Marine Levé

En France, plus de la moitié de la population se trouve en ville et ce chiffre croît. L'urbanisation change les opportunités de rencontre des habitant.e.s avec la nature, même si leur connaissance de la biodiversité est relativement bonne. L'urbanisation a également des effets, souvent négatifs, sur les populations des autres êtres vivants, dont les insectes pollinisateurs. Dans les milieux péri-urbains, un lieu de rencontre entre habitant.e.s et nature est le jardin privé. En écologie urbaine, les études sur les jardins domestiques se développent mais sont encore peu nombreuses. Cette thèse a cherché à montrer que les jardins sont intégrés dans un contexte paysager et sociétal plus large qui leur permet de jouer un rôle dans la conservation de la biodiversité, notamment celle des insectes pollinisateurs. J'ai pour cela travaillé à plusieurs échelles et mobilisé des cadres conceptuels et des outils de l'écologie, la géographie et la psychologie de la conservation, afin de caractériser différents aspects du socio-écosystème jardin. Je me suis d'abord placée à l'échelle de l'Île-de-France et ai montré que les jardins et zones denses en jardins sont des espaces favorables à la diversité en insectes pollinisateurs au sein d'une matrice urbaine. Par la suite, j'ai précisé les déterminants de la variété (diversité, type de culture, origine, rareté) des fleurs, ressources pour les insectes pollinisateurs dans les jardins : j'ai confirmé l'effet négatif de l'urbanisation, j'ai mis en évidence des effets variables de la structure des jardin et enfin je n'ai pas identifié de relation avec le degré de connexion à la nature des habitant.e.s. L'évolution des ressources se fait de fleurs spontanées et communes à plus cultivées et rares au fil de la saison. Je me suis aussi intéressée à deux actions de protection des pollinisateurs (participation au suivi photographique des insectes pollinisateurs et plantation de fleurs nectarifères) à l'échelle du jardin et j'ai montré l'importance de l'aspect expérientiel de ces actions pour motiver l'intention de réaliser le comportement. Enfin, une dernière partie prend en compte le vécu des habitant.e.s dans leur jardin et montre que habiter un jardin se fait sous la forme d'un réseau de relations plus ou moins dense englobant les éléments de nature : le jardin est un lieu de fleurissement mais aussi d'attention portée au vivant et parfois point de départ pour toucher d'autres lieux ou personnes, dans une perspective de conservation. Cette thèse offre des perspectives pour la prise en compte des expériences et contextes locaux dans la conservation de la biodiversité des insectes pollinisateurs. Une recommandation qui en découle est la nécessité d'un dialogue renouvelé entre les désigné.e.s expert.e.s de la conservation en milieu urbain et les habitant.e.s.

Urban expansion is correlated to negative biodiversity trends. The amount of impervious surfaces in urban areas is a determinant of pollinator species assemblages. While the increase in urbanization and impervious surfaces negatively impacts pollinators, cities also encompass urban green spaces, which have a significant capacity to support biodiversity. Among them, domestic gardens that represent a non-negligible fraction of green spaces have been shown to benefit pollinators. Domestic gardens may form habitat clusters in residential areas, although their value at a landscape scale is still unknown. Here, we investigate the combined effects of impervious surfaces and domestic garden areas on pollinator richness. Due to the difficulty of accessing privately owned domestic gardens, we chose to use citizen science data from a well-established French citizen science program known as SPIPOLL. Using regression tree analysis on buffers located from 50m to 1000m around the data points, we show the importance of pollinators being in close proximity to domestic gardens as locally favorable habitats that are embedded within a landscape, in which impervious surfaces represent unfavorable areas. We highlight the inter-connection between local and landscape scales, the potential for patches of domestic gardens in residential areas, and the need to consider the potential of gardeners’ coordinated management decisions within a landscape context. Highlights: Citizen science provided access to domestic gardens, understudied urban green spaces Impervious surfaces limit pollinators presence at landscape level Sufficient critical amount of gardens increased pollinator diversity at local scale Critical amount of gardens’ knowledge may favor coordinated decisions by gardeners Pollinators may benefit from patches of domestic gardens in an urban matrix

Many chimpanzees throughout the world are housed in captivity, and there is an increasing effort to recreate social groups by mixing individuals with captive origins with those with wild origins. Captive origins may entail restricted rearing conditions during early infant life, including, for example, no maternal rearing and a limited social life. Early rearing conditions have been linked with differences in tool-use behavior between captive- and wild-born chimpanzees. If physical cognition can be impaired by non-natural rearing, what might be the consequences for social capacities? This study describes the results of network analysis based on grooming interactions in chimpanzees with wild and captive origins living in the Kumamoto Sanctuary in Kumamoto, Japan. Grooming is a complex social activity occupying up to 25 % of chimpanzees’ waking hours and plays a role in the emergence and maintenance of social relationships. We assessed whether the social centralities and roles of chimpanzees might be affected by their origin (captive vs wild). We found that captive- and wild-origin chimpanzees did not differ in their grooming behavior, but that theoretical removal of individuals from the network had differing impacts depending on the origin of the individual. Contrary to findings that non-natural early rearing has long-term effects on physical cognition, living in social groups seems to compensate for the negative effects of non-natural early rearing. Social network analysis (SNA) and, in particular, theoretical removal analysis, were able to highlight differences between individuals that would have been impossible to show using classical methods. The social environment of captive animals is important to their well-being, and we are only beginning to understand how SNA might help to enhance animal welfare.

Whereas most experiments indicate that monkeys have no theory of mind, a study carried out by Wood and collaborators (2007) claimed that they can make inferences about the intentions of another individual. We applied the experimental procedure devised by these authors to investigate whether monkeys can recognize goal-directed actions. We tested 16 Tonkean macaques (Macaca tonkeana) and 12 tufted capuchin monkeys (Sapajus apella). Each subject was submitted to 24 trials in randomized order. The experimenter presented 2 containers, 1 of which was potentially baited with a food reward. After the experimenter had either intentionally or accidentally made an action on 1 of the containers, the subject was asked to select 1 of them. We found that individuals in both species failed to distinguish between accidental and intentional actions. However, they displayed a significant preference for the container touched by the experimenter in the hand conditions, and not in the elbow conditions. These results do not support those reported by Wood and collaborators, but they are consistent with other studies concluding that monkeys are not capable of mind reading.

Network optimality has been described in genes, proteins and human communicative networks. In the latter, optimality leads to the efficient transmission of information with a minimum number of connections. Whilst studies show that differences in centrality exist in animal networks with central individuals having higher fitness, network efficiency has never been studied in animal groups. Here we studied 78 groups of primates (24 species). We found that group size and neocortex ratio were correlated with network efficiency. Centralisation (whether several individuals are central in the group) and modularity (how a group is clustered) had opposing effects on network efficiency, showing that tolerant species have more efficient networks. Such network properties affecting individual fitness could be shaped by natural selection. Our results are in accordance with the social brain and cultural intelligence hypotheses, which suggest that the importance of network efficiency and information flow through social learning relates to cognitive abilities.

By distinguishing the attentional cues of their mates, animals can learn what part of their environment is of potential interest. However, recognizing the attentional states of others through auditory perception appears to be difficult, since these states are generally not accompanied by ostensive signals liable to reveal them. In this context, one study found that rhesus macaques withhold their action when unobserved, then concluding that they know what others can hear. We replicated this study by testing 18 Tonkean macaques in an experimental setting where subjects had to choose between two boxes containing a food reward. One box made a noise when opened, and the other opened silently. An experimenter was present and could either have her back to subjects or be facing them. If subjects aimed to avoid attracting the experimenter's attention, they were expected to select the silent box while the experimenter's back was turned. Results showed that subjects did not discriminate between boxes, whatever the experimenter's position. We thus found no evidence that Tonkean macaques are able to take the auditory attentional states of a human into account. It is therefore premature to conclude that monkeys can establish a link between hearing and knowing.