Systematics and biology of Caloptilia triadicae (Lepidoptera: Gracillariidae), a new species of leaf-mining moth of the invasive Chinese tallow tree (Triadica sebifera (L.) Euphorbiaceae).
A new species of leaf-mining moth, Caloptilia triadicae, is described from the southern United States from Florida to eastern Texas. Larvae of this moth are known to feed preferentially and at high densities on the Chinese Tallow tree, Triadica (=Sapium) sebifera (L.) Roxb. (Euphorbiaceae), a tree first introduced into Georgia in 1772 from Asia, which has since become an invasive plant species of grave concern over much of the southeastern United States and California. Caloptilia triadicae is also known to feed rarely on Gymnanthes lucida Sw. (Euphorbiaceae), a tree not known to occur in the Old World but native to Florida, the Bahamas, the Caribbean, and Central America. Because of the origin of the preferred host and the morphological affinities of the moth to the Chinese species, Caloptilia hamulifera Liu and Yuan, it appears likely that C. triadicae also originated from Asia. The larvae of Caloptilia are hypometamorphic and possess two distinct larval body forms and feeding behaviors - an early stage sap-feeding form with a flattened body and prognathous mouthparts and a later stage tissue-feeding form with a more cylindrical body and possessing hypognathous mouthparts. The sap-feeding larvae initially construct long, serpentine, subepidermal mines on the upper (adaxial) leaf surface. After developing to the tissue-feeding form, the larva of C. triadicae leaves the mine and crawls to the edge of the leaf and cuts a narrow strip of leaf which is rolled into a tight coil. It continues feeding externally on the leaf inside the roll in which it eventually forms a silken cocoon for pupation.