Tuesday 22 December 2009

UK sites for spotting Odonata: Little Bradley Ponds


Little Bradley Ponds, near Bovey Tracey in Devon is a small nature reserve run by Devon Wildlife Trust. There are two large and several tiny ponds on old clay workings. The old pond:



and the new pond, created in 1991:





Despite the small size of the nature reserve (~1 ha of water, with parking limited to just 2 cars at the site with space for another 2 further up the lane), it is a nationally-important site for a number of rare species. In total it has 25 species of odonata including the scarce blue-tailed damselfly, red-eyed damselfly, hairy dragonfly, lesser emperor, downy emerald and keeled skimmer. The first Devon record of brown hawker was recorded at the new pond in 1999.

Some of the most frequently seen species are the emperor dragonfly (Anax imperator):





beautiful demoiselle (Calopteryx virgo):



golden-ringed dragonfly (Cordulegaster boltonii):


southern hawker (Aeshna cyanea):


and the four-spotted chaser (Libellula quadrimaculata):

Tuesday 30 June 2009

What do dragonflies and damselflies eat?

I'll refer to only adult dragonflies and damselflies here - more on Odonata larvae in the near future.

The adult dragonfly is a formidable hunting insect. It uses the basket formed by its legs to catch insects while they are flying. Adult dragonflies and damselflies eat other flying insects, particularly midges and mosquitoes. They also eat mayflies, butterflies, moths, bees, bugs and smaller dragonflies and one Asian species even feeds on spiders from their webs.

Large red damselfly (Pyrrhosoma nymphula) feeding:



Monday 22 June 2009

Odonata

The insects are classified into about 32 orders and 939 families. Dragonflies and damselflies form the order Odonata (25 families). The word Odonata comes from the Greek for tooth and is a name derived using a classification devised by Fabricius. Johan Christian Fabricius (1745-1808) was a Danish entomologist and economist who classified insects based on their mouthparts, which he thought were more important than other traits like wings, because feeding provides the sustenance of life.

Entomologists have been puzzled as to why Fabricius chose the name Odonata for the dragonflies and damselflies since the mandibles of most insects are toothed and a name indicating "toothed mandibles" is no more significant for dragonflies than it would be for beetles or grasshoppers. For more information on the name Odonata see the article The significance of the dragonfly name "Odonata" by Clarence E Mickel in the Annals of the Entomological Society of America.

Front view of the head of a four-spotted chaser (Libellula quadrimaculata) showing the chewing mouthparts:



Side view of the head of a male southern hawker (Aeshna cyanea):

Sunday 21 June 2009

Welcome to the dragonflies and damselflies blog

Welcome to the dragonflies and damselflies blog: an assorted collection of articles on topics including dragonfly and damselfly names, anatomy, biology, ecology and folklore.