Thursday 30 May 2013

A new species of Leaf Mining Moth from Brazil.

Moths of the Family Gracillariidae are found throughout the world except on Antarctica and some remote islands. Their larvae are leaf-miners, worm-like caterpillars that live in tunnels inside leaves. Some groups of Gracillarid Moths are specialist miners of the leaves of some of the most ancient groups of Angiosperms (flowering plants) such as Laurels and Magnolias, and fossils leaf mines that resemble those of the Moths have been found in fossilized leaves from the Cretaceous of North America, which also suggests this is an ancient association. However the oldest fossils of the Moths themselves are from (Eocene) Baltic amber, and there is no way to connect these moths to the leaf mines, so it is quite conceivable that the Moths have only recently colonized these plants, and that the burrow shape is coincidental, simply a good shape for a leaf mine in this sort of leaf.

In a paper published in the journal Zootaxa on 12 December 2012 a team of scientists led by Rosângela Brito of Departamento de Zoologia at the Instituto de Biociências at the Universidade Federal do Rio Grande do Sul, describe a new species of Gracillarid Moth from the Atlantic Rain Forest of southern Brazil.

The new Moth is placed in the genus Phyllocnistis, which has a global distribution and which is known to target a wide range of plants, though the majority are found in North America, where their larvae feed particularly on Laurels, Magnolias and Witch-Hazels. The new species spends its larval stage on the Passion Vine, Passiflora organensis, the first member of the genus found on a plant found on a plant of the Family Passifloraceae, and the first from the Brazilian Atlantic Rainforest.

It is given the specific name Phyllocnistis tethys, after Tethys, a Titan goddess in the Greek mythology; the wife of Oceanus, and the mother of rivers, springs, streams, fountains and clouds, a reference to the cloudy and humid nature of the area of the Brazilian Atlantic Rain Forest where the new species was first found.

Phyllocnistis tethys is a ~2.5 mm feathery whit Moth with yellow markings on the tips of its wings. It is known only from a single site at an altitude of 900 m in the Atlantic Rainforest of Rio Grande do Sul State.

Phyllocnistis tethys. (A) Adult, wings spread, pinned, dorsal view. Scale bar is 0.5 mm. (B) Adult, wings folded, on Passiflora organensis leaf, in dorsal view. (C) Adult, wings folded, on Passiflora organensis leaf, in lateral view. Brito et al. (2012).

The eggs of Phyllocnistis tethys are laid on the underside leaves of Passiflora organensis, a Passion Vine known to horticulturalists as the Organensis Passionflower or Batwing Passionflower. The emergent larvae drill into the leaves of the vine, where they remain for the rest of the larval part of their life cycle, molting three times within the leaf; the final larval stage, typically slightly under 5 mm long, does not breed, but spins a silk cocoon within which it  pupates, emerging as an adult.

The leaves and flower of Passiflora organensis. Ruhr Universität Bochum.

Larval and pupal morphology of Phyllocnistis tethys under light microscopy. (A) First larval (“sap-feeding”) instar, dorsal and ventral views. Scale bar 100 μm. (B) Third larval (“sap feeding”) instar, dorsal and ventral views. Scale bar 400 μm. (C) Fourth larval (“cocoon spinning”) instar, dorsal and ventral views. Scale bar 400 μm. (D–F) pupa, dorsal, ventral and lateral views. Scale bar 300 μm. Brito et al. (2012).

Life history of Phyllocnistis tethys: (A) Passiflora organensis shoot twining around on a fern at the type locality, showing several leaves with leaf mines at different development stages. Scale bar 100 mm. (B) Leaf mine on abaxial leaf surface (open and closed arrows, respectively, indicate empty chorion on leaf surface, and sap-feeding larva seen through transparent mine). Scale bar 1 mm. (C) Egg containing developing embryo. Scale bar 0.2 mm. (D) Freshly hatched larva (indicated by closed arrow; open arrow indicates green frass lines left within the egg chorion. Scale bar 0.3 mm. (E) Third-instar (sap-feeding) larva. Scale bar 1 mm. (F) Detail of frass lines and damage on leaf parenchyma, left by the larva within the mine. Scale bar 1 mm. (G) fourth-instar (spinning) larva. Scale bar 1 mm. (H) Passiflora organensis containing several pupae, seen by transparency (indicated by arrows). Scale bar 20 mm. (I) A pupal chamber in detail, showing a pupa by transparency. Scale bar 5 mm. (J) Pupa, lateral view. Scale bar 0.5 mm. (K) Pupal exuvium protruded (arrow) from mine exit hole, just after the adult emergence. Scale bar 2 mm. Brito et al. (2012).

See also The taxonomic implications of host preference in Large Blue ButterfliesNew species of Owlet Moth from Sichuan Province, ChinaFive new species of Snout Moth from ChinaNew Tiger Moths discovered in east Asia and New species of Leaf-Mining Moth from northern Chile.

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