Monoxia sp. 2

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 : 48

Monoxia sp. 2

( Figs. 113–115 , 169 )

Reared specimens. COLORADO: Pitkin Co., Redstone, Avalanche Creek , near Rte. 133, 12.vii.2015, em. 29.vii.2015, C.S. Eiseman, ex Herrickia glauca , # CSE1894 (1♀, MLBM) .

Collected specimens. COLORADO: Pitkin Co., Redstone, Avalanche Creek , near Rte. 133, 12.vii.2015, preserved 22.vii.2015, C.S. Eiseman, ex Herrickia glauca , # CSE1756 (5 larvae, MLBM) .

Host. Asteraceae : Eurybia glauca (Nutt.) G.L. Nesom.

Biology. The single leaf mine we photographed begins at a lump of frass on the upper leaf surface, a few millimeters from the apex. The mine is full-depth, occupying the full width of the leaf, with just a few scattered fecal pellets inside ( Figs. 113–114 ). We collected numerous similar mines on 12 July, each containing a single larva. By the next day, several had exited their mines and were feeding externally, mostly leaving the opposite epidermis intact but occasionally eating holes all the way through ( Fig. 115 ). Before long, all of the larvae had exited and were feeding in this manner. One larva pupated on 20 July, and the adult emerged nine days later.

Notes. This species is likely undescribed, but male genitalia are important for diagnosing species of Monoxia (S.M. Clark in litt.). No leaf-mining insect has previously been reported from Eurybia sect. Herrickia (Wooton & Standl.) G.L.Nesom. Abandoning leaf mines to feed externally is almost unheard of among Nearctic leaf-mining beetles, and the only exceptions of which we are aware are Altica cf. lazulina (discussed above) and two introduced species that are said to do so in Europe: Neogalerucella pusilla (Duftschmid) ( Chrysomelidae ), on Lythrum salicaria L. ( Lythraceae ), and Hypera rumicis (Linnaeus) ( Curculionidae ), on Polygonaceae ( Ellis 2017) . Larvae of another galerucine, Erynephala maritima (LeConte) , mine in Salicornia L. ( Amaranthaceae ) stems in early instars and switch to feeding externally as they grow larger ( Eiseman & Blyth 2022). The only previous report of Monoxia larvae feeding in a mode other than leafmining is Santiago-Blay’s (2004) statement that “some of the chenopodfeeding Monoxia larvae seem to bore and live in the unopened flower buds or fruits.”

Figures

FIGURES 107–117. Leaf mines and larvae of Monoxia spp.; 107: M. elegans on Atriplex canescens; 108: same (transmitted light); 109: M. inornata on Grindelia squarrosa; 110: same; 111: Monoxia sp. 1 on Atriplex hymenelytra (vacated); 112: same (with larva); 113: Monoxia sp. 2 on Eurybia glauca; 114: same mine in transmitted light, showing larva at lower left; 115: externally feeding larva of Monoxia sp. 2 on Eurybia glauca; 116: Monoxia sp. 3 on Isocoma acradenia; 117: same (transmitted light).

FIGURES 162–173. Chrysomeloidea adults; 162: Dibolia cf. obscura; 163: Mantura floridana; 164: Phyllotreta liebecki; 165: Phyllotreta sp. 2; 166: Monoxia elegans; 167: M. inornata; 168: Monoxia sp. 1; 169: Monoxia sp. 2; 170: Monoxia sp. 3; 171: Yingabruxia brisleyi; 172: Zeugophora puberula; 173: Z. varians.