Dragonflies And Damselflies
As we move into June the birds become less vocal and are certainly less easy to see and for many folk who enjoy wildlife June is the month to look for dragonflies and damselflies. The spectacular dragons really are the tigers of the insect world. Not only do they rule the roost in the ponds and waterways they have lived in, but once out of their watery world they rule the roost in the skies. The damsels are more delicate and much less powerful. Both are great to watch and some are brilliantly coloured. Both dragons and damsels belong to the order Odonata and are divided into two distinct sub-orders, the Zygoptera or Damselflies and the Anisoptera or Dragonflies. How can we tell the difference? Well both have membranous wings, large eyes, slender bodies, and small antennae. There are however differences and if you learn these then you will certainly find it easier to identify the different species. The most obvious differences are the eyes, wings, body and resting position. Now bear with me on this a little because some of the differences are relative and consequently subjective, sorry.
Eyes: The dragons have eyes close together at the top of their head whilst damsels’ eyes are at the side and further apart.
Wings: The dragons’ front and rear wings are different in size whilst damsels’ wings, front and rear, are the same size.
Body: The elegant damsels have a long slender body whilst that of the dragonflies is usually stocky.
Wing Position: When at rest the dragons’ wings are held open but they can be horizontal or downwards. Damsels’ wings at rest are always closed, usually over their abdomen.
For a really good guide to helping identify these insects visit the British Dragonfly Society Identification help page.
It is however the lifestyle of these creatures that is the most fascinating. We usually only see them as they fly, having emerged from the water, crawled up a plant stem and undergone the most incredible metamorphosis. Most female odonata after mating deposit their eggs in the stems of plants, often under water, sometimes on land near water. Some dragons, but no damsels, deposit their eggs directly on the surface of the water. They do this by flying over the water and dropping the eggs at regular intervals on to the water. Eventually the egg hatches, when depends upon the species, it can be from a few weeks to overwintering before the eggs hatch. From the egg comes what we call a prolarva which quickly moults into a true larva. These are the aquatic nymphs which terrorise the ponds and waterways of their birth.
During this aquatic stage, odonata nymphs breathe through gills. Damselfly gills are located at the end of the abdomen, while the gills of dragonfly larvae are found inside their rectums. The nymphs prey upon anything from a tadpole to an arthropod to even small fish. The nymphs are predators. Their hunting methods vary. Some species lie in wait for prey, and hide by either burrowing in the mud or resting within the vegetation. Other species hunt actively, sneaking up on prey or even swimming in pursuit of their meals. Odonata nymphs have modified lower lips, which they can thrust forward in a split second to grab an invertebrate, passing tadpole or small fish. Not much is safe from these ferocious predators. Whilst under water odonata undergo a series of moults, perhaps as many as 17 times. During these moults, or instars, and especially during the later ones their wings begin to develop, although they are kept well hidden under wing pads. Eventually with their wings fully developed under water the nymphs crawl out of the water and make that remarkable transformation into the elegant and beautiful insect we know. Larval development typically takes one or two years, but ranges from 2–3 months in the case of the Emerald damselflies to more than five years in the Golden-ringed Dragonfly.
Identifying dragons and damsels is not easy and made harder because often males and females are different. For an identification guide visit the British Dragonfly Society Website and look closely at their flight period, habitat and regions they are found in. Also in the case of dragonflies there are three types: Hawkers, which are usually dark with bright spots or stripes, although some can be mostly brown, others brightly coloured. They are generally large and robust and never have dark wing markings although they can have wingspots. They hunt by doing as the name says, they hawk over the water for their prey; Darters, Chasers and Skimmers, these, especially darters, tend to wait in ambush for their prey and can have a blue, red, yellow or brown body or a combination of some of these colours. They are generally smaller and stout bodied; Emeralds are as the name suggests usually emerald green in colour. Damselflies don’t fall so easily into groups and colour can be an important identification guide, but look at the wing colour and patterns, look out especially for the brilliantly patterned banded and beautiful demoiselles.
Look for these insects over and around any slow moving or still waterway and if you are lucky you may even see a nymph emerging from the water and undergoing that amazing change from a water loving creature to an aerial predator. I’ve also seen dragonflies eating bumblebees. A pair of close focusing binoculars is a good aid in watching these magnificent creatures.
Fossils of very large dragonfly ancestors have been found from 325 million years ago which had wingspans up to about 750mm (30in).
Nigel Heptinstall (Outdoors2015)
How Stean Blog May 2016 (Updated May 2019)