Maxence Gérard

Maxence Gérard
Stockholm University | SU · Department of Zoology

PhD in Zoology

About

58
Publications
14,200
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389
Citations
Introduction
Postdoctoral research fellow (Wenner Gren Grant) at the University of Stockholm (Zoology Department). I am an ecologist who studies the impact of stressors, as well as biotic/abiotic conditions on pollinators, particularly on their phenotype. I am currently involved in INVISMO (INsect Vision and MOvement) and POSHBEE projects. I was previously involved in CLIPS (CLImate change and effect on Pollination Services ; Excellence Of Science) and STEP (Status and Trends of European Pollinators).

Publications

Publications (58)
Article
Full-text available
In a context of rapid global change, understanding how environmental stressors can impact phenotypic variation, and which phenotypic traits are predominantly affected can be particularly relevant. Indeed, potential pheno-typic modifications could affect the functionality of traits from taxa that are in decline but that are keystone species in many...
Article
Full-text available
Bee foraging behavior provides a pollination service that has both ecological and economic benefits. However, bee population decline could directly affect the efficiency of this interaction. Among the drivers of this decline, global warming has been implicated as an emerging threat but exactly how increasing temperatures affect bee foraging behavio...
Article
Full-text available
Specific floral resources may help bees to face environmental challenges such as parasite infection, as recently shown for sunflower pollen. Whereas this pollen diet is known to be unsuitable for the larval development of bumble bees, it has been shown to reduce the load of a trypanosomatid parasite (Crithidia bombi) in the bumble bee gut. Recent s...
Article
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Global warming has been identified as a key driver of bee declines around the world. While it is clear that elevated temperatures during the spring and summer months – the principal activity period of many bee species – is a factor in this decline, exactly how temperature affects bee survival is unknown. In vertebrates, there is clear evidence that...
Article
Full-text available
Safeguarding crop pollination services requires the identification of the pollinator species involved and the provision of their ecological requirements at multiple spatial scales. However, the potential for agroecological intensification of pollinator-dependent crops by harnessing pollinator diversity is limited by our capacity to characterise the...
Article
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Climate change and increasing average temperatures are now affecting most ecosystems. Social insects such as bumblebees are especially impacted because these changes create spatial, temporal and morphological mismatches that could impede their ability to find food resources and mate. However, few studies have assessed how the colony and life cycle...
Article
The decline of pollinators has been demonstrated scientifically and this phenomenon is widely recognized by both the general public and by stakeholders. Since pollinators face different threats that are all linked to human activities, there is a unique and unprecedented responsibility for people to conserve pollinators, requiring political action t...
Article
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The selection of appropriate food resources by bees is a critical aspect for the maintenance of their populations, especially in the current context of global change and pollinator decline. Wild bees have a sophisticated ability to forage selectively on specific resources, and can assess the quality of pollen using contact chemosensory perception (...
Article
Full-text available
Global changes are severely affecting pollinator insect communities worldwide, resulting in repeated patterns of species extirpations and extinctions. Whilst negative population trends within this functional group have understandably received much attention in recent decades, another facet of global changes has been overshadowed: species undergoing...
Article
Full-text available
• Against the context of global wildlife declines, targeted mitigation strategies have become critical to preserve what remains of biodiversity. However, the effective development of conservation tools in order to counteract these changes relies on unambiguous taxonomic determination and delineation. • In this study, we focus on an endemic bumblebe...
Data
Single page summary of Vanderplank et al (2021) - contains a QR code for accessing the paper
Article
Full-text available
Current global change substantially threatens pollinators, which directly impacts the pollination services underpinning the stability, structure and functioning of ecosystems. Among these threats, many synergistic drivers such as habitat destruction and fragmentation, increasing use of agrochemicals, decreasing resource diversity as well as climate...
Article
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Recent bumble bee declines have made it increasingly important to resolve the status of contentious species for conservation purposes. Some of the taxa found to be threatened are the often rare socially parasitic bumble bees. Among these, the socially parasitic bumble bee, Bombus flavidus Eversmann, has uncertain species status. Although multiple s...
Article
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Body size is a key parameter of organism fitness. While the impact of climate change on body size has received increasing attention, the long‐term consequences of landscape fragmentation are still poorly known. These two major global threats may potentially induce opposite trends: the decrease of body size in warmer environments (e.g. individuals d...
Article
Global change affects species by modifying their abundance, spatial distribution, and activity period. The challenge is now to identify the respective drivers of those responses and to understand how those responses combine to affect species assemblages and ecosystem functioning. Here we correlate changes in occupancy and mean flight date of 205 wi...
Article
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Abstract: Wild bees are facing a global decline mostly induced by numerous human factors for the last decades. In parallel, public interest for their conservation increased considerably, namely through numerous scientific studies relayed in the media. In spite of this broad interest, a lack of knowledge and understanding of the subject is blatant a...
Article
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Wild and managed bees are essential for global food security and the maintenance of biodiversity. At present, the conservation of wild bees is hampered by a huge shortfall in knowledge about the trends and status of individual species mainly due to their large diversity and variation in life histories. In contrast, the managed Western honey bee Api...
Article
Full-text available
The mutualism between plants and their pollinators provides globally important ecosystem services, but it is likely to be disrupted by global warming that can cause mismatches between both halves of this interaction. In this review, we summarise the available evidence on (i) spatial or (ii) phenological shifts of one or both of the actors of this m...
Article
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Since the beginning of taxonomy, species have been described based on morphology, but the advent of using semio-chemicals and genetics has led to the discovery of cryptic species (i.e. morphologically similar species). When a new cryptic species is described, earlier type specimens have to be re-evaluated, although this process can be challenging a...
Article
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Bumble bees ( Bombus spp.) are a widespread corbiculate lineage (Apinae: Corbiculata: Bombini), mostly found among temperate and alpine ecosystems. Approximately 260 species have been recognized and grouped recently into a simplified system of 15 subgenera. Most of the species are nest-building and primitively eusocial. Species of Bombus have been...
Article
Species can respond differently when facing environmental changes, such as by shifting their geographical ranges or through plastic or adaptive modifications to new environmental conditions. Phenotypic modifications related to environmental factors have been mainly explored along latitudinal gradients, but they are relatively understudied through t...
Conference Paper
Full-text available
Body size clines have been widely explained by the Bergmann's rule (i.e. larger individuals in colder conditions) in homeothermic vertebrates. However, there is no general consensus in poikilotherms organisms particularly in insects. Among them, bees are a highly diverse pollinators group with high economic and ecological value. Nevertheless, no co...
Article
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While many bee species are experiencing population declines, some host plant generalist bees remain common in Europe, partly because they seem able to shift to new resources. However, foraging on a new alternative plant, such as an invasive species, can modify diet quality and have a potentially detrimental effect on bee health. Herein, we investig...
Article
While bumblebees have been the focus of much research, the taxonomy of many species groups is still unclear, especially within circum-polar species. Delimiting species based on multisource datasets provides a solution to overcome current systematic issues of closely related populations. Here, we use an integrative taxonomic approach based on novel...
Article
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Abstract Human activities can generate a wide variety of direct and indirect effects on animals, which can manifest as environmental and genetic stressors. Several phenotypic markers have been proposed as indicators of these stressful conditions but have displayed contrasting results, depending, among others, on the phenotypic trait measured. Knowi...
Article
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Aim Genetic diversity is a key factor to species survival. This diversity is unevenly distributed across the species range, delimiting genetic diversity hotspots (GDH). Focusing conservation efforts on regions where GDH of several species overlap (i.e., multispecies GDH) could rationalize conservation efforts by protecting several taxa in one go. H...
Article
Full-text available
Body size latitudinal clines have been widley explained by the Bergmann's rule in homeothermic vertebrates. However, there is no general consensus in poikilotherms organisms in particular in insects that represent the large majority of wildlife. Among them, bees are a highly diverse pollinators group with high economic and ecological value. Neverth...
Article
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Population connectivity is an important source of information for planning conservation strategy. The degree of connectivity implies using alternative conservation prioritizations based on the appropriate spatial scale for management units. In species with low population connectivity, it is important to preserve local populations in order to mainta...
Article
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Morphological traits can be highly variable over time in a particular geographical area. Different selective pressures shape those traits, which is crucial in evolutionary biology. Among these traits, insect wing morphometry has already been widely used to describe phenotypic variability at the inter-specific level. On the contrary, fewer studies h...
Data
Supplementary Figures A, B and C, and Supplementary Tables A, B and C. Figure A: interpolation graphs generated with a distance weighting parameter a = 1. Figure B: interpolation graphs generated with a distance weighting parameter a = 10. Figure C: PCoA (principal component analysis) performed on the overall matrix of estimated morphological dista...
Article
The current bumblebee decline leads to inbreeding in populations that fosters a loss of allelic diversity and diploid male production. As diploid males are viable and their offspring are sterile, bumblebee populations can quickly fall in a vortex of extinction. In this paper, we investigate for the first time a potential pre-mating mechanism throug...
Conference Paper
Full-text available
Being efficient pollinators of many flowering plants, bumblebees are an important group for temperate ecosystems services. Over the last decades they experience a strong decline in Europe because of different primary factors such as habitat fragmentation. These primary factors lead to genetic stresses that can reinforce the decline. This is particu...
Article
Full-text available
Presence of diploid males in wild bees reflects inbreeding and provide information about the health status of a colony or population. Detection of diploid males, and discrimination from haploid males and workers has, however, been limited to molecular diagnostics. Here we present a novel method based on differences in wing shape, e.g. venation patt...
Conference Paper
Full-text available
Being efficient pollinators of many flowering plants, bumblebees are an important group for temperate ecosystems services. Over the last decades they experience a strong decline in Europe because of different primary factors such as habitat fragmentation. These primary factors lead to genetic stresses that can reinforce the decline. This is particu...
Conference Paper
Full-text available
By detecting the presence or absence of vocal species, the study of soundscapes unveils information about ecosystems. The present work is an analysis of sound records collected at the beginning of July 2014 in the rural, publicly owned nature park of Chevetogne, Belgium. A continuous 24-hour window is focused on. The primary microphone is set up in...

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Projects

Projects (2)
Project
Understand the impacts of climate and habitat changes on pollinators worldwide.
Archived project
The goal of this project is to describe different bee species at population level. We consider at different geographical level (region, country, continent) their genetic diversity/structure, morphology and ecology. We aim to record the trend of the population to assess their risk of extinction. These data are used as basic information for red list following IUCN criteria. We are participating now to the bumblebee specialist group of the IUCN (see report: https://www.researchgate.net/publication/314204789_IUCN_BBSG_-_Bumblebee_Specialist_Group_Report_2016).