The Small Tortoiseshell (Aglais urticae) is a well-known colourful butterfly, found in temperate Europe. There are a few records from New York City which, however, are believed to have arrived human-assisted.
This is a species often found in gardens. The caterpillars feed on nettles, as do those of several Nymphalidae butterflies.
The adult is striking, with its dark body and red and yellow wings, which have a row of blue dots around the rear edge. However, the underwings are dull, which helps to conceal stationary or hibernating individuals. When threatened, resting individuals rapidly open their wings, presenting the dramatic display of colors. This can frighten away young or inexperienced birds.
The butterfly is abundant in most areas of the United Kingdom and Ireland. However, its availability often varies yearly. Its commonness may often depend on the status of the common wasp in that particular season, as the wasp is known to feed on the Tortoiseshell's pupae.
Source: en.wikipedia.org/wiki/Small_Tortoiseshell - 04.10.2010
With their nearly agravic constitution und their gaudy colours the butterflies set special focusses.