Local feeder (Diptera: Cecidomyiidae) in petioles and stems of Scrophularia

Record Details

Record no.:	0496
Feeding guild:	Local feeder in petiole and stem
Taxonomy:	Diptera: Cecidomyiidae: Neolasioptera sp.
Stages observed:	trace, larva, pupa, adult
Distribution observed:	IA
Hosts in Scrophularia:	undetermined S. sp. (figwort), either S. lanceolata (lance-leaf figwort) or S. marilandica (Maryland figwort)

Some individuals of this cecidomyiid form globular galls at nodes on stems of the host. At least one individual I observed was dwelling in a leaf petiole that lacked any obvious swelling or other outward distortion to the plant tissue. I assume that the petiole feeder and stem gallers belong to the same Neolasioptera species, but the reared adults have not yet been examined closely to confirm this. Determination to genus by R. Gagné (pers. comm. after examining specimens).

Featured Images

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Image #: 496-01 Gall on stem at node. (Photo date: September 8, 2016)

Image #: 496-02 Closeup of gall on stem at node.

Image #: 496-03 Dissected stem gall, showing blackish fungal discoloration and cocoon of larva.

Image #: 496-04 Detail, fungal discoloration with cocoon of larva.

Image #: 496-05 Overwintered stem gall in springtime, after an adult has emerged; the pupal exuviae of the emerged adult can be seen protruding from the gall.

Image #: 496-06 Pupal exuviae of an emerged adult protruding from stem gall.

Image #: 496-07 Detail, pupal exuviae protruding from gall.

Image #: 496-08 Adult reared from overwintered stem gall.

Image #: 496-09 Overwintered stem gall, dissected, showing a cecidomyiid cocoon in the hollow gall interior.

Image #: 496-10 Pupal exuviae protruding from a petiole, near where the petiole attaches to the stem, the adult having recently emerged. The plant material is shown after having been in a container indoors for several weeks, hence its brown color. (Photo date: August 30, 2021)

Image #: 496-11 Pupal exuviae protruding from a petiole. Note the petiole's apparent lack of swelling or other significant outward distortion.

Image #: 496-12 Pupal exuviae protruding from petiole. I detached the petiole from the main stem for photography.

Image #: 496-13 Adult reared from petiole.

Image #: 496-14 Dorsal views, adult reared from petiole.

Image #: 496-15 Lateral view of adult reared from petiole.

Specimen Data for Images

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Coll. 09/08/16, photographed same day (01); coll. 09/08/19, photographed same day (02-04); coll. 04/18/23, adult em. 05/12/23, photos on 05/23/23 (05-07,09) and 05/13/23 (08); coll. 07/26/21, adult em. by 08/30/21, photos on 08/30/21 (10-15).

Page created: September 16, 2023. Last update: March 21, 2026