jccurd's picture

Suspect Moustache

Observed: 30th August 2011 By: jccurdjccurd’s reputation in Invertebratesjccurd’s reputation in Invertebratesjccurd’s reputation in Invertebratesjccurd’s reputation in Invertebrates
IMG_1437_Moustached_maybe
IMG_1437_Moustached_maybe 1
Description:

I've never seen (knowingly) a Moustached/Vagrant Darter before but I'm wondering if this is one (same individual). Thorax isn't that of a S. striollatum. It doesn't look Ruddy Red or Southern Orange and it DOES have a moustache.

Identifications
Species interactions

No interactions present.

Comments

RoyW's picture

Interesting...

This is an interesting observation for a number of reasons - in particular the fact that it makes a very interesting ID challenge.

I know what it is, but I'm not going to post an ID yet, I'll see what others make of it first ;)

jccurd's picture

You tease, Roy!

We've got to get others to stumble into it, first. :D

I've been agonising about this one. Most things seemed to say Vagrant but I thought the legs looked wrong, more like a Ruddy, according to the illustrations, that is.

BTW, please try to look at my other couple of posts recently. I suspect I had:

Pretty confident about the second but the first ...? ;)

All the best, John

RoyW's picture

Male or female?

Consider what sex this dragonfly is (if you haven't already) before you try and identify the species.

You are correct with the two damsels.

Enjoy the rest of your stay in France!

jccurd's picture

OK, Roy ...

... I did initially look for either a vulvar scale or hamule but decided I couldn't actually see either. This I put own to my angle of view perhaps being a little too high. I didn't look further because the red colouration of the abdomen suggested male so I went looking for a matching male Sympetrum.

However, now you've prompted I think the appendages look female - there's apparently no lower appendage.

The pattern on the side of the thorax and black legs look classic Ruddy and they do have drooping moustaches. The dark marks on the side of the abdomen seem light and the red is a worry but ...

Leap of faith: maybe this is a female Ruddy Darter in disguise.

[Aside: since more Sympetrum species seem to have moustaches than not, I think we should discard the Moustached Darter name.]

PS. I did write this before reading your email which I only just found and for which, I thank you. Clear explanations as ever. :)

jccurd's picture

Not Red-veined

A Red-veined Darter would have

  • a blue underside to the eyes,
  • black-lined yellow pterostigma
  • yellow patches at the wing base
  • red or yellow veins depending on sex

none of which are in evidence here.

RoyW's picture

Ruddy Darter - Female.

Some female dragonflies develop the colouring that is normally associated with males, and these can pose an identification hazard for the unwary. In this case, the abdomenal appendages, 'swollen' second abdomen segment, and lack of male secondary genitalia show that this is a female - even though it is red.

The all black legs are a feature of only four European darter species, two of which can quickly be discounted: Banded Darter (no black wing bands), and Black Darter (which is never red). Southern Darter can also be readily ruled out because the legs are largely yellow and should never look as black as this (+ they lack black 'moustaches').
However, female darters which develop red colouration are usually considered to be older, very mature individuals, and the yellow leg stripes can become very difficult to see on older darters, so it is probably best to use another feature as well before ruling out species like Common, and Vagrant. Females of both these species show a prominent vulval scale (particularly Vagrant), which should be visible in these photos - and this feature does not vary with age! Females of the two other widespread European species, Red-veined and Yellow-winged Darter, both have an obvious, almost complete black stripe along the side of the abdomen (which is not present here) as well as the features in the wing that they are named after.

This leaves the two remaining black legged species, Ruddy Darter and Spotted/Marshland Darter. Spotted Darters are named after the prominent triangular spots along the side of the abdomen, which are present on both males and females, and tend to have more 'cells' towards the edges of the wing (not easily visible in these photos). Spotted Darter would also be a scarce species in the part of France were the photo was taken, so I am confident that this is a Ruddy Darter.