The weather’s warming up: water beetles, pond skaters and backswimmers are on the move

I photographed this spotted backswimmer climbing out of my pond on the reedmace, before flying off, last spring

Attention at this time of the year tends to focus on amphibians.

But now is the time when water beetles, backswimmers, lesser water boatmen and pond skaters are on the move too – nearly two months before the first damselflies and dragonflies make their appearance in May these animals are flying from pond to pond (and to lakes, rivers and streams too).

Last weekend we had the first really warm day of the spring and there were backswimmers flying off from our pond (I expect they were arriving too), and pond skaters have flown in after being absent for the winter.

No doubt the more flighty water beetles will be on the move now too, looking for suitable breeding sites.

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9 Responses to “The weather’s warming up: water beetles, pond skaters and backswimmers are on the move”

  1. Diana S. Says:

    I saw an actual Great Diving Beetle in our pond yesterday – it was diving in and out of the frog spawn so if it was laying eggs somewhere underneath there is obviously a good food supply for the larvae when it hatches! Although we had masses of the larvae last year, I did not see a sign of a beetle. I guess I was lucky just to come along at the right time but unfortunately I did not have my camera with me. Lesson number one – always take your camera with you when looking at pond. I had not realised how large the beetle was, quite something.

  2. Bob Eades Says:

    I saw my first adult mayfly of the season today by our garden pond – invertebrates are on the move even in the Yorkshire Pennines! Caught me by surprise: I’ve seen a few adults of larger insects, such as Peacock butterflies and various bumblebees, in flight through the recent sunny days, but these could well have overwintered as adults. Mayflies, on the other hand, are noted for their short adult lifespans, so I have to assume that this one had just emerged.

    No camera to hand, naturally!

  3. Diana S. Says:

    Saw the great diving beetle again today, diving in and out of wriggling tadpoles – I assume they eat tadpoles? I also saw another beetle, slightly smaller I think but a greyish brown colour? Is this another species?

    Also Bob’s comment above about bumblebees reminded me of strange behaviour (at least to me) of a bumblebee two days ago. There had been a dead bumblebee in the garden for a couple of days and then another bumblebee approached it and spent some considerable time examining it and flying round it and it appeared as thought it was trying to turn it over or ascertain whether or not it was really dead. Has anyone else observed this behaviour? I have never seen this before.

  4. Jeremy Biggs Says:

    Hi Diana – the other beetle was, indeed, a different species. You can tell because the adult beetle is an adult and, like all adult insects, doesn’t change size once it’s emerged as an adult.

    All the growing is done as a larva – which starts out tiny when it hatches from the egg and then grows up to be a whopping great thing (at least if it’s a great diving beetle) or a moderately whopping great thing if it’s one of the other larger diving beetles, or a not very big thing if its one of the many smaller beetles.

    But the one rule that applies to them all is that, once they are an adult beetle, they don’t grow. So if they are a different size (allowing for say 10% size variation which naturally happens from one individual to another), they are a different species.

    A quite large, maybe two-thirds the size of a great diving beetle, brown beetle could well be what I’ve nicknames the Common Brown Diving Beetle, Colymbetes fuscus – a pretty creature which turns up regularly in our pond and almost certainly breeds. You can see nice pictures at Biopix, the Danish natural history photo website.

  5. Diana S. Says:

    Hi Jeremy – thanks so much for your reply. Yes, that looks like it. My Observers Book of Pond Life doesn’t include it – you would have thought as it’s named common it would have been included! Great pictures on Biopix though.

  6. Sue Orchard Says:

    Hi. We have several large (3cm?) beetle larva in our new (last autumn) pond. They are growing at a frightening rate and seem to be consuming just about all the other animal life in the pond! With the depletion of tadpole numbers and the other smaller vegetarians there is now little to eat the algae and the pond seems ‘out of balance’.

    Should I let nature take it’s course? I’m sure you’ll say yes Jeremy but I wonder if other natural pond enthusiasts have had similar experiences?

    • Jeremy Biggs Says:

      Hi Sue

      What an interesting conundrum – I’ve been wondering just how important grazers are in controlling filamentous algae.

      I’ll write something longer later as have busy busy time now.

      Have you sent pictures of your pond before because it would be interesting to see what it looks like? Also did you do the Big Pond Dip last year so we’ve got some info about what’s in the pond. If not you might like to do it.

      And it would be interesting to hear the experience of others too.

      Jeremy

  7. Diana Says:

    Hello again – we left for about three weeks away at the end of April, pool was awash with tadpoles and I had seen one or two small beetle larvae emerging. By the time I got back, tadpole numbers were much decreased (thank goodness) but there are still a fair number. I have not seen as many beetle larvae as last year but obviously there was mayhem whilst we were away and there may have been more around at that time. I have seen some fairly large beetle larvae and also some smaller ones. One very small one had a tadpole larger than itself clamped to its jaws! The larvae seem to favour the water louse and there are not many of them around but there is other life. Some very small silvery darting animals (?) and some triangular objects and other things which I cannot identify. We also have whirligig beetles and other small beetles. This week there was a small dead frog (very pale, obviously life sucked out) I think one of last year’s. I managed to take a photo of it. Would that have been the larvae or the beetle itself? Yesterday I saw two beetles clamped together and assumed initially they were mating but it went on for such a long time, I wondered if they preyed upon each other? We also seem to have two or three larger frogs, but not the size that were mating this year, who seem to spend quite some time sitting in my pot of water forget-me-nots. I think it probably because it has been so dry and our garden being very sandy dries out quite quickly. New pond therefore taking long time to fill up but delivery of another water butt has helped and we are praying for more rain. I am presuming that from year to year a balance will be struck – if there is nothing for beetle larvae to eat they won’t survive and other life will recover. Certainly, since we no longer have fish, more tadpoles have survived. However, we were intending to put more fish back in the old pond once new pond is established but would they survive the beetles? Sorry about long post – becoming rather obsessive here!

  8. Sue Orchard Says:

    Hi Jeremy – thanks for finding the time to reply. The pond was only filled last autumn/early winter so no pond dip last year. (I’m the idiot who filled the pond with tap water – you were kind enough to check the water company’s website for me) I shall certainly dip this year and will be happy to send some photos when I send in the results.

    With regard to the algae I know it’s only anecdotal evidence but we had a fair bit before the tads hatched then, as they grew there was less and less until I actually resorted to feeding them as they (and the other beasties) had hoovered up the lot! Then the beetle larvae appeared, the tads etc. were decimated and the algae is growing again.

    Hi Diana – this being our only pond and very new I was really excited to have any sort of life at first but am now really fearing for what’s left of the tadpoles and all the other small fry (not literally – no fish in the pond)
    I too have seen the larvae with large tadpoles in their jaws but now the larvae are bigger than anything else in the pond. I fished one out this am and it measured over 5cm!! Quite a frightening beast out of water and thrashing about in the net but I did put it back. We’re on sandy soil too and our water butts have long since been emptied – never thought I’d long for wet weather.

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