The Blue-tailed Damselfly – Ischnura elegans, is an abundant damselfly, and the female has distinct colour forms at different stages of its life-cycle.
|Coenagrionidae||Blue or red Damselflies|
Abundant damselfly – the most common in Bedfordshire. The abdomen is predominately black, with a distinctive coloured ‘tail-light’ on segment 8 that makes them easy to spot, especially as they move.
Males are blue, with thin shoulder stripes on the thorax and a black abdomen. The tail-light is blue, matching the thorax. Immature males may appear greenish blue.
Females are polymorphic and occur in multiple colour forms. There are two separate immature colour phases (violacea and rufescens) that last only a few days, but the mature female’s final colouring is determined by genetic factors. In total there are 5 distinct colour forms of the female (2 immature, 3 mature), making identification more difficult.
The female shares the tail-light, but its colour is dependent on the colour phase, and may be blue, violet, green or brown.
The development of the different female colour forms is summarised in the table below:
Overall length: 30 – 34 mm
Wings: 14 – 20 mm
There are several other broadly similar species that might cause some confusion:
Found almost anywhere where there is water, and is common around most rivers and ponds. More tolerant of polluted waters than most Odonata, and often the only species visible in poor weather.
Very common throughout Bedfordshire and is likely to be found almost anywhere where there is water.
Visible between early May and late September, peaking in June and July.