The Common Blue Damselfly (Enallagma cyathigerum) certainly lives up to its name, being widespread and often abundant throughout much of its range. This is a species that can be seen on the wing locally from May until September, with males being most noticeable as they patrol the water's edge in search of females or when aggressively engaging with other trespassing males. Like most other members of the dragonfly family, females and immatures are less likely to be encountered, spending time in vegetation that may be well away from water.

 

The females occur in two distinct colour forms, blue and green, but it is the extremely blue males that catch the eye, as they flit over open water or alight on waterside vegetation. There are other similar blue damselflies (Azure and Variable) that can easily be confused with the Common Blue in Argyll, so you always need to be mindful that you may be looking at something other than what you may initially think!

 

Interesting abdominal markings are found on females that include a 'thistle'-like shape on the second segment near the top of the abdomen, various 'rocket'-like shapes that could have come from an early 1980's video arcade game, as well as a 'triangle' near the tip of the insect's body. These features can't always be picked up with the naked eye, so this is when a pair of binoculars or photographs can be very handy in determining identity.

 

 Common Blue males are broad-shouldered with thick pale blue antehumeral stripes. These are the stripes that are present on the shoulder of the insect's thorax. They are thicker (broader) than those that appear on any other 'blue' damselfly. Another useful fail-safe when trying to distinguish which male 'blue' damselfly you are watching is to check for the existence of a black line that runs part-way along the side of the thorax. This is referred to as a Coenagrion spur, as it can be found on all species that belong in the genus Coenagrion. The Common Blue damselfly belongs to a different genus and does not show this feature.

 

As is the case with most dragon and damselflies, the males often adopt a predatory approach to their liaisons with members of the opposite sex. Males will often remain 'in tandem' with their partners while they oviposit, only releasing them when they begin laying in deeper water. Sometimes, the females struggle to release themselves from the grip of the water's surface tension and require the help of a male to do so.

 

This may not be the male that she has just mated with and this assistance comes at a cost, with the 'Prince' expecting a reward for his 'kindness'!