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
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.

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]
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