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Caterpillar Hunt - Saturday May 16, 2009

John also brought along some additional samples of Geometrids he collected the day before, including the Half-Wing moth caterpillar (Phigalia titea), an excellent stick mimic. It feeds only on the newest foliage, and will starve if provided only with mature leaves.

This member of the Geometridae family is the fall cankerworm (Alsophila pometaria). Later in the year, the adult female moth pushes its eggs into bark crevices, where they overwinter. Upon hatching, caterpillars like this one drop down on silken threads to be carried off by spring breezes that disperse the population. Some fall cankerworms reproduce without mating, a phenomenon known as 'parthenogenesis' which is unusual among butterflies and moths.

Another type of caterpillar we found was this Oak Leafroller, a member of the Tortricid family of micro-moths. These caterpillars hide themselves in the daytime in leaves either rolled-up or webbed together with silk.

We also found one member of the Owlet Moth family (Noctuidae), the largest family of moths and butterflies with more than 35,000 species world wide. This is probably the Intractable Quaker Moth (Himella intractata).

We found just one butterfly specimen, this puparium of a species in the Brush-footed butterfly family (Nymphalidae), which includes the fritillaries, mourning cloak, red admiral, painted lady, and buckeye.

One larva we found was neither moth nor butterfly, but the caterpillar-like larva
of a green oak sawfly (Hymenoptera: Symphyta).
Sawfly larva have more prolegs than do butterfly and moth caterpillars.

One of our young naturalists found something small that was not an insect at all, but a tiny slug. Slugs are shell-less molluscs that helps break down leaf litter into soil.

Photos by Michael Wilpers and Ed Murtagh. Insect identification by John Lill, who also edited the text. Text compiled by Michael Wilpers, drawn in part from David L. Wagner, Caterpillars of Eastern North America (Princeton, 2005) and E. R. Eaton and Kaufman, Kaufman Field Guide to the Insects of North America (Houghton Mifflin, 2007).

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