The evolution of social timing

Sociality and timing are tightly interrelated in human interaction as seen in turn-taking or synchronised dance movements. Sociality and timing also show in communicative acts of other species that might be pleasurable, but also necessary for survival. Sociality and timing often co-occur, but their shared phylogenetic trajectory is unknown: How, when, and why did they become so tightly linked? Answering these questions is complicated by several constraints; these include the use of divergent operational definitions across fields and species, the focus on diverse mechanistic explanations (e.g., physiological, neural, or cognitive), and the frequent adoption of anthropocentric theories and methodologies in comparative research. These limitations hinder the development of an integrative framework on the evolutionary trajectory of social timing and make comparative studies not as fruitful as they could be. Here, we outline a theoretical and empirical framework to test contrasting hypotheses on the evolution of social timing with species-appropriate paradigms and consistent definitions. To facilitate future research, we introduce an initial set of representative species and empirical hypotheses. The proposed framework aims at building and contrasting evolutionary trees of social timing toward and beyond the crucial branch represented by our own lineage. Given the integration of cross-species and quantitative approaches, this research line might lead to an integrated empirical-theoretical paradigm and, as a long-term goal, explain why humans are such socially coordinated animals.

Behavioural specialization and learning in social networks

Interactions in social groups can promote behavioural specialization. One way this can happen is when individuals engage in activities with two behavioural options and learn which option to choose. We analyse interactions in groups where individuals learn from playing games with two actions and negatively frequency-dependent payoffs, such as producer-scrounger, caller-satellite, or hawk-dove games. Group members are placed in social networks, characterized by the group size and the number of neighbours to interact with, ranging from just a few neighbours to interactions between all group members. The networks we analyse include ring lattices and the much-studied small-world networks. By implementing two basic reinforcement-learning approaches, action-value learning and actor-critic learning, in different games, we find that individuals often show behavioural specialization. Specialization develops more rapidly when there are few neighbours in a network and when learning rates are high. There can be learned specialization also with many neighbours, but we show that, for action-value learning, behavioural consistency over time is higher with a smaller number of neighbours. We conclude that frequency-dependent competition for resources is a main driver of specialization. We discuss our theoretical results in relation to experimental and field observations of behavioural specialization in social situations.

A System for Automated Interaction with the Cricket Utilizing a Micro Mobile Robot

This paper describes our trials in developing automated interaction systems with crickets by using a micro mobile robot for attracting pheromone behavior. The cricketGryllus bimaculatusmodifies its behavior based on experience that is based on pheromone interactions between individuals. In developing systems, a micro mobile robot with a cricket’s head is controlled based on online visual tracking information. In this paper, we describe implementing automated micro mobile robot control based on image processing and attempt experimental trials in interaction between the cricket and micro mobile robot. The cricket shows a typical response to the pheromone stimulus for approaching by the micro mobile robot. Results also show that the developed system could contribute to novel biological research, for example, manipulable experimental conditions for interactive experiments.

Aggressive behavior in the antennectomized male cricket Gryllus bimaculatus

Male crickets (Gryllus bimaculatus) exhibit intensively defensive aggressive behavior towards attacking males most often culminating in fighting. After the fight, the loser no longer exhibits aggressiveness in a second, separate encounter with another male; rather, the defeated male exhibits avoidance behavior. Here, we investigated the role of sensory input from the antennae in male defensive aggressive behavior. When we removed antennae from males (antennectomized males), we found that they showed little aggressiveness towards each other whereas they continued to exhibit typical fighting behavior towards an intact male. In addition, in a second encounter, antennectomized losers showed significantly higher aggressiveness towards another male than did intact losers. We further found that antennectomized crickets do not utilize visual or palpal sensory input to elicit aggressive behavior. In contrast, intact males showed aspects of aggressive behavior to male cuticular substances before and after winning a fight, and if they lost a fight they showed avoidance behavior. It thus appears that antennal sensory information is crucial in the mediation of aggressive and avoidance behaviors. However, sensory inputs from the antennae are not necessary to elicit defensive aggressive behavior but are necessary to discriminate conspecific males and initiate attacks against them.