Richard Dickson's picture


Observed: 22nd October 2012 By: Richard DicksonRichard Dickson’s reputation in InvertebratesRichard Dickson’s reputation in InvertebratesRichard Dickson’s reputation in Invertebrates

Two identical male ants were in my moth trap on 22nd October - quite a late date. They're clearly Formicinae. Antennae with 13 segments, inserted close to the posterior margin of the clypeus. Gonopalpi present. Orifice of propodeal spiracle circular. Middle and hind tibiae and antennal scapes with pubesence but without erect or suberect hairs. Orifice of metapleural gland with guard hairs. Mandibles with an apical and preapical tooth.

Species interactions

No interactions present.


Brian Cambridgeshire's picture

Probably L.mixtus despite keying to sabularum sometimes?

Your photos and descriptions are excellent. The late date is interesting (see below).

I think you're right to be confused. In Skinner & Allen's (1996) handbook, your specimens key to Lasius sabularum, a rare species very close to L.mixtus and L. umbratus, distinguished in that key by having only two teeth at the tip of the mandibles in males.

However... Seifert (1988), who raised sabularum to species level (previously subspecies of mixtus or umbratus), disagrees. He gives sabularum as having an average of 4.27 additional mandibular teeth behind the apical pair (av 0.69 in mixtus); and the m-cu cross-vein is found four times as often in mixtus as in umbratus (scoring 1=present, 0=absent,0.5=imperfect cross-vein, sabularum scores 0.273 whereas mixtus scores 0.88). Assuming Seifert didn't change his mind later, on both features your specimens would be mixtus, and the key in Skinner & Allen needs to be used with caution. Annoyingly, Seifert's 2007 handbook doesn't key out males at all.

The date is tantalising: Seifert gives the flight period of mixtus as 12.vii-28.ix, and sabularum as 'later' and 17.ix and 20.x (but very few records).

I've never seen L. sabularum, and I don't have any specimens of male L. mixtus or umbratus to check. It would be really useful to find a nest of the species next year. As you probably know, all three species have yellow workers, superficially like L. flavus. But in my experience, mixtus and umbratus has all its workers quite large, not the wide variation in size found in flavus.

Good hunting!

Richard Dickson's picture


Thank you, Brian, for a very thorough treatment. It seems that an early priority is updating my literature. I already have the Polish book on order and will now look into Skinner & Allen (but noting your caution).
Until last year we had a 'L. flavus' nest in the garden, but it seemed to be taken over by L. nigra s.l.. I wonder now...... The thing about moth-trap records, of course, is that they could have come from anywhere, but I'll certainly take an interest in any yellow Lasius I can lay my pooters on.
I posted this more in desperation than hope, and am delighted to have had so much help so quickly.

Richard Dickson

Brian Cambridgeshire's picture


Hi Richard

I hope you're lucky with the Polish guide - some booksellers report it's out of print already, though others may have stocks. Seifert (2007) is in German, and covers northern and central Europe. I understand he's working on a whole-Europe monograph, which is likely to be in English.
Skinner & Allen is generally very good - this is the first problem I've noticed - but may also be out of print - a chap on a course I ran in the summer bought one on Amazon for £30. (I still like Bolton & Collingwood as the quickest key to run through).

The changing nest in your garden is interesting. Not sure about flavus/niger but in comparison with the other yellow species, niger is at the bottom of the heap... it can be taken over by queens of umbratus or mixtus, which in turn are host to L. fuliginosus (which is much more conspicuous - trails of big black workers - but seems much commoner than either of its hosts).

There's lots more to learn about ants in Britain, and they may well change distribution rapidly in response to climate warming. As a general naturalist, I find them a good group for late summer, when most families of beetles, for instance, are at a low point.


Richard Dickson's picture

ants, ants, ants

More wisdom. Thanks. I think I've secured the Polish book from Pemberley.

I like the ants too, but so far have studied them only through casual encounters - as is apparent here.

If I manage to get any further with the L. mixtus/sabularum/umbratus males - not too likely - I'll report back.

Your comment about L. fuliginosus interested me. I've long been a bit uneasy about the large numbers of alates I record and virtually never workers.

Richard Dickson