Hooded Dryomyza

D. anilis adults are medium-sized, ranging in overall length from 7–14 mm, but are typically 12 mm long. Their coloration is light-brown and orange with large red eyes. Generally, the species can be separated from other species of Dryomyzidae by their nearly-bare arista (apical bristle), covered lunule (a crescent-shaped mark, found around the wing margins), and developed prostigmatic and prescutellar bristles. Dryomyzidae are characterized by closely spaced first antennal segments, a protruding oral margin, a strap-shaped or oral prosternum that is not joined to the propleura, and a lack of costal spines. D. anilis have short posterior spiracular tubes, lack hooks on their posterior spiracular plates, and have well-developed tubercles on segment 12 only. The fly's life span is between 28 and 178 days in the laboratory.

Taxonomy. Adult morphology indicates that Dromyzidae, Helcomyzidae, and Helosciomyzidae are more closely related to each other than they are to Sciomyzoidea. Therefore, though Dryomyzidae were previously part of Sciomyzidae, the family is now considered separate and has two subfamilies: Dryomyzinae and Helcomyzidae. There are two genera, Droymyza with ten species and Oedoparena with two species that are presently recognized. Moreover, as compared to other Dryomyza species found in the eastern United States (Dryope decipita and Dryomyza simplex), D. …

D. anilis is Holarctic, present in Canada and many northern states of the United States in the Nearctic realm. The fly is also widespread in the Palearctic realm from the United Kingdom to Japan. Within the United Kingdom, the fly is common and widespread in England and Wales, but is less common in Scotland. D. anilis are typically most prevalent in the wild from May to September. Adult flies are found in moist, shady habitats among low-growing vegetation and excrement. Adult habitats have been found in human excrement, fox and pheasant carrion, and malodorous stinkhorn fungi. Eggs have been found in human excrement, and larvae have been found in pheasant carrion. D. anilis can develop from egg to pupa on dead animal matter but not on decaying plant matter. Experimentally placed larvae were unable to attain maturity when grown on rotting grass, decaying pumpkin flesh, decaying lettuce, or cow manure. They did attain maturity when grown on hamburger, dead earthworms, dead crane flies, dead polygrid snails, a dead milkweed caterpillar, a dead slug, and rotting agaric mushrooms.

D. anilis can survive on food sources ranging from insects and vertebrates to rotting fungi. Pharyngeal ridges in the skeletons of larvae suggest that larvae derive nutrition from micro-organisms in the rotting organic food source. These ridges selectively sift through their food supply, ensuring that only nutritious food enters. Larvae that feed on living tissue do not have these pharyngeal ridges. The short incubation period of the fly (around 24 hours) may provide a competitive advantage in exploiting limited resources. No predators or parasites of D. anilis have yet been studied, but experimentally several larvae of Mydaea urbana were able to destroy a large population of D. anilis on human excrement.

Conservation. D. anilis serve as saprophages in the ecosystem. D. anilis, together with Calliphora terraenovae, were found using Pacific salmon carcasses as a food source and egg-laying substrate for D. anilis in the coastal North Pacific. Therefore, there is concern that continued decline in salmon populations could threaten D. anilis and other salmon-dependent communities.

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