Tuesday, 9 July 2013

THE BLUE-TAILED DAMSELFLY AND HIS COLOURFUL FEMALES





The Blue-tailed Damselfly (ischnura elegans) is one of our commonest species and  is abundant from May to September in lowland habitats around still and slow-moving water. It avoids fast flowing and acidic water but is tolerant of brackish and sewage-enriched waters.


The abdomen in both sexes is mainly black on top with the exception of (segment) S8 which is blue or, brown in some females. Both sexes have two-toned wing spots (pterostigma) on the front wings, which are whitish towards the tip and twice as long as they are wide.



Male (typica)




Female (typica)






Apart from the typica form the female occurs in four other colour forms.



The violacea  form with violet sides





which will mature into the typica male type colouration or the olive-green thorax with brown S8  of the infuscans form as seen in the mating wheel (or Copula - 'in cop') below.





The rufescens form with orange - pink sides





 which will mature into the pale brown colours, with dull brown S8, of the rufescens-obsoleta form.






and seen again 'in cop' in the image below.






These are the most likely Damselflies to be observed 'in cop' as they can typically stay  in the mating wheel position for up to six hours....in some of the Dragonfly species, such as the Chasers, it can be as little as a few seconds!





* information taken from the excellent reference book... Britain's Dragonflies by Dave Smallshire and Andy Swash.  Published by WildGuides Ltd.





18 comments:

ADRIAN said...

This is a great post. I never knew that so many variations occurred.
I'll investigate the book. It looks a step up from the Collins pocket insect guide.

The Herald said...

Thanks Adrian. Yeh, it gets complicated with all the different colours!

It's a good book, and there's lots of others, on different subjects, in the series...[;o)

ADRIAN said...

Had a look they aren't too expensive either. I like the new header.

grammie g said...

HI Trevor...I know they know I am coming for them , because they are of just as I am about to hit the button!! : ) I did see two yesterday "in cop" (as you say ) that weren't any more then an inch, long. Didn't have the camera, but I don't know if the micro lens would do it any justice!!
This one is a pretty color, I can just imagine just how hard it is to ID them.

As usual great job!!

Grace

Frank said...

Excellent post and pics Trevor. Always helps to have a good ID guide to sort out these variations.

The Herald said...

Thanks Adrian. They're a good series of books, I've just recently bought the one on Hoverflies...around 300 pages of confusion at the moment!!...[;o)


Hi Grace...Thank you. Stealth is the way to go, I creep up on them slowly and snap them with the 100mm Macro lens. Or...looking at it another way...It might be that my 16 stone bulk blocks out the sun and momentarily sends them to sleep which makes them a little easier to photograph!..lol.

Whichever way, the 'hit rate' is quite low!

It's easy taking the photographs Grace, it's afterwards, when I'm trying to ID what I've taken, that the pain starts!!...[;o)

The Herald said...

Thank you Frank. it's much easier with a good book!..lol....[;o)

Bob Bushell said...

Pretty little things.

The Herald said...

Pretty, but a tad confusing at times Bob!...[;o)

Findlay Wilde said...

What brilliant pictures of the damsel flies. Couldn't you just watch them for ages and ages. From Findlay

The Herald said...

Thanks Findlay. Yeh, they're interesting to watch and photograph..amazing creatures!...[;o)

FOREST SNAPPER said...

Trevor, your header is fantastic and thanks for the I D yesterday too.


peter

The Herald said...

Thank you Peter, no problem...[;o)

Roy Norris said...

Amazing images Trevor, not seen this species as yet.

Roy Norris said...

Forgot to mention your great new header shot.

The Herald said...

Thanks Roy...[;o)

Maria said...

Great photos; great quality!

The Herald said...

Thanks Maria...[;o)