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Some KS diving beetles


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Ornate Diving Beetle - Thermonectus ornaticollis

Love these guys...extremely active, very colorful. The camera doesn't quite capture the

contrasting red of the legs.





Intermediate Diving Beetle - Thermonectus intermedius

These are relatively new to me, and the ID is tentative. Kansas is the first place I've found

them and I haven't had a chance to really key them out with a dissecting scope just yet.

They're readily breeding though so I should have some larvae soon enough.




Fringed Giant Diving Beetle - Cybister fimbriolatus

The best of the Dytiscids in my view!



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Great photos, Shoegazer! Thanks a bunch for sharing. It is especially useful to see the size comparison on the coin.


Does T. ornaticollis range into Arizona? I collected some very similar looking beetles down there and have been wondering. I do recall the black band across the elytra being a bit darker in the ones I found, but maybe memory is off a bit. I also saw a similar species here in Oregon. Any thoughts on it's identity?


What are your Cybister eating?



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Hi Peter,


To my knowledge, ornaticollis are an eastern US species and stop at the western edge of the great plains. In AZ and the southwest in general, they're replaced by the Black-banded diving beetle (T. nigrofasciatus), which is what you most likely saw, as well as the Sunburst Diving Beetle (Thermonectus marmoratus), Intermediate Diving Beetle (Thermonectus intermedius), and Sibley's Diving Beetle (Thermonectus sibleyi). Like you, I've seen the black-bands in AZ, around Tuscon, sharing their pools with Sunbursts. I know in a lot of literature, ornaticollis is treated as a subspecies of nigrofasciatus, so there ya go.


As for what you're seeing in Oregon, I don't think there are any Thermonectus that far north in the western US. They're probably Acilius or Graphoderus. I'd love to see a photo sometime!


I feed the Cybister any animal matter...usually chopped earthworm, crickets, bugs from my porchlight, etc. They'll readily take table scraps too. If I miss a few days of feeding, they start decimating the aquatic snails.









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I saw what looked very much like a Thermonectus sp. in a local pond not too far from where I live in Oregon. It was April this year, I believe...definitely spring. And it had the sort of gold with slight black markings appearance that many other Thermonectus spp. seem to exhibit. Of course, I'll be making a trip back soon (and reminds me this is whooly bear season down there too)!


Thanks for the info, Nate! I've seen them together in the pools too, with giant water bugs and frogs, corixid water boatmen, etc. I meant to check that special location again this year and was within half an hour of it for several days, but never made it around to that side of the canyon (too busy catching beetles this year on my AZ trip).


I'm going to bump over to that water beetle aquarium post because I have a few questions that are better placed there...


Thanks again!



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