May 2012 Archives

Hi,

My buddy and I were walking back into our office today and he noticed a brown spot in the grass. Upon closer examination, we realized that it was a giant pile of ants and could not figure out what they were doing. We just wanted to know why they were all grouped up like that and what they were doing. Please let us know if you have any input - it would be greatly appreciated.

Thank you,

Val

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Hello Val,

These are the common pavement ant, variously known as Tetramorium caespitum or here at Ant Web (pending publication of research on its classification) Tetramorium species E. Originally from Europe, it is now established across the northern half or so of the US and in southern Canada, in urban areas. It has also made it to another outpost of European culture, in South America, south of Buenos Aires, Argentina! This species is famous for its pitched, but rarely lethal, territorial battles among neighboring colonies and you have found a particularly good example of this behavior.

Regards,

James C. Trager of the AntAsk Team

I have recently wondered why all ants are placed in one family Formicidae, if you look at how diverse the subfamilies are from each other - for example, Myrmicinae, Formicinae, Ponerinae, Dolichoderinae, Ecitoninae, etc. I believe there are currently 15 ant subfamilies. If you look at other Hymenoptera, bees for example, are divided into 5 families, wasps into many families. Could it be because not all bees and wasps are social, but all ants are ? If that is the case why are termites which are all social put in 4 different families in North America? It seems some of the ant subfamilies are as diverse or more so than the termite families are from each other. Or am I missing something that puts all ants in one family? If I am please let me know.
I hope this is not a dumb question.

Mike M. -- Orange Co., CA

This is not a dumb question at all, Mike. Ants are quite diverse in form, and there are clearly some well-defined monophyletic lineages (though those who study higher taxonomy of ants might not agree the number is your suggested 15). However, the subfamilies vary in age and level of internal diversification, so even their ranking as presumably equivalent subfamilies is itself arbitrary. On the other hand, it is true that as a group, ants are a coherent, monophyletic lineage among the stinging Hymenoptera, with no apparent close relatives, perhaps one reason we consider them a single family. But in taxonomy, rank above the species level is arbitrary, and in this case, ant taxonomists have simply settled on the convention of treating all ants as one family. As Chicago Field Museum myrmecologist, Corrie Moreau, says, "Higher taxonomic ranks are certainly arbitrary. There are more ant species than birds and there are tons of bird families."

I received this additional comment from Dr. Phil Ward, one of the world's premier ant systematists. "The rank of taxa is quite arbitrary (as you say James), and largely a function of idiosyncratic taxonomic history. There is no such thing as a family-level difference or a phylum-level difference. So, families of Hymenoptera are not equivalent and there is no objective way to assign family-level rank. A ranked classification can be justified only from a practical (as opposed to objective) point of view. A ranked phylogenetic classification (i.e., a ranked classification where all supra-specific taxa are monophyletic) has the wonderful property that the taxa of any given rank are mutually exclusive. Very handy for sorting and curating specimens, and perhaps organizing information."

James C. Trager of the AskAnt Team



at 11:30pm, 20 May 2012, Gerald wrote:
This year at my home there are no ants in my yard, garden, nowhere
In Cathedral City, Ca.
Do you think we are going to have a big earth quake
Gerald

at 12:30pm, 21 May 2012, Jesse wrote:
Dear Gerald,

RUUUUN!

Just joking. Ants have not been shown to be able to predict earthquakes. During careful behavioral observations of the harvester ants Messor pergandei, John Lighton and Frances Duncan noted no change in activity before, during, or up to three days after a magnitude 7.4 earthquake in the Mojave desert in 1992 (they published the report in 2005 in the Journal of Experimental Biology - doi: 10.1242/​jeb.01735). The authors conclude that "anecdotal accounts of the effects of earthquakes or their precursors on insect behavior should be interpreted with caution."

It is more likely that ant activity is very low because of recent weather patterns, or your town (or an overzealous neighbor) has used broadcast insecticides to get rid of some type of insect pest. You might consider contacting your town hall to see if there have been any recent applications of pesticides, for mosquitos, or a particular crop pest, for example.

Hope this helps!
Jesse Czekanski-Moir & the AntAsk Team


at 1:06pm 21 May 2012 Gerald wrote:
Well this morning we had 3.7 in Kern county

at 1:45pm 21 May 2012 Jesse wrote:
Hey Gerald,

That's interesting. It's possible that there were some different cues leading up to your earthquake that weren't present for the 1992 earthquake Lighton and Duncan observed. In the case of both your observations and theirs, this situation underscores the need for replication in science. In your case, I would caution that "correlation does not imply causation," and that without controlled experiments and/or a lot of careful observations, we can't come to any conclusions with respect to ants' ability to predict earthquakes. In the broader, philosophy of science scheme of things, you failed to falsify the hypothesis that ants can predict earthquakes, but Lighton and Duncan's observations falsified that hypothesis. Again, they're both one-time observations, but you or someone else would need to gather more data to cast Lighton and Duncan's findings in doubt.

I'm sure you get quite a few earthquakes in your area, so it would be great to initiate some citizen science that involves ant monitoring. It would be a great way, for example, to get kids involved in science and natural history. If you were able to coordinate with some local summer camps, for example, you could gather quite a bit of useful data with respect to this very practical question, and give kids a taste of what it's like to do science that's important to their community.

best,
Jesse



Greetings AntAsk!

I must say, having Googled my way to your site while searching for possible identification of the new ants that have found their way in, I found myself going through many pages of archives and forgetting why I started reading your blog in the first place. But I do have an identification issue I'd like your two cents on, if you could. Picture attached (after trying two different cameras and about 30 minutes of fiddling with settings to finally get a shot that wasn't just a massive blur).

I am in northeast Texas, and early last week we got hit by the mother of spring rains including damaging hail and some tornadoes. I also had our quarterly pest control visit 5 days ago. I think these guys got washed out or relocated by the weather, then further disrupted by the Orkin man. I noticed ants in our kitchen two days ago - though NOT by the food or the pets' water bowl not four feet away, just crawling along the baseboard by the backdoor. One quick Terro treatment and they were gone. This morning I found the same kind of ants on my bedroom windowsill.

This time, though, they weren't marching anywhere. There are three relatively gigantic (half-dollar-sized) collections of them clinging to the wood and the wall along the corner of the windowsill and only a couple moving in through what I can only assume is a microscopic crack in the window. I have another Terro treatment down and have a call in to the Orkin man for a re-visit, but I kind of want to know what you think.

My Google-assisted guess is that they're Argentine ants potentially out recolonizing/mating, but I'm very much a layman when it comes to mermecology, so that's just a stab in the dark from a curious mind. Two questions come to mind right now: 1) what are they, and 2) how much weatherproofing am I looking forward to in order to shore up any cracks in windows/doors/baseboards/etc.?

Thanks in advance!

Carissa
Dallas, TX

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Dear Carissa,

Thanks for the question. Unfortunately, some of these likely subjects are difficult to tell apart with out a microscope. There's a good chance they're the common Tapinoma sessile. One of our other experts, James Trager, writes: "I'd be willing to make a small bet they're Tapinoma sessile. Terro baits keep them at bay in my house (at my wife's insistence), without, I am glad to say, harming the numerous colonies around the yard that do not enter the house."

It is difficult to rule out Linepithema humile, however. In general, T. sessile is more likely to be spotted inside a house. In the field, they actually can be distinguished by their odor if you pick them up and schmush them a little between your fingers, but this takes practice, and some familiarity with both. The difference in odor is difficult to describe (T. sessile has been described as being somewhere between 'coconut' and 'citronella').

Regardless, the fact that they are attracted to terro baits is encouraging. No matter what the species, the trick is that one treatment is never enough. At most, you generally take out 80-90% of the ants, so they'll quickly bounce back if you don't keep applying. For the cost conscious, the terro-bait recipe can be pretty much replicated with sugar, water, and Borax by following these instructions (click here).

Weatherproofing would probably help, but personally, I'd wait a little while to see how the bait was working.

Hope this helps!
best,
Jesse Czekanski-Moir & the AntAsk Team

Please help! Do all ants have 6 legs (3x2) and in your opinion is this an ant or spider on this picture?
Thanks a lot.
Toni Mindoljevićspider ant mimic.JPG
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Hi Toni,

All ants do have six legs you are correct. However, the attached picture is NOT an ant. On the original website, it is identified correctly as an Ant-mimic spider, although the title of Eight Legged Ant is rather tongue-in-cheek. You can clearly count the legs to see all eight legs of a typical spider. It does appear though that this little mimic is holding one pair of legs out front to imitate ant antenna. The spider is from the family Salticidae, a jumping spider, and can be easily recognized by the large prominent four eyes in front and two smaller pairs along the side of the cephalothorax. This gives them excellent vision, and some species have even been recorded as even being able to see colors and watch TV.

The subject of ant mimics has been addressed in a previous AntBlog post, so take a peek to learn a more.

Best wishes,
Rebekah Baquiran & the AntAsk Team

Hey guys!

Just got a short question. I and a friend of mine were walking down the street a couple of days ago, when suddenly we saw this big ant walking on the pavement. Could you tell me what kind of ant it is?
Some extra information, we live in The Netherlands, Europe, maybe that could be of any help for you!

Sincerely,
Steffan
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Hi Steffan,

Great find! The picture you sent in is actually not an ant at all, but a beetle from the family Meloidae, likely from the genus Meloe.
Several species do occur throughout Europe, although without a better look at this beauty, I can't say definitively what species this is.
They are also commonly called blister beetles or oil beetles due to their ability to release oily droplets containing a poisonous chemical compound called cantharidin. When this chemical comes in contact with skin, it can cause painful blisters and swelling of the affected area. If ingested, it can prove lethal but will otherwise cause nasty gastrointestinal or renal problems. This is the same compound found in Spanish fly, and the potential for unfortunate side effects or death is the main reason it is banned in many countries.

Best wishes,
Rebekah Baquiran & the AntAsk Team