Stem borer (Diptera: Agromyzidae) in Thlaspi

Record Details

Record no.:	0574
Feeding guild:	Stem borer
Taxonomy:	Diptera: Agromyzidae: Melanagromyza sp.
Stages observed:	trace, puparium, adult
Distribution observed:	IA
Hosts in Thlaspi:	T. arvense (field pennycress)

I reared an adult of this stem borer in March 2022 from a puparium collected from a tunneled stem in early August 2021.

The puparia have extremely pronounced black horns on the posterior spiracular plates -- perhaps the strongest horns I encountered on Melanagromyza puparia in the survey.

One puparium I found in a tunneled stem was accompanied by a tiny Coleoptera larva, which gave rise to an equally tiny reddish-brown adult beetle that appeared to belong to the Latridiidae (minute brown scavenger beetles).

Featured Images

[?] Top

Image #: 574-01 Tunneled stem with *Melanagromyza* puparium and ?latridiid larva.

Image #: 574-10 Beetle larva accompanying puparium, tentatively identified as Latridiidae based on the appearance of the adult beetle it produced.

Image #: 574-03 Two puparia from *Thlaspi* stems, with a millimeter ruler for scale.

Image #: 574-04 Posterior spiracles of puparium, showing very strong black horns.

Image #: 574-05 Black horns on posterior spiracular plates.

Image #: 574-07 Reared adult. Note blue-green color of iridescence on abdomen.

Page created: October 2, 2026. Last update: none