Quantifying the impact of habitat modifications on species behavior and mortality: A case study of tropical tuna.

Ecosystems and biodiversity across the world are being altered by human activities. Habitat modification and degradation are among the most important drivers of biodiversity loss. These modifications can have an impact on species behavior, which can, in turn, impact their mortality.

Direct assessment of tropical tuna abundance from their associative behaviour around floating objects.

Managing populations of wild harvested species requires the ability to regularly provide accurate abundance assessments. For most marine species, changes in abundance can only be monitored indirectly, using methods reliant on harvest-based indices, with significant inherent limitations surrounding the estimation and standardization of harvest effort. Tropical tunas are some of the most exploited marine species in the world and are among several species in critical need of alternative methods for estimating abundance.

Emergence and retention of a collective memory in cockroaches.

The stability of collective decisions-making in social systems is crucial as it can lead to counterintuitive phenomena such as collective memories, where an initial choice is challenged by environmental changes. Many social species face the challenge to perform collective decisions under variable conditions. In this study, we focused on situations where isolated individuals and groups of the American cockroach (Periplaneta americana) had to choose between two shelters with different luminosities that were inverted during the experiment.

A Data-Driven Simulation of the Trophallactic Network and Intranidal Food Flow Dissemination in Ants.

Food sharing can occur in both social and non-social species, but it is crucial in eusocial species, in which only some group members collect food. This food collection and the intranidal (i.e.

Differential Gene Expression Correlates with Behavioural Polymorphism during Collective Behaviour in Cockroaches.

Consistent inter-individual variation in the propensity to perform different tasks (animal personality) can contribute significantly to the success of group-living organisms. The distribution of different personalities in a group influences collective actions and therefore how these organisms interact with their environment. However, we have little understanding of the proximate mechanisms underlying animal personality in animal groups, and research on this theme has often been biased towards organisms with advanced social systems.

Does a high social status confer greater levels of trust from groupmates? An experimental study of leadership in domestic horses.

In collective movements, specific individuals may emerge as leaders. In this study on the domestic horse (Equus ferus caballus), we conducted experiments to establish if an individual is successfully followed due to its social status (including hierarchical rank and centrality). We first informed one horse about a hidden food location and recorded by how many it was followed when going back to this location.

Schooling in habitats with aggregative sites: The case of tropical tuna and floating objects.

Many marine and terrestrial species live in groups, whose sizes and dynamics can vary depending on the type and strength of their social interactions. Typical examples of such groups in vertebrates are schools of fish or flocks of bird. Natural habitats can encompass a wide range of spatial heterogeneities, which can also shape the structure of animal groups, depending on the interplay between the attraction/repulsion of environmental cues and social interactions.

The effect of idiosyncrasy on aggregation in group-living organisms.

We use a minimalistic mathematical model with a limited number of parameters to evaluate the impact of interindividual differences in the collective decision-making of a group. As it turns out, in most cases, heterogeneous groups are more efficient in their decision-making than homogenous ones, especially when considering small group sizes. In reality, being different disfavours the emergence of an hysteresis and a collective threshold which are characteristics of such cooperative species while keeping inter-attractions the same between individuals.

Consensus driven by a minority in heterogenous groups of the cockroach .

Many social species are able to perform collective decisions and reach consensus. However, how the interplay between social interactions, the diversity of preferences among the group members and the group size affects these dynamics is usually overlooked. The collective choice between odourous and odorless shelters is tested for the following three groups of social cockroaches () which are solitary foragers: naive (individuals preferring the odorous shelter), conditioned (individuals without preference), and mixed (combining, unevenly, conditioned, and naive individuals).

Variation in personality can substitute for social feedback in coordinated animal movements.

Collective movements are essential for the effective function of animal societies, but are complicated by the need for consensus among group members. Consensus is typically assumed to arise via feedback mechanisms, but this ignores inter-individual variation in behavioural tendency ('personality'), which is known to underpin the successful function of many complex societies. In this study, we use a theoretical approach to examine the relative importance of personality and feedback in the emergence of collective movement decisions in animal groups.

A methodological framework for characterizing fish swimming and escapement behaviors in trawls.

Knowledge about fish behavior is crucial to be able to influence the capture process and catch species composition. The rapid expansion of the use of underwater cameras has facilitated unprecedented opportunities for studying the behavior of species interacting with fishing gears in their natural environment. This technological advance would greatly benefit from the parallel development of dedicated methodologies accounting for right-censored observations and variable observation periods between individuals related to instrumental, environmental and behavioral events.

Effects of habitat modifications on the movement behavior of animals: the case study of Fish Aggregating Devices (FADs) and tropical tunas.

Background: Aggregation sites represent important sources of environmental heterogeneity and can modify the movement behavior of animals. When these sites are artificially established through anthropogenic actions, the consequent alterations to animal movements may impact their ecology with potential implications for their fitness. Floating objects represent important sources of habitat heterogeneity for tropical tunas, beneath which these species naturally aggregate in large numbers.

Colony co-founding in ants is an active process by queens.

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.

Modelling persistence over generations in biological and cultural evolution based on differential paces of change.

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 groups composed of connected units to live on despite the occurrence of deleterious mutations that occur at probabilities ranging from 10 to 10.

Hierarchical networks of food exchange in the black garden ant Lasius niger.

In most eusocial insects, the division of labor 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 characterize the network topology of a eusocial insect to understand the role and centrality of each caste in this network during the process of food dissemination.

Conflictual influence of humidity during shelter selection of the American cockroach (Periplaneta americana).

In collective decision-making, when confronted with different options, groups usually show a more marked preference for one of the options than do isolated individuals. This results from the amplification of individual preferences by social interactions within the group. We show, in an unusual counter-example, that when facing a binary choice between shelters with different relative humidities, isolated cockroaches of the species Periplaneta americana select the wettest shelter, while groups select the driest one.

Alteration of the aggregation and spatial organization of the vector of Chagas disease, Triatoma infestans, by the parasite Trypanosoma cruzi.

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 T.

A spatiotemporal analysis of the food dissemination process and the trophallactic network in the ant Lasius niger.

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 starved Lasius niger ant colonies. Thanks to tracking methods we are able to record spatial locations of the trophallactic interactions in the nest.

Division of labour in the black garden ant (Lasius niger) leads to three distinct proteomes.

Task specialization in social insects leads to striking intra-specific differences in behaviour, morphology, physiology and longevity, but the underlying mechanisms remain not yet fully understood. Adult colonies of black garden ants (Lasius niger) have a single queen fertilized by one or a small number of males. The inter-individual genetic variability is thus relatively low, making it easier to focus on the individual molecular differences linked to the division of labour.

Weber's Law-based perception and the stability of animal groups.

Group living animals form aggregations and flocks that remain cohesive in spite of internal movements of individuals. This is possible because individual group members repeatedly adjust their position and motion in response to the position and motion of other group members. Here, we develop a theoretical approach to address the question, what general features-if any-underlie the interaction rules that mediate group stability in animals of all species? We do so by considering how the spatial organization of a group would change in the complete absence of interactions.

Symmetry breaking and inter-clonal behavioural variability in a slime mould.

Cells are dynamic systems capable of switching from isotropic growth to polarized growth even in the absence of any pre-existing external asymmetry. Here, we study this process of symmetry breaking in the acellular slime mould Physarum polycephalum. In these experiments, slime moulds could grow on two identical opposed sources of calcium.

The role of personality variation, plasticity and social facilitation in cockroach aggregation.

Personality variation has been proven to affect ecology, evolution and group behaviour in many ways. Nevertheless, how social context influences behavioural strategies and individual personality variation has rarely been addressed. This study sheds light on the relationship between social interactions, personality variation and plasticity in a collective context.

Food dissemination in ants: robustness of the trophallactic network against resource quality.

Insect societies are often composed of many individuals, achieving collective decisions that depend on environmental and colonial characteristics. For example, ants are able to focus their foraging effort on the most rewarding food source. While this phenomenon is well known, the link between the food source quality and the intranidal food dissemination networks and its dynamics has been neglected.

The interplay between personalities and social interactions affects the cohesion of the group and the speed of aggregation.

Collective decision-making plays a central role in group-living animals and can be crucial to the survival of a group and the fitness of its members. As group-level properties emerge from individual decisions, personality variation can be a major determinant of collective behaviours. Here, we explore the relationship between personality and social interactions to explain the speed and cohesion of collective decision making during the aggregation process of the American cockroach (Periplaneta americana).

Same length, different shapes: ants collectively choose a straight foraging path over a bent one.

In socials insects, exploration is fundamental for the discovery of food resources and determines decision-making. We investigated how the interplay between the physical characteristics of the paths leading to food sources and the way it impacts the behaviour of individual ants affects their collective decisions. Colonies of different sizes of had access to two equal food sources through two paths of equal length but of different geometries: one was straight between the nest and the food source, and the other involved an abrupt change of direction at the midway point (135°).