Ants in your house or yard: August 2012 Archives

Dear AntBlog,

Thanks for your cool site. It's nuptial flight day for the ants that live under our patio (I don't know what species they are, but they seem to be normal for the south of England where I live.) The queens and males are milling around a lot before they take off, opening up their wings and then not being very successful at flying to start with. Whilst they're doing this, there are loads of worker ants rushing around them, and quite often coming up to them and touching them (with their antennae I think, but it's hard to see in detail) often 'face to face' but sometimes on the queens' legs or on the backs of their wings. Why are they doing this? Are they giving them directions? Encouragement? Licking off dirt? My mum thinks they're biting them to make them want to fly away. Hope you can enlighten us.

All the best,

Sarah Weatherhead


Hello Sarah,

Thank you for your very keen observations! Without knowing exactly what species of ants these are or under what precise conditions this event happened to take place (not to mention how the whole thing eventually played out) it's difficult to say with any degree of certainty whether this was in fact a "planned" nuptial flight or a kind of "false start" initiated by impatient alates.
Assuming that the weather and time of day was favorable to the release of the colony's winged reproductives (virgin queens and males), your suppositions are right on the mark. Obsessive grooming of this sort would have served both to motivate the already restless assembly of sexuals as well as to ensure that said sexuals--prospective progenitors of future generations--were free of any dirt and bacteria, and therefore fit to spawn a new colony.
However, in the absence of all the appropriate environmental cues, worker ants will actively interfere to prevent the over-eager alates from taking flight prematurely, in many cases physically grounding them or dragging them back to the nest. This might explain why the workers appeared to be "biting" the queens as you mother observed, but in this scenario it would have been a form of discouragement rather than persuasion.
In theory, the timing of these seasonal nuptial flights is dependent on just the right combination of circumstances--humidity, wind speed, time of day, temperature, probability of rainfall, etc.--and is uniformly observed across different colonies of the same species to maximize the likelihood of interbreeding. When workers perceive that conditions are not entirely auspicious for a successful, synchronized launch, they will forcibly keep the queens and males at bay.
As a UK-based witness of this extraordinary phenomenon, you might be interested in the Society of Biology's "flying ant survey", an initiative that seeks to document appearances of nuptial flights around the country and thus decode the various stimuli that are believed to influence these mysteriously well-timed events. The link featured in the above article will direct you to a page where you can record the date, time and precise location of your sighting, in addition to the type of weather you remember experiencing at the time.
The survey assumes that the ants in question are black garden ants, Lasius niger, but given your remark about the species being fairly common in the region and recalling that you observed the event in late July, I wouldn't be surprised if this was the same species.

Thanks for your interest!

Alexandra Westrich & the AntAsk Team


We live in San Jose, CA.

We have been reading your blog for sometime.
We are facing the ants problem.
attached pictures were just taken at a corner of my dinning room.
Hope you would help.

some ants have visited our house last year around October by crawling in from the windows to the bedrooms and kitchen.
the situation was under control after using the Terro ants bait stations; we saw less ants around.

this year, we started to see a few ants visit our kitchen counter in May.
Without knowing where their nest was, we just killed them when we saw them around.
Fortunately, they had not discovered our food cabinet yet and we have put all food in airtight container already.
Until one morning in early July, the troop found some leftover on the kitchen counter and hunderds of them paraded to the food source.
Knowing there was no use to just kill the workers, we chose to use the Terro ants bait stations again and let them enjoy the sweet fluid.
By this incident, we noticed from they came in from the tiny holes at the corner in the dinning room.
After a day, we decided to get the Terro liquid ants killer and starts to place several stations in front of the little holes as shown in the pictures right in front from where they come out.

After feeding them Terro for more than a month, they are still very active.
Hunderd of them coming out to enjoy Terro everyday.
In a hot day, which they are more active, they consumer twelve to fifteen drops of terro only within a morning and a bit less at night.
we have used up around half a ounce in the past month.

We do not want to spray pesticide inside the house.
However, sprinkle baby powder on the ant trails means asking them to walk in the walls.
and they also find a NEW way to crawl in the kitchen counter.
I need to watch carely when I prepare dinner, as they pop up all the time!

We wish to get the lemon oil or orange oil or Orange Guard from the neighbourhood stores but not successful.

Yesterday, I have lost my control as I see them again on my kitchen counter (on which I sprinkle baby powder on the side) but they finally found the opening to crawl in.

My husband bought a Hot Shot Natural with lemongrass oil and start to wipe in the ant trail.
This morning, we find less ants come out fromt the hole, while we are still placing few ant bait station in front the hole.
but the foreager still try their best to searching around.
We have consider to fill the holes, but we are afraid they will search a new opening that might be in our bedroom.

would you give us some suggestions:

1. would you please help to identify the type ants from the attached pictures? are they Argentine ants?
2. what do you suggest us to do now.

thank you very much!


from San Jose Bay Area, CA




Dear Emmy,

Thank you for the wealth of information, and I'm sorry your home is infested! Indeed, one of our experts Dr. James Trager has confirmed that these are the Argentine ant Linepithema humile, which is the most common ant in the Bay area. If you want to read more about Argentine ants, please see a few of our other posts here, here, or here.

In terms of solving your infestation problem, we get this request fairly often, so we actually have a pretty wide literature on the subject. This post is the most detailed, but you can also refer to here or here.

Good luck on getting rid of the Argentine ants!


Max Winston & the AntAsk Team

I live in Raleigh North Carolina and I was stung (felt like an intense sting) by a dark colored ant on my pinkie finger as I was getting into my car. The car was parked in a large shopping mall parking lot but our spot was located at the end of a row, under a tree. I did not see where the ant came from or how it got onto my finger, it was probably close to 1 cm in length and had a wider body - vs the small thin bodies of the ants I have seen around the house and yard. It did not have a smooth shiny body like I picture a carpenter ant to have and it almost seemed like it could have been hairy. The bite was painful and it felt like a sting that intensified the longer the ant was on my finger. I kept shaking my hand but the ant wouldn't come off... (of course the intake nurse at the ER said "this is when you use your other hand to swat it away" but I don't know why I didn't do that) The pain did not go away after the ant was off of me and 1 hour later I felt sunburned and my hands, feet and face were red and hot and my eyes were bloodshot. I was sweating and my heart was racing. I then developed weakness and had difficulty seeing, as it looked like I was looking directly into the sun. By the time I got to the emergency room my symptoms were starting to lessen and I was ultimately told that I must have had a toxic response to the bite. I was given an antihistamine but there was no sign of a bite mark on my finger. ( if I didn't have a witness, I probably would have sounded crazy) The next day I had a raised hard bump on my finger at the site of the bite/sting and the entire finger was swollen for 2 days and itched for a few days more. 2 weeks later I can still see the bite mark but the symptoms are otherwise gone.

Any idea of what bit me? I have looked up fire ants and this ant was bigger than the description of the fire ants I have read about/seen online

Any insight would be appreciated


Dear Abby,

We are sorry to hear that you were stung by an ant and had such a terrible reaction. Although it is difficult to be sure, it sounds like the ant you may have been stung by is the Asian needle ant, Brachyponera chinensis.

The School of Ants has a very nice summary of this species on their website, including information about the painful sting:

Best regards,
Corrie Moreau & the AntAsk Team

Dear AntBlog,

I have ants in my yard and garden. Should I leave them there or try to get rid of them? What good are ants?


Dear David,

Ants are very important and we are glad you asked!

Although ants can spoil our picnics or become unwelcome visitors inside our homes, most ants are actually beneficial to have in our yards. Ants are important to many organisms through their environmental and ecological impacts. There are over 12,000 species of ants that scientists have given names and there are at least double and maybe triple out there waiting to be discovered. Not only do ants turn more soil than earthworms, aid in decomposition, and disperse the seeds of many plants, but they also kill pest species.

Soil Makers: Like earthworms, ants help create healthy soil. By digging tunnels, ants aerate and turn over the dirt, bring nutrients closer to the surface, and allow rainwater to circulate more fully through the soil.

Seed Sowers: Seed-harvesting ants increase the dispersal, survival, and germination rate of seeds. By carrying them to new habitats and storing them in nutrient-rich ant nests, the seeds can sprout in a safe environment, protected from seed predators as well as drought. This helps plants thrive in the wild.

Pest Police: Many ants prey on the eggs and larvae of bothersome household insects such as flies, fleas, silverfish, bed bugs, and even cockroaches. If left to colonize the pe- rimeter of your yard, ants can act as a barrier to termites and help keep pest populations down overall. The diversity of the total ant species in an ecosystem can be an indicator of overall environmental health. Having a diverse community of ants and other insects helps keep the entire ecosystem in balance, which is important for all the plants, fungi, and animals (including us) that share the environment.

So unless the ants are coming into your home, I would suggest that you leave them to preform their important roles in your yard. If you are having problems with ants in your home, then you can try following some of the advice we have given in the past:

So the next time you come across ants in your yard, take a minute to watch them and appreciate the important role they are playing in maintaining a healthy planet.

Enjoy the ants,
Corrie Moreau & the AntAsk Team

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