Evolution of female choosiness and mating frequency: effects of mating cost, density and sex ratio

International audienceChoice for mate quality and number of mates are key components of female mating strategies. We investigated how selection on female choosiness also influences number of matings in various ecological conditions. In our individual-based model, females choose their first mate according to an evolving acceptance threshold and then mate with males of increasing quality (trade-up choice). We simulated evolution of this threshold under various conditions of density, sex ratio and mating cost. Thresholds rapidly evolve towards a small set of values that depend on the tested parameters. Consistent with intuitive predictions, choosier females are selected when either number of encounters with males or mating cost is high. Selection results in most females sharing the same threshold. Variation in female mating patterns remains because some variation in thresholds is maintained, at least by mutations, and because of random events affecting number of matings. Our model indicates that mating cost strongly affects evolution of female choosiness and mating frequency. Moreover, it influences the relative importance of other factors: when mating cost is low, selection on acceptance thresholds is weak and relatively more females use thresholds that differ from the norm. In that context, mate quality is therefore the most important factor affecting female reproductive success. When mating cost is high, females evolve thresholds such that both the cost of multiple mating and the risk of remaining unmated become as important as mate quality. High mating cost, by selecting for high choosiness, also leads to females mating with fewer males

Domestic gardens as favorable pollinator habitats in impervious landscapes

International audienc

Approvisionnement social et prévisibilité des ressources

en français : Pour trouver leur nourriture, les individus peuvent utiliser des informations qu'ils ont recueillies eux-mêmes précédemment ou des informations obtenues par l'observation de leurs congénères. Le type d'information utilisé dépend beaucoup de la prévisibilité de leur nourriture. Quand la nourriture n'est pas prévisible, l'information personnelle n'a que peu de valeur. C'est le cas des vautours Gyps qui s'approvisionnent socialement pour trouver des carcasses. Certaines activités humaines changent la prévisibilité des ressources, par exemple en installant des charniers qui rendent la nourriture plus prévisible pour les nécrophages. Dans cette thèse, j'étudie l'impact de la prévisibilité des ressources alimentaires sur la stratégie d'approvisionnement et sur le service écologique rendu par les vautours. J'ai créé un modèle individu-centré spatialement explicite du comportement journalier des vautours proposant plusieurs stratégies de recherche et différents contextes de gestion. Le modèle montre que les individus favorisant les charniers rendent un service d'équarrissage plus faible et souffrent plus de la compétition lors de l'exploitation car ils s'agrègent davantage sur les ressources que des individus recherchant en groupe. Je discute des conséquences de ce travail sur le plan de la conservation et de la gestion des populations de vautours. Ce travail sera utilisé à court terme pour aider à l'analyse d'un suivi GPS. Enfin, il sera intégré dans une étude incluant des aspects socio-économiques afin d'avoir une vue d'ensemble du service rendu par les vautours et de sa sensibilité aux activités humaines.en anglais : Foraging individuals may use either personal information derived from their own previous experience or social information based on conspecific observation. Which kind of information is used depends largely on food predictability. When resources are unpredictable, personal information may be of little use, as illustrated by Gyps vultures that mostly rely on social foraging strategies to find carrion. Some human activities increase resource predictability, e.g. supplying feeding stations makes food patches more predictable for scavengers. In this thesis, I explore the impact of different levels of resource predictability on the use of personal or social information in foraging strategies and on the ecological service provided by vultures. I developed an individual-based spatially explicit model of foraging Gyps vultures at a daily scale to explore different behavioural hypotheses as well as different management scenarios. The results show that individuals using previously acquired personal information provided a less efficient scavenging service, tended to be more aggregated on resources and thus suffered more strongly from competition while feeding than individuals foraging in groups. Then, I discuss the consequences of this work in terms of conservation and population management. This work will also be used to help analyse GPS tracking data. Finally, it will be integrated in a study that takes into account socio-economical aspects to better understand all sides of the vultures' ecological service and its sensitivity to human interventions.PARIS-AgroParisTech Centre Paris (751052302) / SudocSudocFranceF

Behavioral Correlates of Primates Conservation Status: Intrinsic Vulnerability to Anthropogenic Threats

<div><p>Behavioral traits are likely to influence species vulnerability to anthropogenic threats and in consequence, their risk of extinction. Several studies have addressed this question and have highlighted a correlation between reproductive strategies and different viability proxies, such as introduction success and local extinction risk. Yet, very few studies have investigated the effective impact of social behaviour, and evidence regarding global extinction risk remains scant. Here we examined the effects of three main behavioral factors: the group size, the social and reproductive system, and the strength of sexual selection on global extinction risk. Using Primates as biological model, we performed comparative analysis on 93 species. The conservation status as described by the IUCN Red List was considered as a proxy for extinction risk. In addition, we added previously identified intrinsic factors of vulnerability to extinction, and a measure of the strength of the human impact for each species, described by the human footprint. Our analysis highlighted a significant effect of two of the three studied behavioral traits, group size and social and reproductive system. Extinction risk is negatively correlated with mean group size, which may be due to an Allee effect resulting from the difficulties for solitary and monogamous species to find a partner at low densities. Our results also indicate that species with a flexible mating system are less vulnerable. Taking into account these behavioral variables is thus of high importance when establishing conservation plans, particularly when assessing species relative vulnerability.</p></div

Common birds during winter in the face of urbanization, foraging ecology questioned thanks to an original citizen science scheme (BirdLab)

Supplementary feeding of birds during the winter is a widespread phenomenon in temperate countries. While such practice can boost individuals' winter survival, not all species are likely to use bird feeders. We were particularly interested in examining if feeders on private gardens adjacent to areas impacted by agriculture could benefit farmland birds. Since 2014, the French Museum of Natural History started an ambitious citizen science schemes named BirdLab to observe the bird communities and the intra- and inter-specific interactions on a pair of birdfeeders by asking participants to reproduce the movements (arrival, feeder switch, and leaving) of each bird on two identical birdfeeders (platform or tube), on their smartphone or tablet by drag and drop small characters representing species, for a protocol of exactly 5 minutes. Four seasons after, this with more than 25000 five minutes' samples that observe around 500000 birds of 27 easily recognisable species among the most common species that used the birdfeeders in France.  Thus, after work to verify that the expertise level of contributors does not affect the quality of data provided by this citizen science scheme, we use this big and well-standardised dataset to study winter bird diversity at feeders at the national level of France. In particular, we examine whether the proportions of artificial and agricultural territories, forests and semi-natural environments, wetlands and water areas in the buffer zone of 500 m around the feeders affect the avian diversity multifaceted indicators (as the number of visits, species richness, trophic index, and Shannon's index). As expected, the diversity of species recruited to feeders increases with the presence of natural elements in the gardens such as trees and edges but also it diminishes with urbanisation, and this even for low gradients of urbanisation. Nevertheless, our results point to a clear synergy between agricultural territories and urban areas around the gardens, with diversity increasing in urban areas adjacent to agricultural territories. Our result supports the hypothesis that private gardens may participate in the conservation of declining farmland species, and with some precautions to limit the risks associated to the local increasing bird densities on feeders (predator attack, epidemic risk), they offer an alternative source of seeds to granivorous species, particularly in farmland intensive landscape which does not provide food for animals during the whole winter. Furthermore, this innovative application and citizen science encourages reconnection to nature and allows highly standardized data production by novice naturalists. In addition, the data provided will make it possible to question the species interactions in the bird feeder context.peerReviewe

Effectiveness of interventions for managing human-large carnivore conflicts worldwide: Scare them off, don't remove them

International audienceHuman-wildlife conflicts are associated with a threat to large carnivores, as well as with economic and social costs, thus challenging conservation management around the world. In this study, we explored the effectiveness of common management interventions used worldwide for the purpose of conflict reduction using an evidence-based framework combining expert assessment of intervention effectiveness, impact and uncertainty of assessment. We first conducted a literature review of human-large carnivore conflicts across the world. Based on this review, we identified three main types of management interventions (non-lethal, translocations, and lethal management) and we assessed their effectiveness. Our review indicates that, although the characteristics of conflicts with large carnivores are heavily influenced by the local context and the species, the main issues are depredation on livestock, space-sharing, and attacks on humans. Non-lethal interventions are more likely to reduce conflict, whereas translocations and lethal interventions are mostly ineffective and/or harmful to carnivore populations, without fostering successful long-term coexistence. The literature on conflict management is often imprecise and lacks consistency between studies or situations, which generally makes comparisons difficult. Our protocol allows for the reliable comparison of experiments characterized by heterogeneous standards, response variables, protocols, and quality of evidence. Nevertheless, we encourage the use of systematic protocols with common good standards in order to provide more reliable empirical evidence. This would clarify the relative effectiveness of conflict management strategies and contribute to the global reduction in the occurrence of human-large carnivore conflicts across the world

The phylogenetic inertia of the conservation status in Primate species.

<p>Species names are written in different colours according to their conservation status.</p

Best explanatory models according to the AICc (ΔAICc ≤ 2 in relation the smaller AICc).

<p>Signs indicate the sense of the effect of the variables included in the model. The number of signs inform on the significance level of the estimates (***: p ≤ 0.05, **: 0.05 < p ≤ 0.1, and * p > 0.1).</p><p>Best explanatory models according to the AICc (ΔAICc ≤ 2 in relation the smaller AICc).</p

Non-linear effects of landscape on pollination service and plant species richness in a peri-urban territory with urban and agricultural land use

International audiencePollination contributes to both human food security and the reproduction of the majority of wild plant species, but pollinators are facing a rapid decline, a major cause of which is habitat conversion and degradation due to human activities. Urbanization is one of the major types of habitat conversion, but its influence on pollination has been surprisingly mixed, ranging from markedly negative to strongly positive effects. One hypothesis proposed to explain these discrepancies is that pollinator responses to urbanization are highly dependent on the nonurban control habitat, with negative effects when the controls are natural or semi-natural areas but positive when they are intensive agricultural areas. It was also proposed that the pollination response along an agricultural-tourban gradient is non-linear, with maximum pollination observed at an intermediate level of urbanization due to increased environmental heterogeneity. To test these two hypotheses, we selected a group of 38 sites in a periurban area near Paris, France, using a semi-stratified sampling strategy that ensured that all three of the urban, agricultural and semi-natural gradients were maximized. We then estimated pollination using two approaches: we evaluated the pollination success of Lotus corniculatus, a strictly entomogamous self-sterile plant species pollinated mainly by bees, and we measured the species richness of entomogamous and non-entomogamous plants, the difference in their response being expected to relate to the pollination service provided by the overall pollinator community. We found that in our study area, pollination success of L. corniculatus responds positively to the agricultural to urban gradient but not to the semi-natural to urban gradient. The diversity of both entomogamous and non-entomogamous plants is highest at sites surrounded by intermediate proportions of urban and agricultural areas. In addition, high proportions of urban areas have a negative effect on the diversity of non-entomogamous but not entomogamous plant species, suggesting that pollinators are able to partially buffer entomogamous plant species against the negative effect of urban development. Our results show the importance of urban areas in pollination conservation plans and demonstrate that the interaction between different anthropogenic land-use is an important factor for understanding pollination