Enallagma – ‘American’ Bluets
Common Bluet – Common Blue Damselfly- Enallagma cyathigerum – UK European Dragonfly photo
The Common Bluet – Common Blue Damselfly ( Enallagma cyathigerum ) is as common as its name implies and is one of the most widespread damselflies in the region and indeed the world. It is found mainly on larger waters with Tatton Mere in Cheshire UK shown below being a good example quite near to my home. Acidic waters free of fish provide the highest densities. Tolerance of colder temperatures and brackish waters also contribute to the success of the Common Bluet. The more recent photos show a freshly emerged Large Red Damsel ( Pyrrhosoma nymphula ) above its exuvia on the other side of the reed stem to a Common Bluet plus a male just arching its abdomen to transfer sperm. A tandem pair with the female being of the drab greeny blue form which is more frequently found than the blue form is also shown.
KEY I/D FEATURES :
The broad antehumeral stripes, large postocular spots and plain blue of the sides on the thorax show well in the first photograph. These are the same in both males and females. Segments 8-9 of the abdomen are blue on males. A size comparison with the Clover flower is given in the third picture. The markings on Segment 2 are a very helpful guide to the male ‘blue’ damselflies and the classic mushroom mark on the Common Bluet is shown in the fourth photograph although this can often vary in shape and size. Immature males are lilac before developing their darker blue overall colour.
Females come in a drab and blue forms. The thoracic stripes and the abdomen are straw coloured with prominent black torpedo shape markings on tenerals of the drab form. These black markings are the same on a blue base on the blue form.