Tag: The Consult-ant

Posted on

Can ant larvae get too cold or hot?

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.

10)  If the eggs, larvae, and pupae were placed in bad conditions, specifically temperature, for a short period of time, would they be harmed?

As you might expect, the optimal temperature for rearing larvae depends on the ant species. In his 1988 paper, Porter found that fire ant larvae (Solenopsis invicta) grew and developed between 24° C and 36° C, with optimal growth at 32 °C. Abril et al. found a range of 18°C to 32°C for larvae of the Argentine ant, Linepithema humile, with optimal development closer to 26°C. Argentine ant larvae held at temperatures above 32°C did not survive.

Of course if the temperatures are hot enough to burn or cold enough to freeze, then the larvae would be harmed even with brief exposures. But what about temperatures that are not extremely hot or cold, but just outside of the range for normal development? Once again, depending on the species, there could be critical windows of development that can be missed if the larvae aren’t reared at proper temperatures. Exposure to low temperatures could potentially stimulate larvae to enter diapause, as well.

Adult worker ants are much less susceptible to changes in temperature. Types of desert worker ants may survive soil surface temperatures of 60 to even 70° C! (Marsh 1985)

ant-brood

In an actual nest, the nurse workers move the larvae from chamber to chamber to ensure the larvae are exposed to the correct temperatures.

Let me know if you have more specific questions.

References:

Abril S, Oliveras J, Gómez C. 2010. Effect of temperature on the development and survival of the Argentine ant, Linepithema humile. Journal of Insect Science 10:97 available online: insectscience.org/10.97

Marsh, A.C. (1985). Thermal Responses and Temperature Tolerance in a Diurnal Desert Ant, Ocymyrmex barbiger. Physiological Zoology, Vol. 58, No. 6 (Nov. – Dec., 1985), pp. 629-636.

Porter SD. 1988. Impact of temperature on colony growth and developmental rates of the ant, Solenopsis invicta. Journal of Insect Physiology, 34(12): 1127-1133.

Posted on

Can Ants Digest Chitin?

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.

9) Ants(obviously) eat other insects, and I probably lack observation skills but do the ants also eat the exoskeleton also? Do they (or the larvae) have some way of digesting chitin? I did see that the ants pretty much leave MOST of the exoskeleton intact, and go for soft parts.

You have definitely got some challenging questions here. I’m going to give this one a try, but if anyone knows more about this, please jump in.

You probably have seen bug bits (discarded exoskeletons) littering the trash heaps around ant nests.

ant-trash-heap

trash-heap3Many arthropods, including insects, have long chain polysaccharides in their cuticle known as chitin. (Chitin is also found in fungi, which was one of the lines of evidence that moved fungi into their own Kingdom.) The exoskeleton of insects is also made up of various proteins and waxes.

Chitin is known to be difficult to digest. It’s long chain polysaccharide structure is similar to cellulose, which is also difficult for animals to use as food. The digestion of chitin requires special enzymes, chitinases, to break the strong bonds between the molecules. For a time it was thought that chitinases only occurred in a few bacteria, but evidence is showing up that certain animals have chitinases in their digestive systems, too.

It turns out that insects have chitinases able to break down chitin, but they aren’t where you might expect them. The chitinases in insects are in the cuticle and are used to move chitin during molting.

We know that adult worker ants can’t digest solids, so they can’t digest chitin. What about larvae?  It is highly unlikely, because the larval digestive system is also lined with chitin. When insects molt, they also shed most of their digestive tract, which is derived from the same tissues as the exoskeleton. Therefore, it seems larval ants probably couldn’t digest chitin without digesting their own alimentary canal.

Many arthropod predators of insects suck out the insects fluid insides. Think about spiders, assassin bugs, lacewing larvae, etc. They are all feeding on fluids.

If it is true that insects can’t digest chitin as a food source, this leads to some other questions. Leafcutter ants feed on special fungi, which they grow in their nests. Do the fungi they grow have chitin? Do the leafcutters have gut symbionts or some other means to digest that chitin?

If there are any chitin experts out there, it would be great to have some clarification.

Posted on

Feeding Ant Queens

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.

Question 8. If I were to catch a queen ant, would it be recommended to feed her some protein as well as sugary foods like honey? I was thinking about this because I’ve read that the eggs and larvae would need protein to grow properly (I’m guessing for muscle development and such). So is peanut butter a good protein choice, in substitute of other insects? I’m worried that peanut butter wouldn’t have all the essential amino acids because peanut butter is an incomplete protein. But I’m not sure about ant development and physiology, so I’m curious.

The answer to this question depends on what kind of ant queen you find. In many temperate ant species, the queen starts a colony via what is called “claustral” founding. In this case, she seals herself off from the world as much as possible, often forming a special chamber. Then the queen lays her first batch of eggs. Until those eggs complete development and eclose into worker ants, it is likely the queen will not feed at all. Usually a queen in this case is surviving on the fat reserves she stored while in her natal colony, as well as the breakdown products from the deterioration of her flight muscles. The queen has no further use for her flight muscles once she has removed her wings, so the muscles break down.

queen-1
Carpenter ant queens have claustral founding.

You might want to give new queens a bit of honey- or sugar-water solution absorbed into a piece of cotton ball or paper towel wad. Just so you know, adding any food always increases the chance of introducing unwanted molds or bacteria.

Once the little colony is underway, you can start feeding. To figure out the best foods, do some research on your particular species. Many scientists prepare a general diet useful for a variety of species. One of the earliest is known as the Bhatkar diet, named for the scientist who developed it. Hoelldobler and Wilson have a section on culturing ants in the back of their book, The Ants. It gives the recipe for Bhatkar diet. (Try Google Books). The Myrmecology Forum also has a link to a .pdf file of the original paper with the recipe. Basically it is honey, an egg, vitamins and agar (available online). You mix it up, cook it to get the agar to thicken, and then cool.

Supplement the diet of predator or scavenger ants with small amounts of freshly killed insects, such as mealworms or crickets, both available at many pet stores. You can also maintain mealworm/cricket cultures of your own. I have used tuna in a pinch. I’ve never tried peanut butter. It might be a bit sticky and the ants could get stuck in it, depending again on what kind of ants you have.

The maker of this video has some good ideas, such as putting the food on a bit of foil, to help with clean up. I would also soak it into cotton or paper towel to prevent workers getting stuck and drowning, but this person didn’t find that necessary.

For more information:

BHATKAR, A. P., AND W. H. WHITCOMB. (1970). Artificial diet for rearing various species of ants. Florida Entomol. 53: 229-232.

COHEN, A. C., AND L. K. SMITH. (1998). A new concept in artificial diets for Chrysoperla rufilabris: The efficacy of solid diets. Biol. Control. 13: 49-54. This diet has been used for fire ants successfully.

Ant Cam website has many FAQ’s useful for ant farms. Try What is good food for ants in my ant farm? for two different diets and advice.

Does anyone have any other great websites or papers with useful information on feeding queen ants and new colonies?

Posted on

Ant Trophallaxis

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.

7) I’ve read a little about trophallaxis (I hope I spelled that right, because Microsoft Word does not help in scientific terminology), but I don’t see ants perform trophallaxis much. I was observing pavement ants though, so perhaps it has to do with the species. But my question is, do they perform it more underground, as in their colony? Or is it all because these ants weren’t hungry at the time? And what does an ant have to do induce another ant to perform trophallaxis? Some kind of touch communication by antennae?

Yes, you did spell trophallaxis correctly.

trophallaxis

When ants feed on liquid food, it goes to the crop, an organ inside the gaster. The crop can be called the ant’s “social stomach” because food collected there may be given to other ants via regurgitation. Ants pass food from mouth to mouth via a process called trophallaxis, which may look like kissing to the untrained observer. Any food the ant doesn’t share with other ants is passed to the ant’s own midgut where it is digested.

Most of the ants you see at the surface are foraging ants intent on getting food back to the nest as soon as possible. Outside the nest is a dangerous place. Thus, it is more common for the ants to engage in trophallaxis underground, as you surmised.

Dr. Bert Hoelldobler studied how certain beetles are able to trick ants into giving them food this way. He was able to show that tapping an ant lightly with the antennae and/or forelegs (tarsi) in the right parts of the body, usually the labium, is enough to trigger an ant to regurgitate food. He was then able to use a human hair to touch an ant and get it to regurgitate.

Dr. Alex Wild from Myrmecos blog, has an absolutely fabulous video of ants performing trophallaxis, which due to the wonders of YouTube, I can show you here. Thanks Dr. Wild! He also has some awesome photos of trophallaxis.