Mechanisms behind collective decision-making, a case of cockroaches

Planas-Sitjà I (Laboratory of Systematic Zoology, Department of Biological Sciences, Tokyo Metropolitan University)

coauthors: Laurent Salazar M-O² , Nicolis SC1, Sempo G¹, Calvo-Martin M¹ & Deneubourg, J-L¹

¹ Biological and Artificial Self-organised Systems - CP 231, Université libre de Bruxelles, Belgium

² University of the Ryukyus (Okinawa, Japan)

Aggregation is one of the most widespread social processes in the animal kingdom and it is largely based on collective decision-making. Animals living in groups often face critical decisions for their survival (eg. where to rest or nest, when to leave or which resource exploit) and they need to decide collectively in order to maintain the cohesion of the group and keep the social benefits. These decisions mainly arise from individual preferences and their amplification through the interactions between individuals. Most of the time individuals have poor knowledge of their environment and can show different preferences and temperaments, thus reaching a fast and accurate decision can be very challenging.

The American cockroach (Periplaneta americana) is a model organism for many studies in biology, including research on aggregation and decision-making. We used a combination of experiments and computation modelling to study the mechanisms driving collective dynamics during the aggregation process of P. americana. First of all, we have demonstrated that these cockroaches show high rates of individual and group repeatability of behavioural traits over time (personality variation). Second, we show that significant differences observed among groups in terms of collective dynamics during the aggregation process depend on the variation of personalities inside the group. These results bring new insights regarding the influence of personality variation on decision-making, where key-individuals have an asymmetrical influence during the aggregation process and affect the exploitation and exploration of environmental resources by the entire group. We finally propose that personality variation should be considered in a social context in order to achieve a global understanding of collective dynamics.

7th June 2019, 16:30-

Building 12 Room 102, Minami Osawa Campus, Tokyo Metroplitan University