Dating back at least 250 million years, damselflies are evolutionary masterpieces. Despite having been around long before the first dinosaurs, their anatomy has changed very little since, and they still thrive across six of the earth’s seven continents (Antarctica being too cold for these cool-blooded creatures). These incredible insects belong to the suborder zygoptera, one of the two distinct groups that make up the order Odonata. While they are similar in appearance and life cycle, members of zygoptera differ from those of anisoptera (dragonflies) in several key aspects. Most notable among these is the damselfly’s smaller size and more delicate body. Other differences include the way damselflies hold their wings folded at rest as opposed to open, and their inferior flying ability compared to dragonflies. Although these rules are generally reliable for distinguishing between the two, they are not foolproof. For instance, some damselflies do hold their wings open at rest, most notably the family Lestidae, and the Odonata member with the largest wingspan is in fact a damselfly. This title belongs to Megaloprepus caerulatus of South and Central America, with a wingspan of up to a whopping 19 centimetres. Damselflies are sexually dimorphic, which is most notable in the way that male and females of the same species often differ in colouration. The colour of a damselfly may also change with age.
Damselflies, which are smaller and daintier than dragonflies, hold their wings closed when at rest. This is an azure bluet (Coenagrion puella) resting on a reed over a lake in South West England.
The main exceptions to the rule that damselflies close their wings when at rest are the damselflies in the family Lestidae. This male emerald damselfly (Lestes sponsa) clings on to a reed over a pond in Northern Scotland in August.
The larger and more robust dragonflies hold their wings open at rest, as shown by this dragonfly in North West Italy. The dragonfly is photographed devouring a horsefly that it caught by a small, slow stream.
Dragonflies are much stronger and quicker flyers than damselflies. This Southern Hawker dragonfly puts on an aerial display above a lake in South West England.