Kinked Damselfly

[Rambling Rob]

This damselfly spotted on Alder at Yarbridge Mead, IoW yesterday seemed to be flying normally (I followed its flight to this branch) but it had a severe kink in the abdomen.
Any theories on why this could be? Just one of those things?

Also I wonder if anyone can ID the damselfly for me?

Thanks for looking..Rob

[NickCantle]

Kinky!

[Rambling Rob]

Has just occured to me that damselflies adopt quite contorted positions while mating - could it have pulled a muscle / done its back in, so to speak?

[RoyW]

Hi Rob,

This is what happens when damselflies emerge too near to a twig, or other obstruction. The expanding abdomen hits the obstruction causng it to kink - the exoskeleton then hardened like that so the damsel is stuck with this shape. I have a number of shots of similar damsels that I might be able to post sometime (the wings are often affected as well).

As for the Id, it's a female Blue-tailed Damselfly, Ischnura elegans of the form Infuscans-obsoleta.


Roy.

[Hedge Witch]

Roy, isn't the black antehumeral stripe visible (rather than the mid-dorsal black stripe)? This would mean it derived from form violacea, i.e. it's form infuscans? Any help with this much appreciated.

[Jason Green]

Nick:

Roy: Very knowledgeable reply there. I just wonder if it could also have been caused by a spider bite? I've seen a photo of such an event on here...

[Rambling Rob]

Thanks for the ID Roy / Hedge Witch. I can see how that twig theory would work.

Regarding the spider bite theory, Jason, would that need to happen during / soon after emergence?

Nick - kinky ab. could be a useful contour-hugging adaptation for alighting on bumpy ground? Probably not..

Rob

[Jim Ford]

Originally Posted by RoyW

This is what happens when damselflies emerge too near to a twig, or other obstruction. The expanding abdomen hits the obstruction causng it to kink - the exoskeleton then hardened like that so the damsel is stuck with this shape.

I've had a mantid that was similarly crippled by its exoskeleton hardening before it had fully emerged. It was unable to catch its food and consequently died.

Jim

[RoyW]

Originally Posted by Jason Green;486322[B

Roy:[/b] Very knowledgeable reply there.

It might have been if it was correct!

Originally Posted by Hedge Witch

Roy, isn't the black antehumeral stripe visible (rather than the mid-dorsal black stripe)? This would mean it derived from form violacea, i.e. it's form infuscans? Any help with this much appreciated.

Perhaps you can provide me with the help on this Hedge Witch!
After looking at the image again it does appear to be form infuscans, photographed from slightly below so that the humeral stripe looks like the mid dorsal stripe. (The ante-humeral stripes, if present, are always pale. The dark stripe below this is the humeral stripe).
In my defence, I had only popped in for lunch after a morning in the field, and was very keen to get back out again - a poor excuse perhaps, but it's all I have so there!

Anyhow, if we ignore the precise identification of the damselfly, at least part of my answer was perhaps OK. This unfortunate 'damsel in distress' appeared in front of me this afternoon - as if wanting to prove that I was right and it happens quite regularly!



Roy (thinking of signing up with 'Incorrect ID's anonymous'!)

[Hedge Witch]

Great

I shall try and remember:

Antehumeral = pale stripe.
Humeral = dark stripe below this.