Phyllotreta undefined-1

Phyllotreta sp. 1 (Fig. 101) Reared specimens. OKLAHOMA: Payne Co., Stillwater, 22.iii.2016, em. 14.iv.2016, M.W. Palmer, ex Lepidium oblongum, # CSE3069 (3 adults, MLBM). Host. Brassicaceae: Lepidium oblongum Small. Biology. The larva is slender and yellow with dark spots, seemingly identical with that of P. chalybeipennis figured by Eiseman (2015). The single photographed mine is full-depth and linear, about 0.5 mm wide, following the margin of a leaf whose main body is only 1 mm wide, and entering some of the narrow lobes (Fig. 101). Frass particles form a more or less continuous central line. Notes. The genus Phyllotreta includes 48 Nearctic species, which are generally associated with mustards and related plants (Brassicales) (Riley et al. 2003; Clark et al. 2004). The immature stages of many species are unknown, and just seven are reported to be leafminers; most feed on roots and a few are stem borers. The species with maculate elytra were revised by Smith (1985), including five leafminers: P. armoraciae (Koch) (normally feeding only in the midrib and petiole), P. constricta Smith, P. liebecki (discussed above), P. oregonensis (Crotch), and P. zimmermanni (Crotch). The immaculate species mostly have not been taxonomically studied since Chittenden (1927), when genitalia were not yet known to be critical for identifying species in the genus. Even so, based on external characters, our specimens do not match well with the published descriptions of any of the species known to occur in North America, and they most likely belong to an undescribed species. However, extensive taxonomic research would be required to confirm this (S.M. Clark, in litt.). The two immaculate species known to mine leaves are P. aeneicollis (Crotch), which is recorded from several genera of Brassicaceae, and the Cakile Mill. (Brassicaceae) specialist P. chalybeipennis. Chittenden (1923) reported Lepidium as a larval host for P. aeneicollis, P. liebecki, P. oregonensis, and P. zimmermanni; the record for P. oregonensis, as well as the assertion that it is a leafminer, requires confirmation, since Chittenden’s concept of P. oregonensis included at least two other species (Smith 1985).