Black-tailed Skimmer, Orthetrum cancellatum
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Size
Medium sized; body length 30mm to 35mm.
Colour-patterning
Males are a dark brown colour with a blue abdomen that becomes black over the posterior third. The sides of the abdomen are edged yellow brown in younger specimens. There are no thoracic stripes behind the eyes. Females
have a lighter brown ground colouration than the males and lack the blue and black abdominal colours of the male. Instead they have pair of darkened longitudinal stripes running down either side of the abdomen.
Behaviour
It is an active Skimmer that patrols its territory aggressively, frequently resting on patches of bare ground or stones although it will occasionally rest up in vegetation. Mating takes place initially in flight but is completed either on the ground or vegetation. Females lay their eggs whilst skimming low over the water.
Where to look for it
It favours open areas of still water that has a hard, not muddy, substrate. It is an early coloniser of such bodies of waters which often occur when mineral workings are abandoned. The only site where it is known to occur in the City is privately owned but it should be looked for on other abandoned sites holding bodies of water.
Distribution and status
Very rare and restricted to a single known site in Plymouth where there is a small, and probably unsustainable, breeding population with no more than three or four males.
When to look for it
Late May to August.
Similar species
The pair of darkened longitudinal abdominal stripes of the female should immediately separate it from females of the Broad-bodied Chaser, Libellula depressa, Keeled Skimmer, Orthetrum coerulescens and Common Darter, Sympetrum striolatum. The characteristically black-tipped blue abdomen is found in no other local dragonfly.