Synonyms and other taxonomic changes
Anthomyia platura Meigen, 1826
Pegomya fusciceps Zetterstedt
Hylemya cilicrura (Rondani)
and many more synonyms.
Identification
"Males of [Delia platura] may be identified by the leg chaetotaxy, especially the rather numerous (23-30) pv on t3 in combination with absence of an extended pv row on f3." (Graham C. D. Griffiths)
Eggs and larvae of this species and D. florilega are at this time not distinguishable.
Broad-fronted males or male-type intersexes can occur.
Range
Cosmopolitan, probably originally from Europe
Food
Decaying organic matter, roots, seeds including crops such as corn, grasshopper eggs
Infestations of larvae on roots of brassica, radish, etc are generally secondary, following primary invasion by larvae of D. radicum and D. floralis. However, primary infestations of D. platura on radish roots can also occur. Mixed primary infestations of D. platura and D. florilega also occur on leguminaceous crops during seed germination in the northern Nearctic and on solanaceous crops. Further south, Delia platura becomes the only species involved.
On onions, mixed infestations occur along with D. antiqua. Finlayson (1956) also reports these joint infestations of even the aerial parts of onion as well as roots.
Other plants reported to be damaged by this species include corn, carrots, cucurbits, spinach, cotton, sugarbeet, and artichoke.
Some degree of decomposition of food is supposed to be necessary for the larvae to grow properly. Food sterilized of bacteria did not result in ill effects on the larvae. Bacteria were shown to be effective elicitors of oviposition. Larvae have been reared from fecal matter of people, cattle, sheep, and more, but females are not attracted to these for oviposition.
Very interestingly, Lindley & McSwain reported rearing this species from the cells of digger bees (Anthophora linsleyi), but it's possible the larvae could have been scavengers not attacking the bee.
Griffiths (1993) recorded larvae of this species on a fungus (Rhizopogon) as well.
Life Cycle
Several generations per year. Pupa overwinters.
Remarks
There are probably many unidentified photos of this species on BugGuide, as it is both common and widespread.
Two well known predators and parasitoids of Delia species are Aleochara bilineata (Coleoptera: Staphylinidae) and Trybliographa rapae (Hymenoptera: Figitidae). Aleochara verna is also reported as a control agent. Both species can also predate on adults. Two ichneumonoid wasps are also recorded at low levels, Phygadeuon (Ichneumonidae) and Aphaereta spp. (Braconidae).
Predators of adult flies include tiger flies (Coenosia tigrina in Muscidae) and Scathophaga spp. The significance of carabids and staphylinids as predators on larvae has been little investigated in North America.
The entomopathogenic fungi Entomophthorae muscae and Strongwellsea castrans cause a lot of mortality in these flies and many other Anthomyiidae.
D. platura have been found to house soft root bacteria in the intestinal tract of larvae and adults, and are postulated to be implicated in the facultative transmission of a few other plant pathogens (Griffiths, 1993).
See Also
Delia florilega differs in details of hairs on hind leg.
