Variable Damselfly - Coenagrion pulchellum
Adult SizeOverall length: 33 - 38mm Hindwing length: 16 -23mm
Distinguishing features.The variable damselfly is another blue damselfly which has a very patchy distribution and resembles both Common Blue Damselfy, Azure Damselflly & Southern Damselfly. Care needs to be taken with identification as as its name suggests its distinguishing features can vary! All historical records in Dorset have been rejected due to the problems of verification. If it does occur it's very restricted overlooked or possibly extinct (see status below).
Identification - for help with terms see glossary
The distinguishing feature of this species are the very thin broken pale blue antehumeral stripes resembling exclamation marks, though rarely stripes are complete. Segment 2 has a ‘wine goblet’ shape, though sometimes the ‘stem’ is absent. Can appear darker than other 'blue' males due to larger areas of black than blue on abdomonal segments. The pronotum in both males and females is markedly 3 lobed, which can be seen on close inspection. Eyes are blue
Are diamorphic, a blue form, somewhat similar to a male and a darker form, with a dark green base. Antehumeral stripes usually complete and there is a bar between the eyes. The blue form shows more blue than Azure Damselfly and has even blue and black markings. There is a varaible ‘mercury’ or ‘thistle’ like shape on segment 2. Dull form similar to dull Azure Damselfly form so possible only shape of pronotum, tri-lobed can realistically distinguish these two forms of female. Immature females blue form have brown/yellow base colour pale antehumeral stripes, green thorax and eyes.
HabitatBreeds in well vegetated ponds. ditches, lakes and fens, more rarely in slow moving rivers or canals.
BehaviourBehaves very like the Azure Damselfly, tending to stay close to bankside vegetation, males do not appear to be territorial.
Status and distributionAs well as its appearance it also seems to have a variable distribution and often absent from sites which should or could support the species. In Ireland its very common, but in the rest of Britain it is very patchily distributed. It seems to be sensitive to disturbance such as bankside and ditch clearance. Very rarely recorded in Dorset, and all records have been found to be unverifiable so at present that status in Dorset is that it may well be extinct in the county. Any records of this species would need to be accompanied by photos and precise location so that a site visit could be made.
Flight periodMain flight period is mid May to Late August, peaking in June/July summer.
Similar speciesSimilar in appearance to the other three Coenagrion 'blue' species, Common Blue Damselfy, Azure Damselfy and Southern Damselfly, care is needed to identify these species. In males always look at segment 2 for the distinguishing marks which could also vary. Females of this group are extremely difficult though not impossible to separate, but males will always be more conspicuous where the species is present.
More photographsClick on the photos below to enlarge...
All photographs by kind permission & © of Ken Dolbear unless otherwise stated. All rights reserved.