Dalila Bovet

Individual differences in exploratory activity relate to cognitive judgement bias in carpenter ants

Emotional state may influence cognitive processes such as attention and decision-making. A cognitive judgement bias is the propensity to anticipate either positive or negative consequences in response to ambiguous information. Recent work, mainly on vertebrates, showed that the response to ambiguous stimuli might change depending on an individuals affective state, which is influenced by e.g. the social and physical environment. However, the response to ambiguous stimuli could also be affected by the individuals behavioural type (personality), a question that has been under-investigated. We studied the link between individual differences in exploratory activity and the response to an ambiguous stimulus in the ant Camponotus aethiops. Exploratory behaviour, quantified with an open-field test, was variable among individuals but consistent over time within individuals. Individual ants learned to associate a spatial position to a reinforcement and another spatial position to a punishment. Once the ants had acquired this discrimination, cognitive judgement bias was tested with the stimulus in an intermediate position. Fast explorers in the open-field took significantly more time to approach the ambiguous stimulus compared to slow explorers, suggesting a negative judgement bias for fast explorers and a positive bias for slow explorers. This previously unknown link between individual difference in exploratory activity and cognitive bias in a social insect may help understanding the evolution and organization of social life.

Tool selection during foraging in two species of funnel ants

Tool use by nonhuman animals has received much research attention in the last couple of decades. Nevertheless, research has focused mostly on vertebrates, particularly primates and corvids, even though tool use has also been documented in insects. One of the best documented examples involves ants using debris (e.g. sand grains, mud, leaf fragments) to collect and transport liquid food to their nest. However, little is known about the factors that determine the selection of materials to be used as tools. We investigated tool selection in two species of Aphaenogaster ants by giving them the choice between different kinds of potential tools (natural and artificial objects). Ant workers showed a clear preference for certain materials to be used as tool objects. Tool selection was also shaped by familiarity with the material as ants developed a preference for artificial tools with a good soaking capacity that cannot be found in their natural environment. Our results indicate that ants of this genus have evolved unique foraging strategies and show plasticity in their behaviour.

On Public Influence on People's Interactions with Ordinary Biodiversity.

Besides direct impacts of urban biodiversity on local ecosystem services, the contact of city dwellers with urban nature in their everyday life could increase their awareness on conservation issues. In this paper, we focused on a particularly common animal urban species, the feral pigeon Columba livia. Through an observational approach, we examined behavioral interactions between city dwellers and this species in the Paris metropolis, France. We found that most people (mean: 81%) do not interact with pigeons. Further, interactions (either positive or negative) are context and age-dependent: children interact more than adults and the elderly, while people in tourist spots interact more than people in urban parks or in railway stations, a result that suggests that people interacting with pigeons are mostly tourists. We discuss these results in terms of public normative pressures on city dwellers’ access to and reconnection with urban nature. We call for caution in how urban species are publically portrayed and managed, given the importance of interactions with ordinary biodiversity for the fate of nature conservation.

Motivation and manipulation capacities of the blue and yellow macaw and the tufted capuchin: a comparative approach.

This study compared the motivation of the blue and yellow macaw (n=8) and the tufted capuchin (n=3) to manipulate objects that presented different features, their manipulative repertoires, and their ability to solve complex manipulation tasks. Results show that both species seem to be more motivated to manipulate objects that look like food items and that manipulative behavior may be considered as play behavior in the blue and yellow macaws, and would improve foraging motor skills. The tufted capuchins performed more different action styles than the macaws when manipulating objects, and performed substrate-use behavior - the object is put in relationship with a substrate - while the macaws did not. This is an interesting difference because these characteristics are supposed to be precursory of tool-use, behavior never observed in this macaw species. It may be due to the arboreal lifestyle of the macaw and its neophobic character that do not allow it to easily contact objects. Following the same method and using more individuals, further comparative studies should be conducted in order to test these hypotheses. Both species were able to solve complex manipulation tasks.

Sociality enhances birds’ capacity to deal with anthropogenic ecosystems

Urban species often adjust their behavior to survive in urban environments, characterized by the proximity of humans, habitat fragmentation and heterogeneous, fluctuating ecological resources. Several hypotheses have been put forth to explain how species manage living in heterogeneous and complex anthropogenic habitats. The ability of individuals or species to beneficially modify their behaviors in response to changes in the environment has indeed been alternatively explained based on phylogenetic, adaptive, and ontogenic arguments. In this study we investigated the role of sociality as a driver of behavioural flexibility in urban birds. Sociality can be defined as the tendency to associate with conspecifics or form a group and may influence a species’ ability to survive in an urban ecosystem to the extent that it represents advantages to species or individuals in terms of resource exploitation, fitness, and predation risk-avoidance. Given the potential benefits of sociality we hypothesized that sociality is a further characteristic that may explain how species have successfully expanded their range into urbanized areas. Based on this hypothesis, we predicted that pigeons (Columba livia) will show higher behavioural flexibility when in larger groups, whatever their genetic background and living-circumstances. Using pigeons as a model system, we compared 27 groups in France and Italy composed of four different genetic strains and varying living-conditions: free-living feral pigeons in urban areas, free-living domestic pigeons at the property of a local breeder captive, feral pigeons in a French ecological field station, captive domestic pigeons in an Italian ecological station. We tested two standardized behavioral measures of behavioural flexibility: thresholds for fear or neophobia and rates of problem solving. We found that group number affects neophobia and to a lesser extent problem-solving, suggesting that sociality is a factor enhancing birds’ faculties to establish in and cope with heterogeneous urban environments. We consider this hypothesis here as compatible and complementary to existing hypotheses on species’ adaptation to urban ecosystems.