Carpenter ants in my plants.

[Kevin_PR]

While I am relatively unfamiliar with species of ants, I have seen small black ants, which I believe are called carpenter ants in my some of my pots and mounts. They can be seen scattering with pupae in mouth when I water the plant or move it. I have had them crawl up my arm(probably close to 100) when I did not notice them right away and they do not bite. They are definitely not fire ants, which are in abundance here in PR and seem to be only terrestrial. I was wondering if they beneficial to the plants. I do believe they will contribute to the deterioration of the growing medium, but because of their feeding and excrements could it also be said that they will help fertilize the plant make the environment slightly more acidic and keep certain pests away from the plant?

There is also another species that likes to build small "structures" out of processed plant material(like termites). I sometimes find them at the base of leaves or in the crown where a new leaf is emerging. They seem to like aerangis that have the leaves closely space. Also they are never great in numbers probably 10 or 20. My concern with these guys is rot caused by the decaying plant material used by these critters. I usually brush them off when I see them so I have not experienced any rot yet. And all my plants are pest free without the use of any chemicals, save for snails.

[Island Girl]

I'm not really sure about all of that, at least I'll give you a bump, but, considering your questions, you could just watch them, and see what they do? The one thing I do know about ants, is that (not sure about Carpenter ants, but def others) they will "farm" other insects.... Meaning, they bring in other pests like mealy bugs, aphids, etc (carry them in, i.e. on their backs) so the insects can (eat the plant, and in turn,) then excrete "honey dew" and the ants then feed on that.

[james mickelso]

The ants in the leaf area of your plant are herding small aphids/scale/mealy bugs which are feeding on your plant. They milk the bugs for sweet excrement and are protecting the bugs as a source of sugars. The ants that come out of the pot/media with pupae in there mouths are building a nest in your media. While the ants themselves cause no harm, the fungal gardens they grow in the media do. Ants grow fungal gardens within the media using chewed upo vegetable matter as compost and because of the nature of the garden environment can introduce fungus that can cause serious damage to the orchid's root system. Get some garden type pest spray, mix it in a shallow container in which the orchid will sit, add a little bit of soap, and water the media with this mixture. It will kill the ants and the eggs will die of neglect.

[Vanda lover]

I had a big problem with this once. I brought my plants in from outdoors and they were full of ants. I submerged the pots in pails of water, which helped a lot. Then I was still finding ants all over and I discovered colonies in my curtain rods! After that they colonized the hinge of my fish tank. I bought ant traps at the hardware store and eventually I was rid of them all.

[desertanimal]

I think we're conflating different species of ants. The various genera of leafcutter ants farm fungus, but they don't tend aphids. There are quite a few species of ants that tend aphids, but they don't farm fungus. Leafcutter colonies are massive and require many different castes to make a living--they wouldn't be able to "cut it" (haha) by making their home in your orchid pot. Leafcutters are also brick red in color, so that's not what you have. Regardless, you don't want either leafcutters or the various aphid-tenders in your plants. Leafcutters can defoliate a small bush in a day (which is very irritating when you've just planted the thing), and who wants anyone protecting the aphids?

If you don't have aphids and you don't think the ants are bothering the plants and you don't plan to bring them in and they're not annoying you, I would leave them. But that's just me. Lots of ants will take advantage of any "happy sap" the plants produce. I've had carpenter ants visiting my outdoor orchids this summer for that reason, and it doesn't cause any harm. The species of carpenter ants I have here are omnivores, so I figure they might also snag any plant pests they find while they're around. I have my plants in S/H, so carpenter ants are unlikely to nest in the substrate and haven't, which is important for me because I have to bring the plants in soon.

If you really care and can get good pictures and size estimates, I could probably get you IDs, at least down to genus.

[Vanda lover]

The carpenter ants that I know of are huge and eat decks, etc.

[Subrosa]

Originally Posted by Vanda lover

The carpenter ants that I know of are huge and eat decks, etc.

Yup! I had to remove a branch from a maple in my yard two years ago and it was infested with Carpenter Ants. Great, big, nasty, black things they are.

[james mickelso]

I know PR has been invaded by Argentine ants or as we call them in SoCal, sugar ants. They infest kitchens and gardens all over SoCal. Very invasive. Little black ants which do not sting. They love building nests in loose material such as bark in orchids pots. My cyms were infested many times when I lived down in San Diego. I would water a pot and they would pour out of the media swimming for their lives with pupae in their mouths. These grow gardens of fungi down in the humid media.

[Kevin_PR]

Originally Posted by james mickelso

I know PR has been invaded by Argentine ants or as we call them in SoCal, sugar ants. They infest kitchens and gardens all over SoCal. Very invasive. Little black ants which do not sting. They love building nests in loose material such as bark in orchids pots. My cyms were infested many times when I lived down in San Diego. I would water a pot and they would pour out of the media swimming for their lives with pupae in their mouths. These grow gardens of fungi down in the humid media.

Sounds like the ants I'm talking about.
Guess they gotta go!! Thx

[JC Espinosa]

What kind of orchids do you have? My Schomburgkias mounted on palms host big ants without a problem. I found out how nasty than can be years ago when I tried to divide a lovely specimen on a queen palm. I am not sure what role they play, but I have seen no harm. The ones to worry about are the farming kind. We have carpenter ants and they will eat your house and your termites. The ants in my schoms look like carpenters, but they are a different species. We have so many exotic invasive ants that I have lost track of the species. A new myrmecological horror story every year.