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Questions About Ant Pheromones

Mike wrote to the “Consult-Ant” with a number of questions about ants. I am going to try to answer each one in a separate post. For the original list of questions and links to all answers, visit here.

4)      Besides making trails and setting alarms, are there any other kinds of unique pheromones? Such as, attracting the queen ant or inducing certain behaviors like digging.

Sure, there are a lot of different pheromones in ants. Ants use pheromones to

  • recruit to food sources,
  • mark the way to new nest sites during emigration
  • aggregate
  • mark territories
  • recognize nestmates
  • “call”- the release of pheromones by reproductive females to attract males
  • induce nestmates to defend the nest (alarm)

to name a few. Some queens release pheromones that induce workers to kill larval forms that would become reproductives, or that prevent virgin queens from shedding their wings. In carpenter ants, the males release a pheromone from their mandibular glands that signals to the female reproductives that it is time to fly from the nest and join the mating swarm. (Holldobler and Maschwitz 1965, as cited in LD Hansen and JH Klotz, Carpenter Ants of The United States and Canada).

Behaviors like digging can also be stimulated by non-chemical signals, such as stridulation (making sounds) by buried worker ants trying to get nestmates to dig them out.

Knowledge of ant pheromones a bit rusty?  Let me explain what we are talking about. Ants produce chemicals, in fact they are walking chemical factories. Bert Holldobler and E.O. Wilson wrote extensively about how ants use chemicals for communication in Chapter 7 of their book, The Ants (starting on page 227).

The term “pheromone” is defined as a substance released by an organism to the outside that causes a specific behavioral or physiological reaction in a receiving organism of the same species. [Nordlund, D. A. and W. J. Lewis. (1976). Terminology of chemical releasing stimuli in intraspecific and interspecific interactions. J. Chem. Ecol. 2: 211-220.]

For example, this video shows an ant laying trail pheromones. Other ants will detect the chemical in the trail and follow it back to the food.


All of these chemicals are made in exocrine glands found throughout the ant’s body.

In the head are the

  • mandibular gland – often produces alarm and defense compounds, extends all the way to the gaster in certain Camponotus
  • maxillary gland -source of digestive enzymes
  • propharyngeal gland – source of digestive enzymes
  • postpharyngeal gland – source of cuticular hydrocarbons (colony odor) and also food for larvae
  • antennal glands – found in Solenopsis fire ants

In the alitrunk are the

  • labial gland – equated with a salivary gland
  • metapleural gland (labeled in illustration) – source of antibiotic compounds, occasionally alarm pheromones/repellents
  • (Archetype has an awesome post about the structure and function of the metapleural gland.)

In the gaster, we find the

  • poison gland – source of defensive formic acid in Formicinae, recruitment to food in some myrmecines
  • rectal gland
  • sternal gland (Pavan’s gland) – trail pheromones
  • Dufour’s gland – often the source of trail pheromones
  • pygidial gland
  • etc.

ant-glands

The presence or absence of these glands, their structure and their contents varies between ant species, and even within individual caste members of a given species. The pheromones used and the message they contain are species specific by definition. That means what scientists learn about the pheromones of one species may not have general application to any other species, although some have been found to overlap.

To learn more about the chemistry of ant pheromones, try The Pherobase, a website of known pheromones, attractants, etc. You can search the database by animal taxon, or go directly to the Formicidae page.

There you can find out, for example, that the trail pheromone for Atta texana is me-4me-pyrrole-2-carboxylate, and what it’s structure looks like. Or the mandibular gland components of the exploding carpenter ants of Camponotis cylindricus group. Solenopsis invicta queens apparently produce (E)-6-(1-Pentenyl)-2-pyranone for recognition, that is so that the workers know she is their queen. This site is really cool if you are an ant geek.

5)      The ant uses their antennae to pick up ant pheromones, so if that’s the case, then do ants necessarily ‘smell’ food if the pheromone is blown towards the ant’s way? Essentially speaking, can ants smell their way to food?

Oh, definitely yes. In a recent post I discussed how certain ants can even use odors as a type of chemical map to find their way around. Their way of orienting can be called a “topochemical” map. Of course ants may use a variety of cues to find food, including sight, but it makes sense that they can detect plant chemicals and even those of sources of honeydew like aphids and scales.

If anyone has posts or references that might be helpful to Mike, please let us know.

17 comments to Questions About Ant Pheromones

  • I had no idea there are so many different pheremones used by ants. Thanks for such a wonderfully informative post. Also, I didn’t realize that ants used sound, and I’m amused by the image of a little buried ant shouting “help! get me out of here!” to his co-workers.

  • Roberta

    Yes, ants do make sounds, and you are right, it is interesting to think about. Try my post about ant sounds for some links to recordings.

  • Rob

    I’m doing a chemistry experiment and I’m trying to figure out how to break down the pheromones? Suggestions?

  • Roberta

    Sorry it took me so long to get back to you. Pheromones can be a variety of different structures, depending on the source. The same things will break them down as any other chemicals: heat, enzymes, mixing with other chemicals. Are you working with a particular pheromone?

  • zubaidah

    WOW ants are pretty amazing!!!!

  • Moondahgi

    Hi! My son is doing a science fair project on ant pheromones. He is going to use two different types of ants (the red and and the leaf cutter ant) to see if the ants will follow the others pheromones or if they are restricted to their own specie. Do you have any information that could help with this? Are there any separations in the genus or phylum that would make these different types of ants NOT follow the pheromones? Does each colony have it’s own pheromone or are they all the same? (i.e. all red ants have the same pheromone and all leaf cutters have the same pheromone?) Thanks.

  • Roberta

    Ants produce a number of different chemicals that elicit different behaviors. For example, a single species may have different chemicals that act as trail pheromones, alarm signals, nestmate recognition odors, etc.

    Some chemicals are highly specific to a given species and ants of other species won’t respond. Other chemicals can be detected by more than one species, although the two species might not respond the same way. For example, a slave-making species of ant sprays a chemical (acetates) when it invades a nest of potential slaves. The slave-making workers are attracted to the odor. The slave species can also detect it, but they run away.

    Sometimes closely-related ant species may have the same alarm pheromones.

    I’m not sure what kind of ants you are calling “red ants.” Do you mean harvester ants? If you could be more specific, perhaps I can figure out some of the pheromones they might use.

  • Karren

    I found a circle of black ants laying ontop of larva on the side walk .why would this happen.I had though the ants were dead but when touched they moved and you could see the larva under them.

  • Roberta

    Karren,

    I would suspect that the ants were feeding on the larva, depending on what kind it was. The worker ants suck the juices out of dead insects they find lying around.

  • anoop

    Roberta, would you please inform us about an ant’s internal symmetry/asymmetry, in terms of its organs and their placement (preferably of Diacamma ants).

  • Roberta

    Most ants have a similar arrangement of organs, although some have more glands than others.

    By and large the internal organs are asymmetrical, but a few are paired, such as ovaries and mandibular glands. The paired ones would be symmetrical. Muscles would be symmetrical, too.

    Here’s a link to a labelled diagram that seems pretty complete: http://www.flickriver.com/photos/msitua/4068661194/

  • Leon C.

    Do you know approximately how long the average fire ant pheromone trail takes to degrade?

  • Roberta

    Hi Leon,

    According to Walter Tschinkel, the trail only lasts a few minutes on glass and up to 20 minutes on paper or soil. Not very long…

  • manish

    i stutied a common ant found in india (shimla) commnly called white ant. i found that it has three rings two on head portion and one on abdomen portion, it was bigger than other two. please help me to find what it was. i can post u images of ants i have taken. send me an e mail.

  • Roberta

    Manish,

    What we call white ants are usually termites. Do you still need help with your identification?

  • Gordon

    can a pheromone be reproduced that will last longer than the natural

  • Roberta

    I assume that there are ways to alter the chemistry to make it longer lasting, but I’m not sure how to go about it.

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