Common blue damselfly

Enallagma cyathigerum

"Enallagma cyathigerum" is a European damselfly. The species can reach a length of 32 to 35 mm. It is common in all of Europe, except for Iceland.
Enallagma cyathigerum Enallagma cyathigerum, copula Common blue damselfly,Enallagma cyathigerum,biodiversity,coenagrionidae,insecta,insects,odonata,summer,zygoptera

Appearance

The common blue damselfly can be easily mistaken for the azure damselfly, but on the back and the thorax, the common blue damselfly has more blue than black; for the azure damselfly it is the other way around. The second segment of the thorax has a distinctive spot with a line below connecting to the third segment.

Another difference can be observed when inspecting the side of the thorax. The common blue damselfly has only one small black stripe there, while all other blue damselflies have two.

During mating, the male clasps the female by her neck while she bends her body around to his reproductive organs – this is called a mating wheel. The pair flies together over the water and eggs are laid within a suitable plant, just below the surface.

The eggs hatch and the larvae, called nymphs, live in the water and feed on small aquatic animals. Nymphs climb out of the water up a suitable stem to moult into damselflies.
Common Blue Damselfy - female side view, Heeswijk, Netherlands Tricky to identify as females of blue damsels are highly variable. I had some help from an expert noting the broad shoulder stripe and near blank chest piece as keys. There was also a behavioral sign: this one was scooting over water easily, which apparently isn't done by the Azure damselfly. In dutch for this reason we call this one the "snuffle damselfly", meaning it "sniffs" the water, so to speak.

A fact about this species that blew my mind: larvae sometimes overwinter twice.

On this photo you can see the chest piece where in the second seam, there's no black stripe, whilst most blue damsels do have a stripe there. This poster (in dutch) visualizes the difference:
https://assets.vlinderstichting.nl/docs/b80fe318-b9b8-41ee-acba-c7cebd27c2fb.pdf

The top view shows the torpedo-like black stripes which are typical for the female of this species:
https://www.jungledragon.com/image/62422/common_blue_damselfy_-_female_top_view_heeswijk_netherlands.html
Front view:

https://www.jungledragon.com/image/62420/common_blue_damselfy_-_female_front_view_heeswijk_netherlands.html Common blue damselfly,Enallagma cyathigerum,Europe,Heeswijk-Dinther,Netherlands,World

Behavior

This small, brightly coloured damselfly is probably the most common of dragonflies and damselflies throughout much of Britain. It inhabits a wide range of habitats, from small ponds to rivers. They are especially common at lakes and reservoirs.

This damselfly requires a close look for a beginner to distinguish them from an Azure Damselfly. Typically, they fly low through the reeds and often fly well out over the water, unlike azure damselflies. They are also a brighter blue than azures. They can be easy to get close to, but to tell them apart from an azure damselfly it is good to know what to look for.

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