May 2013 Archives

Hello there,

I have a query about these ants we saw in our local park in Madrid, Spain. The ants themselves seemed fairly standard, with one nest hole, and a long line of foraging ants heading out to a nearby area and coming back with various tasty tidbits. As can be seen from the photo the ants were a number of different sizes.

Ants.jpg

However, amidst the ants were several white creatures (in the photo centre left, bottom right and the tail of one top left).

Ants_2.jpg

These looked nothing like ants, but appeared to be coexisting with them peaceably. They were going in and out of the ant hole, and were ignored by the ants. One or two travelled along the foraging line, but didn't appear to do any actual foraging. They were quite quick too, about as nimble as the ants.

Any information as to what these might be would be gratefully appreciated. My guesses would be a) some precursor ant stage (pupa or some such) b) other insect living symbiotically with the ant or c) I have no more ideas.

Many thanks!

David

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Hi David,

Your second guess is correct! The other insects in your photograph are in fact silverfish, cohabiting with the harvester ant Messor barbarus. There are many species of such myrmecophilous (or "ant-loving") Zygentoma around the world, with 16 occurring in the Iberian Peninsula alone. Unfortunately, without a clearer image, it is difficult to provide you with a more precise ID (several different species have been observed in Messor nests in particular), but based on a superficial diagnosis, they most likely belong to the genus Neoasterolepisma.

Silverfish are among a wide variety of other arthropods (including beetles, crickets, spiders, millipedes, even cockroaches) known to inhabit the nests of ants, either commensally or parasitically, and like other myrmecophiles, silverfish have evolved very successful strategies for avoiding detection by their ant hosts. While looking nothing like the ants, as you say, these scaly symbionts are able to blend in with the rest of the colony by rubbing against "callow" or immature workers and adopting the unique chemical profile that sister ants use to recognize one another. In this way, the silverfish enjoy easy access to shelter and resources within the nest and can intermingle freely with foragers on the outside (no doubt pilfering some of the tasty tidbits you observed being brought back to the harvester's granaries). Of course, this chemical disguise is only temporary, so the silverfish must also rely on another characteristic adaptation--speed--if their cover starts to fade, hence their nimble-footedness around the workers.

While some myrmecophilous silverfish are apparently highly specialized, demonstrating a preference for a single ant species, most are generalist interlopers, using their peculiar knack for chemical mimicry to infiltrate the subterranean strongholds of a variety of different ants. Another widespread Mediterranean silverfish species, Proatelurina pseudolepisma, for example, was found in the nests of a total of 13 different species of ants! Those of Messor barbarus, incidentally (the same species in your photograph) happened to be the most popular.

Hope this helps!

Alexandra Westrich & the AntAsk Team

We found these ants below in Anduki (Seria, Brunei):

Cataulacus.jpg

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Hi Uli,

The ants pictured belong to the genus Cataulacus, a group of arboreal-nesting ants widely distributed across the Old World tropics. The exact species is likely Cataulacus latissimus, one of the more sizable of the dozen or so Indo-Australian species, known to occur in West Malaysia, Sumatra, Singapore, and of course Borneo.

Thanks for the photo,

Alexandra Westrich & the AntAsk Team



Dear Ant Blog,

All the photographs I see show ants using their mandibles like tongs. Can they rotate them like we can rotate our arms?

Katrina

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Dear Katrina,

Despite the fact that ants use their mandibles for a multitude of different functions including prey capture, manipulation, and escape, there are no ants that have been proven to have fully rotational mandibles. Humans have a ball-and-socket joint that allows great range of motion, and although ants have a ball-and-socket joint for their antennae, their mandibles usually have a single plane of motion. Although this limits range of motion, it allows for much greater strength.

In case you are interested in reading more about mandibles, Chris Schmidt wrote a basic introduction to mandibular function as a part of the Tree of Life project. There are also several academic papers that detail the movements of mandibles (see Jurgen Paul), as well as some of the most extreme mechanical "trap-jaws" that have been convergently evolved by several ant species.

Hope this answers your question!

Best,

Max Winston & the AntAsk Team


Hi,

We've had this ant problem for a long time now. There are these red ants about the length of a fingernail that inhibit a tree opposite our house across the road, they seem to be making a nest in the leaves or something. We usually park our car near the tree because there is limited space here (our neighbours including ourselves have 3 cars each). These ants are always found on the car but I've never considered them anything more than an annoyance. I'm only afraid that they might be inside the car while we're driving and my folks say they have a painful bite which scares me. Plus these ants are cannibalistic I think, I see them rushing to one of their own dead and picking them up back to their nest. When provoked they lift their torso and front 2 legs in some kind of intimidating pose. Today, we found a horde of them all over our car, many were dead due to a chemical smoke run conducted by the local town council to get rid of mosquitoes. What's next? The whole colony is going to come down and collect their dead? I quickly pulled a hose and washed away everything but those that were alive had really strong grip and won't budge even to strong water pressure, so I squashed them and in the process had some crawling up my legs.

Please tell me what to do if anything. I'm tired of it.

Thank you,
Joseph
Petaling Jaya, Malaysia
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Joseph,

It sounds like these ants are probably in the genus Oecophylla (pictured below), or more commonly known as weaver ants because they weave leaves together with larval silk to make their nests.

longinoda11-S.jpg
(Photo by Alexander Wild)

They are highly territorial, but even though they lack a functional sting, they can inflict painful bites and will spray formic acid in the bite wound to intensify the pain.They are probably sticking to your car due to a hairs on their feet that can stick to very smooth surfaces! As for collecting their dead, they are not cannibalistic, but they do take their dead back to a 'trash heap' near their nest. Ants are very tidy animals and communicate using pheromones, so when one ant dies, it emits a certain smell that indicates that it is no longer alive. To prevent any potential spread of disease, they gather their dead (similar to the way we collect and contain our waste).

You can read a bit more about weaver ants in this previous post:
http://www.antweb.org/antblog/2013/01/what-is-happening-in-this-photo-vidarshana.html

And more about the hygienic behaviors of ants here:
http://www.antweb.org/antblog/2010/08/do-ants-carry-away-dead-ants-tom-perris-ca.html

Good luck!

Gracen Brilmyer & the AntAsk Team