Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Beetle at Home on Lily Pad - Donacia

Beetle at Home on Lily Pad - Donacia
East of Buckhannon, Upshur County, West Virginia, USA
August 16, 2005
Found this beetle while stalking Vesper Bluets on Lily pads. Confirmation, denial, elaboration of ID appreciated.

Moved from Donacia.


Sure Donacia!
- elongated hind legs, also water lilies are not food plants of Plateumaris spp.

aquatic leaf beetle
Apparently, Plateumaris species are very similar to Donacia. The only difference mentioned in this key to Alabama Donaciinae is whether the sutural margin of the elytra is straight to the apex [Donacia] or sinuate near the apex [Plateumaris]. Judging from the diagram, it's a small difference that would be difficult to see in most photos.
I wonder whether at least some of the photos on the Donacia page are actually Plateumaris species. Does anyone know a way to distinguish these two genera based on photographs?

Next year
These beetle seemed common enough. Next year I'll try to get a high resolution dorsal view of the rear of the elytra.


Stephen Cresswell
Buckhannon, WV

In the meantime...
since none of the photos currently on the Donacia page have been identified to species, and none of the comments under the photos have explained how Plateumaris can be distinguished from Donacia, I think it would be safer to move all the images to the subfamily level.

pretty sure youre genus is correct, we have some in florida from this genus and they look almost exactly the same, unfortunately we never id'd ours to species...