Stem borer (Coleoptera: Mordellidae) in Helenium

Record Details

Record no.:	0262
Feeding guild:	Stem borer
Taxonomy:	Coleoptera: Mordellidae
Stages observed:	trace, larva, adult
Hosts in Helenium:	H. autumnale (sneezeweed)

The larva in the photos below, found overwintering in a dead stem of the host, occupied a relatively short (length ~80mm) chamber in the upper stem from which nearly all the pith had been consumed; the lower end of the chamber had been filled with a significant amount of compacted frass. Pupation occurred in this chamber and the adult emerged in spring. Mordellistena convicta and Mordellina pustulata have been previously reared from this hostplant in the Upper Midwest (Lisberg and Young 2003).

Featured Images

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Image #: 262-01 Compacted frass in lower end of stem chamber occupied by larva. (Photo date: January 11, 2023)

Image #: 262-02 Compacted frass in stem.

Image #: 262-03 Boundary between compacted frass and the open, cleared-out portion of the chamber in which the larva was found.

Image #: 262-04 Larva in stem. (Photo date: January 11, 2023)

Image #: 262-07 Urogomphi on posterior end of larva.

Image #: 262-09 Pupation chamber in stem, after adult's successful emergence.

Image #: 262-10 Pupation chamber in stem, after adult's successful emergence, with pupal exuviae crumpled up at far left.

Image #: 262-11 Pupal exuviae in pupal chamber in stem.

Specimen Data for Images

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Coll. 01/11/23, photos of larva and plant damage same day (01-08), adult em. 05/12/23, photos of pupal exuviae and pupation chamber same day (09-11), photos of adult on 11/11/23 (12-13). All specimens above from Iowa, USA.

References

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Lisberg, A.E. and D.K. Young. 2003. An annotated checklist of Wisconsin Mordellidae (Coleoptera). Insecta Mundi, vol. 17, no. 3-4, Sept.-Dec. 2003, pp. 195-202.[return to in-text citation]

Page created: March 10, 2026. Last update: none