Dr Irengbam Mohendra Singh
I have always maintained that animals including insects, have intelligencelike humans and not just instincts. It’s now proven true by researchers. What’s equally true is that fish and earthworms can feel pain like humans. Fish, like us, have a nervous system that includes a central brain, spinal cord and many branching nerve fibres. They also have neurones (nerve cells) called nociceptorsthat is responsible, among other things, for sensing pain. Fish produce the same opioids, a morphine-like substance as humans do, to kill pain sensations.
Earthworms also have a nervous systemincluding a tiny brain like ours. There is experimental data that if an earthworm is injured, its nervous system excretes opioids, highly suggestive of its experience of pain.
It’s debated whether or not insects feel pain. I think they do. Insects have a nervous system consisting of a nerve cord (like our spinal cord) that runs the length of the body, with several ganglia. A ganglion (singular for ganglia), is a cluster of neurones like our brain cellswith nerves stretching all the way to the extremities of the appendages (legs, eyes, antennae etc.).One has only to see howa fly goes crazy when an insecticide is spread on it as the poison acts on its nervous system.
Ants are’eusocial’, meaning, having the highest level of organisation of animal society. They obtain knowledge though their leading tutors. Ants may be the only group apart from mammals where interactive teaching (like the lioness teaching its young how to hunt) has been observed.
Ants havedivision of labour, communication between individuals, and an ability to solve complex problems. These are parallel with human societies. A recent study on Matabele antsby Dr Erik Frank,a behavioural ecologist from Julius-Maximilians University, Germany,was published in Feb 2018, in the journal, Proceedings of the Royal Society B. In three years of field experiments in the humid savannah woodland at Comoé National Park, Ivory Coast in the sub-Saharan desert, Frank and colleagues watched more than 200 Matabele ant raids from 16 Matabele ant colonies in Ivory Coast, as well as in laboratories.”The fascinating thing about ant society is that you can get very complex and sophisticated behaviour without any need of cognition or knowledge of what you are doing,” said Frank
They studied violent clashes between these ants and termites that they eat. Matabele ant colonies were found to launch their raids on termite settlements, two to four times a day, at the risk of their life and limbs.They observed how ant armies employ a system of emergency medicaltreatment to soldiers that are injured at the battlefield. They evacuate soldier colleagues that are badly injured at the battlefield for treatment in their nest. Researchers say this behaviour is the first such example discovered in the animal kingdom. It’s similar to that used my humans at the battlefield during wars.
Termites normally live in mounds. A termite mound is built below and above ground and can be as large as 12 m across, and as tall as 7 m. They are formidable architects. In human terms, they can build a skyscraper mound twice the height (555m) of BurjKhalifa (previously BurjDubai), the tallest skyscraper in the world. The structure is so built for aeration. They are made of mainly soil, sand,wood chips and other stuff, fastened with saliva of termite workers.A termite mound may have a population of one million. Matabele ants are one of the largest ants (10 -20mm long), and are widely distributed in the sub-Saharan Africa. They are strictly termite-eating. They attack termites at their feeding sites in their column-like raiding military formation. Because of their fierce battle drill they were given the common name Matabele ants after the Matabele tribe warriors (Zimbabwe), who overwhelmed other tribes in the 1800s.
Ants communicate with each other using pheromone(a chemical substance that triggers a social response in members of the same family), sound and touch. They perceive smells with their long antennae.Ant medics lick wounded soldiers at the battlefield to give first-aid.Those that are badly injured are evacuated and taken back home, where they are given treatment by other medics. Everyone is not evacuated. It depends on the severity of wounds. “This was not limited to selective rescuing of lightly injured individuals by carrying them back, butincluded a differential treatment inside the nest.”
“Other critically injured ants refused to allow themselves to be rescued in an apparent act of selfish heroism. Heavily injured ants (loss of five extremities) were not rescued or treated. This was regulated not by the helper but by the unresponsiveness of the injured,” added Frank.
An average raiding army consists of between 200 and 600 soldiers. They would march in files, on to a termite settlement, where they would do a savage battle with termites, in an attempt to kill and haul them back home for food. The resisting termites, though smaller (average 8 mm), would fight withtheir strong jaws that rip through the ants’ limbs.
Matabele ants live in relatively small colonies of 1,000 to 15,000 individuals as their birth rate is very low, about 10-15 per day. Individual ants are thus very valuable. They have thus developed the skill of saving lives of fellow ants. Termites are their staple food for breakfast, lunch and dinner. So they are always on the lookout for termite settlements.
They would send scouts to know well-defended termite mounds, and where to attack. When a scout returns with a termite sighting, the ants prepare a raiding party, consisting of up to 600 able-bodied individuals.They would bypass heavily defended termite mounds and attack termites that feed on dead plant matter under the ground in the savannah. On arrival, the larger and stronger ants break through the overlying mud, while the smaller ants charge in to kill their prey, eat and carry the carcasses home.
Those injured during the raid party and need help, would do so by putting out a distress signal by secreting a pheromone. When paramedics arrive, the injured ants tuck in their legs so they can more easily be carried back to the nest, but the ants soon move on if their fallen comrades failed to tuck into the right position. When the battle is over, the warriors head home after gathering the wounded. Once inside the nest, the open wounds of the evacuated ants are treated by specialist ants, by intensive licking for many minutes. This according to scientists, is an unprecedented programmed nursing in nature. The treatment significantly reduces deaths in the colony. They think their saliva might contain some antibiotics.
These researchers, in order to study more in detail,moved six colonies of ants into artificial nests at the national park’s research lab, and videoed how they cared for the war-wounded without limbs. “We don’t know if they are just removing dirt from the wound or applying an antimicrobial substance to fight off an infection. But we do know that if they don’t receive the treatment, 80% die within 24 hours. If you allow the treatment for an hour, the ants survive,”Frank said.
Further, “After the battle, the first priority of an injured ant is to stand up into a resting position. From here, it can releasepheromoneto call for help. Heavily injured ants are those who have lost 5 or 6 legs and cannot get up again. They keep thrashing around, ignoring everything around them. As a result, the most severely injured either fail to call, or do not assume the right position to be carried home, and are left for dead. It’s simple. It enables the ants to triage the injured. If you can stand up you are still useful.”
Ant societies have always been fascinating for us. They have been observed from the dawn of history. Many, like Mark Twain (1880) and HG Wells (1905) wrote about them. In modernity (1992), a video simulation game of an ant colony, won ‘Codie [annual software] award’ for best simulation programme. Studies of ants have tested hypotheses in ecology and social biology, and have been particularly important in examining the theories of ‘evolutionarily stable strategies’. The theory describes tactics used by individual organisms when competing with one another for a given resource, as a natural consequence of evolution.
Ants evolved from a lineage of stinging wasps, dating back to around 92 million years ago.Ants, especially winged ants, look like termites, but ants are darker withsmall knob-like waists. They have angled antennae, and eyes on the sides of the head. Ancestors of modern insects like butterflies, evolved about the time land plants appeared on Earth, about 480 million years ago.
We humans have not been on Earth very long. Modern humans (Homo sapiens)evolved fromjust one African woman who lived between 50,000 and 500,000 years ago, known as ‘Mitochondrial Eve’ (Eve from biblical Adam and Eve).The theory comes from the original analysis of DNA in mitochondria (powerhouse of our cells) of modern humans. The result suggests that all modern humans share DNA of a single individual female who lived a few thousand years ago in Africa (cf. author’sHumans didn’t evolve from apes in Africa, but we shared a common ancestry).
The writer is based in the UK
Dr Irengbam Mohendra Singh