The coming and goings of ants, how are social skills shaped in a changing world

Survival of the nicest: Have we got evolution the wrong way round? A reply to Silvertown’s Comment on Evolution of the Nicest

The author could have discussed how amorality in most of the natural world doesn’t apply to humans. Similarly to other organisms, our evolutionary heritage makes us social, but whether that sociality is ‘good’ or ‘bad’ is a moral, not a scientific, question. This distinction from the other cooperative processes that Silvertown outlines could have been explained better.

Silvertown used examples from nature to show that cooperation is common in nature. For instance, bacteria called rhizobia thrive in the root nodules of legumes — and turn nitrogen from the air into a soluble form that the plants can use. Some beetles cooperate to bury animal corpses that would be too large for any single insect to manage alone, both reducing the risk of other animals stealing food and providing a nest for beetle families to live in.

And many bacteria indicate their presence to each other using a chemical-signalling system called quorum sensing, which is active only when members of the same species are tightly packed together. This allows each cell to adjust its gene expression in a way that benefits the individuals in the group — to release a poison to kill other species, for instance, when enough bacteria are clustered together to mount a decent attack.

Source: Survival of the nicest: have we got evolution the wrong way round?

Piracy and the Biology of Lyman-alpha: A Brief History of Mutualism and Parasitosis in the Early 1900’s

According to Silvertown, eighteenth-century piracy is an example of effective cooperation. Pirates worked together on their ships, and used violence more often against outsiders than as an internal mechanism for law enforcement.

Take lichens, for instance — ‘composite organisms’ in which an alga or cyanobacterium lives within a fungus. Simon Schwendener argued that a lichen is a parasites and that it forced its slaves into its service. One way to see the relationship is that the two organisms are dependent on one another and grow better together than they would on their own. There is not a clear cut line between mutualism and parasitism. It is a matter of perspective.

Similarly hazy boundaries are found in the biology of our own cells. The first structures that generate energy were created by the cells more than a billion years ago. Today’s organisms rely on the function of the Mitochondria in their cells. The cells of the parasites could be considered slaves. Or maybe they are adopted family members.

What does ecology tell us about interactions in the natural world? – Slave Gordon’s comment on “Adiabatic ants and anant colonies in their natural environment”

Gordon argues that the nature of the environment and the resources it provides determine the types of collective-foraging mechanism that evolve — not just for ants, but for all social organisms. She thinks that the extent to which ecology drives social behavior has been overlooked.

It is a reflection of the human tendency to apply human moral frameworks to biological phenomena. The use of emotionally charged words such as ‘slave’ and ‘adopted’ takes us away from rigorous science and leads us to see biological interactions as ‘good’ or ‘bad’, rather than as the morally agnostic, transactional processes that they truly are.

Current and deep problems regarding the anthropomizing of biological processes. It is easy to make false pretenses in the natural world, like saying that an ant is acting for the good of its colony, or that aviruses wants to be transmitted. I would have liked to hear Silvertown’s views on the category error. I felt that he might have made his understanding more explicit in some places. Instead, he sometimes sacrifices that carefulness for unnecessary jokes, noting, for instance, that bacteria “are essentially singletons who like to party”.

I think the confusion arises because Gordon conflates proximate (mechanistic) and ultimate (evolutionary) processes. Her book sheds light on the processes that regulate collective behavior on a day-to- day basis, as well as how the environment affects that behavior. I think that the interactions between organisms and their environments have become more overlooked, because fewer people are researching animals in their natural environments. But these insights are not at odds with the prevailing theory of how collective behaviours evolve.

But I am less convinced by Gordon’s suggestion that her ideas are at odds with the ‘prevailing theory’ for social behaviour. Inclusive fitness theory — an idea put forward by UK evolutionary biologist William Hamilton in 1964, and accepted widely in the field — suggests that social behaviours evolve when the benefits of cooperating with relatives exceed the costs (W. D. Hamilton J. Theor. Biol. 7, 1–16; 1964). strong experimental and theoretical evidence supported Hamilton’s ideas, which was derived from his observations of birds and insects in their natural habitats.

Gordon has spent decades studying the natural history of two ant species that live in very different environments, paying acute attention to how the insects’ stirring, dynamic habitats shape their behaviour. These observations form the bedrock of her book.

Both turtle ants and pochos solve problems in different ways. How they do it is dictated by their environment. Gordon borrows concepts from network science to describe how turtle ants function in modules — units in which most information flow occurs — to keep communication local, enabling them to respond rapidly to the ever-changing availability of resources. By contrast, the centralized regulation of pogos is the epitome of low modularity: the nest is the sole source of communication.

Gordon says that the answer is simple. The ants follow the easiest path, with the highest level of smell, and try to reinforce profitable routes until something tells them to stop, such as a broken branch. The ants have the ability to find the most lucrative spots and quickly adjust the flow of information in order to change their behaviour in a constantly changing environment.

Next, Gordon turns to the arboreal turtle ant, Cephalotes goniodontus, which forages in the canopies of Mexico’s dry tropical forests. Unlike the desert harvesters, turtle ants spread their brood across many nests perched in the canopy, connected by a complex net of tangling vines, shifting leaves and moving stems. Their food sources are ephemeral and foragers must exploit them.

Gordon shows that this trade-off is achieved by a slow but robust mechanism which foragers use to recruit other people to their nest. When a female returns to the nest with her bounty, she releases hydrocarbon from her outer skin to let her sisters know there is food in the desert.

A fleeting touch from a forager’s antennae sends others scuttling out of the nest. The seeds are spread on the desert floor, not in patches, and that’s good for them. Plentiful food and favourable environmental conditions — days that are not too hot, for instance — mean that many foragers return to the colony and recruit many others. Less ants come back to muster recruits in bleaker circumstances. Positive feedback regulates the behavior of thousands of ants.

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