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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


Hello Antweb,
I've been doing some research on ant species richness and was wondering what locality is considered to have the highest species richness and if there is any literature to back up this information, thanks!


Hi Alejandro,

Ant diversity is highest at low latitudes (the tropics) and drops off towards the poles. This is a common phenomenon among many groups of organisms and Terry McGlynn has a relatively accessible piece about it here. This website is also a great way to explore the distribution of ant genera across the world. There is quite a bit of literature on the subject including, but certainly not limited to, the references listed below and the citations therein. The book "Ant Ecology", listed first in the below references, is a great overview of many ant related subjects, including their geographic distribution.

Thanks for your question,
Ben Rubin & the AntAsk Team

References:
Dunn RR, Guénard, B, Weiser, MD & Sanders, NJ. 2010. Geographic gradients. In Ant Ecology (eds. L. Lach, C.L. Parr & K.L. Abbott) pp. 38-58. Oxford University Press, Oxford, United Kingdom.

Guénard B, Weiser MD & Dunn RR. 2012. Global mode ls of ant diversity suggest regions where new discoveries are most likely are under disproportionate deforestation threat. Proceedings of the National Academy of Sciences USA 109: 7368-7373.

Kaspari M, Ward PS & Yuan M. 2004. Energy gradients and the geographic distribution of local ant diversity. Oecologia 140: 407-413.

Kusnezov N. 1957. Numbers of species of ants in faunae of different latitudes. Evolution 11: 298-299.

Jeanne RL. 1979. A latitudinal gradient in rates of ant predation. Ecology 60: 1211-1224.

Jenkins CN, Sanders NJ, Andersen AN, Arnan X, Brühl CA, Cerda X, Ellison AM, Fisher BL, Fitzpatrick MC, Gotelli NJ, Gove AD, Guénard B, Lattke JE, Lessard J-P, Mcglynn TP, Menke SB, Parr CL, Philpott SM, Vasconcelos HL, Weiser MD & Dunn RR. 2011. Global diversity in light of climate change: the case of ants. Diversity and Distributions 17: 652-662.

Trophic eggs (Mark)



Hey, AntAnswerers!

So, I've been thinking a bit about the situation with trophic eggs in ants. It apparently seems a pretty common practice among ant queens to eat some of their unembryonated eggs. Fair enough.
What I don't understand is the energetics of this practice- calorie for calorie, wouldn't it be costing a queen more to produce these trophic eggs than she is gaining from eating them?
I could understand making the best of a bad situation (i.e., for other arthropods that overshoot the optimal number of offspring, cannibalism retrieves some of the calories from a previous, poor decision), but I'm not sure that kind of argument applies for ants. Any thoughts from you guys?

I am similarly confused about the energetics of dracula ants, for similar reasons (i.e., the food comes from within the "extended phenotype").

Many thanks!
-Mark


Dear Mark,

Typically, trophic eggs are unfertilized eggs laid by workers and used predominantly to feed larvae and queens but can also be fed to other workers. This type of resource sharing is similar to the regurgitation (trophallaxis) that occurs frequently between ants that you may be more familiar with.

Queens can also produce trophic eggs and new foundresses often use these to feed their young larvae. They certainly could eat these themselves and they may be useful as a way of storing food until it is needed, but most are fed to their offspring.

Also, larvae do sometimes cannibilize other larvae as you mention. This system of feeding larvae may or may not be optimal for the colony but it undoubtedly benefits the larval aggressors.

Dracula ants are incapable of consuming solid foods because their mouthparts are not built for chewing. The larvae, however, can consume and digest these foods, producing a resource rich hemolymph. Many ant colonies operate in this way, indirectly feeding on the digestive capabilities of the larvae. Dracula ants are special because the larvae do not have the ability to regurgitate nutrients and must, therefore, be bitten open by the workers. Larvae of most other species are perfectly capable of regurgitation so this complicated method of sharing resources is not necessary.

Great question!
Ben Rubin & the AntAsk Team


How difficult, if possible, is it to transfer an ant colony from a small easy maintenance starter farm to a much larger farm. Also how big would my farm have to be to have a full colony of pavement without 'controlling' population size? I can build one as big as I need. And what are the chances that my pavement ant colony will have more than one queen producing, I read that they will sometimes have more than one producing queen per colony. I think it would be very interesting to watch a multi queen colony.

Thank you so much,
Justin

Dear Justin,

It should not be too difficult to transfer your colony to a new farm, though you will probably lost some individuals in the process. Take a look at our previous post here.

I doubt that there will be any need to "control" the population size. The colony will grow until it is mature or runs out of resources so keep it well fed and it should be fine. Pavement ant colonies can grow to tens of thousands of workers so if you want your colony to reach its maximum possible size, you should probably make the farm rather large. Be sure to take a look at this previous post for tips on building a habitat.

Steiner et al. (2003) found multiple queens in five of 35 pavement ant colonies collected, so it is certainly possible that your colony contains multiple queens. Although you may need to do some more whole colony collecting if you are determined to find this type of colony.

Good luck with the farm!
Ben Rubin & the AntAsk Team

References:
Steiner FM, Schlick-Steiner BC, Buschinger A. 2003. First record of unicolonial polygyny in Tetramorium cf. caespitum (Hymenoptera, Formicidae). Insectes Sociaux 50: 98-99.


How do I get my ant farm to produce more queens and how do I collect them?

Dear Anthony,

This can be a very difficult goal to accomplish. Ant colonies need to be very well established before they will begin producing reproductives. Depending on the species, this can take up to a few years. Also, if your ant farm doesn't have its own queen, it can't possibly produce new ants because, with a few exceptions, worker ants cannot produce fertile eggs.

Allowing your colony to grow and providing it with abundant resources is the best way to ensure that it will attain maturity and will eventually be able to produce new queens.

Good luck!
Ben Rubin & the AntAsk Team


We have been battling ants for about a month now and I'm just curious if we need to take it to the next level (ie- call in a professional) or if we are on the right track.

First, some background, we live in the Kansas City area, and we've had a fairly mild winter up until about a month ago. We have had 3 snowstorms in the last month, all producing more than 6" of snow (two with more than a foot!). The first two snowstorms were 5 days apart and we first noticed the ants between those two storms.

We have a split-level home, and I first noticed the ants in our dining room area, and as I started looking around more, I realized they were everywhere. In the dining room (which is connected to the kitchen, but they weren't trailing to any food in the kitchen), they were also in our front living room near the window and the fireplace, they were also in our walk-out basement. None were noted in the storage room (where the dogs and their food are), or any of our bedrooms which are on the same level as the kitchen/dining room.

Initially we sprayed indoors which I now realize was foolish. We couldn't spray outside because there was collectively 2 feet of snow after the first two storms. After doing a bit of research I decided that the terro traps were the way to go (because we were still seeing live ants every day). We went out of town on March 1st, and we laid terro traps in the areas we'd been seeing the ants. We were gone for 10 days, and when we returned, there were THOUSANDS of dead ants all over. The most concentrated areas were near our fireplace, the front window, and near the door to the walk-out basement. I vacuumed all of the dead, and continued to see new live and dead ants each day, but the numbers slowly dwindled over the following 2 weeks. I also sprayed the perimeter of the home (outside) once the snow melted. I felt like we were finally getting ahead of the game because it seemed like we weren't seeing any more accumulate.

Then out of the blue this morning (after our third snowstorm happened overnight last night) I noticed a few more near the front window, however they were different. Instead of being small, black (what I think were odorous house ants), there are a fair number of dead, larger, winged ants. They have a good waist to them, so I don't think they are termites, and they are all dead, or almost dead, no swarms.

My question is, is this a good sign? Have we killed enough that the end of the colony is coming out dead? Or is this a bad sign that more breeding ants are coming out and developing new colonies? We continue to have the terro traps in place and have not given up the battle yet. I just need to know if it's time to call in a professional, or are we making progress and just need to keep at it?


Dear Christina,

It is hard to say but it is very possible that you are on the home stretch of ridding yourself of these ants. Oftentimes, when ant colonies are on the verge of death due to depleted resources, disease, or attacks from other ants, they will devote their remaining resources to producing winged reproductives in a last ditch effort to reproduce before dying. Therefore, the colony occupying your house may be teetering on the edge of collapse.

Good luck! Hopefully an exterminator will not be necessary!

Ben Rubin & the AntAsk Team

I am a typical mom who knows only three things about ants: they have structured colonies, they carry 3x their weight, and they invade our home during the rainy season. I had never noticed this behavior before and came upon your website in trying to research if what i think is happening is true. The black ants that I see in my bathroom are scouting for food and I don't kill them because I know they will not find any and will eventually leave, but some lone ants have become lost or stranded and I will see them roaming in the same area for a day or two and then they seem to die. Is it from starvation or cold temperature at night, or emotional distress at being alone with no way back to what they know as home?
Also, when they first invade there are many following a trail but soon I see that some break into groups of a dozen or so that scatter when they detect me, do they communicate in this way? I thought they were more like little robots following programmed instincts so they used chemical scent trails, but it almost looks to me like they are having a meeting to discuss their options. I use Clorox wipes to clean and have looked at the spot were they grouped to make sure there wasn't anything that could have served as food like my son's bubble gum toothpaste. I hope to learn more as I respect these tiny hard workers.

Thank you!
Claudia from central California


Hi Claudia,

Rather than thinking of ants as robots following programs, it might help understand what they are doing by imagining them as small people with a limited view of the world and very short-term memories. Contrary to popular belief, no single individual is in charge of an ant colony, not even the queen. Instead, an ant colony's behavior is accomplished through the independent action of each individual together. So every ant has to use the relatively small amount of information available in the immediate area to figure out what she should be doing. Oftentimes, this means "asking" other ants what they are doing and if they have an opinion on what everyone else should be doing. This type of communication is usually accomplished through antennal contact and scents and could certainly result in the formation of groups of ants all "talking" to each other, figuring out what they should all do next. Of course, it is always a possibility that they just found something interesting on the ground.

The ants that you find in your house are almost certainly looking for food. They could also be exploring for new nesting sites and, as your house is probably relatively warm, it might appear ideal at first. Unfortunately, no matter the reason for their exploration, foraging ants have very high rates of mortality around 15% per day. Many of these ants are the victims of predation or, in hot and dry areas, dehydration, but many simply get lost, as some of the ants in your house seem to. A scent trail may be too faint, may get disturbed, or the ants may get separated from it inadvertently and be unable to find their way home. Their eventual death is likely the result of starvation or dehydration although cold temperatures could certainly be a factor as well.

Deborah Gordon's book, Ants at Work is about how ants get all of their work done and it sounds like the subject might be of interest. You may want to check it out.

Thanks for your question,
Ben Rubin & the AntAsk Team


The other day I was sitting outside my house with my friend. He and I were just sitting on the ground. There were a number of small black ants around us going about their business but not really in our way. After some time they began to fixate around the area I was sitting. They climbed on my feet and gave little nips and so on. After a while it got a little ridiculous so I moved to the other side of my friend where there were no ants at all. It was completely clear and not in (what I thought to be) their trail. It wouldn't have been more than five minutes later and then they were back again. They were all around me and the spot I had been in previously was completely clear. I just couldn't figure out what it was about me??? I should point out that my friend was left alone the entire time. It occurred to me later however that it had been "that time of month" for me and was wondering if they were reacting to the change of hormone levels?

Thanks for any help you can give me
CJ


Dear CJ,

I have never heard of ants being attracted to human hormones before but without doing an experiment, it would be difficult to say for sure what was happening. Ants would be more likely to respond to food smells. Were you carrying any food or had you been cooking recently? A sweet smelling perfume could also be attractive to ants. However, smells and insect responses to them are often unpredictable. For example, certain termites recognize pen ink chemicals as trail pheromones and can be tricked into following ink lines.

Thanks for your question,
Ben Rubin & the AntAsk Team


IMG_4578 (Copy).jpg

Dear Vidarshana,

This really is a great photo! Thanks for sending it to us! The darker ant in the center belongs to the genus Diacamma and the lighter ants surrounding and attacking it are members of the genus Oecophylla. The aggression between the ants may be the result of territoriality, predation, or a variety of other reasons.

Ben Rubin & the AntAsk Team

Hello,

How come when it gets really hot ants are still able to run around on bitumen and pavers without burning their feet?

Regards
Anna W
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Dear Anna,

Although the thermotolerance of ant tarsi (feet) on hot bitumen or pavement has not been directly studied, there are a few biomechanic studies out there that can help us make some educated guesses.

Part of the reason ants may be able to run quickly over hot pavement is that their tarsi are composed of sclerotized chitin, which is a really tough polymer of many connected glucose molecules. The toughness of this biomaterial is often compared to the keratinized tissue seen in vertebrate hooves--such as horse hooves--many of which are also able to walk on hot bitumen and pavement. This is very different than human feet, which have many nerves and soft, burnable tissue on the bottom of our feet. Yet, even humans can walk on hot pavement if repeated friction and pressure forces the formation of calluses that insulate the sensitive tissue in your foot from the pavement.

While this explanation helps us understand how ants don't burn their tarsi (feet), it does not get around the larger of issue of how the ants on hot pavement deal with the increased body temperature (ants are small!). Well, as it turns out, there are some extremely interesting studies on ants that have adapted to hot, dry environments. One ant in particular--the Sahara Desert ant (Cataglyphis bicolor)--has adapted such a high thermotolerance that its proteins can operate at higher temperatures (4-5 degrees Celsius) and it can forage normally at body temperatures above 50C or 122F. Considering this ant makes a living by running on the hot sand to find and consume insects that have died of heat exhaustion, it makes sense that it can withstand this heat. While you wouldn't commonly find Cataglyphis running on pavement, there has been recent research showing that ants found in urban and suburban areas are more likely to come from hotter, drier habitats because of the prevalence of open areas in the urban and suburban landscape. Thus, it is logical that the ants you see running around on pavement might have also have some thermotolerance themselves!

Thanks for your question,

Max Winston & the AskAnt Team

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