Aphilodyctium fidum (Cresson, 1880)

Baine, Quinlyn & Looney, Chris, 2019, Plant associations for three sawfly species (Hymenoptera, Tenthredinidae) in the Pacific Northwest, Journal of Hymenoptera Research 74, pp. 27-33 : 27

Aphilodyctium fidum (Cresson, 1880)

Notes.

One male A. fidum was reared from a stem of Rosa rubiginosa Linnaeus, 1758, hand-collected in March 2018 and connected to a Diplolepis rosae (Linnaeus, 1758) gall measuring about 29 mm in diameter. The gall was from a previous season, and all gall wasps and the associated component community had already emerged. The sawfly emerged from the apex of the cut stem, leaving a hole that measured about 3.5 mm in diameter leading to a frass-filled gallery through the stem pith, about 23 mm in length. The discarded larval skin of the sawfly was discovered at the end of this gallery, as well as a partial adult head and some exoskeletal remnants of a different unidentified hymenopteran.

One male A. fidum was reared from a gall of D. rosae also collected from R. rubiginosa . The gall was collected in the fall and stored at 0 °C for 90 days to simulate overwintering conditions ( Williams et al. 2003). After this the gall was transferred to room temperature to allow insects to emerge. Galls were checked several times a week, with insects pinned or transferred to vials of 70% EtOH as they emerged. This gall was not retained, but was instead dissected as part of a different research project. It therefore isn’t clear if the insect was feeding within the gall or if, like the M. pulla specimen from Oregon, it was feeding or overwintering in other associated plant tissue.

Specimen data.

United States; 1♂; Washington, Clark County, Port of Vancouver; 45°38.60'N, 122°42.33'W; Mar. 2018, em. unknown; C. Looney leg.; ex: Rosa rubiginosa . United States; 1♂; Idaho, Ada County, Boise; 43°34.36'N, 116°8.78'W; 26 Dec. 2006, em. Feb. 2007; E. Poor leg.; ex: Rosa rubiginosa .