Posts about ants

Insect Architecture

In this webcast The Brain Scoop takes an interesting look at the homes of eusocial animals and other insects. The video includes many interesting details including that adult weaver ants can’t produce the silk used to weave leaves together so they pick up their larva and use them like a glue stick.

Related: For Many Crops Ants Can Provide Pest Protection Superior or Equal to Chemicals at a Much Lower CostWhy Don’t All Ant Species Replace Queens in the Colony, Since Some DoSymbiotic relationship between ants and bacteriaHuge Termite Mound in Nigeria

In Many Crops Ants Can Provide Pest Protection Superior or Equal to Chemicals at a Much Lower Cost

Ants are as Effective as pesticides

The review [of over 70 studies] was conducted by Aarhus University’s Dr Joachim Offenberg, an ecologist who has studied ants for almost 20 years. It includes studies of more than 50 pest species on nine crops across eight countries in Africa, South-East Asia and Australia.

Most of the studies in Offenberg’s review are on weaver ants (Oecophylla), a tropical species which lives in trees and weaves ball-shaped nests from leaves. Because weaver ants live in their host trees’ canopy, near the flowers and fruit that need protection from pests, they are good pest controllers in tropical orchards.

All farmers need to do is collect ant nests from the wild, hang them in plastic bags among their tree crops and feed them a sugar solution while they build their new nests. Once a colony is established, farmers then connect the trees that are part of the colony with aerial ‘ant walkways’ made from string or lianas.

After that, the ants need little, except for some water in the dry season (which can be provided by hanging old plastic bottles among the trees), pruning trees that belong to different colonies so that the ants do not fight, and avoiding insecticide sprays.

The review shows that crops such as cashew and mango can be exceptionally well protected from pests by weaver ants.

One three-year study in Australia recorded cashew yields 49% higher in plots patrolled by ants compared with those protected by chemicals. Nut quality was higher too, so net income was 71% higher with ants than with chemicals.

Similar studies in Australian mango crops found that ants could produce the same yield as chemical control, but because the ants were cheaper, and fruit quality better, net income from mangoes produced with ant protection was 73% higher.

Those crops are special cases in which the ants are vastly superior. But in many other cases ants are as effective and much cheaper than chemical options. Different species of ants are suited to protecting different types of drops. Weaver ants require a canopy, other ants can protect crops without a canopy.

I hope more farmers adopt ants to help protect their crop yields.

Related: Pigs Instead of PesticidesWhy Don’t All Ant Species Replace Queens in the Colony, Since Some DoHow To Make Your Own Pesticide with Ingredients from Your KitchenAnother Bee Study Finds CCD is Likely Due to Combination of Factors Including Pesticides (2013)

Why Don’t All Ant Species Replace Queens in the Colony, Since Some Do

My response to: There are other species of ants that do replace the queen, so why did some species not do this?

Basically the method they evolved copes well with losing the queen. Out of various ways of dealing with having a dominant Queen some may lead to replacement if she dies.

There are lots of examples of method is very effective at creating lots of successful offspring but happens to be less than ideal in some situations. Natural selection is pretty amazing and awesome at creating effective genes but we certainly can look at the results sometimes and see improvements that would be useful.

Likely if losing the queen was very common a good way of dealing with that would be found (or that species would be disadvantaged and at risk). If the queen happens to evolve to being very reliable coping with her death becomes less important. If they produce lots of useful offspring but have a less than ideal method of coping with their home colony losing her it is entirely sensible to imagine that species could flourish.

I would imagine species with queens that had shorter lifespans, that invested more in the home colony, that were less effective at setting up new colonies… would be more likely to have better queen replacement strategies/results.

Related: Ants, Ants, AntsE.O. Wilson: Lord of the AntsAmazonian Ant Species is All Female, Reproduces By CloningRoyal Ant GenesHuge Ant Nest

Evolution of Altruism in Robots

The webcast explores robots evolving cooperative behavior. A Quantitative Test of Hamilton’s Rule for the Evolution of Altruism (open access paper)

One of the enduring puzzles in biology and the social sciences is the origin and persistence of altruism, whereby a behavior benefiting another individual incurs a direct cost for the individual performing the altruistic action. This apparent paradox was resolved by Hamilton’s theory, known as kin selection, which states that individuals can transmit copies of their own genes not only directly through their own reproduction but also indirectly by favoring the reproduction of kin, such as siblings or cousins. While many studies have provided qualitative support for kin selection theory, quantitative tests have not yet been possible due to the difficulty of quantifying the costs and benefits of helping acts. In this study, we conduct simulations with the help of a simulated system of foraging robots to manipulate the costs and benefits of altruism and determine the conditions under which altruism evolves.

By conducting experimental evolution over hundreds of generations of selection in populations with different costs and benefits of altruistic behavior, we show that kin selection theory always accurately predicts the minimum relatedness necessary for altruism to evolve. This high accuracy is remarkable given the presence of pleiotropic and epistatic effects, as well as mutations with strong effects on behavior and fitness. In addition to providing a quantitative test of kin selection theory in a system with a complex mapping between genotype and phenotype, this study reveals that a fundamental principle of natural selection also applies to synthetic organisms when these have heritable properties.

Related: Robots That Start as Babies Master Walking Faster Than Those That Start as AdultsFriday Fun: Robocup 2010, Robot FootballToyota Develops Thought-controlled Wheelchair
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Ants, Ants, Ants

Ants really are amazing. The internet makes it easy to learn about these creatures. My Dad found them fascinating and I picked up that view. I had a flying one, flying around my house yesterday.


“Ants: The Invisible Majority” including Dr. Brian Fisher, chairman of the Department of Entomology at the Cal Academy of Sciences looking for ants in San Francisco. He created AntWeb, an online resource. The video discusses the Argentine Ant super colonies.

Related: Ants Counting Their StepsE.O. Wilson: Lord of the AntsSymbiotic relationship between ants and bacteria

Fungus-gardening Ant Species Has Given Up Sex Completely

The complete asexuality of a widespread fungus-gardening ant, the only ant species in the world known to have dispensed with males entirely, has been confirmed by a team of Texas and Brazilian researchers.

photo of christian rabeling excavating ants in BrazilGraduate student Christian Rabeling excavating fungus-farming ant nests in Brasilia.

Most social insects—the wasps, ants and bees—are relatively used to daily life without males. Their colonies are well run by swarms of sterile sisters lorded over by an egg-laying queen. But, eventually, all social insect species have the ability to produce a crop of males who go forth in the world to fertilize new queens and propagate.

Queens of the ant Mycocepurus smithii reproduce without fertilization and males appear to be completely absent, report Christian Rabeling, Ulrich Mueller and their Brazilian colleagues in open access journal PLoS ONE this week.

“Animals that are completely asexual are relatively rare, which makes this is a very interesting ant,” says Rabeling, an ecology, evolution and behavior graduate student at The University of Texas at Austin. “Asexual species don’t mix their genes through recombination, so you expect harmful mutations to accumulate over time and for the species to go extinct more quickly than others. They don’t generally persist for very long over evolutionary time.”

Previous studies of the ants from Puerto Rico and Panama have pointed toward the ants being completely asexual. One study in particular, by Mueller and former graduate student Anna Himler (now at Arizona State University), showed that the ants reproduced in the lab without males, and that no amount of stress induced the production of males.

Scientists believed that specimens of male ants previously collected in Brazil in the 1960s could be males of M. smithii. If males of the species existed, it would suggest that—at least from time to time—the ants reproduce sexually.

Rabeling analyzed the males in question and discovered that they belonged to another closely related (sexually reproducing) species of fungus-farmer, Mycocepurus obsoletus, thus establishing that no males are known to exist for M. smithii. He also dissected reproducing M. smithii queens from Brazil and found that their sperm storage organs were empty.

Taken together with the previous studies of the ants, Rabeling and his colleagues have concluded that the species is very likely to be totally asexual across its entire range, from Northern Mexico through Central America to Brazil, including some Caribbean islands.

As for the age of the species, the scientists estimate the ants could have first evolved within the last one to two million years, a very young species given that the fungus-farming ants evolved 50 million years ago.

Rabeling says he is using genetic markers to study the evolution and systematics of the fungus-gardening ants and this will help determine the date of the appearance and genetic mechanism of asexual reproduction more precisely in the near future.

Full press release

Related: Bdelloid Rotifers Abandoned Sex 100 Million Years AgoAmazonian Ant Species is All Female, Reproduces By CloningFemale Sharks Can Reproduce AsexualityAmazon Molly Fish are All Female

Ants Counting Their Step

Ants That Count!

Most ants get around by leaving smell trails on the forest floor that show other ants how to get home or to food. They squeeze the glands that cover their bodies; those glands release a scent, and the scents in combination create trails the other ants can follow.

That works in the forest, but it doesn’t work in a desert. Deserts are sandy and when the wind blows, smells scatter.

It’s already known that ants use celestial clues to establish the general direction home, but how do they know exactly the number of steps to take that will lead them right to the entrance of their nest?

Wolf and Whittlinger trained a bunch of ants to walk across a patch of desert to some food. When the ants began eating, the scientists trapped them and divided them into three groups. They left the first group alone. With the second group, they used superglue to attach pre-cut pig bristles to each of their six legs, essentially putting them on stilts.

The regular ants walked right to the nest and went inside. The ants on stilts walked right past the nest, stopped and looked around for their home…

I posted about this back in 2006: Ants on Stilts for Science, but the webcast by NPR is worth a new post.

Related: E.O. Wilson: Lord of the AntsHuge Ant Nestposts showing the scientific method of learning in action

Ant mega-colony

Ant mega-colony takes over world

Argentine ants living in vast numbers across Europe, the US and Japan belong to the same interrelated colony, and will refuse to fight one another. The colony may be the largest of its type ever known for any insect species, and could rival humans in the scale of its world domination.

In Europe, one vast colony of Argentine ants is thought to stretch for 6,000km (3,700 miles) along the Mediterranean coast, while another in the US, known as the ‘Californian large’, extends over 900km (560 miles) along the coast of California. A third huge colony exists on the west coast of Japan.

While ants are usually highly territorial, those living within each super-colony are tolerant of one another, even if they live tens or hundreds of kilometres apart. Each super-colony, however, was thought to be quite distinct. But it now appears that billions of Argentine ants around the world all actually belong to one single global mega-colony.

The team selected wild ants from the main European super-colony, from another smaller one called the Catalonian super-colony which lives on the Iberian coast, the Californian super-colony and from the super-colony in west Japan, as well as another in Kobe, Japan.

Ants from the smaller super-colonies were always aggressive to one another. So ants from the west coast of Japan fought their rivals from Kobe, while ants from the European super-colony didn’t get on with those from the Iberian colony.

But whenever ants from the main European and Californian super-colonies and those from the largest colony in Japan came into contact, they acted as if they were old friends.

Related: posts on antsE.O. Wilson: Lord of the AntsHuge Ant Nest

Amazonian Ant Species is All Female, Reproduces By Cloning

Ants inhabit ‘world without sex’

The ants reproduce via cloning – the queen ants copy themselves to produce genetically identical daughters. This species – the first ever to be shown to reproduce entirely without sex – cultivates a garden of fungus, which also reproduces asexually.

Dr Himler’s interest in Mycocepurus smithii was originally sparked not by their unusually biased sex ratio, but by their ability to cultivate crops. “Ants discovered farming long before we did – they have been cultivating fungus gardens for an estimated 80 million years.

“They collect plant material, insect faeces and even dead insects from the forest floor and feed it to their crops,” she said.

Related: Royal Ant GenesBdelloid Rotifers Abandoned Sex 100 Million Years AgoBlind “Ant From Mars” Found in AmazonAmazon Molly Fish are All Female

E.O. Wilson: Lord of the Ants

This is a great webcast on E.O Wilson‘s career studying ants and animal behavior from NOVA.

Not only is the scientific knowledge very interesting it again shows that challenging conventional wisdom, while part of the scientific method, does not mean it is an easy process for those pioneers. From his web site:

In 1971 Wilson published his second major synthesis, The Insect Societies, which formulated the existing knowledge of the behavior of ants, social bees, social wasps, and termites, on a foundation of population biology. In it he introduced the concept of a new discipline of sociobiology, the systematic study of the biological basis of social behavior in all kinds of organisms. In 1975 he published Sociobiology: The New Synthesis, which extended the subject to vertebrates and united it more closely to evolutionary biology. The foundational discoveries of sociobiology are generally recognized to be the analysis of animal communication and division of labor, in which Wilson played a principal role, and the genetic theory of the origin of social behavior, which he helped to promote and apply in his 1971 and 1975 syntheses. Sociobiology: The New Synthesis was later ranked in a poll of the officers and fellows of the international Animal Behaviour Society as the most important book on animal behavior of all time, and is regarded today as the founding text of sociobiology and its offshoot, evolutionary psychology.

Related: Journey to the Ants: A Story of Scientific Exploration
by Bert H̦lldobler and Edward O. Wilson РHuge Ant NestSymbiotic relationship between ants and bacteriaRoyal Ant Genesposts on antsEncyclopedia of Life

Ancient Ants

Blind “Ant From Mars” Found in Amazon

An ant so unlike all other living ants that it was given an extraterrestrial name has been discovered in the Amazon rain forest, biologists announced today. The tiny new species is the only known surviving member of an ant lineage that separated from the main family more than a hundred million years ago, DNA analysis revealed.

The pale, eyeless ant appears to be adapted to living underground, possibly surfacing at night to forage. Its long mandibles suggest that the 0.08-inch-long (2-millimeter-long) animal is a predator, most likely of soft-bodied creatures such as termite larvae.

Christian Rabeling, a graduate student at the University of Texas in Austin, found a single specimen of the new species, thought to be a worker ant, in tropical soils near Manaus, Brazil. Rabeling’s team named the new creature Martialis heureka—”Martialis” means “of Mars

The new species’ genes suggest that it broke away from the main ant family before the origin of all other living ant groups, which include 20 subfamilies that together contain more than 12,000 species.

Related: New Ant Species Discovered in the Amazon Likely Represents Oldest Living Lineage of AntsSwimming AntsSymbiotic relationship between ants and bacteria

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