Water beetles

Community and Forum → Insects images → Water beetles

Alexandr Rusinov, 29.02.2008 14:20

Something on our forum water beetles were overlooked, in my opinion undeservedly. I propose to put photos of water beetles in this topic, I hope our forumchane will support me. So:
Dytiscus lapponicus Gyll. Yaroslavl region, peat lake in a swamp.
picture: Dytiscus_lapponicus.jpg

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09.03.2008 18:35, Victor Titov

Two regular floaters:
Rhantus (Rhantus) frontalis (Marsham, 1802)
Yaroslavl region, Rostov region, Spirtsovo village, Mokza River, near the shore, 01.05.2006.
picture: DSC01215__1_.jpg

Rhantus (Rhantus) exsoletus (Forster, 1771)
Yaroslavl region, Rostov region, locality along the highway S. Varnitsy-S. Markovo, staritsa, 29.05.2004.
picture: DSC01204__1_.jpg

And a water lover who came across me in the Yaroslavl region only once and quite unexpectedly:
Hydrochara dichroma (Fairmaire, 1892)
Yaroslavl region, Rostov, Lake Nero, 03.05.1996.
picture: DSC01219.JPG

P.S. I admit my guilt, measure, degree, depth!!! Colleagues who expressed doubts about the correctness of my definition during the discussion of this post turned out to be absolutely right. The photo shows no Hydrochara dichroma (Fairmaire, 1892), but an under-colored specimen of Hydrochara caraboides (Linnaeus, 1758). Many thanks to botanque for clarifying this issue.

This post was edited by Dmitrich - 10.10.2010 19: 02

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10.03.2008 2:52, Victor Titov

"Hydrochara dichroma"
It took me a day to understand that earlier (at the time of the "green" determinant) this genus sounded:
"Hydrophilus"
I'm getting old.
And it's great that you found this view north of what is indicated (Ukraine).

In the days of the "green" I could not identify this beetle at all, I was lost in guesses. It was only relatively recently that I was able to identify it using the identifier of A. G. Kireichuk and A. G. Shatrovsky (thanks to the Zinovsky site).
And the specified range of this water lover is really far from our Yaroslavl region (Ukraine, Caucasus, Central Asia, Western Siberia. Hungary, the Balkans, Western Asia, and Northwestern China). However, after a "throw to the north" of a number of species (the same Oxythyrea funesta, Agrilus convexicollis), and this my find seems interesting, but not paradoxical.

This post was edited by Dmitrich - 10.03.2008 03: 01

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10.03.2008 21:45, Victor Titov

Do you know where exactly in / in Ukraine? In "green", for example, it says simply Crimea. So the advance to the north may not be small. With Shatrovsky http://www.zin.ru/animalia/Coleoptera/rus/shatrovs.htm haven't you talked about it?

Alas, I did not communicate and I do not know the scale of the movement of this species to the north...

And in the classic "green" 1965 edition of the H. dichroma species available to me, there is no such thing at all, please tell me where you found that the Crimea is indicated specifically for it? There, only two species of the genus Hydrophilus (syn. Hydrochara) are listed in the definition tables: H. caraboides and H. flavipes...

This post was edited by Dmitrich - 10.03.2008 21: 47

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13.03.2008 11:51, Victor Titov

Dmitrich!!!
Can't it be your H. dichroma, H. caraboides with under-painted legs??? And??

I suppose it can't. In H. caraboides, the terminal segments of the maxillary palps are unicolored, dark, and relatively longer (width - to-length ratio 1:5) And in H. dichroma, these tentacle segments are yellow or light brown with a darkened apex and somewhat shorter (width to length 1:4) At my beetle-just such. In addition, according to the illustration to the determinant by A. G. Kireichuk and A. G. Shatrovsky, the shape of the spike on the keel of the prothorax is also different: in H. caraboides it is more "triangular", the base is wider, and in H. dichroma it is narrower, "spike-like" (like in my specimen). I'm 99% sure of my definition. But I would like to wait for A. G. Shatrovsky's answer. Not yet. Waiting-from

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13.03.2008 13:54, Victor Titov

In H. caraboides with under-colored legs, under-colored palps are usually attached, so you probably need to focus on the length / width ratio of the last segment. In my opinion, the laid-out copy is relatively shorter than the standard caraboides. Only here the place of discovery is already much north of the main area... Although there is a large railway junction nearby, delivery is also possible... In general, we will wait for the answer of A. G. Shatrovsky.

That's it. At the same time, the final segments of the palps are clearly two-colored: the top is black (unfortunately, this is not too noticeable in the photo, but believe me, this is a fact). Again, the shape of the spike on the keel of the prothorax. Besides, I may be fantasizing wildly, but here's another thing. The beetle was found not in the water of Lake Nero, but on the shore, in the immediate vicinity of the Saviour-Yakovlevsky Monastery. And there are numerous pilgrims from all places, and bus excursions... In addition, I have never met such a topic: is it possible to settle (drift) insects with migratory waterfowl? There are a lot of them on Lake Nero: ducks, geese, even swans are marked on the flight...

This post was edited by Dmitrich - 13.03.2008 13: 55

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