Saturday 5 May 2012

New species of Leaf-Mining Moth from northern Chile.

Leaf-Mining Moths have complex life-styles, with larvae that initially bore inside the leaves of plants, then graduate to a second larval feeding stage once they become to large for this strategy, typically feeding on leaves externally, stem-boring or gall formation, before pupating then emerging as an adult moth, which mates, then lays new eggs, restarting the cycle. New World Leaf-Mining Moths are well studied in North America, and a number of species have been described from Central America, the Caribbean Islands and the Galapagos, but to date the only species recorded from South America is Bucculatrix thurberiella, a widespread cotton-pest.

In a paper published in the journal Zootaxa on 4 May 2012, Hector Vargas of the Departamento de Recursos Ambientales at the Facultad de Ciencias Agronómicas at the Universidad de Tarapacá and Gilson Moreira of the Departamento de Zoologia at the Instituto de Biociências at the Universidade Federal do Rio Grande do Sul, describe a new species of Leaf-Mining Moth found growing on the herbaceous plant Baccharis salicifolia (Mule Fat, Seepwillow or Water-Wally) in the northern coastal desert of Chile, and named Bucculatrix mirnae in honor of Mirna Martins Casagrande of the Departamento de Zoologia at the Universidade Federal do Paraná.

Bucculatrix mirnae. (A) Adult male. (B) Adult female. Scale bars are 1 mm. Vargas & Moreira (2012).

Bucculatrix mirnae has five larval instars (in insects and other arthropods an instar is a growth stage between molts). The first three of these are lived as leaf-borers, internal to the leaf, the last two as leaf skeletonizers, feeding externally upon leaves.

Schematic representation of variation in Bucculatrix mirnae. (A-C) head and prothorax, dorsal view (first, third and fifth instars, respectively); (D-F) body, lateral view (first, third and fifth instars, respectively). Scale bars = 25, 100, 200 μm and 0.1, 0.25, 0.5 mm, from A to C and from D to F, respectively.

Habitat, larval host plant and life history of Bucculatrix mirnae (A) type locality, Azapa Valley, Arica municipality, Chile, showing scattered larval host plants, Baccharis salicifolia; (B) plant of B. salicifolia in close view; (C) B. salicifolia leaves in detail (enlarged view of rectangle area in B); (D) egg on adaxial surface of leaf; (E) mine on leaf; (F) egg chorion remaining at the beginning of a mine (indicated by open arrow in E); (G) detail of orifice left by third-instar larva at the mine end (indicated by closed arrow in E); (H) molting cocoon on leaf, showing larval exuvia by transparency; (I) leaf damage caused by fifth- instar larva; (J) pupal cocoon, lateral view, with anterior portion indicated by closed seta). Scale bars = 0.5, 5, 1, 1, 0.5, 1, 1 mm, from D to J, respectively.

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