Predatory and Parasitic Insects Associated with Urophora cardui L. (Diptera: Tephritidae) Galls on Canada Thistle, Cirsium arvense L. (Asterales, Asteraceae) in North Dakota

Abstract

We surveyed the insect fauna associated with Urophora cardui L. (Diptera: Tephritidae) galls on Canada thistle, Cirsium arvense L. (Asterales, Asteraceae), in parts of the northern Great Plains, U.S., by field-collecting galls and rearing or dissecting out the insects. We also examined the relationships between gall biomass and insect density and biomass. Urophora cardui were widespread, and the gall biomass was positively correlated with fly density and fly biomass. We recovered Isohydnocera tabida (LeConte) (Coleoptera: Cleridae) from galls in two counties, which represents a new host record and provides vital information on the little-known immatures of this predatory species. Pteromalus elevatus (Walker) (Hymenoptera: Pteromalidae) was the dominant parasitoid that emerged from the U. cardui galls. Individual galls typically only had one insect species, and occasionally both U. cardui and P. elevatus were present, but it was rare for other insects to be present in galls housing I. tabida. This study adds to the taxonomic literature of gall-inhabiting insect species and provides new information on the predators of U. cardui, specifically a little-known clerid beetle species.

Arthropod communities associated with gall-inducingAciurina bigeloviaeandAciurina trixa(Diptera: Tephritidae) in New Mexico

“…Both of these Aciurina -associated communities appear to be far richer than those documented from other studied Asteraceae-galling Tephritidae species (e.g. Valentibulla spp., Tephritis conura, Eutreta diana, Eutreta xanthochaeta, Tomoplagia rudolfi, Urophora cardui ) by at least two-fold (Wangberg 1978, Romstock-Volkl 1990, Emlen 1992, Hernández-López et al 2021, Maia and Silva 2021, Swenson et al 2022). The most closely-related tephritid fly with a species-level community description, Eurosta solidaginis , only hosts 3 associates (Walton 1988).…”