Jean-Louis Deneubourg

Université Libre de Bruxelles | ULB · Faculty of Sciences

Human-induced habitat modifications can severely impact the biology and behavior of wild species. Drifting fish aggregating devices (DFADs), used by industrial purse-seine tropical tuna fisheries, significantly increased the number of floating objects found in the open ocean, with which tropical tuna associate. This habitat change has raised concer...

Food sharing can occur in both social and non-social species but is crucial in euso-cial species in which only some group members collect food. This food collection but also intranidal (i.e. inside the nest) food distribution through trophallactic (i.e. mouth-to-mouth) exchanges are fundamental issues in eusocial insects. However, the behavioural r...

Synchronization in pulse-coupled oscillators has been broadly studied under different perspectives. We present a game with simple rules to describe synchronization in such kinds of oscillators. This game, intended to describe easily how fireflies synchronize, constitutes a discrete model different from those based on maps, ordinary differential equ...

Gregarious arthropods are able to perform collective decision-making when having different options. In this study, we investigate how the sexual group composition and the geometry of the shelters influence the aggregation patterns of Periplaneta americana. We show that groups of males, groups of females and mixed groups composed of males and female...

Cooperative breeding may be selected for in animals when, on average, it confers greater benefits than solitary breeding. In a number of eusocial insects (i.e., ants, bees, wasps, and termites), queens join together to co-create new nests, a phenomenon known as colony co-founding. It has been hypothesised that co-founding evolved because queens obt...

Paces of change are faster in cultural evolution than in biological evolution due to different levels of stability in information storage. This study develops mathematical models to investigate the consequences of differential mutation rates on the ability of groups of information units to survive over many generations. We examined the ability of g...

In most eusocial insects, the division of labour results in relatively few individuals foraging for the entire colony. Thus, the survival of the colony depends on its efficiency in meeting the nutritional needs of all its members. Here, we characterise the network topology of a eusocial insect to understand the role and centrality of each caste in...

Triatominae insects are vectors of the parasite Trypanosoma cruzi, the etiological agent of Chagas disease affecting millions of people in Latin America. Some species, such as Triatoma infestans, live in the human neighborhood, aggregating in walls or roof cracks during the day and going out to feed blood at night. The comprehension of how sex and...

Intranidal food dissemination through trophallactic exchanges is a fundamental issue in social insect colonies, but its underlying mechanisms are far from being clear. In light of the division of work, network theory and collective food management we develop a framework to investigate the spatiotemporal dynamics of the trophallactic network in star...

We investigate the hypothesis that long-term memory in populations of agents can lead to counterproductive emergent properties at the system level. Our investigation is framed in the context of a discrete, one-dimensional road-traffic congestion model: we investigate the influence of simple cognition in a population of rational commuter agents that...

Albeit synchronous behavior of some fireflies species is one of the paradigmatic examples of synchronization, there are not many efforts to model in a realistic way this astounding phenomenon. One of the most important features of fireflies synchronization is the cooperative behavior of many fireflies giving rise to the emergency of synchronization...

We present investigations on the influence of individual heterogeneity on self-organised patterns in the termite nest construction model. The presented results extend the original model (Bruinsma 1979; Deneubourg 1977) from theoretical biology which has served as foundation and inspiration for computational optimisation approaches. Our findings hav...

A robot introduced into an animal group, accepted by the animals as conspecifics, and capable of interacting with them is an efficient tool for ethological research, particularly in studies of collective and social behaviour. In this paper, we present the implementation of an autonomous mobile robot developed by the authors to study group behaviour...

Synchronous flashing in Fireflies is perhaps the first observed natural phenomenon displaying synchronization of a large ensemble. During a long time, this collective behavior was not recognized and validated as synchronous, but nowadays it constitutes a paradigmatic example of synchronization. In this chapter, we explain biological aspects related...

Collective decisions regarding food source exploitation in social insects are influenced by a range of parameters, from source quality to individual preference and social information sharing. Those regarding the elevation of the physical trail towards a food source have been neglected. In this work, we investigated the effect of ascending and desce...

This review offers the first synthesis of the research on mixed-species groupings of arthropods and highlights the behavioural and evolutionary questions raised by such behaviour. Mixed-species groups are commonly found in mammals and birds. Such groups are also observed in a large range of arthropod taxa independent of their level of sociality. Se...

Group-level properties, such as collective movements or decisions, can be considered an outcome of the interplay between individual behavior and social interactions. However, the respective influences of individual preferences and social interactions are not evident. In this research, we study the implications of behavioral variability on the migra...

Some organisms, including fungi, ants, and slime molds, explore their environment and forage by forming interconnected networks. The plasmodium of the slime mold Physarum polycephalum is a large unicellular amoeboid organism that grows a tubular spatial network through which nutrients, body mass, and chemical signals are transported. Individual pla...

Estimating the abundance of pelagic fish species is a challenging task, due to their vast and remote habitat. Despite the development of satellite, archival and acoustic tagging techniques that allow the tracking of marine animals in their natural environments, these technologies have so far been underutilized in developing abundance estimations. W...

Tree-killing bark beetles are widely studied at epidemic population densities because of their significant impacts on forests. At endemic levels, these species are restricted to poorly defended resources, such as wind-felled, lightning-struck, or suppressed trees. It is poorly understood how these scattered and unpredictable resources are discovere...

The study of the topic of guided aggregation in biology brings together decision making, collective motion and the dynamical interplay between individuals and groups. At the same time it meets statistical mechanics and the physics of complex systems in a new paradigmatic thinking. We propose a research platform for implementation and for undertakin...

Inter-individual variability has various impacts in animal social behaviour. This implies that not only collective behaviours have to be studied but also the behavioural variability of each member composing the groups. To understand those effects on group behaviour, we develop a quantitative methodology based on automated ethograms and autonomous r...

The main goal of this thesis is to focus on the spatial distribution of individuals as well as the phenomenon called aggregation, to which various definitions have been given (based on the source of stimulus being social interaction or enviromental factors). Largely based on the paper “Self-organised choice based on inter-attraction: the example of...

Woodlice are fully terrestrial crustaceans and are known to be sensitive to water loss. Their half-ellipsoidal shapes represent simple models in which to investigate theoretical assumptions about organism morphology and rates of exchange with the environment. We examine the influence of surface area and mass on the desiccation rates in three eco-mo...

The main goal of this thesis (due to Erasmus+ exchange programme - 3month internship at CeNoLi, ULB) is to focus on the spatial distribution of individuals as well as the phenomenon called aggregation, to which various definitions have been given (based on the source of stimulus being social interaction or enviromental factors). Largely based on th...

We studied synchronization and clustering in two types of pulse-coupled oscillators, namely, integrate-and-fire and light-controlled oscillators. We considered for the analysis globally coupled oscillators, either by a mean-field type coupling or a distance-dependent one. Using statistically diverse measures such as the transient, probability of to...

Porcellio scaber is one of the most common crustaceans on land. Essentially to limit its desiccation rate, this woodlouse aggregates in shelters. The relation between the behavioural responses to conspecifics and to environmental heterogeneities (shelters) is imperfectly known in woodlice as in many species. In previous studies with binary choice t...

Blowfly (Diptera Calliphoridae) larvae are usually found on vertebrates cadavers in large masses of hundreds to thousands of individuals. One of the most impressive consequences of these aggregations is the elevation of temperature inside the aggregate. This local increase of temperature can be an efficient mechanism to reduce development time on c...

In the animal kingdom, living in group is driven by a tradeoff between the costs and the benefits of this way of life. This review focuses especially on the benefits of aggregation and crowding in woodlice (Crustacea: Isopoda: Oniscidea). Indeed, woodlice are well known to live in groups. Their aggregation behavior, as described in the early works...

Increasing catch rates are considered the main impact of dynamic fisheries practices on marine ecosystems, but other effects can be equally important and are often ignored. Here we quantify a major, previously unknown source of shark mortality: entanglement in drifting fish aggregating devices, now widely used in the global tropical tuna purse-sein...

Approximately 300 pelagic fish species naturally aggregate around floating objects (FOBs) at the surface of the oceans. Currently, more than 50% of the world catch of tropical tuna comes from the industrial tuna fisheries around drifting FOBs. Greater understanding of the complex decision-making processes leading to this aggregation pattern and the...

ABSTRACT: Fishers have exploited the associative behavior displayed by several pelagic fish species with floating objects for decades, through the use of man-made fish aggregating devices (FADs), which facilitate the capture of such species. However, our understanding of this associative behavior and its adaptive value is poor and the scientific co...

Tropical tunas associate with objects floating at the surface of the ocean, a behavior widely exploited by fishers. However, the respective roles played by environmental variables and behavioral processes (e.g., social behavior) in the formation of these aggregations remain elusive. To investigate the role of social behavior in the dynamics of such...

A robot accepted by animals as conspecific is a very powerful tool in behavioral biology, particularly in studies of gregarious animals. However in experiments where animals and robots share the same physical environment, there is always a risk of a robot accident that can lead to animal injuries. Safety regulations have to be developed to guide th...

Population growth can be positively or negatively dependent on density. Therefore, the distribution pattern of individuals in a patchy environment can greatly affect the growth of each subpopulation and thereby of the metapopulation. When population growth presents positive density-dependence (Allee effect), the distribution pattern becomes crucial...

Spatial distribution of ant workers within the nest is a key element of the colony social organization contributing to the efficiency of task performance and division of labour. Spatial distribution must be efficiently organized when ants are highly starved and have to get food rapidly. By studying ants’ behaviour within the nest during the beginni...

Terrestrial isopods are known to be sensitive to humidity, brightness or temperature. Until now, aggregation was assumed to depend on these sensitivities as a result of individual preferences. In this paper, we show that the social component is also important in the isopod aggregation phenomenon. In experimental arenas with two identical shelters u...

Demonstrating and quantifying the respective roles of social interactions and external stimuli governing fish dynamics is key to understanding fish spatial distribution. If seminal studies have contributed to our understanding of fish spatial organization in schools, little experimental information is available on fish in their natural environment,...

In social insects, the foraging activity usually increases with the length of food deprivation. In Lasius niger, a mass-recruiting ant species, the foraging adjustment to the level of food deprivation is regulated by the scout that fed at the food source and by the response of the nestmates to signals performed by the scout inside the nest. In this...

Interactive robots have the potential to revolutionise the study of social behaviour because they provide several methodological advances. In interactions with live animals, the behaviour of robots can be standardised, morphology and behaviour can be decoupled (so that different morphologies and behavioural strategies can be combined), behaviour ca...

Response to synchronization seems to be a widespread phenomenon specially in biological systems. We highlight this phenomenon studying the courtship of flashing fireflies in which a typical collective rhythm occurring only among the males arises and it is followed by a response of the females. Based on a model issued from electronic fireflies, we e...

Social Network Influences Decision Making During Collective Movements in Brown Lemurs (Eulemur fulvus fulvus)

While food recruitment and foraging have been the subject of many studies, the regulation of the food sharing behaviour remains poorly understood. In this study, we focused on trophallaxis (or mouth-to-mouth food exchange) within a group of worker ants as the first step in characterizing food sharing behaviours. In particular, we wanted to investig...

The aggregation of woodlice in dark and moist places is considered an adaptation to land life and most studies are focused on its functionality or on the behavioural mechanisms related to the individual's response to abiotic factors. Until now, no clear experimental demonstration was available about aggregation resulting from inter-attraction betwe...

To design, to study, and to control mixed animals-robots societies is a challenging field of scientific exploration that can bring new frameworks to study individual and collective behaviors in animal and mixed robot-animal societies. In the Chicken Robot project we aim at developing a mobile robot, able to collaborate with a group of chicks and to...

We study the influence of white gaussian noise in a system of two mutually coupled light-controlled oscillators (LCOs). We show that under certain noise intensity conditions, noise can destroy or enhance synchronization. We build some Arnold tonguelike structures in order to explain the effects due to noise. It is remarkable that noise-enhanced syn...

Living in groups necessarily involves a certain amount of within-group competition for food. Group members may have different motivations, implying the reaching of a consensus to stay cohesive. In some cases individuals fail to reach a common decision and the group splits; this can be temporary, as seen in fission-fusion dynamics, or even irreversi...

Exploration allows animals to discover food resources, detect competitors and update their general knowledge of the habitat surroundings. Although the vital importance of exploration, its functional and proximal complexity is often underestimated. In this article, we study the exploring activities of Lasius niger, an aphid-tending ant species that...

The environment of animals is often heterogeneous, containing zones that may be dedicated specifically to resting, drinking or feeding. These functional zones may spread over a more or a less extensive area. Thus, mobile animals may have to move from one patch to another when resources are locally depleted or when they need to change activity. The...

In primates, authors have reported the specific organization of individuals during collective movements. Some authors have suggested that intentional mechanisms underlie this particular organization because primates have high cognitive abilities that can allow them to use this kind of behaviour. However, mechanisms underlying the emergence of compl...

In group-living animals, collective movements are a widespread phenomenon and occur through consensus decision. When one animal proposes a direction for group movement, the others decide to follow or not and hence take part in the decision-making process. This paper examines the temporal spread of individual responses after the departure of a first...

Tetranychus urticae (Acari: Tetranychidae) is a phytophagous mite that forms colonies of several thousand individuals. Like spiders, every individual produces abundant silk strands and is able to construct a common web for the entire colony. Despite the importance of this silk for the biology of this worldwide species, only one previous study sugge...

Foraging in leaf-cutting ants is generally organized along well-defined recruitment trails supporting a bi-directional flow of outbound and nestbound individuals. This study attempts to reveal the priority rules governing the organization of traffic on these trails. Ants were forced to move on a narrow trail, allowing the passage of only two indivi...

In social biology, it is often considered that an organized society cannot exist without exclusion behaviour towards newcomers from another nest. Unlike most vertebrate and invertebrate social species, social spiders such as Anelosimus eximius accept unrelated migrants without agonistic behaviour. Does it imply that spiders cannot recognize non-nes...

In social species, the interactions that occur between individuals and also between individuals and their environment can lead to various spatial distributions. Our goal was to understand how both factors (social and environmental) can affect such spatial distribution of individuals. Aggregation experiments were conducted on the ant Crematogaster s...

We discuss and investigate collective decision-making, i.e. the process whereby a population of autonomous units jointly identifies and adopts one out of many possible configurations, in the absence of any internal hierarchical structure (leadership), pre-existing blueprint, or runtime instructions from an external authority. Collective decision-ma...

Ant colonies that undergo long starvation periods have to tune their exploratory and foraging responses to face their food needs. Although the number of foragers is known to increase with food deprivation in the ant Lasius niger, such enhanced food exploitation is not related to a more intense recruitment by successful scouts. We thus suggest that...

Self-medicative behaviours have been largely documented in vertebrates and, in particular, the use of plants for pharmacological purposes has been mainly reported in primates. White-faced capuchins are known to rub specifically chosen plants and other substances on their fur. To better understand the mechanisms underlying this phenomenon and invest...

In their natural environment, capuchins select certain plants, containing secondary compounds with bactericide, insecticide or fungicide properties, to rub their pelage energetically (i.e. fur rubbing). Fur rubbing can be performed in solitary, or collectively in subgroups of variable size and composition, and most of the time fur rubbing happens i...

We study the influence of uniform noise on a system of two light-controlled oscillators (LCOs) under three different configurations: uncoupled, master–slave and mutually coupled LCOs. We find that noise can induce desynchronization via a phase transition-like phenomenon depending on the noise intensity and the characteristics of the LCOs.

Collective behavior based on self-organization has been shown in group-living animals from insects to vertebrates. These findings have stimulated engineers to investigate approaches for the coordination of autonomous multirobot systems based on self-organization. In this experimental study, we show collective decision-making by mixed groups of cock...

During habitat selection, the presence of conspecifics can frequently drive a nonuniform distribution of animals across habitats of equivalent quality. In group‐living species, subgroups of individuals might display mutual attraction while differing in their preferences for environmental resources. The final decision to settle requires individuals...