jccurd's picture

Curious dragonfly wing structures

Observed: 17th September 2009 By: jccurdjccurd’s reputation in Invertebratesjccurd’s reputation in Invertebratesjccurd’s reputation in Invertebratesjccurd’s reputation in Invertebrates
IMG 3332 Red-veined Darter
IMG 3338 Red-veined Darter

I snapped this darter in southern France last Sept. I think it's a Red-veined Darter but I am VERY curious about the red bead-like structures on the wings.

Species interactions

No interactions present.


miked's picture

Was it alive? Some random

Was it alive?
Some random thoughts, possibly the fluid that it uses to expand the wings has escaped, I've never seen this so could easily be talking rubbish here. or could be one of the microorganisms that infect insects and erupt out to release their spores, sometimes see insects stuck on the top of plant stems covered in spores but never seen a dragonfly infected like this and masses of spores more likely on body rather than wings.

jccurd's picture

Very alive

Yes, Mike, it was very much alive and very actively hunting. A red-veined Darter is suppose to have, well, red veins which don't seem present here so I did have thoughts about the red beads being related to that colouration. It seemed a bit fanciful but you seem to have gone that route, too, so who knows?

Martin Harvey's picture


Some extraordinary photos! Mike's idea about the haemolymph fluid leaking from the wing veins seems feasible, but I don't know if that is a known phenomenon. The British Dragonfly Society recently published a paper on tiny biting midges (family Ceratopogonidae, species Forcipomyia paludis) that attach themselves to the wings of dragonflies and feed on the haemolymph in the veins, but they made no mention of this causing such droplets to form (and I can't see any midges in your photos).

Very intriguing.

Entomologist and biological recorder

RoyW's picture

These are parasitic mites

Dragonflies (and damselflies) quite regularly have a few of these parasitic mites on them, which will be feeding on the dragonflies body fluids while hitching a lift to a new waterbody. They can also be found on dragonflies in Britain.

The dragonfly is not a Red-veined Darter (the lower half of the eye is always a blue colour in that species). It is an old female, and is probably a Southern Darter (based on the very plain sides to the thorax, the pale pterostigma, and the large amount of yellow on the legs). I wouldn't like to completely exclude Common Darter based on these two photos though.
Incidentely, Southern Darter is a species that is frequently found to have heavy infestations of this type of mite.

Heres a link to some photos/ information about this type of mite on an American dragonfly; http://bugguide.net/node/view/125964/bgimage

jccurd's picture

Thanks again

Many thanks for more very informative help, RoyW. I now have a relatively new copy of the Field Guide to the Dragonflies of Britain and Europe (Dijkstra & Lewington) and I see that does mention these mite infestations particularly on the Southern Darter.

I'll check my other photos to see if they are any more diagnostic as to species. I hope it's a Southern. :))

RoyW's picture

It does look like Southern

The most diagnostic feature that you may be able to see in your other photos is the vulval scale. If you have a shot which is from the side (but not so much of a dorsal view as the one you attached), you are likely to be able to see the vulval scale clearly if it is a Common Darter - if it's a Southern it should be harder to see.

jccurd's picture


Last year, my first getting very close to odonata, I was taking pictures more for artistic merit than identification. I can see I'll have to amend my approach and take both.

Thanks again - I so appreciate your help.

dshubble's picture


If you have access to the New Naturalist 'Dragonflies' by Corbet & Brooks (2008), there's a section on these parasites on pp.194-197. This states that the water-mites parasitising Sympetrum spp. belong to the family Limnocharidae.

RoyW's picture

Hosts of mite families

The mite family most frequently found on Odonata is apparently Arrenuridae, and these do parasitise Sympetrum species even though there are no specfic examples mentioned in Corbet & Brooks (the example phtos I linked are of a sympetrum species). Sympetrum are mentioned in the New Naturalist as one of the odonata genera that the Limnocharidae family have been found on - they are not the only mites found on this genus.

Having said that, I have no idea whether the identification on the link I gave is 100% correct! (sorry).
Next time I find some mites on a dragon/damselfly I may try and get them under a microscope for a closer look...

dshubble's picture

Mites & hosts

Ta for that - not something I know a lot about - there is supposed to be a European Water Mite webpage at www.watermite.de but it wasn't working when I went to have a look.

Martin Harvey's picture


Thanks Roy, good to know the explanation.

Entomologist and biological recorder

Norwichnaturalist's picture

the red dots are mites,

the red dots are mites, uncommon in the UK but more so in warmer climes

Colin Jacobs.
Wild Flower Society member