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nortino: Leptothorax interruptus? (26. Apr 2008 21:00)

Hi guys,

With the naked eye I thought this was some kind of Myrmica, but when I got her home and looked at her under a microscope, and looked at an identification guide I came to the conclusion that she's probably a Leptothorax interruptus - in particular the form of the antennae with the thick, dark tips, and the long curved spines on the propodeum:

Anyway, if anyone knows anything about L. interruptus, I'd be grateful for any information, I can't find much on the web.

She was found in Bournemouth, Dorset, UK by the way, and is about 1.8mm long.

JimmyVe: (27. Apr 2008 13:13)

First off all, very nice pictures. ;)
No i'm sorry i can not tell you more about this species.

tail__: (27. Apr 2008 13:25)

I know some Leptothorax are small but 1.8 mm?! And you still can make so nice pictures :| For sure it looks like Leptothorax, but exact identification of species is very hard, they all look very similar. Their style of life is also similar - they like shady areas, their colonies are small, usually less than 1000, and they aren't very agressive and always try to evade fights with another ants. Other species tolerate them on their area, because they aren't threat or serious competition. They don't tend aphids, relying mostly on hunting very small insects.

nortino: (27. Apr 2008 16:55)

Thanks tail, what you said about other species tolerating them is really interesting and exactly fits with what I observed, which is that I found this ant walking around in an area infested with Formica rufa, and I wondered how they survived.

My book ('Ants' by Gary J Skinner and Geoffrey W Allen) lists five Leptothorax species for the British Isles, namely L. acervorum, L. nylanderi, L. interruptus, L. tuberum and L. unifasciatus; of these, L. unifasciatus is restricted to the Channel Islands, so I assume it's not this, L. nylanderi doesn't have the dark tips to the antennae that you can see on the photo, L. tuberum has short straight spines on the propodeum whereas L. interruptus has long curved spines - if you look on the first photo you can see these quite clearly just above where the rear legs join the body - these look long and curved to me, making her L. interruptus rather that L. tuberum. As for L. acervorum, apparently it has 11 segments on the antennae whereas the others have 12; it's a bit hard to count them when she's alive (even with a microscope) and I don't want to kill her because I'm nice :-), so I can't definitely say it's not L. acervorum, but anyway the spines on the propodeum make me lean towards L. interruptus.

About the photos, all I've got is a normal 'point and click' digital camera (Kodak 'EasyShare' Z650, 6.1 mega-pixels), and basically I just put it in the 'close up' setting, turn off the flash, don't use zoom, get as much light on the subject as possible, and give the ant some honey so the damn thing will stand still for a minute! Then get the lens as close as I can before the camera stops auto-focusing, and take the photo. Also have the image set up as big and high quality as the camera will allow.

Here's an offtopic (sry) picture of a Formica rufa caught in the same place as the Leptothorax, using the same 'technique':

JimmyVe: (28. Apr 2008 16:15)

Great pictures. Can you make it fit into the window. (make it a bit smaller) Thanks

kaefer: (7. Mai 2008 16:45)

I think this one is no Leptothorax or better Temnothorax at all. From the first picture, where you can see the "shoulders-edges" on the pronotum the ant looks like a Tetramorium.

Roland