Denis Michez

Université de Mons · Department of Zoology

Pollinators are threatened worldwide and strategies and measures to support their conservation are proliferating. Among them, the approach “Farming with Alternative Pollinators” (FAP) aims to support pollinators by seeding strips of pollinator-attracting cultivated plants surrounding the crops, and simultaneously providing income to the farmer. In...

Climate, landscape composition, management practice, and wild bee pollination are all variables thought to play significant roles in commercial apple production. However, how these variables affect production efficiency under field-realistic conditions has not been investigated at large geographical scales. We combined intensive standardized field...

Flower-visiting insects in agroecosystems forage on field-edge weeds often exposed to agrochemicals that may compromise the quality of their floral resources. We conducted complementary field and greenhouse experiments to evaluate the: 1) effect of low concentrations of agrochemical exposure on nectar and pollen quality and 2) relationship between...

The microbiome of honeybees ( Apis spp.) and bumblebees ( Bombus spp.) is highly conserved and represented by few phylotypes. This simplicity in taxon composition makes the bee’s microbiome an emergent model organism for the study of gut microbial communities.

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...

Food production is highly dependent on pollination services provided by insects; 75% of the leading global food crops need animals for successful production. Pollinators, including managed and wild bees, are declining in many parts of the world. The loss of natural habitats providing nesting sites is considered as one of the main factors driving th...

Commercial apple production relies on managed honey bees for pollination, and on intensive management for pest control. Previous studies revealed the detrimental effects of these factors on wild bee diversity in agroecosystems, and the pollination services they provide. However, the extent to which honey bee dominance and management interact under...

Pollinators are facing declines at a global level. One of the main factors driving this decline is insufficient access to floral resources due to habitat loss and degradation that can affect both diet generalist species as well as those with more restricted floral preferences. Here we evaluated the effect of a novel mitigation strategy in agricultu...

With 2,000 species currently recorded in Europe, bees are a highly diversified and efficient group of pollinating insects. They obtain their nutrients from nectar and pollen of flowers. However, the chemical composition of these resources, especially of pollen (e.g., protein, lipid, amino acids, fatty acids, or sterol content), is highly variable a...

Pollinator declines have prompted efforts to assess how land-use change affects insect pollinators and pollination services in agricultural landscapes. Yet many tools to measure insect pollination services, require substantial landscape-scale data and technical expertise. In expert workshops, 3 straightforward methods (desk-based method, field surv...

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...

Commercial apple production relies on managed honey bees (Apis mellifera) for pollination, and on intensive management for pest control. Previous studies have highlighted the potentially detrimental effects of intensive crop management on wild bee diversity in agroecosystems, potentially jeopardizing the pollination services they provide. However,...

The mining bees (Andrenidae) are a major bee family of over 3000 described species with a nearly global distribution. They are a particularly significant component of northern temperate ecosystems and are critical pollinators in natural and agricultural settings. Despite their ecological and evolutionary significance, our knowledge of the evolution...

Snodgrassella is a Betaproteobacteria genus found in the gut of honeybees ( Apis spp.) and bumblebees ( Bombus spp). It is part of a conserved microbiome that is composed of few core phylotypes and is essential for bee health and metabolism. Phylogenomic analyses using whole genome sequences of 75 Snodgrassella strains from 4 species of honey bees...

The bumblebee Bombus terrestris is used worldwide for crop pollination. Despite its positive impact on crop yield, it has become a widespread threat to biodiversity due to its interactions with local bumblebee populations. Commercial subspecies introduced to the Iberian Peninsula since the 1990s without any regulation have colonized the environment...

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...

Climate change is related to an increase in the frequency and intensity of extreme events such as heatwaves. In insect pollinators, heat exposure is associated with direct physiological perturbations and, in several species, could lead to a decrease of fitness related to a decrease in fertility. Here we developed a new experimental protocol in cont...

Bee populations have declined in many parts of the world, raising concerns over their conservation and the pollination services they provide. As a result of declines in agricultural areas, agri-environment schemes have been designed and implemented in order to reverse these trends. Until now, these schemes have largely focused on providing an abund...

A reduction in floral resource abundance and diversity is generally observed in agro-ecosystems, along with widespread exposure to pesticides. Therefore, a better understanding on how the availability and quality of pollen diets can modulate honeybee sensitivity to pesticides is required. For that purpose, we evaluated the toxicity of acute exposur...

PoshBee is a 5-year funded project (2018-2023) that aims to support healthy bee populations, sustainable beekeeping, and consequently pollination for crops and wildflowers across Europe. To do this we take a range of approaches, from the laboratory to the field, from molecules to ecosystems, and from fundamental science to risk assessment. This doc...

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...

Iberia has one of the richest bee faunas in the world, and the genus Andrena is no exception with around 200 species known from the Peninsula. The fauna of Andrena was largely revised in the 1970s, but since then, it has received little attention. Molecular investigation of the taxonomically challenging subgenus Taeniandrena has revealed that the s...

Bumble bees (Bombus) are a group of eusocial bees with a strongly generalised feeding pattern, collecting pollen from many different botanical families. Though predominantly generalists, some bumble bee species seem to have restricted dietary choices. It is unclear whether restricted diets in bumble bees are inherent or a function of local conditio...

Bumblebees are ubiquitous, cold-adapted eusocial bees found worldwide from subarctic to tropical regions of the world. They are key pollinators in most temperate and boreal ecosystems, and both wild and managed populations are significant contributors to agricultural pollination services. Despite their broad ecological niche at the genus level, bum...

The study of wild bees has markedly increased in recent years due to their importance as pollinators of crops and wild plants, and this interest has been accentuated by increasing evidence of global declines in their abundance and species richness. Though best studied in Europe and North America, knowledge on the current state of wild bees is scarc...

• 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...

Single page summary of Vanderplank et al (2021) - contains a QR code for accessing the paper

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...

Many bees possess a tongue resembling a brush composed of a central rod (glossa) covered by elongated papillae, which is dipped periodically into nectar to collect this primary source of energy. In vivo measurements show that the amount of nectar collected per lap remains essentially constant for sugar concentrations lower than 50% but drops signif...

Climate change is an important driver of bee decline despite the fact that many species might respond to climate change differently. One method to predict how a species will respond to climate change is to identify its thermal tolerance limits. However, differences in thermal tolerance might also occur among distant populations of the same species...

Algeria, the largest country in Africa, has a species rich bee fauna because of its ecological conditions, climate and diversified flora. The present work represents a list of the genus Andrena Fabricius, 1775 in western Algeria. The survey, carried out during the period 2017–2019, has allowed identification of 56 species of Andrena in a total of 7...

Multisource approaches in taxonomy gather different lines of evidence in order to draw strongly supported taxonomic conclusions and constitute the basis of integrative taxonomy. In the case of overlooked taxa with disjunct distributions for which sampling is more challenging, integrative approaches help to propose stable hypotheses at the species a...

Wild bees represent a global group of highly diversified insect pollinators, nowadays concerningly well known for their widespread observed patterns of decline. Amongst them is the genus Dasypoda, a widespread Palearctic clade of solitary bees generally poorly represented in entomological collections. Among the 39 accepted species of the genus, 35...

Many wild bee species are declining globally. To design efficient mitigation strategies to slow down or reverse these trends, we urgently need to better understand their basic ecological requirements. In this context, we studied two specialist species for which ecological data are scarce: Dasypoda visnaga and Dasypoda maura. We provide for the firs...

PoshBee is a 5-year funded project (2018-2023) that aims to support healthy bee populations, sustainable beekeeping, and consequently pollination for crops and wildflowers across Europe. To do this we take a range of approaches, from the laboratory to the field, from molecules to ecosystems, and from fundamental science to risk assessment. This doc...

Climate plays a key role in shaping population trends and determining the geographic distribution of species because of their limits in thermal and water tolerance. An evaluation of species tolerance to temperature changes can therefore help predict their potential spatial shifts and population trends triggered by the ongoing global warming. In thi...

Morocco is a well known hot-spot of biodiversity in the Mediterranean basin. While some taxa like vascular plants are relatively well recorded, important groups of pollinators like bees are still understudied. This article presents an updated checklist of the bee species of Morocco and includes a summary of global and regional distribution of each...

1. Climate change is related to an increase in frequency and intensity of extreme events such as heatwaves. It is well established that such events may worsen the current worldwide biodiversity decline. In many organisms, heat stress is associated with direct physiological perturbations and could lead to a decrease of fitness. In contrast to endoth...

A new species of vernal Hesperapis Cockerell (Melittidae: Dasypodainae: Hesperapini) is described and figured from localities spanning Texas, Oklahoma, and southern Kansas in the United States. Hesperapis (Carinapis) infuscata Engel & Michez, new species, is distinguished from its relatives in subgenus Carinapis Stage and particularly the carinata...

Aim: Among the numerous anthropogenic pressures threatening biodiversity, habitat destruction and climate change are pointed to as dominant. In response, a number of mitigation strategies are elaborated to save endangered living organisms. However, the taxonomic level and geographical extent at which conservation strategies should be designed and i...

Dasypoda morawitzi Radchenko, 2016, a cryptic bee species separated from D. hirtipes (Fabricius, 1793) and recently described from Eastern Europe, Western Kazakhstan, Caucasus and Turkey, is for the first time recorded from Czech Republic, Romania and Spain. We also provide additional new records for several other countries. An additional comparati...

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...

Morocco has a diverse bee fauna, but one that has also been relatively understudied in recent years. Here a revision of the species-rich genus Andrena is presented that reveals eleven new species for science and substantially improves our understanding of North African Andrena. From Morocco, Andrena (Aciandrena) semiadesus Wood, sp. nov., Andrena (...

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...

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...

Urbanization is one of the major threats to wild plants and pollinators, and its global increase demands a better understanding of the mechanism driving its negative impact. Urban warming and altered local environmental conditions have the potential to affect the timing of flowering and of pollinator activity. While previous evidence has shown that...

Bumblebees (Hymenoptera: Apidae: genus Bombus Latreille, 1802) constitute an important group of pollinators for many wild plants and crops in north temperate regions and South America. Although knowledge of these insects has been increasing over the last decades, some geographic areas remain poorly studied and additions to the knowledge of their fa...

Bumblebees are undergoing strong declines in Europe caused by habitat loss and fragmentation, agricultural intensification, and climate change. Long-term records are necessary to estimate population trends precisely and to propose appropriate mitigation strategies. Based on an original database of 173,788 specimens from museum collections, scientif...

For the first time a subgeneric classification of the oil-collecting bee genus Rediviva is presented. Five subgenera comprising 33 species are recognized based on morphological characters. Three of them are described as new: Deriviva subgen. nov., Albiviva subgen. nov. and Gigaviva subgen. nov.. The genus Redivivoides rendered Rediviva paraphyletic...

West Palearctic bumblebees are common wildflowers and crop pollinators that are well studied in their central and northern distribution ranges, but fewer information is available on their southern distribution areas. Lebanon falls on the southern limit of their distribution and no published information is available on the local bumblebees. Our stud...

Sterols are essential nutrients for bees which are thought to obtain them exclusively from pollen. It is possible that variability in pollen sterol content shapes pollinator-flower relationships, as bee species require the physiological capacity or behavioral adaptations to cope with unfavorable sterolic composition of pollen. One behavioral adapta...

With 2000 species currently recorded in Europe, bees are a highly diversified and efficient group of pollinating insects. Their decline could therefore lead to a risk for ecosystems functioning and crop yields. The drivers of this decline have been well documented in Europe and involve multiple factors such as pesticides, pathogens, poor nutrition,...

Recent improvements in taxonomy considers multiple operational criteria. The integrative taxonomy provides a methodological framework merging these multisource approaches. Bumblebees are considered as a uniform group where their taxonomy remains one of the most difficult. Here, we investigate the taxonomic statuses inside a monophyletic group inclu...

Cyprus, the third largest island in the Mediterranean, constitutes a biodiversity hotspot with high rates of plant endemism. The wild bees of the island were studied extensively by the native George Mavromoustakis, a world-renowned bee taxonomist, who collected extensively on the island from 1916 to 1957 and summarised his results in a series of ei...