Ant colony 'personalities' shaped by environment

[knocker]

Fascinating creatures.

 

 

Ant colonies have their own personalities, which are shaped by the environment, a US study suggests.

 

Colonies of several hundred ants show consistent differences in the way they behave, just like individual people do.

 

Certain behaviours go together - for example, a colony that explores more widely for food also tends to respond more aggressively to an intruder.

 

http://www.bbc.co.uk/news/science-environment-28658268

[pottyprof]

Fascinating creatures indeed.  I have a nest under the greenhouse and they've removed sand and cement from under the slabs the greenhouse sits on.  Amazing feat given their size.  I encourage them to nest in the composter too as they make beautiful seed compost.

 

This year was the first time I've seen them carry a new queen back to the nest after the annual deluge of flying ants.  Amazing...

[knocker]

Indeed pp amazing hardly covers it. Take the fungus growers. It's difficult to believe what they get up to and the organisation that it all entails. A brief extract from Holldobler and Wilson's definitive book, The Ants

 

The Fungus Growers

 

Members of the myrmicine tribe Attini share with macrotermitine termites and certain wood-boring beetles the sophisticated habit of culturing and eating fungi. The Attini are a morphologically distinctive group limited to the New World, and most of the 12 genera and 190 species occur in the tropical portions of Mexico and Central and South America. Besides their unique behavior and the many peculiar behavioral and physiological changes associated with it, the Attini are distinguished from other ants by an unusual combination of anatomical traits, including the shape of the antenna! segments; a less-than-absolute tendency toward hard, spinose, or tuberculate bodies; and a proportionately large, casement-like first gastral segment.

 

It is conceivable that fungus growing originated only once in a single ancestral attine living in South America during that continent's long period of geological isolation from late Mesozoic times to approximately 4 million years ago. Exactly when the event occurred is open to conjecture, but it was almost certainly prior to the Miocene Epoch. Extinct but modern-looking species of Trachymyrmex (Baroni Urbani, 1980) and Cyphomyrmex (Wilson, 1985h) have been found in Dominican amber, which is believed to date from either late Oligocene or early Miocene.

 

In Africa, southern Asia, and other parts of the Old World tropics, the Attini are replaced by fungus-growing termites (Macrotermitinae), which in their turn do not occur in the New World. No one can be sure whether this complementary global pattern is due to a mutual preemption involving competitive exclusion of one group by another or whether it is simply one more accidental outcome reflecting the extreme rarity of the evolutionary origin of fungus gardening. The latter possibility is more likely to be the case, which means that if attines were to be introduced today into the range of the macrotermitines, or vice versa, the two kinds of insects could coexist with little interference. This is possible because attines utilize insect excrement and fresh plant material for the most part, whereas the macrotermitines use dead plant material. Also, fungus-growing ants forage above ground, often even in trees; fungus-growing termites are primarily subterranean.

 

The Attini, where they exist, are an enormously successful group. One species, Trachymyrmex septentrionalis, ranges north to the pine barrens of New Jersey, while in the opposite direction several species of Acromyrmex penetrate to the cold temperate deserts of central Argentina. In the vast subtropical and tropical zones in between, attines are among the dominant ants. Many of the species gather pieces of fresh leaves and flowers to nourish the fungus gardens, and Atta and Acromyrmex rely on this source exlusively, since they attack most kinds of vegetation, including crop plants, they are serious economic pests. The species of Atta in particular  are among the scourges of tropical agriculture. They are familiar to local imhabitants as the wiwi in Nicaragua and Belize, the bibijagua in Cuba, the hormiga arriera in Mexico, the bachac in Trinidad, the bachaco in Venezuela, the sauva in Brazil, the cushi in Guyana, the coqui in Peru, and the leafcutting or parasol ant in most English-speaking countries, the last name alluding to the fact that an Atta worker holding a leaf fragment over her head gives the impression that she is carrying a parasol: The problems of agriculture in Atta country have been humorously epitomized in the following anecdote by V. Wolfgang von Hagen (1939), in connection with his attempt to grow a vegetable garden in Belize:

 

My Indian servants, dusky, kinky-haired Miskito men, lamented all

this work. It was useless, quoth a toothless elder, to plant anything

but bananas or manioc, as the Wiwis were sure to cut off all the leaves.,

Without the slightest encouragement the Miskito Indians would

launch forth on the tales of the ravages of the Wiwi  Laca  , but un

swayed by the illustrations, like Pangloss I could only remark that all

this was very well but let us cultivate our garden . In two weeks the

carrots, the cabbages, the turnips were doing well. The carrots had

unfurled their fernlike tops, the cabbage grew as if by magic. From

our small palm-thatched house my wife and I cast admiring eyes over

our jungle garden. Our minds called forth dishes of steaming vege

tables to replace dehydrated greens and the inevitable beans and

yucca. Even the toothless Miskito elder came by and admitted that

white man's energy had overcome the lethargy of the Indian. Then

the catastrophe fell upon us. We arose one morning and found our

garden defoliated: every cabbage leaf was stripped, the naked stem

was the only thing above the ground. Of the  carrots nothing was

seen. In the center of the garden, rising a foot in height, was a conical

peak of earth, and about it were dry bits of earth, freshly excavated.

Into a hole in the mound, ants, moving in quickened step, were car

rying bits of our cabbage, tops of the carrots, the beans-in fact our

entire garden was going down that hole. I could see the grinning face

of the toothless Miskito Indian. The Wiwis had come

 

The leafcutting ants of the genera Atta and Acromyrmex were preadapted for their role as agricultural pests by their abilty to use many plant species with the aid of their symbiotic fungi. which serve as a sort of ancillary digestive system. The ants also build up high population densities, such as 5 colonies per hectare in Atta vollenweideri and 28 per hectare in Atta capiguara, with each colony containing a million or more workers (Fowler et al., 1986a,b).

 

There is much more of course.

 

An article from Science in 1966

 

 

Fungus-growing ants (Attini) are in reality unique fungus-culturing insects.There are several hundred species in some dozen genera, of which Acromyrmex and Atta are the conspicuous leaf-cutters. The center of their activities is the fungus garden, which is also the site of the queen and brood. The garden, in most species, is made from fresh green leaves or other vegetal material. The ants forage for this, forming distinct trails to the vegetation that is being harvested. The cut leaves or other substrate are brought into the nest and prepared for the fungus. Fresh leaves and flowers are cut into pieces a millimeter or two in diameter; the ants form them into a pulpy mass by pinching them with the mandibles and adding saliva. Anal droplets are deposited on the pieces, which are then forced into place in the garden. Planting of the fungus is accomplished by an ant's picking up tufts of the adjacent mycelium and dotting the surface of the new substrate with it. The combination of salivary and anal secretions, together with the constant care given by the ants, facilitates the growth of the ant fungus only, despite constant possibilities for contamination. When the ants are removed, alien fungi and other organisms flourish.

A mature nest of Atta Sexdens may consist of 2000 chambers, some temporarily empty, some with refuse, and the remainder with fungus gardens. Thousands of kilograms of fresh leaves will have been used. A young laboratory colony of Atta cephalotes will use 1 kilogram of fresh leaves for one garden. The attines are the chief agents for introducing organic matter into the soil in tropical rain forests; this matter becomes the nucleus for a host of other organisms, including nematodes and arthropods, after it is discarded by the ants.

One ant species cultures a yeast; all others grow a mycelium. In the higher species the mycelium forms clusters of inflated hyphae. Mycologists accept as valid two names for confirmed fruiting stages: Leucocoprinus ( or Leucoagaricus) gongylophora (Moeller 1893) and Lepiota n. sp.

 

http://www.sciencemag.org/content/153/3736/587.short

 

Some interesting info here with a couple of good videos.

 

http://www.antark.net/ant-species/leaf-cutter-ant-atta-cephalotes.html#.U-ipQ6Oz1X4

Edited August 11, 2014 by knocker

[knocker]

And then there are the dreaded Mymelachista schumanni.the devil's gardeners.

 

Ecology: 'Devil's gardens' bedevilled by ants

 

'Devil's gardens' are large stands of trees in the Amazonian rainforest that consist almost entirely of a single species, Duroia hirsuta ^{1, 2, 3, 4, 5}, and, according to local legend, are cultivated by an evil forest spirit. Here we show that the ant Myrmelachista schumanni, which nests in D. hirsuta stems, creates devil's gardens by poisoning all plants except its host plants with formic acid. By killing these other plants, M. schumanni provides its colonies with abundant nest sites — a long-lasting benefit as colonies can live for 800 years.

 

A synopsis of the study.

 

Ants, not evil spirits, create devil's gardens in the Amazon rainforest, study finds

http://news.stanford.edu/pr/2005/pr-devil-092805.html

Edited August 11, 2014 by knocker

[knocker]

And they are even cleverer than we thought.

 

Ants as a powerful biotic agent of olivine and plagioclase dissolution

 

Abstract

The biotic enhancement of Ca-Mg silicate weathering has helped maintain Earth's habitability over geological time scales by assisting in the gradual drawdown of atmospheric CO₂. 25 years of in-situ measurements of Ca-Mg silicate mineral dissolution by ants, termites, root mats, bare ground, and a control reveals ants to be one of the most powerful biotic weathering agents yet recognized. Six sites in Arizona and Texas (USA) indicate that eight different ant species enhance mineral dissolution by ∼50×–300× over controls. A comparison of extracted soil at a 50 cm depth in ant colonies and adjacent bare ground shows a gradual accumulation of CaCO₃ content for all eight ant species over 25 yr. Ants, thus, have potential to provide clues on how to enhance contemporary carbon sequestration efforts to transform Ca-Mg silicates and CO₂ into carbonate. Given that ants underwent a great diversification and biomass expansion over the Cenozoic, a speculative implication of this research is that ant enhancement of Ca-Mg silicate dissolution might have been an influence on Cenozoic cooling.

 

http://geology.gsapubs.org/content/early/2014/07/14/G35825.1

 

From Scientific American

Ants May Boost CO2 Absorption Enough to Slow Global Warming

 

http://www.scientificamerican.com/article/ants-may-boost-co2-absorption-enough-to-slow-global-warming/?&WT.mc_id=SA_DD_20140812

Edited August 14, 2014 by knocker

[Yarmy]

And they are even cleverer than we thought.

 

Ants as a powerful biotic agent of olivine and plagioclase dissolution

 

http://geology.gsapubs.org/content/early/2014/07/14/G35825.1

 

From Scientific American

Ants May Boost CO2 Absorption Enough to Slow Global Warming

 

http://www.scientificamerican.com/article/ants-may-boost-co2-absorption-enough-to-slow-global-warming/?&WT.mc_id=SA_DD_20140812

 

 

Jeez, maybe I need to stop executing the little buggers outside my patio doors then. 

 

Richard Feynman did some studies into ant behaviour and was even published, I believe. I can't recall the exact details, but I think he was convalescing from some illness and started to watch them on his bedroom windowsill. Anyway, there's more here:

 

http://www.mathpages.com/home/kmath320/kmath320.htm