[ad_1]
The new study shows that humidity helps guide insects to complete their tasks.
Termites are often called nature’s architects. Their nests are several meters high and are intricately constructed, with galleries ensuring efficient communication and automatically ventilating the interior of the nest in a manner that would be the envy of human engineers. How do thousands of insects coordinate their efforts to build a strong, functional nest for the colony?
A new study coordinated by Andrea Perna, Professor of Complex Systems at the School of Advanced Studies at IMT Lucca, is published in the journal electronic lifehave now identified the unique mechanism that termites use to accomplish such extraordinary tasks.
The termites have almost finished building the arch. The red light is the beam used by the 3D scanner to quantify construction progress.Photo credit: Giulio Facchini
To conduct laboratory experiments on termites kind Milk termite straw (originally from South Asia but has spread to the East Coast of the United States), researchers used wet clay to create small arenas with artificial structures of varying heights and shapes.
They then collected a small number of termites from a larger colony and tracked the activities of all termites in the termite colony via video, quantified the termite construction behavior on these structures, and characterized the changes in the 3D structure. In this way, various hypotheses can be tested to discover the coordination mechanisms used for nest building.
Compare insights and experiments
In the case of ants, which in addition to termites are another group of insects capable of building large, complex structures, it is believed that ants impregnate building materials with pheromones, chemicals that attract other ants to building materials. construction sites and “tell them” where to build. In this way, the actions of one worker ant will trigger the activities of other ants, thus forming a self-amplifying process.
If termites, like ants, also rely on pheromones to guide their construction activities, then they should not show a preference for depositing building material particles in any particular location because there will be no pheromones in artificial sites prepared by termites. Experimenter. But that was not the case: While particles were collected throughout the arena, the sediment was concentrated on top of the existing structure. Perhaps they will be able to assess the height of the small columns and the heterogeneity of the ground, and in this way they will continue to add building materials on top of the existing structure. But that’s not the case: in fact, termites deposit their building particles on short and tall columns with equal probability.
A small colony of milky termites added clay particles to the tops of artificial posts placed by experimenters.Photo credit: Giulio Facchini
Another hypothesis is that termites may be able to sense the curvature of building substrates, as some previous models have shown that continuously adding particles at locations of highest curvature is enough to create very complex structures, similar to termite nests of some species. “In our simulations, we observed that small heterogeneities in the surface have a higher curvature than the surrounding flat base, so they expand to form pillars, whose pointed ends in turn attract further deposition of building material and continue grow until they split or merge with another pillar, and so on; very complex structures can be formed with this simple rule,” said Giulio Facchini, first author of the study and a researcher at the CNRS Institute of Materials and Systems Complex in Paris, France.
In fact, when termites were faced with the artificial stimulation provided in the experiment, they always preferred to build at the location of the highest curvature, adding particles at the top of the column (irrespective of the height of the column), and when small wall stimulation was provided, they Particles are most often added at the two corners of a wall, where the curvature is greatest.
Understand the sensory abilities of termites
The question is: How can termites sense the curvature of the structures they build so reliably? Researchers found that water evaporation and humidity may have something to do with this. “Termites are very sensitive to humidity concentrations: unlike most other insects, they have a thin exoskeleton and soft skin, which means that even prolonged exposure to humidity levels below 70% can be fatal to them,” Perna explained. “It’s not surprising that they are able to sense these moisture gradients and respond with their behavior.”
But how to prove it? “We found a solution that one anonymous reviewer for the journal described as a ‘very clever low-tech solution’ electronic life: We prepared the same experimental site as for termites, but this time impregnated the clay with a salt-water solution of sodium bicarbonate. When the water in the salt solution evaporates, tiny salt crystals are left behind, and the growth of the salt crystals marks the areas where evaporation is highest: these are the tips of pillars, the corners of walls: the exact same areas chosen by termites for their construction activities! ” Facchini explained.
“What really surprised us was finding that termites use such simple solutions to solve very complex problems,” Perna commented. “In our experiments, the complexity of the nests resulted from a simple mechanism: the termites only had to add particles of material according to the local humidity, but the particles they added in turn changed all evaporation and humidity patterns, inducing other termites to build in different positions, and so on, until very complex structures are produced.”
Reference: “Substrate evaporation drives collective construction in termites” by G. Facchini, A.rathy, S. Douady, D. Sillam-Dussès and A.Perna, February 8, 2024 electronic life.
DOI: 10.7554/eLife.86843.3
[ad_2]
Source link