[ID] Springtail: Isotomurus palustris?

[Jason Green]

Hi all,

Can anyone confirm this as being Isotomurus palustris? If so, as I am 99% sure it is, it will be my first. From distance it was brown as opposed to the darker Tomocerus sp., and too small for my regular Entomobrya spp.

I had to get into quite an awkward position and wait for it to crawl onto an old train ticket (I knew forgetting to deal with them would come in handy one day! ) so I could photograph it at a good angle - where it was, it was too dark, the images would have been blurred. After a five-minute stand-off it gave in...

15/01/10

About 3-5mm

Thanks for looking!

Take care,

Jason

[Dogghound]

I agree its a good possibility but not sure you could say 100% as it is similar to species like I.maculatus. Looks more like I.palustris though.

[Jason Green]

Thanks Dan!

[JRsbugs]

I think if you look at the third pic it can be seen the line doesn't go all the way through the middle, which points to I. maculatus.

Isotomurus palustris in UK and Ireland

Compare the pics on here..

Checklist of the Collembola of the World

Yours looks like the ones I have called I. maculatus.

Janet

[Dogghound]

I noticed this about the medial stripe but after looking at loads of photo's I came to the conclusion it was abit unreliable although I orginally though I.maculatus. I believe to seperate these two 100% you again need a high powered microscope.

[JRsbugs]

Originally Posted by Dogghound

I believe to seperate these two 100% you again need a high powered microscope.

Or a good macro lens

Here's two pics of mine to compare which I have called I. maculatus, same animal but in one you can see the lack of a continuous line more than in the other.

[Jason Green]

Thanks for the images Janet, I was unaware of the median line being an indicator! It may be subjective, so probably best with a microscope (which I assume would be for tarsal claws or maybe genetalia. Features which would be hidden anatomically from view/too small to pick out on a photograph!) to confirm.

[JRsbugs]

Originally Posted by Jason Green

Thanks for the images Janet, I was unaware of the median line being an indicator! It may be subjective, so probably best with a microscope (which I assume would be for tarsal claws or maybe genetalia. Features which would be hidden anatomically from view/too small to pick out on a photograph!) to confirm.

Where you can see a distinctive pattern or other obvious features there should be no need for a microscopic examination (where a macro lens is useful), but when it comes down to needing to see the finer details in order to separate species then yes, a microscope is the only way.

Look very carefully at your third image, I think you will see that it doesn't have the continuous line.

[Jason Green]

Originally Posted by JRsbugs

Where you can see a distinctive pattern or other obvious features there should be no need for a microscopic examination (where a macro lens is useful), but when it comes down to needing to see the finer details in order to separate species then yes, a microscope is the only way.

I've found a key here, stating for maculatus:

Irregular symmetrical patches of pigmentation on tergites. 3+3 setae on lateral flaps of ventral tube. 10+10 to 16+16 setae on submentu.

Unfortunately it makes no mention of the line, here or on Steve's page. In the absense of that, moving on I'd say the pattern IS regular. In my opinion at least, we have 'three-pointed crowns' on each tergite and then the, well, whatever on the tip!

All other points are microscopic features which would confirm either way, if I had a voucher. Will you ever invest in one, Janet?

Steve's page of maculatus: Isotomurus maculatus in UK and Ireland

The key I was referring to: http://www.unisi.it/ricerca/dip/coll...topage/key.htm

Key's picture page of palustris: http://www.unisi.it/ricerca/dip/coll...ge/iso_ind.htm

Key's picture page of maculatus: http://www.unisi.it/ricerca/dip/coll...ge/iso_mac.htm

...both appear to have broken median lines, but you can see how variable both appear

[JRsbugs]

Jason, if you look at the link I gave for I. palustris on Steve Hopkins site you will see this..

In Isotomurus palustris, the central stripe is prominent and unbroken (Fig. 1) whereas in Isotomurus maculatus, the distribution of pigment is much more patchy.

No I doubt I will invest in a microscope, I don't find enough dead insects to warrant it. I would rather invest in a better camera! I did buy one for my son when he was young though...