Microrhopala vittata

Microrhopala vittata (Fabricius) (Figs. 13, 61–62, 140) Reared or barcoded specimens. COLORADO: Gunnison Co., Somerset, Erickson Springs, 11.vii.2015, em. 20.vii.2015, C.S. Eiseman, ex Solidago, # CSE1727 (2 specimens, MLBM); ILLINOIS: Coles Co., 1 mile west of Charleston, 6.vi.2008, em. 20.vi.2008, T. Harrison, ex Helianthus occidentalis (BG 192485); IOWA: Allamakee Co., Decorah, Heritage Valley, 25.vi.2019, em. 13.vii.2019, C.S. Eiseman & J.A. Blyth, ex Oligoneuron rigidum, # CSE5571 (2 adults, MLBM); MASSACHUSETTS: Franklin Co., Northfield, 276 Old Wendell Rd., 25.vii.2017, em. by 31.vii.2017, C.S. Eiseman, ex Solidago rugosa, # CSE4026 (2 larvae, ZFMK); Nantucket Co., Nantucket, Sanford Farm, 27.vii.2017, em. by 10.viii.2017, C.S. Eiseman, ex Solidago rugosa, # CSE4093 (3 larvae, ZFMK). Collected specimen. OHIO: Marion Co., Ohio State University, Larry R. Yoder Prairie Learning Laboratory, 2.vii.2019, C.S. Eiseman & J.A. Blyth, on Oligoneuron rigidum, feeding adjacent to vacated mine, # CSE5408 (1 adult, MLBM). Photographed mine. MASSACHUSETTS: Berkshire Co., Lenox, Pleasant Valley Wildlife Sanctuary, 10.vi.2021, C.S. Eiseman, Solidago patula [with adult resting on leaf] (iNat 203232902). Hosts. Asteraceae: Euthamia graminifolia (L.) Nutt., Solidago altissima L., S. canadensis L., S. gigantea Aiton, S. juncea Aiton, S. missouriensis Nutt., S. mollis Bartl., S. *patula Muhl. ex Willd., S. rigida L., S. rugosa Mill., S. sempervirens L., S. uliginosa Nutt., S. ulmifolia Muhl. ex Willd. (Harris 1835; Chittenden 1902; Hendrickson 1930; Messina & Root 1980; Clark et al. 2004). Chittenden’s (1902) record of “ Solidago lanceolata ” may refer either to a Euthamia species or to S. odora Aiton; we have found a Microrhopala mine on the latter host in Moore Co., North Carolina (BG 1681380), but the dense mass of stringy frass suggests it was made by a species other than M. vittata. Messina & Root (1980) found a few M. vittata egg clusters on E. graminifolia but reported that ovipositing females strongly discriminate against this host. The only beetle mines we have found on Euthamia are those of M. excavata reported above. We have not checked that each Solidago species listed has been reported as a larval host, but we consider them all likely to be used. Some, and perhaps all, records of M. vittata from Silphium spp. refer to M. laetula (Clark et al. 2004). The Illinois specimen listed above, reared from Helianthus occidentalis Riddell, was identified as M. vittata by C.L. Staines from a photograph, but given that this plant is more closely related to Silphium than to Solidago, the beetle may actually represent M. laetula, which Staines does not recognize as a distinct species. Microrhopala vittata is also recorded from “ Aster ”, Balsamorhiza Nutt., and Sericocarpus Greene (Asteraceae), but these may not be larval hosts (Clark et al. 2004). Biology. Eggs are deposited on the lower leaf surface, in clusters or rarely singly, and coated with liquid, dark brown to blackish excrement (Fig. 13). The leaf mines are brown, full-depth, and formed at the leaf apices (Figs. 61–62). Frass is deposited in short strips, evenly distributed throughout the mine; this species does not form a dense frass deposit associated with a pupal blister as is done by Microrhopala excavata and M. xerene. Parasitoids. Adults of Conura albifrons (Walsh) (CSE5545, UFES) and C. odontotae (Howard) (CSE5683, UFES) (Chalcididae) emerged on 11 and 18 July, respectively, from pupae of M. vittata in mines on Solidago rigida collected on 2 July in Ohio. An adult of Neochrysocharis arizonensis (Crawford) (Eulophidae) emerged on 26 July from the Colorado collection (CSE1849, BMNH). Previous records of eulophids from Microrhopala vittata include Baryscapus microrhopalae (Ashmead), Pnigalio uroplatae (Howard), and a species of Chrysonotomyia Ashmead attacking eggs (Burks 1979; Yoshimoto 1983; Damman & Cappuccino 1991). Notes. See Notes above under M. laetula.