Aciurina bigeloviae
Cotton-gall Tephritid

Hosts: Ericameria nauseosa

Galls occur singly or in pairs at axillary buds and appear as puffs of cotton attached to the stems.

Estimating tephritid distribution from host-plant distribution is problematic because some gall-forming tephritid flies are known to be less widely distributed than their hosts, e.g., A. bigeloviae (Cockerell) and A. trixa.

Both A. trixa and A. bigeloviae are known only from C. nauseosus; however, the galls they induce are readily distinguishable and is the best character for species recognition. Aciurina bigeloviae is known to form only large, cottony galls [see also Dodson and George (1986), Figure 2B] that sometimes bear small leaves studding the gall body, rather than a rosette of basal leaves as in A. semilucida (Goeden and Teerink 1996c). The tomentum of A. bigeloviae galls is thick and continuous over the entire gall, appearing like a wad of cotton. Aciurina bigeloviae galls have been collected from several sites in Idaho, Colorado, Arizona, New Mexico and Utah; however, most specimens in collections do not have the galls from which they were reared. The galls of A. maculata (Cole) also occur on C. nauseosus and are cottony; however, they are much smaller than A. bigeloviae galls and the adults are readily distinguishable.