Ants and Myrmecophila christinae

[rbarata]

This genus has a symbiotic relationship with ants.
See here and here.

Definitely not a plant to be grown indoors.

[smweaver]

Originally Posted by estación seca

Don't risk a fire ant sting. They're awful.

I learned that the hard way when I was stationed in Pensacola, Florida. There are no stinging ants in Indiana (or none that I know of, or that are potentially dangerous to humans). So when was out for a run one morning, i stopped to take a break and sat down in the grass near a relatively small ant mound. Poking a stick into it turned out, in hindsight, to have been a not-so-bright idea. That was my introduction to fire ants.

[isurus79]

How tiny are they? Do they move really quickly and really erratically? You might want to look into tawny crazy ants (Nylanderia fulva) to see if that's what you've got. If so, KILL WITH EXTREME PREJUDICE. It's a really bad invasive that will take out electrical systems and can outcompete red imported fire ants (Solenopsis invicta).

[smweaver]

Originally Posted by isurus79

How tiny are they? Do they move really quickly and really erratically?

They are literally less than 2 mm in length. I wouldn't say that they move erratically. I do know, after observing them for the last few days, that they are timid and quickly run away anytime that I put a finger near several of them in an attempt to get one to climb aboard for another photo shoot, but they aren't cooperative or aggressive enough to want to fight me off, big looming potential predator that I might be.

Here is a picture. It's lousy, I know, but I don't think the iPhone's camera, great though it generally is, is capable of capturing a macro image of something this small.

[isurus79]

Ah, that's good! You don't want to be ground zero for a crazy ant invasion!

[thefish1337]

despite all the fear mongering here, I would let them be until they give you a reason not to. they will positively interact with the orchid and provide it nutrients in a way that your fertilizer couldn't.

based on this description of crazy ants I don't think you have them:

-Appearance of many (millions) of uniformly-sized 1/8 inch long, reddish-brown ants in the landscape; foraging occurs indoors from outdoor nests.

-Under a microscope you will find 12-segmented antennae, a petiole (1 node), an acidopore (circle of hairs at the tip of the gaster (abdomen)), and the ant will be covered with many hairs (macrosetae).

-Winged males (see image below) are needed for identification to species (see Gotzek et al. 2012)

-Ants that form loose foraging trails as well as forage randomly (non-trailing) and crawl rapidly and erratically (hence the description “crazy” ant).

-Ant colonies (where queens with brood including whitish larvae and pupae, See image on right) occur under landscape objects like rocks, timbers, piles of debris, etc. These ants do not build centralized nests, beds, or mounds, and do not emerge to the surface from nests through central openings.

[Dimples]

Look up Ghost Ants. They’re a super tiny reddish ant common in the southern part of Florida. Your photo sort of matches their description.

Fish - unless you can positively identify a mystery insect on a plant that has been shipped, the safest course of action is to eradicate them. Humans already unknowingly transport non-native and invasive species around the globe, even with preventive measures in place. The environmental and economic toll from this is huge, but goes unnoticed by most. This is especially true in Florida, the non-native/invasive species capital of the US.

[Merita]

I have lived in Florida for many years and I have never seen that ant. Large ants make colonies everywhere and smaller ones live in my orchid baskets, I put insecticide periodically for all of them. Either way it is a risk that you run if those insects spread on your plants.

[smweaver]

Thank you all for your great comments and suggestions. If this is a truly tropical species, I'm not quite sure how, if a new colony were to be initiated, it would contend with winter temperatures that can drop to -15 F. But yes, I agree completely that invasive species need to be taken seriously. I did ask the guy who sold it to me if he recently imported it. He laughed and said that if it was imported, then that would have happened many decades ago, as the plant was already growing on his property when he purchased it back in the late 1970's.

For now I think I'll let them be. They're probably depressed at having been shipped from Florida to Indiana, which is entirely understandable. Yesterday I gave them a small sliver of mango to cheer them up. Not sure if it worked, but they did come out for a little picnic.

[Orchid Whisperer]

Sooner or later, your ants will die of natural causes (each ant has a short lifespan). You may be able to collect a few for ID by an entomologist. Honestly, any ID will require either bugs you kill (cotton swab, alcohol, preserve in a vial with alcohol) or ones you find dead and preserve.

Or, ask around if you have a university entomology program. Someone my be willing to collect ants from your plant for ID.

My son is an entomology graduate student, and I know that in order to identify, they need the insect (some ID requires a microscope).