Saturday, June 09, 2012

The Ebony Jewelwing

Calopteryx maculata is out now, and will be quite visible along streams for the next few months. This entry is adapted from a prospectus that I gave to Univ. Michigan Press last fall. Note that the map is outdated, as we have records for Saginaw Co. Just shows how much progress can happen in just a year. The text below is not at all indicative of how the MOA page will look, (and we won't have a clickable movie in the book ;)), but it is similar in content.

Ebony Jewelwing, Calopteryx maculata (Beauvois, 1805)

Range/Status: Widespread eastern species, ranging from Nova Scotia S to Florida and Texas, and W to Nebraska.

Extremely common, found in nearly every stream, from slow-moving wooded streams to the slower margins of larger rivers.

Habitat: Shaded streams and slough areas of rivers with undercut banks. Larvae are found amongst exposed roots, aquatic plants, and accumulation of sticks and other debris. Adults need nearby vegetation for perching near oviposition sites.

Identification: 2 in./5 cm. Wings all black in males, females have dark brown to black wings with white pterostigma. Iridescent emerald-green body, black eyes.
Ebony Jewelwing
Male, perched.

Behavior: Its slow flight, large black wings, iridescent emerald-green body, and habit of perching on leaves well away from streams, make it quite easily distinguished from other damselflies and dragonflies. The adults are easily observed in the field, and its biology has been the subject of many studies over the years. Adults typically start emerging in late May, and spend some time away from the stream habitat as they forage on insects at the margins of woods, at openings in the forest, and ecotonal areas where small flying insects are abundant. Once they reach sexual maturity, both sexes return to the stream and mate. A study by Kirkton & Schultz (2001) demonstrated that teneral males leave stream-side emergence sites to forage in forest gaps and build up energy reserves before returning to the streams to establish and hold mating territories. The courtship sequence and mating behavior has been well-described by Johnson (1962) and Waage (1973a). Males perch near oviposition sites at the edge of streams and guard the ovipositing females from other males.

A common resident of shaded streams and slough areas along rivers, it is perhaps the most obvious and easily-identified odonate in Michigan. In some suburban streams C. maculata appears to be the only species of Odonata capable of surviving flash runoff and reduced faunal complexity.
Flight Period.

No comments: