In article ,
Stephen Howard writes:
|
| L.niger is, as popular parlance might put it, 'known for it, Guv'.
| In areas where L.niger actively cultivates an aphid population well
| over a dozen species of aphid have been found in a nest.
| Naturally, their behaviour in Britain may be modified to suit the
| climate, but the species has a strong herding tendency.

Yes, indeed. There is no doubt whatsoever about the association.
The only thing that I question is the causality.

| Their behaviour is quite distinct from Myrmica rubra, which is common
| in these parts ( a fact of which I am often painfully reminded ).
| Their colonies are much smaller, and the ant is rather more
| aggressive. Although I have often seen them in association with aphids
| I haven't as yet observed anything but the most passing of
| relationships.

If it is the reddish one I have, nor have I.

| Which brings me to ask.. which species were you studying, and was it
| the same one across the various plots?
| The point also arises that one species of ant in competition with
| another for the same resources may well find it advantageous to scale
| up any semi-symbiotic relationships.

The only one I am fairly certain about is L. niger, which is the
main one I have looked at. I am no expert, and so cannot tell you
what the others were.

| On my veg patch that wouldn't be the case.
| The beans, and occasionally the peas, are the only things I grow that
| seem to be prone to aphid attack - the salad crops I keep under
| fleece.

No brassicas? A different aphid, of course.

| Given that the beans are the tallest standing crop in the patch I
| would think it likely that they'd be colonized wherever they were
| situated in the plot - and as any cyclist will tell you, aphids can
| fly quite high enough to get over most obstacles!

The only ones I can swear to as flying high are the wheat greenfly,
whatever it is.

| I certainly agree that ants, at least in this country, aren't
| responsible for aphid infestations - but I'm sufficiently convinced
| through observation that their presence adds to the success of an
| aphid infestation.

Hmm. I have observed no difference quite a lot, so my guess is
that any effect is environment dependent.

| I don't use sprays - but I find a casual stroll around the grounds and
| a spot of nifty finger work keeps the little buggers under control.
| It's certainly a more effective means of control than trying to
| eradicate the ants.

Mine is just soft soap - slightly more thorough than fingers, but
I also use them. My experience of systemic insecticides is that
they were counter-productive.

| I've noted that too. I've also noted that ants are sometimes reluctant
| to attack prime prey ( observations, it has to be admitted, that were
| gleaned many years ago by collecting suitably fierce looking bugs and
| popping them bang outside an ants nest ).
| I assume much of this is to do with what the "ant orders for the day"
| are, and the perceived threat.
|
| With regards to your observations, what percentage of them were
| carried out at night?

None. That is a fair point.

| On the issue of aphid placement, yes, I'd go along with that.
| On the issue of sustainment of aphid colonies, I'd say it bears more
| examination. In the meantime I'll trust to my observations and knock
| back both the ants and the aphids on the veg patch.

I certainly agree with the examination. I cannot claim that I
am certain that there is no effect, but I have never had trouble
with even dense ants' nests.


Regards,
Nick Maclaren.