When I am acting as the “Consult-Ant” and answering questions about ant farms, people are generally interested in finding out more about ant queens.
When an ant colony is ready to branch out, the current queen lays eggs that develop into males or new queens instead of workers. Adult male ants are winged, and have small heads and slender bodies. They can easily be mistaken for wasps.
Newly emerged queens are larger than both males and workers, and have four wings.
When conditions are just right, such as after a summer thundershower, the males and new queens fly from the nest. The whole colony is in a tizzy when this happens. Worker ants gush from the nest entrance and mill around. Winged males and queens climb up on grass stalks, trees, or anything tall in the area.
In many species, the winged queens and males fly to meet with males and queens of the same species of ant from other nests. They enter what is called a mating swarm, a swirling cloud of flying and mating insects.
After mating, the males drop to the ground and soon die. The new queens, the ones that escape being eaten that is, also drop to the ground. The queens quickly pull off their wings by rubbing them between the back of their body and their hind legs, twisting and tugging. Once the wings are off, they quickly hide themselves. Ground-nesting ant queens tunnel into the soil while other types of queens may slip into cracks in the bark of logs or creep under nearby rocks. There a queen makes a safe chamber to start her new colony.
You can tell she’s a queen because of the scars on her trunk (middle section) where her wings were.
The queen will lay eggs that develop into tiny worker ants, and a new colony is born.
Have you ever seen swarming ants?
The theme today for Life Photo Meme at Adventures of a Free Range Urban Primate blog is “reproduction.”
Have you heard the buzz about the fungus-gardening ant, Mycocepurus smithii? Apparently the queens can crank out workers and new queens without fertilization of the eggs. Genetic studies have shown the workers to be clones of their queen mother. No males have ever been found in nature, and laboratory colonies can’t be induced to make males either. Although in haplodiploid species males are usually generated without fertilization, this may be the first case of female ants being produced this way.
Parthenogenesis is the development of individuals from an egg that has not been fertilized. Although more commonly known from aphids, a number of species of Hymenoptera are parthenogenetic as well. Recent studies have shown in some of these cases the absence of males is due to infection by a bacteria, such as Wolbachia. The ant researchers indicate that bacterial infection isn’t the case in Mycocepurus smithii.
The consequences of asexual reproduction in these fungus-gardening ants are still under debate. Scientist Anna Himler has already suggested that there is a link between the ants and the fungus that grows in their gardens, because the fungus also reproduces asexually. We will probably hear more as these ants will certainly be given closer scrutiny.
Photographer: April Nobile/antweb.org from Wikimedia Commons
No sex in fungus-farming ants or their crops
Anna G. Himler, Eric J. Caldera, Boris C. Baer, Hermógenes Fernández-Marín and Ulrich G. Mueller
Proceedings of the Royal Society B
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 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,
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.
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.
References:
Bruno Gobin (2005) Larval begging for food enhances reproductive options in the ponerine ant Gnamptogenys striatula. Animal Behaviour vol 69: 293-299
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.
