ENPO110624_D013 Published June 26, 2011 at 800 × 529 in ENPO110624_D013 A regal fritillary flattens itself against a wind gust while nectaring on musk thistle. Dahms 2000 Prairie Restoration – Platte River Prairies, Nebraska. Regal fritillary butterfly (rare species) nectaring on musk thistle (noxious weed). Flattening wings against a stiff wind.