How insect sex helps predict storms – 04/13/2023 – Science

Claiming that animals can predict storms is not utopia.

Brazilian researchers managed to prove scientifically that the change in the sexual behavior of insects can indicate the arrival of storms and winds.

The explanation lies in the ability of insects to detect the slightest changes in atmospheric pressure in nature, according to entomologist and USP professor José Maurício Simões Bento.

A study conducted by the Department of Entomology and Acarology at the Luiz de Queiroz College of Agriculture (ESALQ), at the University of São Paulo (USP), in Piracicaba (SP), in partnership with researchers from the State University of the Midwest (Unicentro) and from the University of Western Ontario, in Canada, proved that insects predict sudden changes in the weather and give indications through changes in their sexual behavior.

“What we noticed is that, when there is an event of low atmospheric pressure, which normally precedes a storm, the insects interrupt mating and seek shelter. This generally happens between four and six hours before the rain, providing a certain amount of predictability” , explained the teacher.

The discovery of this ability in insects and their behavior change began after Professor Bento and his team noticed that, on rainy days, the insects did not mate, even with all the temperature and humidity controlled conditions in the laboratory.

“Since the force exerted by atmospheric pressure is the same, regardless of whether one is in an external or internal environment in a laboratory (or a house), we decided to prove our hypothesis, based on the sexual behavior of insects”, he says.

In the study, the scientists analyzed three distinct species of insects commonly found in Brazil: the beetle, popularly known as ‘brasileiro’ or ‘patriota’, for its green color and yellow spots (Diabrotica speciosa); the potato aphid (Macrosiphum euphorbiae) and the grass caterpillar (Pseudaletia unipuncta).

With the help of a barometric chamber – equipment that can control or change atmospheric pressure – the researchers were able to prove that, under a drop in atmospheric pressure, the three species of insects reduced their sexual activity and mated less than under normal pressure conditions.

“Unlike us humans, who have a clock that shows us the hours throughout the day, allowing us to ‘mark times’, most insects are guided by dawn and dusk (dusk). Therefore, many of them mate in these periods, such as a predetermined meeting, regardless of the time of year. However, what we noticed in our study is that, with the drop in pressure and the predictability of rain, they avoided these meetings to mate and sought shelter.”

This is because insects have a very keen survival instinct in nature.

“The simple impact of a raindrop may seem small to us humans, but for these tiny organisms, like insects, it can be fatal.”

Now, scientists are trying to discover which structures in the body of insects make them capable of perceiving changes in atmospheric pressure, hours before a storm.

“We have already proven that insects are able to foresee storms and windstorms for the sake of survival. They are living beings that have evolved over millions of years, which makes them widely adapted on Earth. Now we want to discover a little more with them, and unveil their structures improving our weather forecasting methods”, pointed out Bento.

ANTS ACCELERATE THE TRANSPORTATION OF LEAVES

Another research by the group carried out at the Luiz de Queiroz School of Agriculture, at USP in Piracicaba, demonstrated that leaf-cutting ants, also called leaf-cutting ants (Atta sexdens) begin to perform routine tasks of cutting and transporting leaves more quickly, hours before a storm.

“Like the other insects, the ants can sense the arrival of rain and speed up their work, with the aim of collecting and storing the greatest possible amount of food for the nest”, explained Bento, who also led the project.

The study carried out using a barometric chamber was divided into stages: in the first, as a way of simulating the arrival of rain, the scientists introduced leaf-cutting ants into an environment of low atmospheric pressure; and, in the other stages, they simulated conditions of stability and high pressure, which represent little risk of rain and storms.

The results showed that in a condition of low pressure – indicative of rain -, the ants left their nests 2.8 times faster than when the pressure was constant.

It was also shown that between 1.5 and 2 times more leaves were cut and brought to the nest by ants during the drop in atmospheric pressure.

“The group’s effort to transport and bring back a greater amount of food in less time, in the face of an imminent storm compared to normal conditions, demonstrated the high capacity of individual decision-making of insects when faced with an indication of risk”, he concluded.

DO ANIMALS PREVENT EARTHQUAKES?

In addition to storms, researchers have been trying to scientifically prove for years whether animals can predict earthquakes. And, if so, in what way.

It was in search of these answers that Professor Jean Pierre Raulin, coordinator of the Center for Radio Astronomy and Astrophysics Mackenzie (CRAAM) participated in a study that explained what led birds and mammals from the Yanachaga Chemillen National Park, in Peru, to leave the region days ago before the Contamana earthquake, measuring 7.0 on the Richter scale, hit the Peruvian Andes in 2011.

In world literature, the oldest recorded reference to unusual animal behavior before a natural disaster dates back to 373 BC, when the Greek historian Thucydides reported that rats, dogs, snakes and weasels abandoned the city of Helix, in Greece, days before a catastrophic earthquake.

Together with English researcher Rachel Grant and Friedemann Freund, from the NASA space agency (United States), Jean Pierre found an explanation: the gas that comes out from below and comes to the surface from the movement of tectonic plates increases the production of positive ions in the atmosphere, which, perceptible to the animals, causes an increase in serotonin levels in the animals, leaving them agitated.

“That’s why they left the region before the earthquake.”

To reach the conclusion, each researcher studied the behavior of the animals before the earthquake in a different way.

From cameras installed in the park, which were activated automatically the moment the animal passed in front of them, without being seen, the researchers attested that, on an average day, the animals were seen, on average, from 5 to 15 times a day.

“However, in the 30-day period leading up to the earthquake, we noticed that the number of animal sightings progressively dropped until it reached zero on the day of the seismic event”, explained Jean.

At the same time, monitoring the propagation of low-frequency radio waves, in the days before the earthquake, found that the same atomic particles released by the gas (from the movement of tectonic plates) caused changes in the radio waves of the atmosphere in the region.

“By joining the data, we came to the conclusion that this may indeed have influenced animal behavior to flee the region before the earthquake happened.”

HOW HUMAN WEATHER FORECAST WORKS

Since before Christ, observing time is crucial for humanity.

In the past, it was by observing the skies that people predicted whether it would rain or not. The objective was to avoid losses in the cultivation of crops that depended on rainfall cycles.

Even the Bible, in Matthew, chapter 16, verses 2 and 3, quotes the way in which the weather was predicted at the time of Jesus. “There will be fair weather, because the sky is red. And in the morning, there will be a storm, because the sky is somber red.”

However, it was from the development of science that human beings began to use equipment to decipher when it would rain.

It was from the 16th century, for example, with the development of the thermometer (temperature) and the barometer (air pressure), that time began to be predicted by man through technology.

Then, in addition to the thermometer and the barometer, professionals began to use a multitude of new technologies to predict whether it will rain or not.

This is how, currently, meteorologists predict the weather using atmospheric data provided by meteorological stations; satellite images; and meteorological radars installed in different parts of the world.

The studies that allow the identification of sudden changes in the weather are based on precipitation data, winds, relative humidity and atmospheric pressure itself – which animals are able to capture without the use of technological equipment.

In Brazil, only the National Institute of Meteorology (Inmet) manages 750 meteorological stations.

As a rule, automatic stations capture data and send it to a meteorological center, where, using supercomputers, meteorologists carry out simulations with the support of satellite images on the weather forecast for the next few hours.

These observations, carried out in a systematic, uniform manner, and at established times, allow the human being to know whether or not it will rain in a given location.

ANIMALS CAN HELP PREVENT NATURAL DISASTERS

With the enormous difficulty encountered in predicting earthquakes, the question arises: will human beings be able to predict storms and earthquakes in advance, based on the observation of animals?

Professor at the University of São Paulo (USP), José Maurício Simões Bento; and Jean Pierre Raulin, from Universidade Presbiteriana Mackenzie, say yes, but rather defend the need for greater investment in research on the subject worldwide.

“The research is just one more indication of how animals do not need human beings to survive in nature, but how much we need them”, defended Bento.