Rhopobota finitimana

Rhopobota finitimana (Heinrich)

(Figs. 14–17)

Material examined. NORTH CAROLINA: Durham Co., Durham, Leigh Farm Park, 14.vi.2017, em. 16.vii.2017, T.S. Feldman, ex Ilex decidua, # CSE3965 (2♀♀, CUIC); Scotland Co., Laurinburg, St. Andrews University, 27.ii.2019, em. 13.v.2019, T.S. Feldman, ex Ilex opaca, # CSE5261 (1♂, CUIC).

Hosts. Aquifoliaceae: Ilex decidua Walter, I. mucronata (L.) M.Powell, Savol. & S.Andrews (Ferguson 1975), I. opaca Aiton, I. verticillata (L.) A.Gray (Heinrich 1923). Prentice (1966) listed a single record of this species as a solitary leafroller of Populus balsamifera L. (Salicaceae). We regard this as likely representing either a misidentified moth or a pupation site rather than a larval feeding site.

Biology. Young larvae form full-depth leaf mines, which on I. opaca tend to be long and narrow and on deciduous hosts tend to be more compact. In either case frass is extruded from a hole in the lower epidermis, usually at the leaf midrib, and is bound together with silk. On deciduous hosts the frass bundle becomes a narrow, curved tube (Fig. 14). The mines are frequently digitate or branching due to the larva’s pauses in feeding to dispose of frass. Older larvae abandon their mines to feed in a leaf shelter, either crumpling one leaf or tying two together. A pupal case is sometimes made by cutting one or two small arcs in a leaf to form a flap in which the larva spins its cocoon (Fig. 15). Our rearing records suggest this species is at least bivoltine in North Carolina.

Comments. Eiseman (2014b) documented identical larval habits in Rhopobota dietziana (Kearfott) on Ilex glabra (L.) A.Gray and I. verticillata, noting that further rearing efforts would be desirable to determine whether R. finitimana is also a leafminer initially. We have found Rhopobota mines on I. vomitoria Aiton in North Carolina, but no adults have been reared from these. The other Nearctic species in this genus, R. naevana (Hübner), also occurs on Ilex but larvae reportedly feed as leaftiers (i.e., not as leafminers but as external feeders within shelters formed by tying leaves together with silk) throughout their development (Eiseman 2014b).