Results tagged “invasive ants”

Dear Ant Experts,

I have a large colony of ants in my yard (or possibly many colonies) in Surprise, AZ. These ants are becoming a small problem because they love to bite my family. So far I have tried many "ant baits" and found that they ignore all of them except for amdro pellets which contain Hydramethylnon. Boiling water works great on them when I can locate their hills, but they always return. Any information on what kind of ants these are and how to eradicate them will be very appreciated! Thank you in advance!


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Dear JJ,

I wish I had some encouraging news for you, but it's likely you have Solenopsis xyloni, a close relative of the Red Imported Fire Ant, Solenopsis invicta. You're already doing some of the most effective things: Amdro was developed specifically to target S. invicta (or RIFA, as it's sometimes called in the invasive species literature). It works best if you pour about 1/4 cup directly onto the mounds, and re-treat every 2-3 weeks. In general, poisoned baits usually kill at most about 90% of the colony, so re-treatment is essential. Boiling water, as you said, is also great when you can find the colonies. Just don't pour it over the Amdro! It doesn't work when wet!

The problem is, unless you and your family live on a 1,000-acre ranch, miles away from town, surrounded by a moat and a flying-ant-proof fence, you'll always risk re-infestation from the surrounding area. Therefore, the only further advice I have is to get organized with your community. It might make sense to bring this problem up with your neighbors, at your children's schools, and any local organizations you're involved with. The "School of Ants" is a citizen-science project that would be a fantastic way to gather information about where other colonies of these ants occur in your area...and the students might even learn a thing or two about the biology and ecology of ants!

One critical bit of information you can get from collaborating with the folks at "School of Ants," or other experts, is a positive identification of these specimens. Solenopsis invicta and Solenopsis xyloni are difficult to tell apart from pictures, but one is a native ant that can be a nuisance, and one is an invasive ant that costs the USA more six billion dollars a year to control nation-wide. More information on Solenopsis invicta, and some advice about distinguishing it from related species, can be found on this excellent site.
Either way, you have the opportunity to raise awareness in your community about ants, so that you can more effectively solve the problem you have now, and be prepared for future ant invasions.

Good luck!
Jesse Czekanski-Moir & the AntAsk Team

Dear AntAsk,
I live in Puerto Rico and am wondering about a tiny ant whose bite
continues to burn after it bites and likes to eat cotton clothing. And
scurries in and out of electronic equipment like my comptuer keyboard
and my other electronic things like the dials on my electric guitar.
They also like paper. and books - I see them outside where they like
very dry wood and leaves - and digest dry wood as well. They look just
like ants - act just like ants - How do I get rid of them as I can't
spray my equipment. and my clothes.



Dear Sonja,

Thanks for contacting AntBlog. Chances are you have one of two species: Wasmannia auropunctata or Monomorium destructor. Wasmannia workers are all the exact same size and their bodies tend to be all the same color (they can be light or dark, but it's usually one or the other). Monomorium destructor are red-brown in the front part of their bodies, and darker in the back. Their workers are different sizes: within one foraging trail, you'll often see workers that are twice as big as the smallest ones, and there will be sizes between those two. Monomorium destructor has more of a tendancy to damage clothing (like you mentioned) and electrical equipment, but both species (and many others) will nest in a variety of small containers like electrical boxes and clothing drawers.

In previous posts (click here, here, here ), we've outlined some general strategies for getting rid of ants using commercially availible poisons like Borax. I would add putting items in the freezer for 24 hours will often kill them in small electronic items (and anything else you can fit in the freezer).

You also might want to check out the website of our friend, Cas Vanderwoude in Hawaii:
He has some useful tips there for how to get rid of Wasmannia auropunctata, and the research his team is doing to fight this invasive species.

Good luck! Sorry you're having so much trouble with these ants!
Jesse Czekanski-Moir & the AntAsk Team

Dear AntAsk,
My name is Hadar and I live in Israel. I am the owner of the company for pest control in Israel that specializes in the extermination of ants using baits
During the last five years we are dealing with the failure of eradication of the species Plagiolepis. We've tried most types of bait offered the U.S. pesticide market without success. Needless to say that spraying pesticides is not effective at all.
We tried various baits containing borax or fipronil or abamectin B1 imidiachloropid.
The baits contain honey dew or protein. Often appears in the attraction of that work and "workers" vigorously and after a while sometimes minutes, sometimes days after the placement of abandoned ant bait
Can I get some information about the lifestyles of this ant? Such as:
What kind of diet prefers this species?
Is there more than one queen in the nest?
How to deal with this pest
This species is very common throughout the country from north to south
Unfortunately, an Israeli research on this species is not done yet
Please help

Dear Hadar,

Sorry to hear that you're having trouble with Plagiolepis. Although only a few species have been studied in depth, it seems that there is evidence of polygyny (multiple queens in the same colony) in every species in which this quality has been looked for ( P. pygmaea, P. xene, P. taurica, P. schmitzii, and P. maura - data and references in Thurin et al. 2011; DOI: 10.1111/j.1365-294X.2011.05161.x).

As for what your Plagiolepis eats in the wild, it is likely that even if we did know what species you were working with, there would not be a complete, published study that would answer this question. What is more important is that you continue to experiment with baits to which this ant might be attracted that you can mix with the appropriate poisons. Invasive ant expert Cas Vanderwoude ( explains:

We have Plagiolepis alluaudi here in Hawai`i. They seem fairly "skittish" and do not seem to feed on any particular food source. I think they are present in homes more for water than anything else.

My standard approach would be to offer a buffet of food items that they might feed on, add a toxicant to the most attractive item and bait with that mixture. So Hadar, try a little (1)peanut butter, (2) jam or jelly, and (3) spam or tuna or fish flavored cat food. Also, try water. Put it in a vial filled with cotton wadding so the ants can "suck" the water from the wadding. You might be surprised - it might be water they recruit to most! If that's the case, thank my friend Evan Harris for that suggestion... if water and sugar are both attractive, you can make a nice attractant out of sugar water (25% sugar) and place it in the vials mentioned previously.

Adding a toxicant is the next step. If you have fipronil it will be the most effective. The most important thing is the dose. DO NOT OVER-DOSE!!! For fipronil, use only 0.1g/kg bait mix - NO MORE! The effective range will be 0.01-0.1 g/kg active ingredient. Any more and it will take effect too soon and leave the queen(s) unaffected. Repeat baiting every 6-8 weeks."

In addition to Cas's tips, I would add that it is important to apply poison at an effective spatial scale. If you're going to poison the ants in one person's house, but they live two meters away from a large colony, there is a very strong likelihood of re-infestation. Cas's point about re-applying baits is also very important; no treatment will kill 100% the first time. Often, treatments will kill around 90% of the ants at most, so it is important to keep re-applying the pesticide at the right time intervals. Ants do not eat while they are in their pupal stage (something like the cocoon a caterpillar makes before becoming a butterfly), so re-applying pesticides while the same ants are in their pupal stages will not increase the effectiveness of the treatment.

For further information about dealing with invasive ants, I'd encourage you to check out Cas's website (above). For example, there is some information on treating potted plants for pests by submerging them in water at 45C which might be useful for some situations.

I hope this helps!
Jesse Czekanski-Moir, Cas Vanderwoude, and the AntAsk Team

Ants in my home (Miri, Puerto Rico)

We live in Puerto Rico, where ants are varied, plentiful, painful (lots of fire ants...) and often like to move into our (concrete block) house.

We've been having frequent infestations of these little (2mm or so) ants. At first I thought they were pharaoh ants but now I'm thinking the coloration is wrong (these guys have light colored abdomens and dark heads, not the other way around). We have been trying to get rid of them using Maxforce and more recently Advion. They swarm the bait and then wander around like they are dazed and confused, sometimes seem to dwindle a bit but they don't die out. They seem to like to make nests in small openings in our walls (e.g., breaks in the grout lines but they also like our kitchen cabinets (but don't seem to bother getting into the food, just collect crumbs etc.) and have even once moved into our clothing chest of drawers (we don't notice their new trail quickly enough).

Seems I need to know exactly what they are to get rid of 'em effectively so would very much appreciate your thoughts.


Dear Miri,

We are sorry to hear you are having problems with ants in your home. The ants you are finding are the ghost ant, Tapinoma melanocephalum. This species is a pest in many places in the world.

You can read more about this species of ant here, here, and here.

In addition, you may try some of our suggestions for other pest ants in homes from this previous post here.

Best regards,
Corrie Moreau & the AntAsk Team

My residence is near Seattle, Washington State, Northwest USA.

We are interested in the Chinese Medicine uses of-
Mountain Ant ( Polyrhachis vicina, Polyrhachis lamellins and other species of nutritional Ant)

Is there a USA variety that might have equivalent nutritional qualities?

Is it possible to buy them, and to raise them?

Thank you,

Dear Michael,

We're so glad you're interested in ants and the way people use them. I had heard people talking about medicinal uses of ants a few years ago, and the results of one study I was able to find do seem convincing. However, a shortcoming of many studies of traditional medicinals is a lack of replication and long-term, controlled studies.

The genus Polyrhachis does not occur in North or South America. Because the chemicals thought to be responsible for the potentially medicinal properties of Polyrhachis extract are not often studied by ant biologists, it is impossible to say if any ants in North America also possess this quality.

Outside of the US, researchers around the world have been experimenting with medicinal qualities of some of their local ants. For example, researchers in Japan studied another Chinese ant, Formica aquilonia, and published their findings here here. They seem to have found some potential for pharmacological activity, although they didn't study effects in living organisms, just in test tubes.

A group from Saudi Arabia found evidence of anti-inflamitory activity in extracts from the ant Pachycondyla sennaarensis. Both of these studies show promise, and it will be interesting to see what other hymenopterans (the group that includes ants, bees, and wasps) might prove to be medically useful. However, we do not recommend you try any of your own experiments unless you are a professional. Remember: the ants, bees, and wasps also can induce anaphylaxis.

We also strongly discourage you from trying to import and breed any ants (or any type of organism) across national borders. Many of the most damaging invasive species are ants. It would be sad if an innocent attempt to learn more about traditional medicine resulted in unnecessary damage to your local ecosystem. Importing ants from other countries (alive or dead) is illegal without the proper permits.

Sorry that we don't have any more positive recommendations. Polyrhachis are among the most beautiful ants, and they are very common in the forests of Northern Australia, Southeast Asia, and Central Africa. Perhaps you could take a trip to learn more about them and see them in the wild!

Jesse Czekanski-Moir & the Antask Team


I am battling hordes of very small ants in the walls and under the floor of an old house. They are too small to be carpenter ants or fire ants.

They instantly find any food and get into containers I would have sworn were unassailable. I tried to ID them, but every ant species I thought might be them is said not to sting or bite - and these DO.

They don't raise a huge welt like a fire ant, but it is a very distinct sharp needle-like prick. I haven't managed to stop myself from slapping at them in time to see if it is a sting or a bite. They are quite small (1/12th of an inch, maybe? tops?) and translucent orange in color, with a slightly darker brown dot on the posterior.

I also get very large solid black ants in one room of the house - also from under the floor or through the wall.

Any idea what they are?

Dear Sarah,

I'm sorry to hear about your problem. Normally I enjoy watching ants go about their daily activities, but I have also had some experience with tiny stinging ants like the ones you've described, and I would want them out of my house, fast.

So, first things first, there are some measures you can take before you call the exterminator. We describe how to get rid of ants in your home here.

Second: What are these ants? There are three species I can think of that more or less fit your description that have established reputations for themselves as world-wide pests. They're all stingers, so no need to stop slapping:
Monomorium pharaonis,
Monomorium destructor,
Wasmannia auropunctata.

Monomorium destructor might be the easiest to tell apart from the other two. Its workers are conspicuously polymorphic; that is, when you see a lot of workers together, there will be some that are different sizes. The largest workers will be almost twice as big as the smallest workers, and there will be workers of intermediate sizes. They are usually orange-brown in front with a darker gaster (the gaster is the last major part of an ant's body). Monomorium destructor earned their species name because in addition to having a painful sting, they are very good at chewing through things like plastic bags, clothing, and even the insulation around wires. If you notice a lot of holes in things near where the ants are, then there's a good chance you have these ants.

Under a microscope, it's easy to tell the remaining two ants apart. There are numerous differences, perhaps most obviously the large spines Wasmannia auropunctata has projecting off the back of its mesosoma (the middle body section of an ant). Without a microscope, however, it can be difficult to distinguish the two. If you saw them side by side (or fighting!), you would notice that Wasmannia has a shorter, more square body shape, and is about the same color throughout its body. Monomorium pharaonis has a longer, more slender shape, and it usually has a darker gaster, but on both ants the color can be variable - Wasmannia can have a dark gaster, and M. pharaonis can be all the same yellow-brown color. Wasmannia auropunctata is sometimes called the "electric ant" because of its uniquely scintillating sting. Unless you're a real connoisseur of ant stings, though, it might just feel like another painful annoyance.

Looking at the pictures I linked to on the web might help, but really the best way to get a confident identification of tiny ants is with a microscope or a very, very close picture.

As far as I know, of those three ants only Monomorium pharaonis has been reported from Texas (based on the list published on AntWeb here, and an older list by Wheeler and Wheeler here), but Monomorium destructor and Wasmannia auropunctata are both very good at dispersing with humans. You haven't just come back from a fun trip to a tropical island by any chance, have you? Both Wasmannia auropunctata and Monomorium destructor can be quite common in Southern Florida and the Caribbean.

I hope this helped.
Jesse Czekanski-Moir & the AntAsk Team



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