"To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand
And eternity in an hour."

From "Auguries of Innocence"

by William Blake

Sunday, 15 July 2012

Dragonfly Exuvia

Whilst exacavating the rockery to put in the waterfall this morning Brian found a dragonfly exuvia floating in the pond.

Dragonfly and damselfly nymphs live in water feeding on animals such as waterfleas, insect larvae and even tadpoles and small fish. They go through a series of moults and complete their development in one or two years although it can take up to five years for larger species. When development is complete they climb stems and leaves of bankside plants at night or early in the morning during late spring or summer. The adult will then emerge over the course of several hours. I have found exuvia (cast-off skins) on plants by our pond before but never been lucky enough to see an adult emerging.

Due to the well developed wing buds I am pretty sure a dragonfly emerged (you can see the exit hole behind the head) from this exuvia rather than it just being a cast-off skin from one of the nymph's moults.

The exuvia was around 45 millimetres long and around 5 millimetres wide.

The shape of the large eyes being almost half the length of the head with an angled rear edge, together with the size of the exuvia, suggest that this may be the exuvia of one of the Aeshna hawker dragonflies.

Unfortunately by the time I had found a dragonfly id guide after taking the first lot of photos and realised it was important to take a photo of the underside of the head and mouthparts to work out the type of labium, the exuvia had fallen off the barbecue and was now in two parts - so a very blurred picture of underside of the head.

My dragonfly identification skills are not particularly good and this is the first time I have attempted to identify which species may have emerged from an exuvia so if anyone can enlighten me more on which species this may be please leave a comment.

Edit - Apologies for the strange appearance of this post - whilst checking it in Preview half the typing seems to be in blue (no idea why!!).


FSC Guide to dragonflies and damselflies of Britain

WildGuides - Britain's Dragonflies by David Smallshire and Andy Swash published by English Nature


Rohrerbot said...

You don't know how cool you are right now. I had a photo shoot yesterday on a family of Grebes. The parent had something in its bill and I couldn't figure out what it was....and then you posted this!!! Now I know exactly what it is. I had no idea that this is what they were called....now I know. Thank you:) We had beautiful rain tonight and the clouds were fantastic at sunset. Hope you have a nice start to your week. "Exuvia patronum!" Sounds like a Harry Potter spell:)

Ragged Robin said...

Rohrerbot - What a coincidence Chris!! So glad I was able to help :).

Glad you have some rain at last and I hope its gone cooler for you.

"Exuvia patronum" - love it!

Have a good week.

ShySongbird said...

What a fascinating post! I have never photographed exuvia but am always on the lookout for it :-) Great photos, a shame about the mishap though ;-)

You are costing me money again Caroline!! Having just recently ordered a secondhand (it's currently out of print) copy of Ina Taylor's Edith Holden book....all your fault!...I have now discovered there is a book called Field Guide to the Larvae and Exuviae of British Dragonflies by Steve Cham. I hear it calling my name...and maybe yours too especially as you have a pond!

I didn't notice the difference in type colour until you mentioned it but I have had the same problem. It is to do with copying and pasting and the only solution I have found is to physically type the piece out :-( Blogger can be a real pain sometimes!

Anonymous said...

That was very interesting, I have never seen one at all.

Not only is part of your post in blue but when you hover your cursor over it, it changes to underlined yellow - most odd.

Ragged Robin said...

ShySongbird - Many thanks Jan. I had several mishaps:( Trying to do everything in a rush. I left exuvia to dry and then managed some photos. Then I came in to put on the macro lens and it had fallen on the floor but it was still in one piece! Then came in to get a moth pot to put it in and by the time I had got back outside it had fallen again and I could only find half!

It so lovely to talk to someone who can't stop buying books either :) You will love the Ina Taylor book - it really is interesting. I bought the Country Diary Companion second hand as it was out of print. You are being exceedingly naughty tempting me with the Larvae and Exuviae book!!! - I shall be searching for it as soon as I have finished my comments :) Trouble is I have to keep away from Amazon as Brian has discovered you can check past history of buying :(

Its strange about the appearance as I didn't do any copy or pasting! The only thing I can think is that when I was inserting lines between photos I may have done something I shouldn't have done - if that makes sense! TBH I reverted back to old blogger and am still using that! I still find it impossible to insert links or bold or italics. One of these days I will experiment so if people see posts appearing and disappearing its me in experiment mode :)

Toffeeapple - Many thanks - its fascinating what you can find at times.

Concerning the colour and underlining as mentioned to Jan above the only thing I can think I may have done wrong was perhaps split a photograph when I shouldn't have done which has adversely affected the typing.

Anonymous said...

Southern Hawker. :)

Ragged Robin said...

Anonymous - Thanks so much for id :)

Dare I ask is it Mandy leaving a comment? Apologies to Anonymous if it isn't.