Baliosus californicus (Horn)

Eiseman, Charles S., Feldman, Tracy S. & Palmer, Michael W., 2024, New larval host records, parasitoid records, and DNA barcoding data for North American leaf-mining leaf beetles (Coleoptera: Chrysomeloidea), Zootaxa 5549 (1), pp. 1-60 : 9

Baliosus californicus (Horn)

( Figs. 3 , 27–31 , 127 )

Reared specimens. CALIFORNIA: El Dorado Co., Pony Express trail, 38.767044, -120.326003, 22.vii.2023, em. 2–15.viii.2023, C.S. &A.B. Eiseman & J.A. Blyth, ex Ceanothus integerrimus , # CSE8346 (8 adults, MLBM); Placer Co. , Mosquito Ridge Rd. , 9.vii.2018, em. 24–28.vii.2018, E. LoPresti, ex Ceanothus integerrimus , # CSE4842 (5 adults, MLBM) .

Photographed mine. CALIFORNIA: San Diego Co., Cleveland National Forest , 32.89513, -116.44807, 29.viii.2024, D.J. Ringer, Ceanothus palmeri (iNat 239729763) .

Hosts. Rhamnaceae : Ceanothus fendleri A.Gray , C. integerrimus Hook. & Arn. , C. *palmeri Trel. , C. velutinus Douglas ex Hook. ( Chittenden 1902; Jones & Brisley 1925; Eiseman 2014). Adults have also been associated with C. leucodermis Greene ( Clark et al. 2004) .

Biology. Eiseman (2014) examined two mines on C. velutinus and noted that each began with a small, ragged hole chewed well away from the leaf margin, with no egg remains evident. When completed, the mines covered 1.5– 2 cm 2 and each had the frass deposited in a mass of fine particles concentrated toward the center. On C. integerrimus , some of the mines began with a similar hole and some did not, but all had the egg deposited in a pit chewed on the lower surface and partially covered with dark brown excrement ( Figs. 3 , 27–31 ). Early mines were distinctly upper-surface rather than full-depth, initially appearing green from above and then becoming whitish. Frass was initially deposited in a central mass, later becoming more scattered but still concentrated centrally.

Parasitoids. Chittenden (1902) noted that an unspecified chalcidid had been reared from the larvae of this species mining leaves of Ceanothus integerrimus . We reared an undetermined eulophine eulophid (CSE8331, CNC / iNat 202988548) from a collection of leaves of the same host that were mostly mined by Baliosus californicus , although there was a small number of Brachycoryna hardyi (Crotch) mines mixed in and we did not confirm which mine was the source of the wasp.

Figures

FIGURES 1–22. Eggs of Chalepini spp.; 1: Anisostena californica; 2: A. lecontii; 3: Baliosus californicus; 4: B. nervosus; 5: same; 6: Brachycoryna hardyi (photo by E. LoPresti); 7: B. pumila; 8: Chalepus bicolor; 9: C. walshii walshii; 10: Glyphuroplata pluto; 11: Microrhopala excavata excavata; 12: M. laetula; 13: M. vittata; 14: M. xerene; 15: Odontota dorsalis; 16: O. floridana; 17: O. horni (top view); 18: same (side view); 19: O. scapularis; 20: Sumitrosis ancoroides; 21: S. inaequalis; 22: S. rosea.

FIGURES 27–35. Leaf mines of Baliosus spp.; 27: B. californicus on Ceanothus integerrimus; 28: lower surface of same mines, showing an excrement-covered egg between each mine and the adjacent hole chewed by the ovipositing adult; 29: a more advanced mine of B. californicus on C. integerrimus, with larva visible at upper left; 30: another example of same; 31: lower surface of same mine, with excrement-covered egg at upper left edge of the dark central spot; 32: B. nervosus on Quercus alba, with two eggs at lower right; 33: B. nervosus on Ulmus americana; 34: B. nervosus on Prunus avium; 35: B. nervosus on Malus, with larva at far left and egg at far right.

FIGURES 122–140. Chalepini adults; 122: Anisostena californica; 123: A. funesta; 124: A. kansana; 125: A. lecontii; 126: A. cf. perspicua; 127: Baliosus californicus; 128: B. nervosus (reared from Alnus serrulata); 129: B. nervosus with DNA barcode differing from that of previous specimen by>10% (reared from Tilia americana); 130: Brachycoryna hardyi; 131: B. pumila; 132: Chalepus bicolor; 133: C. walshii walshii; 134: Glyphuroplata pluto; 135: Microrhopala excavata cyanea; 136: M. excavata excavata; 137: M. laetula; 138: same; 139: M. rubrolineata; 140: M. vittata; 141: M. xerene.