Plant-Insect Interaction: Gall-making insect on giant ironweed

Giant ironweed (Vernonia gigantea, Asteraceae) photographed 10/23/2011 in a floodplain forest near Blissfield Michigan.

In the summer when giant ironweed (Vernonia gigantea, Asteraceae) is full of healthy nectar-laden blossoms, I’ve found it visited by silver-spotted skippers, cabbage whites, and other pollinating butterflies, bees, and wasps.  Now that we’re well into autumn, the dried, dead plants still host other insects.

Giant ironweed (Vernonia gigantea, Asteraceae) infested with an unknown gall-making insect. Photographed 10/23/2011 in a floodplain forest near Blissfield Michigan.

While out in a nearby floodplain forest here in southeast Michigan, I noticed a number of galls along the leaf midveins.  Naturally I split some open to find out what insect was responsible.

Unknown gall-making insect larva in a giant ironweed (Vernonia gigantea, Asteraceae). Photographed 10/23/2011 in a floodplain forest near Blissfield Michigan.

I found the larvae of some unknown insect in the middle of the galls.  I’ve made some effort searching the literature on leaf galls, but I have yet to identify this insect.  At this point I suspect it’s a fly (order Diptera) and possibly a gall midge (family Cecidomyiidae).

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About Jeremy Sell

Science and nature nerd.
This entry was posted in Botany, Ecology, Entomology, Organism Interactions and tagged , , , . Bookmark the permalink.

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