Atta colombica queen
By Christian R. Linder - own photo, Barro Colorado Island, Panama (1999), CC BY-SA 3.0, Link
One of the 'uniquely human' abilities that creationists traditionally cite in support of their childish superstition that humans were magically created out of dirt as a species separate from other animals, is the fact that humans for the most part, indulge in agriculture - i.e., we grow plants as food - or at least other people do. Most of us in the developed economies buy their produce in shops.
a Like all their other claims of human exceptionalism, it's a nonsense fairy tale, of course. Humans have some unique characteristics that make them a distinct species, but then so does every other species, by definition. There is nothing materially different about humans that makes them subject to different laws of chemistry and physics than other species, of course.
And in respect of agriculture, we are far from unique - ants have been at it for about 66 million years - well before creationists imagine the entire Universe was magically created from nothing by a magic god made of nothing. But this is hardly surprising, since some 99.9975% of the history of life on Earth happened before creationism's legendary 'Creation Week'.
Tell me all about ants cultivating fungi, their evolution and distribution, please. Ants that cultivate fungi, particularly in the tribe Attini (attine ants), are a fascinating example of mutualism in nature. These ants have developed a highly specialized form of agriculture, cultivating specific fungi for food. Here’s an overview of their evolution, behavior, and distribution:In fact, the co-evolution and mutualism of ant and fungi is one of the more fascinating example of what evolution can produce give millions of years in which to operate.
- Evolution of Fungus Farming in Ants
Fungus farming by ants is believed to have originated about 50-60 million years ago in the Neotropics, likely after the extinction event that wiped out the dinosaurs. The ant-fungus mutualism is a co-evolutionary relationship where both organisms benefit. The ants cultivate fungi, providing them with plant material, while the fungi produce nutrient-rich structures that serve as food for the ants.
The origin of this mutualism may have arisen when early ants started feeding on decomposing plant material colonized by fungi. Over time, some species shifted from foraging to actively collecting plant material to promote fungal growth.
This farming system is often compared to human agriculture, as the ants must manage their crops, protect them from parasites, and ensure optimal growth conditions.
- Ants' Fungus Cultivation Process
- Leaf-Cutting Ants: Some of the most well-known fungus-growing ants are the leafcutter ants (Atta and Acromyrmex genera). They cut fresh leaves and other plant matter, which they bring back to the nest and chew into a paste. This plant material serves as a substrate for fungal growth.
- Nutritional Exchange: The cultivated fungi break down the plant matter, producing nutrient-rich structures called gongylidia, which the ants feed on. In return, the fungi rely on the ants for sustenance, dispersal, and protection from competing fungal species or pathogens.
- Waste Management: The ants also meticulously manage waste within the colony, removing refuse to special "dump" chambers to prevent contamination of their fungal gardens.
- Co-evolution and Mutualism
This mutualism is so tight that the ants rely on their fungi almost entirely for food. Similarly, the fungi cultivated by the ants cannot survive without their ant farmers. Many species of these fungi have lost their ability to produce spores and must be propagated vegetatively, depending on the ants for dispersal.
Ants also engage in another co-evolutionary relationship with bacteria, particularly Pseudonocardia. These bacteria grow on the ants’ bodies and produce antibiotics that protect the fungal gardens from parasitic molds like Escovopsis, a major threat to the ants' crops.
- Distribution of Fungus-Growing Ants
The distribution of fungus-growing ants is largely confined to the Neotropics, where they originated, and they are mainly found in the Americas:
- Central and South America: Leafcutter ants are especially prevalent in tropical rainforests from southern Mexico through Central America to Brazil and Argentina.
- Caribbean Islands: Certain species are also found in the Caribbean.
- Southern U.S.: Some fungus-growing ants have spread north into the southern United States (e.g., Texas).
- Types of Fungus-Growing Ants
There are over 250 species of fungus-growing ants, classified into different genera within the tribe Attini:
- Lower Attine Ants: These species cultivate fungi that grow on decomposing organic material like leaf litter, seeds, and dead wood. They are less specialized in terms of the fungal species they cultivate.
- Higher Attine Ants: This group includes the famous leafcutter ants, which are much more specialized in their choice of fungal crops, particularly basidiomycete fungi of the genus Leucoagaricus.
- Ecological Impact
Leafcutter ants, in particular, have a significant impact on their environment due to the sheer volume of plant material they harvest. They play a crucial role in the ecosystem by accelerating the decomposition of plant matter, recycling nutrients, and influencing plant community dynamics. In some tropical forests, they are major herbivores, second only to mammals in the amount of plant biomass they consume.
- Challenges and Adaptations
Fungus-growing ants face various challenges, from parasitic fungi like Escovopsis to changes in environmental conditions. They have developed advanced social behaviors and a division of labor within colonies to manage these threats, with specialized workers for foraging, gardening, waste management, and defense.
In summary, fungus-growing ants represent a remarkable example of co-evolution, with both the ants and their fungal partners having adapted to a mutualistic relationship over millions of years. Their distribution, primarily in the Americas, and their complex farming behaviors make them one of the most intriguing groups of insects in the world.
In this context, what do the terms 'higher attine' and 'lower attine' mean?
In the context of ants cultivating fungi, the terms "higher attine" and "lower attine" refer to two different evolutionary groups within the tribe Attini (fungus-growing ants), each with distinct agricultural practices and relationships with their cultivated fungi.
- Lower Attine Ants
- More ancestral group: The lower attines represent the more primitive or ancestral form of fungus farming, having evolved earlier than the higher attines.
- Generalist fungal cultivation: Lower attine ants cultivate a wide variety of fungi that are typically found growing on decaying organic material like leaf litter, seeds, or wood. The fungi they farm are saprotrophic, meaning they naturally grow on dead or decomposing plant material.
- Simpler farming system: Their farming system is less specialized, and the fungi can survive independently in the wild without ant assistance. The ants gather decaying organic material and bring it to their nests, where fungi grow on it, but they do not actively cut fresh plant material like leaf-cutter ants do.
- Smaller colonies: Lower attine ants tend to have smaller colonies and a less complex social structure than higher attines.
- Higher Attine Ants
- More derived group: The higher attine ants are a more recently evolved group. The most well-known examples of higher attines are the leaf-cutter ants (Atta and Acromyrmex), which represent the pinnacle of ant agriculture.
- Specialized fungal cultivation: Higher attine ants cultivate a very specific group of fungi, primarily species from the genus Leucoagaricus (previously Leucocoprinus). These fungi are highly specialized and dependent on the ants for survival. Unlike lower attine fungi, these cultivated fungi cannot grow independently in the wild.
- Leaf-cutting behavior: Leaf-cutter ants are known for cutting fresh leaves and other plant material, which they use as substrate for their fungus gardens. The ants don't eat the leaves directly but feed on specialized structures (gongylidia) produced by the cultivated fungi.
- Larger, more complex colonies: Higher attine ants, especially the leaf-cutter ants, have much larger colonies with complex social organization. They have developed highly efficient agricultural practices, including waste management and pest control (such as using antibiotic-producing bacteria to protect their fungal crops).
Key Differences Between Higher and Lower Attine Ants
- Fungal specialization: Higher attines farm a specific type of fungus that depends on them, while lower attines farm more generalist fungi that can survive without the ants.
- Cultivation substrates: Higher attines actively gather fresh plant material (especially leaf-cutter ants), whereas lower attines use decomposing organic matter.
- Colony size and complexity: Higher attines have larger, more socially complex colonies, while lower attines have smaller, simpler colonies.
In evolutionary terms, the shift from lower to higher attine farming represents a transition from opportunistic fungus growing (relying on wild fungi) to a more advanced and interdependent agricultural system where ants cultivate specialized fungi that cannot survive without them.
The queen and workers of the leaf-cutting fungus-farming ant species Atta cephalotes, collected in Panama, on their higher-agriculture fungus garden.
Karolyn Darrow
Ant Agriculture Began 66 Million Years Ago in the Aftermath of the Asteroid That Doomed the Dinosaurs
Smithsonian Scientists Assembled and Analyzed Sprawling Genetic Database, Finding Some Fungal Crops Later Became Completely Reliant on Ants 27 Million Years Ago
When humans began farming crops thousands of years ago, agriculture had already been around for millions of years. In fact, several animal lineages have been growing their own food since long before humans evolved as a species.
According to a new study, colonies of ants began farming fungi when an asteroid struck Earth 66 million years ago. This impact caused a global mass extinction but also created ideal conditions for fungi to thrive. Innovative ants began cultivating the fungi, creating an evolutionary partnership that became even more tightly intertwined 27 million years ago and continues to this day.
In a paper published today, Oct. 3, in the journal Science, scientists at the Smithsonian’s National Museum of Natural History analyzed genetic data from hundreds of species of fungi and ants to craft detailed evolutionary trees. Comparing these trees allowed the researchers to create an evolutionary timeline of ant agriculture and pinpoint when ants first began cultivating fungi.
Ants have been practicing agriculture and fungus farming for much longer than humans have existed. We could probably learn something from the agricultural success of these ants over the past 66 million years.
Ted R. Schultz, lead author.
Curator or ants
National Museum of Natural History
Smithsonian Institution, Washington, DC, USA.
Nearly 250 distinct species of ants in the Americas and Caribbean farm fungi. Researchers organize these ants into four agricultural systems based on their cultivation strategies. Leafcutter ants are among those that practice the most advanced strategy, known as higher agriculture. These ants harvest bits of fresh vegetation to provide sustenance for their fungi, which in turn grow food for the ants called gongylidia. This food helps fuel complex colonies of leaf cutter ants that can number in the millions
Schultz has spent 35 years studying the evolutionary relationship between ants and fungi. He has conducted more than 30 expeditions to locales in Central and South America to observe this interaction in the wild and has reared colonies of leafcutter and other fungus-farming ants in his lab at the museum. Over the years, Schultz and colleagues have collected thousands of genetic samples of ants and fungi from throughout the tropics.
This stockpile of samples was crucial to the new paper.
To really detect patterns and reconstruct how this association has evolved through time, you need lots of samples of ants and their fungal cultivars.
Ted R. Schultz.
The team used the samples to sequence genetic data for 475 distinct species of fungi (288 of which are cultivated by ants) and 276 distinct species of ants (208 of which cultivate fungi)—the largest genetic dataset of fungus-farming ants ever assembled. This allowed the researchers to create evolutionary trees of the two groups. Comparing wild fungal species with their cultivated relatives helped the researchers determine when ants began utilizing certain fungi.
The data revealed that ants and fungi have been intertwined for 66 million years. This is around the time when an asteroid struck Earth at the end of the Cretaceous period. This cataclysmic collision filled the atmosphere with dust and debris, which blocked out the sun and prevented photosynthesis for years. The resulting mass extinction wiped out roughly half of all plant species on Earth at the time.
However, this catastrophe was a boon for fungi. These organisms proliferated as they consumed the plentiful dead plant material littering the ground.
Extinction events can be huge disasters for most organisms, but it can actually be positive for others. At the end of Cretaceous, dinosaurs did not do very well, but fungi experienced a heyday.
Ted R. Schultz.
Many of the fungi that proliferated during this period likely feasted on decaying leaf litter, which brought them in close contact with ants. These insects harnessed the plentiful fungi for food and continued to rely on the hardy fungi as life rebounded from the extinction event.
The new work also revealed that it took nearly another 40 million years for ants to then develop higher agriculture. The researchers were able to trace the origin of this advanced practice back to around 27 million years ago. At this time, a rapidly cooling climate transformed environments around the globe. In South America, drier habitats like woody savannas and grasslands fractured large swaths of wet, tropical forests. When ants took fungi out of the wet forests and into drier areas, they isolated the fungi from their wild ancestral populations. The isolated fungi became completely reliant on ants to survive in the arid conditions, setting the course for the higher agriculture system practiced by leafcutter ants today.
In addition to Schultz, the new paper included contributions from several coauthors affiliated with the National Museum of Natural History, including Jeffrey Sosa-Calvo, Matthew Kweskin, Michael Lloyd, Ana Ješovnik and Scott E. Solomon. The study also includes authors affiliated with the University of Utah; the Royal Botanic Gardens, Kew; the University of California at Berkeley; the U.S. Department of Agriculture; São Paulo State University; the Instituto de Investigaciones Científicas y Servicios de Alta Tecnología; the Smithsonian Tropical Research Institute; the University of Copenhagen; Emory University; McMaster University; Universidade Federal de Uberlândia; Arizona State University; the University of Hohenheim; and Louisiana State University.
A yeast-farming worker of the fungus-farming ant species collected in Mindo, Ecuador, in 2011. Colonies of ants began farming fungi when an asteroid struck Earth 66 million years ago.
Alex Wild
AbstractThe massive, unnecessarily complex solution to the problem of how to supply ants with food and how to give fungi somewhere to live, betrays the fact that there was no intelligence involved in its production. However, it is exactly the sort of overly complex, Heath-Robinson solution that evolution produces repeatedly in the natural world.
Fungus-farming ants cultivate multiple lineages of fungi for food, but, because fungal cultivar relationships are largely unresolved, the history of fungus-ant coevolution remains poorly known. We designed probes targeting >2000 gene regions to generate a dated evolutionary tree for 475 fungi and combined it with a similarly generated tree for 276 ants. We found that fungus-ant agriculture originated ~66 million years ago when the end-of-Cretaceous asteroid impact temporarily interrupted photosynthesis, causing global mass extinctions but favoring the proliferation of fungi. Subsequently, ~27 million years ago, one ancestral fungal cultivar population became domesticated, i.e., obligately mutualistic, when seasonally dry habitats expanded in South America, likely isolating the cultivar population from its free-living, wet forest–dwelling conspecifics. By revealing these and other major transitions in fungus-ant coevolution, our results clarify the historical processes that shaped a model system for nonhuman agriculture.
Ted R. Schultz et al.
The coevolution of fungus-ant agriculture.
Science 386, 105-110 (2024). DOI:10.1126/science.adn7179
© 2024 American Association for the Advancement of Science.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.
Creationists will look at ant agriculture and, with the incredulity of an uneducated child, will conclude that is must have been designed by a god (who is obviously the locally popular god their mummy and daddy told them about and with whom the pastors at church on Sundays claim to have close relationship with as they wring more money out of the congregation) without once questioning why a supremely intelligent designer went to such lengths to solve relatively small problems, or why a process of gradual improvement over millions of years could not have produced the same 'design'.
So, what they will never do is understand how a similar process in principle could have led to the relationship between humans and the crop plants (and animals) we've domesticated and so to human agriculture and the products they thank their imaginary friend for before every meal.
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