The Common Blue Damselfly – Enallagma cyathigerum, is easily missed unless they are moving, and the female occurs in several colour forms that can make identification more difficult.
|Coenagrionidae||Blue or red Damselflies|
An abundant damselfly, one of several similar species with blue and black markings.
The thorax features broad shoulder stripes and are the best way to positively identify them.
The male has a predominantly blue body with black markings and features a characteristic mark on segment 2, usually described as ‘lollipop’, ‘mushroom’, or ‘club’ shaped. The upper surface of segments 8 and 9 are entirely blue in males, with blue and black markings along the rest of the abdomen. The immature male is a paler, almost grey-violet, blue, but otherwise resembles the mature male.
Females occur in 2 colour forms: blue and drab. Both forms share the same markings. The drab form undergoes a colour change as it matures; first appearing straw coloured and becoming greener with age. Females have a prominent spine on the underside of segment 8, not found on other species in the region apart from the Blue-tailed Damselfly – Ischnura elegans.
Overall length: 29 – 36 mm
Wings: 18 – 20 mm
The broad shoulder stripes of the Common Blue are characteristic identifiers, but there are several other broadly similar species that might cause some confusion:
Large ponds, lakes, gravel pits and slow rivers, with submerged vegetation used as ovipositing sites. Frequents vegetation away from water when not breeding.
Very common at rivers and lakes throughout the county, looking out over large bodies of water, such as those at Felmersham NR or Priory CP, they form a moving blue haze as huge numbers of them hover over the water in search of ovipositing sites.
Visible between mid-May and early October, peaking June to August.