Don't mix up your dragonflies
by Paul Cormacain
THE dragonfly was delightfully coloured. Well, its flight was like a dragonfly's, its body was like a dragonfly's, it was in a bog near water. Only thing was, it was not a dragonfly, but rather a damselfly, a Common Blue Damselfly.
When you see one of these creatures you automatically think dragonfly.
Then you look again, and think again. Both types of insects are closely related but the damselfly is slender and delicate with widely spaced eyes and a slow fluttering flight.
When the damselfly is at rest the wings are folded along the body, or sometimes held open. The big dragonfly wings are permanently outstretched.
As the name suggests, the common blue is common and widely distributed. Numbers of this easy-to-look at insect can build up at rivers and ponds or indeed anywhere there are plenty of water plants. The eggs are laid underwater, in plant stems, hatching as aquatic larvae.
The young of the damselfly are very efficient predators, and they feed on a variety of underwater small animals.
Their jaws are quick, and they grab anything in the vicinity, living well and growing rapidly.
They moult quickly and may change the outer body up to about ten times as they grow. Then they come out of the water and shed their penultimate skin, emerging as an adult damselfly.
They are then a delight to the eye, as well as being a fascinating creature.
It was only a minute or two after seeing the damselfly that I chanced upon a grasshopper. So I checked the books on grasshoppers. All over Europe there are 78 species of grasshopper, but I did find out that there are 15,000 species worldwide. In England and Wales a mere 29 species occur. A mere eight types are found in Scotland, while about 10 are to be found in Ireland.
The scarcity of grasshoppers away from mainland Europe is down to the last Ice Age of some 10,000 years ago. When the south of England started to warm creatures came over from Europe via the then land bridge. By the time this bridge was covered with water there had not been enough time for enough creatures to come over. So species numbers were low.
Creatures headed over to Ireland from Europe via England until that land bridge was covered by water. So, we had the effect that fewer types of creatures existed in England than on Europe, and fewer types of creatures existed in Ireland than in England.
Some snakes got as far as England, but snakes are not all that plentiful there. Some managed to reach Ireland, until in 432 some guy from England came over and chased them all away. His name was Patrick, or something like that. So much for snakes, now back to the grasshoppers!
These creatures are heard more often than seen, but it is easy to track them down when they are holding forth. Just follow the sound.
During the summer the grasshoppers breed. A few days later the female uses an ovipositor to drill her eggs into the ground where they remain till the following June.
Nymphs emerge from the egg, then stages of growth occur, until the insect is fully grown. It remains like that for a few months then dies off. During its adult life it will also have bred, to propagate the species.
There were more interesting creatures that day, but we seem to have run out of space.
Ulster Star
17/01/2001
