Graphomya maculata (Painted Graph Fly)
by Steven Falk
Males of this medium-sized muscid are particularly distinctive, and only really need to be compared with males of G. minor. In G. maculata the abdomen is wider than long and has conspicuous orange markings (abdomen is longer than wide in G. minor and with any orange markings inconspicuous). G. minor also has a short but strong anterodorsal bristle below the middle which is missing in G. maculata.
Females of the two species, whilst readily distinguishable from other muscids, are much more difficult to separate. In G. maculata, the pale median stripe of the thorax is more less as pale as the other stripes and approximately as wide as the black stripes on either side. In G. minor, this median stripe is much darker and narrower. The middle tibiae of G. maculata lack the anterodorsal bristle found in G. minor.
G. maculata is widespread and common, especially in damp woodland, wetlands or along lushly vegetated ditches and water margins. The larvae develop in wet mud where they are predaceous on other Diptera larvae such as the rat-tailed maggots of eristaline hoverflies and the larvae of Ptychoptera craneflies. They have also been reared from water-filled tree rot-holes feeding in the larvae of the hoverfly Myathropa florea. Adults fly from May to October and visit flowers such as umbellifers, composites, scabiouses and Ivy.
NBN map:
species.nbnatlas.org/species/NBNSYS0000030888
