Local feeder (Hymenoptera: Eurytomidae) in stems of Festuca

Record Details

Record no.:	0390
Feeding guild:	Local feeder in stem
Taxonomy:	Hymenoptera: Eurytomidae: Tetramesa sp.
Stages observed:	trace, larva, adult
Distribution observed:	IA
Hosts in Festuca:	F. subverticillata (nodding fescue) (tentative ID)

Larvae were found in culms of this woodland grass in summer 2017. One affected culm was slightly swollen and discolored at the location where a larva dwelled within. I reared adults the following spring; R. Hill identified them to genus (Hill 2018a; Hill 2018b) from photos. Palmer (2018) helped me tentatively identify the host plant as Festuca subverticillata.

Tetramesa festucae has been previously recorded from Festuca sp. (Krombein et al. 1979).

Featured Images

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Image #: 390-01 Culm of host grass, at location where a larva dwells within. (Photo date: July 5, 2017)

Image #: 390-02 Affected culm, dissected, showing larva inside. (Photo date: July 5, 2017)

Image #: 390-05 Anterior end of larva, lateral view.

Image #: 390-06 Affected culm after overwintering, dissected, revealing adult wasp that has not yet emerged from the culm. (Photo date: May 18, 2018)

Image #: 390-07 Adult wasp from culm in previous photo (0390-06). (Photo date: May 18, 2018)

Image #: 390-08 Dissected culm from previous photo (0390-06), with adult wasp removed from culm interior prior to photography; note the exit window not yet used by the adult wasp. (Photo date: May 18, 2018)

Image #: 390-09 Dissected culm from previous photo (0390-06), showing exit window as-yet unused by the adult wasp that was lingering inside the culm before the culm was opened for photography.

Image #: 390-10 Detail, unused exit window in culm.

Image #: 390-11 Unused exit window in culm, backlit and viewed from the culm exterior.

Image #: 390-12 Another adult wasp successfully reared in an overwintered culm; like the previous example, this adult has not yet evacuated the culm. (Photo date: May 15, 2018)

Image #: 390-13 Detail, reared adult in culm.

Image #: 390-14 Reared adult, lateral. (Photo date: May 18, 2018)

Specimen Data for Images

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Coll. 07/01/17, photos of culm chamber and larva on 07/05/17 (01-02, 04-05), adults found in rearing container on 05/15/18 (some out and about in the rearing container and others still in culms), photos of adults and exit window in culm on 05/15/18-05/18/18 (06-15). All specimens above from Iowa, USA.

References

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Hill, R. 2018a. Comment on contributor post at BugGuide.net. Retrieved November 13, 2023 from https://bugguide.net/node/view/1548819.[return to in-text citation]
Hill, R. 2018b. Comment on contributor post at BugGuide.net. Retrieved November 13, 2023 from https://bugguide.net/node/view/1548826.[return to in-text citation]
Krombein, K.V., Hurd, Jr., P.D., Smith, D.R., and B.D. Burks. 1979. Catalog of Hymenoptera in America north of Mexico. Smithsonian Institution Press.[return to in-text citation]
Palmer, M.W. 2018. Comment on contributor post at BugGuide.net. Retrieved November 13, 2023 from https://bugguide.net/node/view/1548836.[return to in-text citation]

Page created: November 13, 2023. Last update: March 10, 2026