AntWeb: June 2012 Archives

Hello,

I saw a picture of a leaf cutter ant and some other ants. The leaf cutter ant has a white circle (eye) on the center of its head. I noticed other ants have something there also but in different arrangements of three spots or the coloration is different. What is this? What is it for?

-Abigail

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Hello Abigail,

The white circle you observed on the leaf cutter ant Atta cephalotes is a simple eye or ocellus. Ocelli occur in many other insect orders and function as auxiliary light sensory organs. Unlike the two main compound eyes, these simple eyes consist of a single ommatidium or "lens" and can perform only basic light/dark distinction. They are not typically found in the worker castes of most ant species but when they do occur, as in the genera Atta and Formica, they range in number from 1-3. The queens and males of all ant species always have 3 ocelli.

Thanks for your question,

Alexandra Westrich, Ben Rubin & the AntAsk Team


When in Borneo, I noticed that the Diacamma ponerines on the forest floor of primary forest surrounded the entrance to their nest at the bottom of saplings with nests of twigs like birds' nests. Do you know what these are for? They also turned out to be regularly spaced.

Thanks,

Ruth Levy

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Hi Ruth,

The stacks of twigs over the entrances of the colonies you found are likely required for proper nest thermoregulation. Temperatures in ant nests must be maintained within particular limits or the ants may die or their young may fail to develop correctly. The twigs can contribute to temperature control by keeping nests out of direct sunlight and protecting against wind. We have several previous posts on colony temperature regulation here, here and here.

Thanks for your question,

Alexandra Westrich, Ben Rubin & the AntAsk Team


hi--this morning we observed a lot of sidewalk ants swarming in our backyard (coming in/out of pavement cracks). there were winged ants (males?) flying up and dropping down periodically. some seemed to be struggling--flying around on their backs before righting themselves. now this evening there is no swarm, but some new piles of debris along some of the pavement cracks that a few ants are tending.

what was going on this morning? any help is appreciated!

tx,
virginia
philadelphia

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Dear Virginia,

Although it is hard to identify the ants without pictures, it is quite possible that they are the common European pavement ant (Tetramorium caespitum), which have become one of the most abundant insects in the Northeastern US. If you want to try to identify them, follow this link to the AntWeb species page for Tetramorium caespitum.

As the winged ants are the reproductive members of the colony, it is possible that the colony you are observing was sending out queens and/or males to reproduce with other nearby colonies. Often, they form mating swarms with queens and males from many different colonies, so if the all the members of the swarm were winged, then it is likely that you were observing a mating swarm.

If there were only a few winged members in the swarm, then it is possible that you were observing a territorial battle between two different colonies of Tetramorium caespitum. These are fairly common on sidewalks and between pavement cracks, and have been documented well by the fantastic photographer Alex Wild. See the picture below for an example of these battles (Photo by Alex Wild).

1018633902_jcYV5-L-1.jpg

I hope this answers your questions!

Best,

Max Winston & the AskAntTeam

Hello,

I've always thought red and black ants were carpenter ants but I cannot find any picture of a carpenter ant that looks like these--and my land is crawling with them. We do have black carpenter ants on our porch (most unfortunately), and these are something else entirely.

Could you identify these for me? Is there anything I need to do to keep them in check within my ecosystem, and what natural controls would be optimal?

Thank you,

Chaya

april 019.jpg

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Hi Chaya,

Carpenter ant is the common name for ants in the genus Camponotus, but the ants on your land are wood ants in the genus Formica. We have a few previous posts that mention these ants here and here. Wood ants are native to North America and play an integral part in your local ecosystem by clearing away other insects and harvesting fallen pine needles for their nests. They are relatively harmless and do not normally require special control measures unless you find them to be excessively bothersome. They often change the location of their colonies so you may notice their numbers vary over time, even without any outside influence. Many wood ants can also construct large thatch mounds like the one shown here:

FormicaObscuripesNest-M.jpg Photograph courtesy of alexanderwild.com

Thanks for being concerned about your backyard ecosystem!

Ben Rubin, Alexandra Westrich & the AntAsk Team


Antweb,

I just found this little line of some LITTLE ants. The have distinctly black heads and clear-brown bodies. Very strange. I have some sugar ants in another part of the kitchen, but these new ants are smaller and definitely different. They seem to be attracted to water/liquids. They move in uniform lines, but they are wide lines. Help?

Nicholas
Tomball, TX

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Dear Nicholas,

Without a picture, it is hard to say what species you have crawling around your house. However, by your description, it sounds like they could be Tapinoma melanocephalum. Follow the link to the AntWeb species page for Tapinoma melanocephalum to see whether your ants match our guess.

In terms of getting rid of the ants, check out this previous post for some good advice.

Hope this helps!

Best,

Max Winston & the AskAntTeam

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