Tag Archives: The Consult-ant

There's a question for the Consult-Ant this week. (The “Consult-Ant” started on the Leaping from the Box website, where I answered questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)

Question:

I sucked an ant up in a homemade bug vacuum and then transported it over a mile from its home.  Will it survive if I let it go?  Do they have to find their way to their original nest in order to survive?

Anon

Answer:

First of all, can a single ant make it on its own? The answer is no, unless that ant is a queen during certain parts of her life cycle. A single worker ant on its own doesn't have much of a chance of survival.

So, could the ant navigate back to its nest if displaced? Different ants use different cues to navigate when outside the nest. Some ants can use cues from polarized light or the position of the sun. Potentially an ant that uses visual cues might be able to re-orient itself over short distances to find its nest.

On the other hand, some ants rely heavily on chemical trails to move back and forth to their colony. Think of army ants, some of which are blind. In that case, the ant would have to wander around until it accidentally ran across a trail. The likelihood this would happen decreases with distance from the nest.

At the distance of over a mile, the chances the ant will be re-united with its nestmates are non-existent. There's a tiny chance it could join a nearby colony, but it is not likely.

What about a flying insect, like a honey bee? Honey bees would stand a much better chance. They have been shown to be able to fly up to five miles from their hive while foraging. They navigate by visual cues. An experienced forager bee might be able to re-orient from a greater distance than an ant on the ground could.

Please let us know if you have any further questions.

Anyone else have any thoughts?

 

Photograph of ant in a bug sucker by Karen Gibson, used with permission.

There's a question for the Consult-Ant this week. (The “Consult-Ant” started on the Leaping from the Box website, where I answered questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)

Question:

This comes from Ol Donyo Orok Hill in Southern Kenya (on the border with Tanzania) at an altitude of around 4500 feet.  I found these ants all dead at the entrance of a hole (what I assumed to be their nest).  This was far enough away from any human habitation, farming, or other activity (other than some goat herding) that I ruled out the use of insecticide.  There were a few more dead, spread out of the the space of about 1 square foot, but the attached photo shows the vast majority of them in a small, dense pile.  Some of their exoskeletons were coming apart (especially the tips of the abdomens), but it didn't look like ruptures from predation, rather just decay.

The stem of the plant in the photo is Solanum incanum (Poison/Sodom Apple), which is both indigenous to the area and poisonous to humans and domestic stock, but I doubt that ants would eat something familiar to them which if it was poisonous.  I don't know what species of ant they are, but the closest I can get is some Pachycondyla sp. (though I'm really not sure).

Do you know what may have caused this seemingly sudden mass die-off?

Answer:

Taking a look at Ants of Africa for ants in the genus Pachychondyla, your identification seems in the right ballpark. Are there any experts out there who can tell us more about what kind of ants these are?

As for what has happened, when I've seen similar piles after a couple of events. Most commonly, either the ant colony had a battle with a neighboring colony or there has been some adverse weather that has caused a mass die off.

If the battle was with a neighboring colony of ants, not all the causalities will be torn apart, particularly if the damage was caused by stings or chemical weapons.

Flooding of portions of the nest during heavy rains can also cause big die offs in species that nest underground.

Readers:  Do you have any suggestions why these ants might have died?

Please leave your thoughts in the comments.

2 Comments

We have a question for the Consult-Ant* this week.

I have an ant question.
 
I was curious about ant eyesight. Not about their color vision but more specifically their quality of vision in the dark. Is it better or worse than a human's night vision?

This is a great question!

The first thing to remember about ants is that they perceive the world in vastly different ways then we humans do. They produce a number of different chemicals and communicate in ways that we can only dimly appreciate. Let's not forget, some ants are completely blind and they get around just fine.

That said, ants do usually live in dark tunnels, either underground or in wood. Many species forage at night, either all the time or during certain seasons. They are able to find their way around in the dark.

camponotus-festinatus1

For example, this carpenter ant lives in the hot desert. It forages at night and is rarely seen during the day.

To study how ants see at night, scientists have been looking closely that the anatomy of  the eyes of ants.

This figure from Invertebrate Vision, edited by Eric Warrant, Dan-Eric Nilsson shows that dark-adapted eyes of invertebrates are structurally different from light-adapted ones.

 

Ajay Narendra and his colleagues (2011) have been studying Australian bull ants (Narendra has photographs of bull ants ) that are active at night and comparing them to day-active species. They found that ants that were active at night had different eye measurements and eye structures, both within a given species (that is active both during the day and night) and between related species. The eye area, facet size, and ocelli (the smaller simple eyes at the top of the head) size, etc. were larger in night-active ants.  Reid et al. discusses more specific information about how the ants use their specialized eyes to see polarized light and landmarks during navigation at night.

Have I danced around your original question long enough? Comparing humans to ants is difficult because in a lot of ways it is comparing apples to oranges, plus our understanding of what other animals perceive is limited. Nevertheless, I'm going out on a limb. All these structural differences suggest that certain ants can be quite specialized for night vision. Based on that evidence, it would seem that ants are probably just as capable, if not more capable of night vision than unassisted humans. Of course humans are capable of inventing and using sophisticated devices to assist our night vision. In that case, humans win hands down.

What do you think about night vision in ants?

For more information:

Ajay Narendra, Samuel F. Reid, Birgit Greiner, Richard A. Peters, Jan M. Hemmi, Willi A. Ribi and Jochen Zeil.  (2011) Caste-specific visual adaptations to distinct daily activity schedules in Australian Myrmecia ants. Proc. R. Soc. B.  278:  1141-1149. (free .pdf available)

Reid, S.F., A. Narendra, J.M. Hemmi and J. Zeil. (2011). Polarised skylight and the landmark panorama provide night-active bull ants with compass information during route following. The Journal of Experimental Biology. 214: 363-370. (free .pdf available)

Wild About Ants post about color vision in ants

 

(* As I mentioned previously, I have been the “Consult-Ant” on the Leaping from the Box website. I answer questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)

9 Comments

Dear Ant Consult-Ant

I have an ant question!

Subject: Ant activity

In mid May at about 6:00 in the evening in Ann Arbor, Michigan, USA, I was walking along the sidewalk and saw some small black ants swarming. I like to watch queens come out so I sat down to watch. I stayed about 45 minutes and I didn't see a single wing. What I did see was amazing. The ants were small black ants. After a few minutes the ants started forming patterns. Two ants that were narrower than most would lock jaws. Then two normal ants would grab onto the heads of these two to form a plus sign or X. They would stay like that for 6-7 minutes then breakup. Sometimes 4 more of the normal ants would grab onto the abdomens of the 4 ants and form a plus sign of eight ants. In the time I was there there were always 15 to 30 of these symbols. I am not sure how many separate nests were participating. I left to get a camera and a collecting jar. When I came back the show was over. Is this common behavior? I have not seen it before. What was going on?

Dear Dave,

Clusters of ants acting in an excited manner do often indicate swarming. As you noticed, however, you would expect to see winged queens and males mingled among the workers. Instead, from what you describe, it sounds like you witnessed a a fight between two nearby colonies of ants.

When ants fight each other, they tend to latch onto antennae and legs and pull hard, thus creating the X's you describe.

Above three ants from one colony pull on a single ant from another colony.

More ants join in, and it becomes a tug of war.

Sometimes one species of ant attacks another, such as these weaver ants attacking a much smaller species.

(Photo from Wikimedia) This one looks more like a Y than a X.

They may use the same behavior with prey.

(Photo from Wikimedia)

Ants may fight other ants to gain access to food, to defend their nest from hostile take over, or to defend the area around their nest (territory).

Some ants are more likely to fight than others. In Mark Moffett's Book Adventures Among Ants, he has a chapter devoted to the territorial disputes between two huge colonies of Argentine ants in California. Along the front line literally millions of ants die every month in what is a never-ending struggle.

On the other hand, a dispute between honeypot ants may be resolved by mere posturing, no actual fighting may occur.

Sounds like you witnessed an interesting event, which left an impression on you. Without knowing the species involved, etc., I hesitate to speculate further as what was happening.

Thank you for sharing this question. Let me know if you make any more interesting observations.

-The Consult-Ant

(Note: As I mentioned previously, I have been the “Consult-Ant” on the Leaping from the Box website. I answer questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)