Saturday, October 06, 2012

I finally decide to take the plunge...

I've been meaning to get around to a blog entry that features underwater wildlife and now that I've made a start on same, have realised that I've probably now got too much for one entry and so may have to spilt it into 2 or even 3 entries.

For starters, let's go BIG...


Dytiscus marginalis
This is a female great diving beetle and is one of our largest beetles in the U.K. The adults come in at around 30mm or so (over 1") and can be found in ponds and lakes.



A closer look at these impressive beetles leaves you in no doubt that they can be fierce predators and have even been know to tackle small fish in garden ponds.

The underside
These beetles can sometimes be spotted coming to the surface, pointing the tip of their abdomen out of the water to replenish the air supply stored beneath the wing case-because, although they tend to spend most of their time below water, they can also fly and often do to colonise new ponds.

CLICK ON ANY PHOTO FOR A LARGER VIEW
Aeshna cyanea dragonfly nymph
 Next is this beautifully marked dragonfly nymph. This particular specimen seems to have quite a lot of blue in the markings,even at this stage.




A couple of closer views of a different specimen that has less blue colour.



These are nymphs of the southern hawker dragonfly, a common species that breeds in ponds and flies June-October.


Another fearless little creature that inhabits most ponds and lakes and preys on all manner of aquatic creatures and insects, is the water boatman or back-swimmer...

Notonecta glauca



To give them their correct title, these are lesser water boatmen-there is also a greater water boatmen, but those swim the right way up making them easy to tell apart.The seems to be some confusion over water boatmen and backswimmers though as I've seen the greater water boatmen described as backswimmers and the lesser described as just water boatmen! 

There are two families:Corixidae for the smaller ones that swim the right way up (are you following this?) and Notonectidae for the larger ones that swim on their backs. There, that's cleared that up?

Even though most water boatman are vegetarians, some will also eat other insects and apparently it's unwise to pick one up, as they can give a painful (although harmless) bite.


This little video I managed to get of one underwater demonstrates two things:firstly,the silvery appearance you see here is caused by a clever trick that allows them to remain under water for longer (up to 6 hours).They hang upside down below the water’s surface and collect air, they then carry this air as a bubble on their body or under their wings.
Secondly, at the end of the video you get a feeling of just how fast they are.


Alongside the dragonfly nymphs, most ponds and lakes and indeed rivers, will have damselfly nymphs also...




I'm not 100% sure on i.d. for these two but think possible the top one is a large red.

Here's my first attempt at filming some damselfly nymphs-it's not over exciting but everyone has to start somewhere and I'm sure I can improve on this...




I think possibly the larger, green one will be a common blue-either that or a blue-tailed, as they are the only ones I've seen as adults at this spot. I'd like to think that it's an emerald nymph and it does look very similar to some I've seen but not seen any where I found this, so not at all sure.

Well, as I suspected, I have lots more pond life to bore... show you yet and so I will endeavour to bring a second update on the same subject soon. If not in the next edition, then the one after...you have been warned!

Until the next time then...


3 comments:

Neil said...

Made 'a start' lol

Took me ages to get anything that good!

Nice stuff, look forward to more

JJ said...

Thanks Neil. I really appreciate your help with photographing these critters and for inspiring me to do so in the first place-your shots are awesome and so I really appreciate your support with my own.

Anonymous said...

Incredible series of shots and videos too! Quite superb!
Maria