The Brede Valley

DRAGONFLIES AND DAMSELFLIES

by Colin Page

Dragonflies and damselflies form two sub-orders of the Odonata order of insects (which translates as ‘toothed jaws’). Generally speaking, dragonflies are the larger of the two and prey on airborne insects of various types, which are caught by clasping their legs together to form a ‘basket’ and are dismembered and eaten in mid air, or at a regular feeding perch, according to species. Damselflies on the other hand are more dainty and can be seen plucking small insects from the leaves of waterside plants, although the common blue-tailed damselfly is sometimes cannibalistic.

All dragonflies and damselflies are aquatic for the first part of their lives. The nymphs of the larger dragonflies spend up to four years among the mud and waterweeds of ditches, ponds and the river, feeding on other aquatic insects, fish fry and tadpoles. At this stage prey is caught by an extendable mouthpart known as a mask, which is capable of snatching prey from some distance away. The adult emerges from the nymph after crawling from the water on emergent vegetation such as reed mace. If weather permits, the new adult will take flight on glistening wings and after a few days will take on its full adult colouration.

The wetland of the Brede Valley is superb for dragonflies and damselflies, but equally important are the many sheltered feeding sites such as woodland clearings and hedgerows where these insects often congregate on cool windy days. On a chilly day in May hundreds of azure damselflies may be encountered sheltering from the north wind in the lea of a hedge. The hairy dragonfly may also be seen hawking close to a hedge or in a tree canopy. In mid summer the broad bodied chaser may be observed in a woodland clearing returning repeatedly to the same perch. The spectacular beautiful demoiselle may also be seen here after travelling from a nearby shady stream, along one of the woodland rides which several species use as corridors from one side of a wood to the other.

On Brede Levels in late summer you are likely to see male migrant hawkers hovering in search of females and dashing up and down ditches trying to defend territory. Nearby, the emperor dragonfly is catching small tortoiseshell butterflies in beds of thistles. Common darters are attracted to patches of bare soil, which they use for sunning themselves, often late into the autumn.

All dragonflies and damselflies need to return to the water to breed, and each species exploits its own particular niche. I have seen the red-eyed damselfly ovipositing (egg laying) with the male remaining attached to the female, while she descends out of sight beneath the water to deposit her eggs on aquatic vegetation. The red darter male also remains attached to the female, but she scatters her eggs on dry mud beside a pond. The southern hawker female oviposits alone, carefully inserting her eggs within the tissue of waterside vegetation. The male black-tailed skimmer dragonfly will hover nearby as the female oviposits by dipping the tip of her abdomen just into the water. The male is there to chase off any rivals.

Below are the species I have actually seen in the Brede Valley, there are probably several others to add to the list, which represents about half of the British list – quite impressive!

Please report any interesting sightings to colin@natureincolour.com (with a copy to info@bredevalley.info) To see a selection of Colin’s wildlife images, visit the website www.natureincolour.com