Aciurina idahoensis

Aciurina idahoensis Steyskal is a univoltine, monophagous fruit fly that forms distinctive, leafy, axillary bud galls on Chrysothamnus viscidiflorus (Hooker) Nuttall, its only known host plant, throughout the western United States.
Wangberg (1981) remarked that "... this species was common throughout southern Idaho and often abundant at various sites, ..." and that its distribution "... appears continuous and co-extensive with its host plant." Aciurina idahoensis has only been found in Deep Spring Valley in California.
The gall of A. idahoensis is a stunted axillary branch, or rarely a branch apex, reminescent of a pine cone (Steyskal 1984). As such, it is subspheroidal when young (Fig. 7A), elongating into an ovoid as it grows and matures (Fig. 7D, E). The gall also bears basally expanded, sessile, linearly tapered, and apically pointed, smooth-margined leaves, which are shortened and more densely packed apically (Fig. 7E). The oldest, basal, overwintered leaves were dead and tan (Fig. 7 A, B); the new leaf growth light green (Fig. 7B). The gall body is largely composed of whitish, expanded leaf bases, nodes, and expanded pith parenchyma (Fig. 7D, F). The gall is uniloculate (monothalmus) and characteristically contains a small, initially subspheroidal (Fig. 7C), later narrow, elongate-ellipsoidal, central open chamber within which the larva feeds (Fig. 7D). This gall is quite unlike the axillary bud galls of A. ferruginea and A. michaeli, both externally and internally (Goeden and Teerink 1996), and indeed, more closely resembles the galls of an apparently unnamed Procecidochares, misidentified as P. stonei Blanc and Foote (Tauber and Tauber 1968, Green et al. 1993), and certain Cecidomyiidae, all of which form fleshy, leafy, bud galls with narrow, elongate, cylindrical central cavities on C. viscidiflorus in southern California (Goeden and Teerink, unpublished data). 



Life History and Descriptions of Adults and Immature Stages of Aciurina idahoensis Steyskal (Diptera: Tephritidae) on Chrysothamnus viscidiflorus (Hooker) Nuttall in Southern California