The difference between Dragonflies and Damselflies

The order Odonata can be devided into the two suborders, the Dragonflies (Anisoptera) and Damselflies (Zygoptera). This blog entry is targeted to beginners and explains the differences between dragonflies and damselflies step by step.

1. Let's start at the beginning of the life of these wonderful insects. Dragonflies and damselflies have aquatic larvae. At the end of their "youth", these climb out of the water , the skin splits and the adult insect emerges. These eclosions can be observed most often in the morning hours in spring and summer and they are a fascinating event. After the adult dragonfly flies off, the empty larval skin (exuvia) remains behind at the hatching spot. These exuviae are useful to differentiate the two suborders, since the body shape of the larvae is different. In addition, the eclosion process itself also differs between dragonflies and damselflies.

Larvae of damselflies are more slender and carry three tail appendages (tracheal gills, german: Kiemenblättchen) that support extraction of oxigen from the water. Larvae of dragonflies are significantly beefier and visually lack these three tail appendages (see images). During the eclosion process, damselflies leave their old skin heads up while dragonflies do it heads down.

Eclosion: Damselfly to the left, Dragonfly to the right. Damselfly larvae posess leaf-shaped tail appendages, dragonfly larvae don't. Damselflies tend to wiggle out of their old skin heads up, dragonflies usually do it heads down.

2. The wing position differs between resting damselflies and dragonflies. Damselflies can fold their wings together, dragonflies lose this ability after their first flight (directly after the hatching process, wings of dragonflies are still folded). Thus, if you see a dragonfly / damselfly sitting in the reed, it will either have its wings spread (dragonflies) or folded together (damselflies).

Left: Damselfly resting with folded wings. Right: Dragonfly resting with spread wings.

But of course there is no rule without exception. Damselflies from the family Lestidae rest with open wings, leading to their common name "spreadwings". Lestidae are quite big damselflies, but still can be easily identified as such with the other characteristics.

The emerald damselfly (or common spreadwing) from the family Lestidae rests with open wings and thus is an exeption within the damselflies.

3. Looking at the head of damselflies and dragonflies, the eyes of the former are clearly sperated, while the eyes of dragonflies touch each other on top of the head.

Different head shapes: While the eyes of damselflies (left) are clearly separated, this is not the case for dragonflies (right)

Summary:

Damselflies: Larvae with tail appendages. Adults are sitting with their wings folded. Eyes clearly separated.

           - Exception "Spreadwings": Larvae with tail appendages, Adults are sitting with open                     wings, eyes clearly separated.

Dragonflies: Beefy Larvae without tail appendages, adults are sitting with open wings, eyes are connected.

 

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