Baliosus californicus (Horn)

Eiseman, Charles S., 2014, New Host Records and Other Notes on North American Leaf-Mining Chrysomelidae (Coleoptera), The Coleopterists Bulletin 68 (3), pp. 351-359 : 352

Baliosus californicus (Horn)

On 16 October 2012, I collected two irregular, brown, upperside blotch mines in leaves of Ceanothus velutinus Douglas ex Hook. (Rhamnaceae) near Camp Sherman, Oregon ( Fig. 1 ). One mine contacted the leaf edge and one did not. Both began with a small, ragged hole chewed well away from the leaf edge, with no egg remains evident. When complete, the first mine covered about 1.5 cm 2 and the second about 2 cm 2. Frass was not evident in reflected light, but in transmitted light it appeared as a dark mass of fine particles concentrated toward the middle of the mine. One adult emerged by 6 November and the other by 18 November, each chewing a conspicuous hole through the lower leaf epidermis to exit its mine (specimens in USNM). The adults then fed in irregular, narrow patches on the leaf underside (typically 1–3 mm long and <0.5 mm wide), only rarely chewing all the way through. This species is apparently specific to Ceanothus L., having been previously associated with Ceanothus fendleri A.Gray , Ceanothus integerrimus Hook. & Arn. , and Ceanothus leucodermis E. L. Greene ( Clark et al. 2004) .

Figures

Figs. 1–6. 1) Baliosus californicus mine in Ceanothus velutinus leaf; 2) Leaf mine in black oak (Quercus velutina) with section of upper epidermis removed to reveal two Baliosus nervosus adults and larval frass pattern; 3) Detail of Baliosus nervosus mine in black birch (Betula lenta) leaf, with ragged hole at lower right; 4) Chalepus bicolor larva mining in deertongue grass (Dichanthelium clandestinum), with frass expelled along the leaf margin; 5) Feeding sign of Chalepus walshii adults; 6) Glyphuroplata pluto larva mining in Panicum leaf, with frass in long strands.