| Dragonflies and damselflies belong to the order of insects called Odonata. They all have two pairs
of densely veined wings, and long, ten-segmented bodies which are often brightly coloured. Dragonflies
are a very old order: fossils of dragonfly-like insects are know from Carboniferous rocks 350 million years old. |
| Odonata are divided into two suborders: dragonflies are placed in Anisoptera, and damselflies in
Zygoptera. There are about 5700 Odonata species known in the world today.
Of the 52 species recorded in Britain, 38 have established breeding populations, one has dubious
taxanomic validity, three formerly resident species have become extinct since 1950, and ten species
are migrants, none of which has established a viable breeding population. |
|
Dragonflies are amphibious. The larvae live under water, adults on land and in the air. The larva
sheds its skin several times as it grows. When it is fully grown, it leaves the water, moults for the
last time and expands its wings and abdomen. When these have hardened sufficiently, it flies off as an
adult dragonfly. Unlike other insects, dragonflies do not pupate. |
| Dragonflies are predators. Both the larvae and adults are hunters. Most prey is invertebrate, but a
large larva may catch tadpoles and small fish. |
|
Dragonflies have a unique method of reproduction, with indirect insemination and delayed fertilization.
Sperm is transfered by the male from the abdomen tip to the secondary genitalia at the abdomen base, from
where it is passed on to the female. Eggs are not fertilised until they are laid, so males can
remove sperm of rival males if they succeed in copulating with a mated female. This is why, in many species, the
male protects the female while she is ovipositing. |
| Sightings in 2012 |
| (Y = year list, G = garden year list, L = life list) |
| Sunday 13th May |
|
There were dozens of teneral damselflies at Whelford Pools today, as well as some which had matured. Most seemed to be
Common Blue Damselflies but I saw one Large Red Damselfly and one Blue-tailed Damselfly (Y3) in
amongst them. There were also a couple of dragonflies about, which I was eventually able to identify as
Downy Emeralds (Y4).
|
| Saturday 12th May |
|
Seen at Otmoor today (along the old Roman road) were six teneral Large Red Damselflies and one teneral Common Blue Damselfly.
|
| Sunday 6th May |
|
Seen today at Farmoor were six teneral Large Red Damselflies (Y1) and one teneral Common Blue Damselfly
(Y2).
|
|
|
|
