In this month’s Gosforth Nature Reserve update, NHSN volunteer Christopher Wren takes a closer look at the colourful Blue-tailed Damselfly. From its many striking colour forms to its hidden life beneath the water, discover more about one of the reserve’s most numerous damselflies.
Discovering the Blue-tailed Damselfly
Blue-tailed Damselflies are perhaps the most numerous damselflies in Gosforth Nature Reserve and have a long flight period from May to August. They are usually found at rest close to the edge of the Meadow Pond and the Heath Pond but can also be seen in the reed beds and near the Dipping Pond.
Both sexes are predominantly black with colour at either end and have two-toned diamond-shaped wing spots. The male Blue-tailed Damselfly has blue eyes, thorax and shoulder stripes and a blue “tail” which is really the eighth abdominal segment, S8.
Immature males are greenish blue.
Female Blue-tailed Damselflies come in many different colour forms but are all the same species. One immature colour form is violacea, with a mauve thorax and either a mauve or a blue S8.
The violacea form matures into either a male-type blue, form typica,
or green with a brown S8, form infuscans.
A second immature form is rufescens, with a salmon-pink or orange thorax and a blue S8.
The rufescens form matures into rufescens-obsoleta, with a brown thorax and S8.
The life cycle of the Blue-tailed Damselfly is the same as most other damselflies. Mating occurs close the water, often in the afternoon, and can be prolonged.
Females may not have attained mature colouration when mating takes place.
The female lays her eggs in floating vegetation and debris. After the eggs hatch the larvae mature through multiple stages (instars) before emerging the following year. Although the flight period is prolonged, each individual adult probably lives for only a week or two so for the large part of its life the Blue-tailed Damselfly is a nymph, living underwater.
You can get more updates on local wildlife from Christopher Wren on his own TrogTrogBlog. You can discover the wildlife of Gosforth Nature Reserve here.