PREDISPERSAL SEED PREDATION OF CANADA THISTLE

Abstract

AbstractPredispersal seed predation of Cirsium arvense (L.) Scop. (Asteraceae) by Orellia ruficauda (Fabr.) (Diptera: Tephritidae) occurs in about 20–85% of the seed heads and the proportion of damaged seeds per attacked head averages 20–80% depending on geographical location and sampling date. Microscopic studies of damaged seeds were performed. Although the impact of this seed predator is not severe, it may be an important factor in the population regulation of the weed.