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On a recent trip to Colorado, I got to spend a few hours in the Rocky Mountains at about 7500 feet. It was an ant lovers paradise. Virtually ever stone I flipped had a colony of ants under it. I found six different species in no time flat.

Although I tried to disturb them as little as possible, I was struck by the range of sizes, shapes and colors of the larvae, so I did manage to snap a few photographs.

The larvae in this case were white. Do you see the egg stack next to the larva at the bottom towards the middle? I'm pretty sure that one is about to have a snack.

Under a nearby rock, some of the larvae and pupae were bright yellow.

These were orange. In contrast, the eggs on the left are the usual white.

This was a different nest, but the larvae are the same orange color.

It was fascinating to see so many colors of larvae in one place. Wish I could have spent a couple of days there.

This is the view those ants have 🙂

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.

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Question:

Sorry I could not find the question box, but me and my cousin were digging through a ant hole and we found ant eggs. What do they need to grow? Sunlight, coldness, what kind of environment can they live in?

Thanks!
Alexis

Dear Alexis,

The first question I have for you is: did you collect ant eggs or ant pupae? The second question is:  did you collect worker ants too?

Ant eggs are tiny (much smaller than worker ants), white, shiny and oval.

ant-eggs

You can see a pile of ant eggs in this photograph in the middle and a little to the left.

Ant pupae are as large or even larger than worker ants and often have a beige silken sac around them.

ant-pupae

They also have a black dot at the end.

If you have eggs, then you will really need worker ants to take care of them. The larvae that hatch from the eggs will need workers to feed them, clean them etc. The larvae are helpless.  I have a post about ant larvae, if you'd like to learn more. And just so you know, there is a chance the workers will eat the eggs.

If you have pupae, they could become worker ants. Again, they will do better if there are some worker ants to take care of them. Without a queen, they will not live as long as they would in nature.

In their nest under the ground, the ants normally grow up in dark, moist and relatively moderate temperatures.

I am glad you are interested in ants. Let me know whether you have eggs or pupae.

(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.)

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Ant larvae are generally not a hot topic. Most people don't see them because they are hidden within the ant nest. When noticed, the young ants seem to be legless grubs passively laying around and waiting to be tended by the adult worker ants. Or are they? Let's take a closer look at ant larvae.

ant-larvae

Ant larvae vary in shape depending on the species of ant, but in general they are legless, plump and resemble a comma or crochet hook in shape. They have a distinct head capsule. Some are sleek,

ant-larva2

whereas others have numerous hairs.

Larval movement:
Ant larvae are not completely inactive; they are capable of movement.

Some species of ant larvae have been shown to sway to attract the attention of passing workers in a behavior that has been described as begging.

Other species can even raise themselves off the ground. Take a look at Mark Moffett's photograph of bulldog ant larvae begging.

If you disturb an ant colony under a rock, you can observe ant larvae alternately straightening and curling, which looks like they are throwing their heads back. Presumably they are trying to attract the attention of worker ants.

This clip is a series of photographs showing ant larvae throwing their heads back. Try to follow the larvae towards the center from slide to slide as they curl and straighten.

(Let me know if you can't follow it and I'll put up the stills.)

Ant larvae as child laborers:

Ant larvae do make active contributions to the colony. The weaver ants, for example, use their larvae to produce the silk needed to tie leaves together to form the nest structure.

Probably the most surprising aspect of ant larvae is that not only do worker ants bring them food, but the larvae are often sources of food themselves.

Having ultra-thin waists (petioles) makes it impossible for adult ants to move solids into their food-processing centers in the hind section of their bodies (gasters). Adult ants can only consume liquids.

Scientists have long known that the worker ants feed all solids to the larvae first for processing. The larvae were thought to chew up, swallow and pre-digest the food, and then regurgitate it back to the workers to distribute throughout the colony.

Recently, however, researchers have shown that in one species of bigheaded ants the workers actually place the food on the surface of the belly of the larvae in a special groove (larvae lay on their backs). The larvae spit out enzymes onto the food, basically drooling on themselves. After a few hours, the workers come back and pick up the slime that results, feeding some of it to the larvae and taking some for themselves. According to videos of the larvae processing bits of fruit fly, the larvae very rarely sip any of the gooey liquid while the food is dissolving; they wait patiently until the food is done and let the worker ants feed them.

Other species of ants resort to feeding on the larvae in various ways. Certain species of ant larvae have special structures that allow the workers to access the internal body fluids (hemolymph), a sort of pump or "tap."

The so-called Dracula ants take things a step further. These rare ants get their name from the fact that they cut holes in the sides of the larvae and suck out hemolymph. Although this sounds pretty gruesome, the larvae survive having holes bitten into them and later become workers themselves.

Another odd behavior of this group is that the workers carry the larvae to their food and place them on it, rather than carrying the food to the larvae, as most other ants do. For example, instead of cutting up a caterpillar into chunks and carrying it into the nest to feed the larvae, Dracula ants carry the larvae out to the caterpillar. Once they have fed, the larvae become food themselves.

Given the evidence, you can't help but to conclude that ant larvae are important members of the ant colony and not just passive babies waiting to become workers.

ant-larva3

References:

Bruno Gobin (2005) Larval begging for food enhances reproductive options in the ponerine ant Gnamptogenys striatula. Animal Behaviour vol 69: 293-299

Keiichi Masuko (1986). Larval Hemolymph Feeding: A Nondestructive Parental Cannibalism in the Primitive Ant Amblyopone silvestrii Wheeler (Hymenoptera: Formicidae). Behavioral Ecology and Sociobiology, Vol. 19, No. 4: 249-255

Keiichi Masuko (1989). Larval Hemolymph Feeding in the Ant Leptanilla japonica by Use of a Specialized Duct Organ, the "Larval Hemolymph Tap" (Hymenoptera: Formicidae). Behavioral Ecology and Sociobiology, Vol. 24, No. 2: 127-132

Keiichi Masuko (2008). Larval stenocephaly related to specialized feeding in the ant genera Amblyopone, Leptanilla and Myrmecina (Hymenoptera: Formicidae). Arthropod Structure & Development Volume 37, Issue 2: 109-117

See more about Dracula ants at Myrmecos Blog

Young Ants in the Kitchen -Science News for Kids Summary based on D. L. Cassill, J. Butler, S. B. Vinson and D. E. Wheeler (2005). Cooperation during prey digestion between workers and larvae in the ant, Pheidole spadonia. Insectes Sociaux Volume 52, Number 4: 339-343.

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