Chrysomelidae Aphthona sp.?

[JRsbugs]

Hi,

Taken on 24th November, size ~2mm. It looks to me like Aphthona nonstriata but there seems to be some lookalikes. The colour of the antennae looks to match this best, however I imagine it will be one of those which remain Apthona sp. but I can ask the experts just in case and hope I at least have the genus correct.

Janet

[Klaas Reißmann]

Hi Janet,

I think you got the right genus, but I don't know which species. In my mind the habbit is to narrow for A. nonstriata. so I guess another species than this one, but I can't tell which one.

Regards
Klaas

[JRsbugs]

Thanks Klaas, but why would the habitat be too narrow? I have a roadside drain which is part of my garden, it's very long and full of Iris pseudacorus which apparently A. nonstriata feeds on. That is not far from where I took the pics. It's mentioned under 'Biological Control'

Iris pseudacorus - Bugwoodwiki

[Klaas Reißmann]

Hi Janet,

I meant the habit or habitus, not the habitat.

Regards
Klaas

[JRsbugs]

Originally Posted by Klaas Reißmann

Hi Janet,

I meant the habit or habitus, not the habitat.

Regards
Klaas

Aah, I now know what you mean, I misread what you put. Or I think I know. You mean it is not broad enough in it's appearance for A. nonstriata.

Would the time of year point to any particular species?

[JRsbugs]

I'm trying to narrow down the species..

Listed Apthona sp. for Britain on Wiki.. if that is up to date:

Aphthona atratula
Aphthona atrocaerulea
Aphthona euphorbiae
Aphthona herbigrada
Aphthona lutescens
Aphthona melancholica
Aphthona nigriceps
Aphthona nonstriata

List of leaf beetle (Chrysomelidae) species recorded in Britain - Wikipedia, the free encyclopedia

A. euphorbiae, herbigrada and Lutescens are the wrong colour. A. nonstriata seem to not fit either, leaving 4 possibilities.

I can't find A. atratula, but A. atrocaerulea is widespread and common, it's also the correct colour.

Aphthona atrocaerulea

Aphthona melancholica I found, it doesn't look the correct shape..

http://www.biol.uni.wroc.pl/cassidae...lancholica.jpg

Aphthona nigriceps is not a candidate..

http://www.biol.uni.wroc.pl/cassidae...0nigriceps.jpg

Aphthona atrocaerulea looks to be the only one at this point, unless there are other species or there's variations in some of the species, or if it happens to be Aphthona atratula.

I found that Aphthona atratula is also called Aphthona atrovirens.. the colour is a little greenish.

http://www.colpolon.biol.uni.wroc.pl...atrovirens.htm

[Klaas Reißmann]

Hi Janet,

I am amazed at how much effort you're running to determine the exact species. For that I'm awfully sorry I can not help. I would try with the beetle itself, but I can't only by the photo.

Not all Halticinae are active in winter and I don't know which are really, but I often find Halticinae in winter as long as it is not freezing, sometimes attracted by light. You even can find them hibernating in moss, in the soil around their feeding plants etc. So I even can't help by knowing their times of activity.

I'm absolutely sorry.
Klaas

[JRsbugs]

Thank you again for your input Klaas, and may I quote you:

Curiosity is the beginning of knowledge

Those who know me know that I will turn every stone until no more stones can be turned. That is how I learn, if I expect others to tell me without doing the research myself I would be at a standstill. I will now know more of what to expect next time I come across one of these beetles.

Effort is what gets me results even if I don't get a 100% result every time, until I ask I do not know.

[theresa dockery]

I'm no expert, but just wanted to give my thoughts on ID based on close examination of all the potential species (if that's helpful in any way ) - I think you've identified it correctly.

Looking at photos of the 8 Aphthona species (Wiki list matches The Coleopterist checklist): Aphthona atrocaerulea looks (to me) like the most likely candidate.

(Basing my opinion on: the head shape, slightly protuberant eyes, antennae are a perfect match, slightly blacker colouration, subtle differences in the shape of pronotum/ident between pronotum & humerus of elytra).

[JRsbugs]

Thank you Theresa, I find elimination is often the best way to go. Seeing what's left and if it matches has to present a most probable candidate. As there's only 8 species and most of them differed in some way, that didn't present too much of a problem once the task was taken in hand.

After all, ID is about looking at other possibilities and elimination as well as looking at ID features surely, whether it's from a specimen or a photo. I think the photos I took of such a small beetle must come close to putting it under a microscope, even better than some magnifications of microscopes perhaps. I realise those who are used to taking specimens will see it differently, but even specimens can present problems.

Having said that, those who have done the years of collecting are often those who have the knowledge so I do appreciate the input and hope we can continue to respectfully knock heads together to increase not only my knowledge but to help others to be aware of what the possibilities are.