The Damselfly

In my last post I talked about Dragonflies, and in this one, I want to talk about their smaller counterparts, the Damselfly, but first the differences between the two..

Dragonflies have eyes that touch, or nearly touch at the top of the head, they are stocky, and have different sized wing pairs.  When they perch, the wings are held open.

Damselflies have eyes that are clearly separated, one on each side of the head, they are long and slender, and have evenly sized wings, which are held close when they perch, as can be seen in the image below.

DSED0659
Blue Tailed Damselfly Perching

Damselflies are carnivorous insects that live and breed near a wide variety of freshwater habitats. They lay their eggs in water, and the immature damselflies spend the first several months or years as aquatic predators. These immature damselflies, called nymphs, have external gills that allow them to extract oxygen from the water. After undergoing metamorphosis, new adult damselflies fly away from the water for a brief period of several days to several weeks, after which they return to breed. Both adult and immature damselflies are predators whose diet consists primarily of insects. (Corbet, 1999; Silsby, 2001)

Damselfly eating an aphid
Damselfly eating an aphid

The mating behaviour of the damselfly is quite unique.  Males have two sets of genitalia.  To mate, the male must grasp the female behind the head, and curl his abdomen into a circle.  In this position the male and female are said to be ‘in tandem’ – if the female is receptive, she will curl her abdomen forward to join the tip of her abdomen with the male’s second set of genitilia, sperm is then transferred from one to another.  This position, called ‘the wheel’.  After mating, the female will lay eggs usually below the water line, often guarded by the male

Mating Damselfly
Mating Damselfly

The average Damselfly, probably only lives between 3 to 4 weeks as an adult, but the damselfly nymphs can spend months in this early stage, depending on food source, temperatures and so on.

Damselfly do need a minimum temperature at which to fly – in the early mornings, they can be seen spreading their wings to dry out the morning dew, and warm up.

Damselfly in morning dew
Damselfly in morning dew

Damselfly and Dragonfly populations are good indicators of environmental quality and population levels are a good indicator of the health of the area.

They are the most ancient of insects, with evidence of them being found as fossils some millions of years ago.

A Summer of Dragons

This week I was out walking with the dogs, and noticed a good number of Damsel and Dragonflies.  By Friday I had a bit of time, and decided to go hunting Dragons…. The majority I saw were Brown Hawkers…

Brown HawkerThe Brown Hawker (Aeshna grandis) is a large dragonfly about 73 millimetres (2.9 in) long. It is a distinctive species and is easily recognised, even in flight, by its brown body and bronze wings. At rest, blue spots on the second and third segments of the male’s abdomen can be noticed; these are absent in female.

It is widespread in England but commonest in the South East; local in Ireland and rare in Scotland. It is found on well-vegetated ponds, lakes and canals. It patrols a regular hunting territory around margins which is vigorously defended against intruders.

The flight time is mainly July to September. The nymph has stripes on the side of the thorax and distinct banding on the legs. (Text from Wikipedia)

Brown HawkerYou can get more information from the British Dragonfly Society
http://www.british-dragonflies.org.uk/