Sylvestris
Figs. 5 and 6 show close ups of the hypopigium of two different midges. Fig. 5 is the same Species as Figs. 1 – 4 i.e. Cricotopus Sylvestris, while Fig. 6 is Nanocladius Rectinervis.
Figs. 7 and 8 show another species of midge that is common in Rome: Chaetocladius Piger.
Ceratopogonidae
Although technically a Family of biting midges, the only species that we have found so far is from the Genus Dasyhelea, which is known to feed on nectar.
