Welcome to my blog

This is where I post various musings about wildlife and ecology, observations of interesting species (often invertebrates)
and bits of research that grab my attention. As well as blogging, I undertake professional ecological & wildlife surveys
covering invertebrates, plants, birds, reptiles, amphibians and some mammals, plus habitat assessment and management
. I don't work on planning applications/for developers. The pages on the right will tell you more about my work,
main interests and key projects, and you can follow my academic work here.

Sunday, 11 August 2013

Dead dragons

After a bit of a break, time to return to the Spot, and with another garden pond update... So far this year, I have counted 11 skins (exuviae) of common darter dragonflies (Sympetrum striolatum) that have emerged from our pond. I've only seen a few of the resulting adults, most appear to have left, presumably to find mates, but one did not get far and was found dead in the water. I don't know what happened (it appears to be hollow so scavengers were there before me I imagine), but it does provide an opportunity to look at some fine structure without killing a specimen.

The dead Sympetrum striolatum - note the fully extended wings and broken abdomen. Also, the colour has either faded aftre death, or was not fully developed.

A close-up of the abdominal segments - the last few are missing, exposing internal structures. Note the tiny teeth around the rear edge of each segment which presumably aid closure against the adjacent segment and/or membrane.

Wings clearly showing the veins and pleating, as well as basal structure and the small amount of basal yellowing/darkening.

The head showing the large compound eyes and small antennae (bottom-right, jutting forwards).

Side view of the thorax - when alive, the large white patches are yellow. Spiracles are visible, such as the elongate hole by the base of the wing.
I have not gone into much detail here - it should however provide a starting point for investigating your own specimens (after all, by far the best way!) - also, as with exuviae, specimens like this can be kept as long as needed and then passed onto others interested in investigating insect anatomy (which is what has happened to the exuviae I collected).

Finally, here are my personal 'top three' useful (and not too expensive) books covering identification of British and continental European dragonflies:

Brooks, S. (2004). Field Guide to the Dragonflies and Damselflies of Great Britain and Ireland (4th ed.). BWP, Gillingham.
Dijkstra, K.-D. B. (2006). Field Guide to the Dragonflies of Britain and Europe. BWP, Gillingham.
Smallshire, D. & Swash, A. (2004). Britain's Dragonflies. WILDGuides, Old Basing

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