ants

ants-vs.-humans:-solving-the-piano-mover-puzzle

Ants vs. humans: Solving the piano-mover puzzle

ants, collective behavior, cooperative behavior, entomology, eusocial insects, Science / /

Who is better at maneuvering a large load through a maze, ants or humans?

The piano-mover puzzle involves trying to transport an oddly shaped load across a constricted environment with various obstructions. It’s one of several variations on classic computational motion-planning problems, a key element in numerous robotics applications. But what would happen if you pitted human beings against ants in a competition to solve the piano-mover puzzle?

According to a paper published in the Proceedings of the National Academy of Sciences, humans have superior cognitive abilities and, hence, would be expected to outperform the ants. However, depriving people of verbal or nonverbal communication can level the playing field, with ants performing better in some trials. And while ants improved their cognitive performance when acting collectively as a group, the same did not hold true for humans.

Co-author Ofer Feinerman of the Weizmann Institute of Science and colleagues saw an opportunity to use the piano-mover puzzle to shed light on group decision-making, as well as the question of whether it is better to cooperate as a group or maintain individuality. “It allows us to compare problem-solving skills and performances across group sizes and down to a single individual and also enables a comparison of collective problem-solving across species,” the authors wrote.

They decided to compare the performances of ants and humans because both species are social and can cooperate while transporting loads larger than themselves. In essence, “people stand out for individual cognitive abilities while ants excel in cooperation,” the authors wrote.

Feinerman et al. used crazy ants (Paratrechina longicornis) for their experiments, along with the human volunteers. They designed a physical version of the piano-movers puzzle involving a large t-shaped load that had to be maneuvered across a rectangular area divided into three chambers, connected via narrow slits. The load started in the first chamber on the left, and the ant and human subjects had to figure out how to transport it through the second chamber and into the third.

Ants vs. humans: Solving the piano-mover puzzle Read More »

ants-learned-to-farm-fungi-during-a-mass-extinction

Ants learned to farm fungi during a mass extinction

agriculture, ants, Biology, evolution, fungi, Science / /

Timing is everything

Tracing the lineages of agricultural ants to their most recent common ancestor revealed that the ancestor probably lived through the end-Cretaceous mass extinction—the one that killed off the dinosaurs. The researchers argue that the two were almost certainly related. Current models suggest that there was so much dust in the atmosphere after the impact that set off the mass extinction that photosynthesis shut down for nearly two years, meaning minimal plant life. By contrast, the huge amount of dead material would allow fungi to flourish. So, it’s not surprising that ants started to adapt to use what was available to them.

That explains the huge cluster of species that cooperate with fungi. However, most of the species that engage in organized farming don’t appear until roughly 35 million years after the mass extinction, at the end of the Eocene (that’s about 33 million years before the present period). The researchers suggest that the climate changes that accompanied the transition to the Oligocene included a drying out of the tropical Americas, where the fungus-farming ants had evolved. This would cut down on the availability of fungi in the wild, potentially selecting for the ability of species that could propagate fungal species on their own.

This also corresponds to the origins of the yeast strains used by farming ants, as well as the most specialized agricultural fungal species. But it doesn’t account for the origin of coral fungus farmers, which seems to have occurred roughly 10 million years later.

The work gives us a much clearer picture of the origin of agriculture in ants and some reasonable hypotheses regarding the selective pressures that might have led to its evolution. In the long term, however, the biggest advance here may be the resources generated during this study. Ultimately, we’d like to understand the genetic basis for the changes in the ants’ behavior, as well as how the fungi have adapted to better provide for their farmers. To do that, we’ll need to compare the genomes of agricultural species with their free-living relatives. The DNA gathered for this study will ultimately be needed to pursue those questions.

Science, 2024. DOI: 10.1126/science.adn7179  (About DOIs).

Ants learned to farm fungi during a mass extinction Read More »

call-the-ant-doctor:-amputation-gives-injured-ants-a-leg-up-on-infections

Call the ant doctor: Amputation gives injured ants a leg up on infections

ant behavior, ants, ants are awesome, Biology, entomology, Science / /
video still image showing woundcare and amputation in C. maculatus

Enlarge / Scientists have observed wound care and selective amputation in Florida carpenter ants.

Florida carpenter ants (Camponotus floridanus) selectively treat the wounded limbs of their fellow ants, according to a new paper published in the journal Current Biology. Depending on the location of the injury, the ants either lick the wounds to clean them or chew off the affected limb to keep infection from spreading. The treatment is surprisingly effective, with survival rates of around 90–95 percent for amputee ants.

“When we’re talking about amputation behavior, this is literally the only case in which a sophisticated and systematic amputation of an individual by another member of its species occurs in the animal kingdom,” said co-author Erik Frank, a behavioral ecologist at the University of Würzburg in Germany. “The fact that the ants are able to diagnose a wound, see if it’s infected or sterile, and treat it accordingly over long periods of time by other individuals—the only medical system that can rival that would be the human one.”

Frank has been studying various species of ants for many years. Late last year, he co-authored a paper detailing how Matabele ants (Megaponera analis) south of the Sahara can tell if an injured comrade’s wound is infected or not, thanks to chemical changes in the hydrocarbon profile of the ant cuticle when a wound gets infected. These ants only eat termites, but termites have powerful jaws and use them to defend against predators, so there is a high risk of injury to hunting ants.

If an infected wound is identified, the ants then treat said wound with antibiotics produced by a special gland on the side of the thorax (the metapleural gland). Those secretions are made of some 112 components, half of which have antimicrobial properties. Frank et al.’s experiments showed that applying these secretions reduced the mortality rate of injured ants by 90 percent, and future research could lead to the discovery of new antibiotics suitable for treating humans. (This work was featured in an episode of a recent Netflix nature documentary, Life on Our Planet.)

Amputation in Camponotus maculatus. Credit: Danny Buffat.

Those findings caused Frank to ponder if the Matabele ant is unique in its ability to detect and treat infected wounds, so he turned his attention to the Florida carpenter ant. These reddish-brown ants nest in rotting wood and can be fiercely territorial, defending their homes from rival ant colonies. That combat comes with a high risk of injury. Florida carpenter ants lack a metapleural gland, however, so Frank et al. wondered how this species treats injured comrades. They conducted a series of experiments to find out.

Frank et al. drew their subjects from colonies of lab-raised ants (produced by queens collected during 2017 fieldwork in Florida), and ants targeted for injury were color-tagged with acrylic paint two days before each experiment. Selective injuries to tiny (ankle-like) tibias and femurs (thighs) were made with sterile Dowel-scissors, and cultivated strains of P. aeruginosa were used to infect some of those wounds, while others were left uninfected as a control. The team captured the subsequent treatment behavior of the other ants on video and subsequently analyzed that footage. They also took CT scans of the ants’ legs to learn more about the anatomical structure.

Call the ant doctor: Amputation gives injured ants a leg up on infections Read More »