Is your lemon in a pot or in the ground? The ants are suppossed to be after the sap left by aphids.I think they also
spread the aphids eggs all over the place.Not 100% sure about
that But i know you dont want the ants all over your plant.
I have a system for pots that works very well.Put saucers
under each pot with three small peices of wood which will
lift the pot an inch or so.This means the plants wont stand
in water and also get good aeration.
Smear vaseline around the lip of the saucer and around the base of the pot.The ants dont like vaseline,so they have to
climb a wall of vaseline,perhaps swim across the water and
then climb the base of the pot with vaseline on as well.
Havent come across a james bond ant yet! As for
in the ground,different story!!! Good luck

Ants drink nectar like many other bugs.

You have to do your best at keeping those little buggers off of your tree. They bring a whole heap of problems to citrus; scale, aphids.. Ack!!!

If you don't see aphids, then check for scale..inspect thoroughly..look under leaves, on stems..they're great hiders unless a plant is infested. They blend in w/the color of stems.
They secrete a honeydew that attracts ants to plant..ants are usually at botton of tree but work their way up. I've seen pics of scale infestation and it's not a pretty sight. Toni

Thanx for the advice!!!! Toni, what does scale look like. I have never had an encounter with it/them. Also, I have just noticed some yellowing in a few of the leaves. I have read that this could be a nutrient deficiancy. Is this true and are there any other possible causes? Thanx a bunch.

Kik, scale look like roundish/oval armored bugs w/shells. They're difficult detecting as babies, but once they mature they're easier spotted.
I'm not sure of all the colors, but those I've seen are brown and blend in w/the stems of a plant. They can be plucked off..In a way they remind me of ticks..they hang on to to a plant for dear life.
The largest I've seen when mature were about the size of a ladybug.
Yellow leaves can be a nutrient or iron/mineral definciency, but can also be caused by insects. Feel the leaves, check if they're sticky. Be sure to look at the trunk of your tree, too..Toni

Ok Toni, I checked the leaves, they are not sticky but there are these little tiny 'things' on them. They are brownish red and about the size of a grain of sand. Any thoughts? Also I checked the trunk and there was nothing unusual on them at least as far as my little bit of experience can tell. As far as the iron/mineral deficency, any organic remedies or close to organice remedies that you can think of. All of you help is greatly appreciated. I am soo happy to see that I didn't kill the little guy, I would just hate for the bugs to.
Ki