The researchers studied and modelled the propagation of information in schools of fish when they collectively change the direction of their movement.
The results, published on 25 April 2018 in the Proceedings of the Royal Society B, show that each fish mimics the behaviour of a small number of its neighbours and that this mechanism spreads from one person to another in the manner of a domino effect.
Collective movements of groups of animals are one of the most spectacular phenomena observed in nature, but the rigorous analysis of these phenomena is very recent and has only been made possible by technological advances in data acquisition and processing. These collective movements result from local interactions between individuals and are accompanied by the formation of large-scale spatial and temporal structures. They play a fundamental role in group defense, reproduction, or foraging, improving individuals’ ability to survive. To understand these collective phenomena, it is important to characterize the dynamics of interactions between individuals in a group.
Researchers from the CRCA-CBI in Toulouse, the Normal University in Beijing, and the University of Groningen in the Netherlands have studied a tropical fish species, the red nose (Hemigrammus rhodostomus), whose schooling behaviour is very pronounced.
“Social conformity and propagation of information in collective U-turns of fish schools”
Lecheval V, Jiang L, Tichit P, Sire C, Hemelrijk CK, Theraulaz G.
Proc Biol Sci. 2018 Apr 25 ;285(1877). pii : 20180251. doi : 10.1098/rspb.2018.0251.
The zero, which symbolizes nothing, the neutral or the absence, being a relatively recent human construction, these results, published in Science on June 8, 2018, question the symbolic importance of the zero in the history of mathematics.
It had already been shown that some vertebrates mastered complex numerical concepts, such as addition or zero, but nothing had been proven in insects. Since bees can count at least 5, researchers have trained them in the concept of “bigger than” and “smaller than”.
Scarlett R. Howard, Aurore Avarguès-Weber, Jair Garcia, Andrew Greentree, Adrian G. Dyer.
“Bees extrapolate ordered relations to place numerosity zero on a numerical continuum”
Science, 2018. DOI:10.1126/science.aar4975