A Dive Into Homeostasis

Homeostasis is the subject, and under review here is an enormous piece of work, published by Frontiers in Physiology by George E. Billman. He credits pioneers Claude Bernard and Walter Cannon with spreading the notion that “the health and vitality of the organism can be said to be the end result of homeostatic regulation,” and also the concept that a physician’s role is to “clear the path so that nature could take its course.”

Billman wrote,

[H]omeostatic regulation is not merely the product of a single negative feedback cycle but reflects the complex interaction of multiple feedback systems that can be modified by higher control centers. This hierarchical control and feedback redundancy results in a finer level of control and a greater flexibility that enables the organism to adapt to changing environmental conditions.

Regulation is an interesting word, because rather than rolling up on a problem with heavy artillery, it suggests more of an incremental approach. One regulates a thermostat, or a carburetor. In order for this to be effective, the parts and the system have to work together as a complex and multifactorial community.

Homeostasis, then, is the tendency of a system to maintain an internal stability as the result of the coordinated response of its parts to any situation or stimulus that disturbs normal conditions or function.

As previously noted, Cannon specified that homeostasis does not mean immobility, but “a condition which may vary, but is relatively constant.” Various things are going on at three different levels:

— physiochemical processes, the organ and tissue functions, the component parts upon which homeostasis acts.
— autonomous (self) regulation… [C]hanges in a given variable are sensed and adjustments of the first level processes are initiated…
— central command and control centers (central nervous system) that process the information transmitted from the second level and integrates it with information from other sensory inputs to coordinate the physiological and behavioral response to changing environmental conditions.

The higher centers can intervene either consciously or unconsciously, but only — and this is vital — if the first and second levels are working properly. For good or ill, there are also higher levels of control outside the organism. The body can signal urgently that it needs water, and the conscious mind may concur, but the reality of the situation, e.g. being lost in a desert, will win.

Another outside control mechanism might be a medical care system that cannot or will not take the appropriate measures. In his Summary, Billman reaffirms that disease is caused by disruption of the homeostatic mechanisms, and “effective therapy must be directed toward re-establishing these homeostatic conditions, working with rather than against nature.”

J. S. Turner in 2017 suggested “dynamic disequilibrium” as a fitting description of homeostasis, and went so far as to say “homeostasis is life’s fundamental property, what distinguishes it from non-life. In short, homeostasis is life.”

Your responses and feedback are welcome!

Source: “Homeostasis: The Underappreciated and Far Too Often Ignored Central Organizing Principle of Physiology,” Frontiersin.org/articles, 03/10/20
Image by Pat Hartman

Do Animals Have Things Figured Out? Continued

The topic continues to be thatch ants who, as we have seen, build enormous domiciles for themselves and their friends. The top part of the abode is a mound secured with dried plant matter, and the living quarters extend into underground tunnels and rooms. All the babies are kept in the central brood chamber. The sun warms the upper part of the home, while underneath, the decay of organic material generates heat. The ants forage for food at ground level, and also high up in trees.

If nearby plants try to encroach and grab too much territory, the ants poison them. An impressive thatch ant colony in Oregon consisted of 210 nests, covering four hectares (almost 10 acres or 48,000 square yards) of ground, and inhabited by probably 56 million individuals. Under normal circumstances, the acute, immediate stress of a predatory incursion rouses the worker ants to mount a vigorous defense of the colony. Against bird, bear, or whoever bothers them, they stand their ground.

If humans poke around, the ants will directly attack:

When a colony was disturbed the surface of the mound was soon covered with workers. Many assumed the defensive position: head up and mandibles widely spread; gaster turned forward under the thorax and ready to spray formic acid into any wound made by the mandibles. Many workers started spraying at the beginning of the disturbance and soon there was an invisible cloud of formic acid vapor above the nest that was irritating to human eyes and noses. The bites of the workers were also annoying.

But priorities can change. Three months after a wildfire had devastated an area, researchers studied thatch ant colonies that had suffered the loss of food sources and beneficent foliage cover, along with massive damage to the aboveground parts of their dwellings:

Many ants were directly killed by the fire […] but some ants survived in underground portions of the nest. We show that the behavioral fight-or-flight response of ants is altered…

After the fire, and after many weeks of living in an atmosphere of chronic stress, the ants manifested an altered response to events that caused acute stress. They became much more likely to flee from aggression, and much less inclined to fight. Their reaction proposes a big, intriguing question.

Could this response also serve a positive purpose? After all, thatch ants have elegantly dealt with so many other issues. Maybe the apparent discouragement is a necessary phase that gives the community a chance to pause, process the current reality, and form a consensus for change. Maybe this is nature’s way of telling them to get out of there and establish a new colony. Basically, we don’t really know what’s going on with them, except that they have been working on their game plans for millennia.

Are animals competent?

An animal will sometimes respond to a threat by doing essentially nothing; grass-picking or some other action that humans call displacement behavior, and regard as a substitute for action they consider more correct. Human observers give the animals a failing grade because they don’t engage in combat or run away, or whatever we have decided they should properly do.

Can we justify labeling the actions as inappropriate, when it might be that we simply don’t understand? In the face of horrendous threats, many animals comport themselves quite capably. Maybe they know exactly what they are doing when they pick at grass, too, or engage in some other action that seems random, out of context or incorrect to us. As oblivious bipeds who don’t know enough to flee from a tsunami, are we really authorized to make rulings about acceptable, effective threat responses?

Everything that behavioralists believe about human drives, and the human tendency to practice displacement activities, may be perfectly valid. Still, it seems rather unfair to take these judgment errors and lay them at the door of animals, who generally seem to have a pretty good handle on things.

Your responses and feedback are welcome!

Source: “Formica obscuripes,” AntWiki.org, undated
Source: “Climate change and wildfire-induced alteration of fight-or-flight behavior,” ScienceDirect.com, July 2021
Image by Upupa4me/CC BY-SA 2.0

Do Animals Have Things Figured Out?

Various creatures, confronted with approaching natural disaster, are able to satisfy their basic, innate drive to survive such catastrophes. Many species have developed effective ways to deal with hurricanes, floods, wildfires, and tornadoes. Wolf experts say,

When wolves first smell smoke, they’ll gather together. They’ll howl for each other to locate every member of the pack, and then they’ll stay close to each other in order to protect each other. They’ll patrol their territory to figure out where the threat of fire is coming from.

In the land bordering the Indian Ocean, prior to an underwater earthquake, elephants and flamingos fled for higher ground. In Thailand, a herd of buffalo near the beach pricked up their ears, looked out to sea, and then stampeded to the top of a hill. Cows, goats, cats, and birds also knew, somehow, to move inland.

Even in 373 BC, Thucydides reported that rats, dogs, weasels, and snakes deserted the city of Helice days before a huge earthquake. In 1805 in Italy, sheep, dogs and geese knew something was up, shortly pre-earthquake. Toads deserted their mating grounds. In Sicily, goats knew to flee the area in advance of a violent volcanic eruption, and just before the 1906 San Francisco quake, horses ran away.

In China, a quake alert system depends on snakes, who will move out of their nests even when the cold would normally encourage them to stay in their cozy homes. In 2014, birds in the Cumberland Mountains of Tennessee abandoned their breeding ground just before 80 tornadoes hit the area. A large French project studies migratory birds who avoid storms over the Pacific.

Even bugs have agendas

When a fire sweeps through an area, some insects rush to arrive on the scene while the trees are still actively burning. Are they nuts, reacting to a threat in such an inappropriate, out-of-contest manner? Absolutely not, because the best place to lay their eggs is in freshly burned wood, so they exploit and capitalize on the devastation by crowding out competitors for the enviable nursery spots, which works out splendidly for them.

Consider the lowly thatch ant (or thatching ant), Formica obscuripes. When starting a new colony, they will claim an open area of ground and establish, under a piece of wood or a stone, a nest that then grows both upward and downward. They build a mound from plant debris, and are very adaptable in the materials they use and how big they decide to make the mounds. They are also gangster enough to take over others’ territory:

These ants are temporary social parasites of Formica fusca-group species, including Formica pacifica. New colonies are established when an inseminated F. obscuripes queen enters the nest of a Formica fusca-group species and is accepted by the host workers. The host queen is eventually killed or driven off, and the host workers raise the brood of the invading queen. Eventually, only F. obscuripes workers remain as the original host workers die off.

But rather than repelling all visitors, they will also, for reasons best known to themselves, accept different kinds of insects as housemates — probably because the guests perform useful functions for the community that humans do not completely understand.

(To be continued…)

Your responses and feedback are welcome!

Source: “What does wildlife do during natural disasters?,” WolfCenter.org, 03/17/21
Source: “The animals that detect disasters,” BBC.com, 02/02/22
Source: “The attraction of insects to forest fires,” Frames.gov, 1972
Source: “Formica obscuripes,” AntWiki.org, undated
Image by Shan Sheehan/CC BY-ND 2.0