What do Damselflies eat?

[Geoff F]

Continuing the recent Damsels and Dragons threads, from several people.

One question which often gets asked is what do they eat. Well the answer is simply anything which moves and is smaller than themselves.

This Azure Blue Damselfly is finishing off a meal from a small moth.



While this immature Common Blue Damselfly is eating some form of fly.

[bnnrcn]

Very nice colours and composition in #1 , also very sharp How big is a damselfly Geoff ?

[DanK]

very nice shots. I prefer #1, which is sharper, in part I think because the critter is nearly parallel to the sensor. Yes, they are fearsome hunters, like dragonflies.

Are you sure of the identification? As i read it, Wikipedia suggests that #1 is a common blue male and that #2 may be a common blue female (http://en.wikipedia.org/wiki/Common_Blue_Damselfly). In a couple of weeks, I will be headed to the Adirondacks, where we have lots of one or the other, but I have never looked to try to figure out which. E.g., this one, which landed on my knee:

[Shadowman]

Nice images and info.

[Geoff F]

What you read on Wikipedia, Dan, 'ain't necessarily so'!

Right then, a quick lesson on Damselfly identification . . .

Look at the thorax sides. With the Azure (image 1) you will see a narrow blue stripe and below the full length black stripe there is a short black line. This shows it is one of the Azure grouping, but it gets a bit more complicated sorting out other species within that group.

The Common Blue has a wider blue stripe and lacks that short black line. As in the second photo which is an immature (pale colour) female. The black 'rocket' shapes on the abdomen shows it to be female. But just to be difficult, there is also a green form of females.

So the one in your photo is . . .that's correct, a male Common Blue.

Try this as a memory aid:-

'The Common Blue is Very Blue'. (Apart from the green female form).

Male Azures play snooker! They carry their cue with them - that short black line on the thorax. Their beer glass needs refilling - look for a black U shape at the start of the abdomen. And they wear a bow tie - the black mark at the tip of the abdomen.

Females have a 'thistle' shape at the start of the abdomen and more black along the abdomen which may be mostly solid or 'rockets'. And the thorax colour can be blue or green.

And if you have an apparent Azure which doesn't look quite right; it is probably another species from that group; but let's not get over complicated for now.

[Geoff F]

Binnur, these Damsels are fairly small, around 1.5 ins body length at most, often a little smaller.

[Geoff F]

OK then, here is a male and green form female. So which species?



Just couldn't get the right angle here, and they then moved to somewhere more secluded to continue!

[deetheturk]

Nice images Geoff, I was just about to press my shutter on one yesterday when a Robber Fly beat me to it I never got close enough for that shot

[bnnrcn]

Very artistic look with lovely colours

[DanK]

Geoff,

Very helpful explanation. thanks.

I am guessing that the last shot is Azures, based on the small line on the thorax, but on the other hand, the abdomen is mostly blue.

Dan

[Geoff F]

That is correct, Dan. That small line on the thorax over rides any colour variation.

For example, here is a freshly emerged Common Blue, identified by the lack of that line. But this new colour is completely different from the adults. It will gradually change into adult colours.

[JBW]

maybe just a little tighter crop? Just kidding. Quick question, are Damsel and Dragonflies related?

[Geoff F]

Yes, Brian, they both belong to the Odonta order.

The simplest way of telling them apart is Dragonflies sit with wings outstretched while Damselflies rest with wings folded. They have identical front and back wings while dragonflies have slightly differently shaped front and back wings.