Wild bee communities in Mediterranean protected habitat : diversity, interactions and co-occurence with honey bee

Confrontés aux demandes grandissantes d’installations de ruches, les gestionnaires d’aires protégées s’interrogent sur les conséquences d’une densité élevée d’abeilles domestiques sur les communautés d’abeilles sauvages. Pour répondre à cette question, au sein du Parc national des Calanques, nous avons inventorié la diversité des espèces de pollinisateurs, leurs traits écologiques, et leurs interactions avec la flore sauvage. À travers un bilan des campagnes de terrain réalisées sur une période de 10 ans, près de 250 espèces de pollinisateurs (Apoidea, Syrphidae et Bombyliidae) ont été répertoriées. Les communautés d'abeilles sauvages étaient sensibles à l’occupation du sol à l’échelle du paysage à 1km. La richesse spécifique et l’abondance des grandes abeilles sauvages diminuaient avec l’augmentation de la densité de colonies d’abeilles domestiques suggérant une compétition pour les ressources florales. Ce résultat a été confirmé à travers l’observation des comportements de butinage des abeilles domestiques et sauvages et s’est manifesté par une exclusion compétitive des grandes abeilles sauvages et un changement de régime alimentaire des petites abeilles sauvages et des bourdons. Enfin, la quantité de ressources florales disponibles (nectar et pollen) estimée à l’échelle du Parc national des Calanques n’est pas suffisante pour couvrir les besoins alimentaires des abeilles domestiques déjà installées. Aux vues de l’importance des habitats protégés méditerranéens pour les communautés de pollinisateurs sauvages, cette thèse propose des préconisations de gestion visant à concilier la pratique de l’apiculture avec le maintien de la faune de pollinisateurs sauvagesConfronted with the growing demand to settle apiaries, managers of protected areas question the consequences of the installations of high densities of honey bee colonies on wild bee communities.To explore these consequences, I estimated the diversity of pollinator species, their ecological traits, and their interactions with the local wild flora in the Calanques National Park. Through the compilation of field campaigns along a 10-yr period, nearly 250 species of pollinators (Apoidea, Syrphidae and Bombyliidae) have been identified. Then, I showed that small bees were sensitive to the composition of local flowering communities and large bees to the land cover composition at the landscape scale. Moreover, specific richness and abundance of large wild bees decreased with the increase in the density of honey bee colonies suggesting a competition for floral resources. The competition for floral resources was confirmed by studying the foraging behavior of honey bees and wild bees and resulted in a competitive exclusion of large wild bees and a change in the floral diet of small wild bees and bumblebees. Finally, a first estimation of the quantity of available floral resources (nectar and pollen) was provided across the Calanques National Park and was not sufficient to cover the food requirements of honey bees installed. Considering the importance of Mediterranean protected habitats for the conservation of wild pollinator communities, this thesis also proposes management advice to allow the maintenance of beekeeping activities while preserving the wild pollinator fauna

Morphometric identification of honey bee subspecies reveals a high proportion of hybrids within a Mediterranean protected area

International audienceThe importance of natural protected areas for the preservation of locally adapted subspecies (or local genotype) of honey bees has been recently emphasized in the literature. In western Europe, initiatives have emerged to protect the native subspecies i.e., the Western European dark bee, Apis mellifera mellifera (Hymenoptera: Apidae). Here, we investigated the honey bee subspecies diversity in a Mediterranean protected area, Calanques National Park, near Marseille, France. We found that the population of honey bees is mainly composed of hybrids between Apis mellifera mellifera and Apis mellifera intermissa. These hybrids might have a better resistance to the Varroa mite and a better adaptation to arid Mediterranean climate. Before promoting the native honey bee subspecies, Apis mellifera mellifera, it appears essential to identify honey bee subspecies used by beekeepers in protected areas

La diversité des abeilles parisiennes

International audienceDespite the forever increasing urbanization, cities often shelter a significant biodiversity. As many other taxa, wild bees may find refuge in urban areas because of relative favorable conditions compared to intensive agricultural environments. In this study, we compiled our joint work to extend the list of Parisian bees. Over 4 years of monitoring (2011, 2014, 2015, 2016), we recorded 87 bee species in intra-muros Paris. In 2016 we added net captures to our sampling procedures with colored pan traps, which provided 11 additional species. The assemblage now represents 8.8 % of the French fauna of Apoïdae. However, this assemblage is mostly dominated by Halictidae and includes only few kleptoparasitic species highlighting an impoverished community.Malgré les perturbations dues à l'urbanisation grandissante, les villes abritent une biodiversité non négligeable. Comme beaucoup d'autres taxons, les abeilles sauvages peuvent être relativement abondantes dans les zones urbaines du fait de certaines conditions favorables par rapport aux milieux agricoles (absence de pesticides, îlot de chaleur urbain, floraison toute l'année). Dans cette étude, nous compilons nos travaux conjoints afin d'enrichir la liste des espèces d'abeilles parisiennes. Au total, le suivi de 4 années (2011 puis 2014, 2015, 2016) a permis de recenser 87 espèces d'abeilles à Paris intra-muros. L'ajout en 2016 de la méthode de capture avec des filets à papillon en plus de la méthode passive avec coupelles colorées a permis de capturer 11 espèces supplémentaires. L'assemblage, qui représente à ce jour 8,8 % de la diversité spécifique des abeilles sauvages de France métropolitaine, est cependant dominé par les Halictidae et ne compte que quelques espèces cleptoparasites, témoignant d'une communauté appauvrie

La ville un désert pour les abeilles sauvages ?

International audienceABSTRACT: Urban ecosystems are expanding worldwide and are often considered as biological deserts. However, environmentally‑friendly management practices may promote the maintenance of urban communities. Such is the case for wild bees (super family Apoideae) with an increasing number of studies reporting relatively diverse bee assemblages in densely urbanized habitats. Here, we report some examples found in the bibliography of cities harbouring relatively diverse bee assemblages, although different methods were used to sample wild bees. We also provide new data concerning the wild bee fauna in the city of Paris (France). During a two‑year field campaign carried out in 7 locations in downtown Paris, we captured 360 individuals belonging to 51 species. This raises the bee species richness in Paris to 67 species. Although this assemblage only represents 6.9 %of the French bee fauna and shows characteristics of a depauperate community (low abundance of parasitic species, dominance of the Halictidae family), some of the Parisian localities sampled exhibit relatively important species richness. This diversity should be preserved given the global pollination crisis and the current context of increasing urbanization. However, emerging management practices in urban environments, such as massive introductions of domesticated honeybee colonies (more than 700 hives are currently established in downtown Paris) could negatively impact on these communities of urban pollinators.RESUME : Les milieux urbains sont en expansion constante et sont parfois considérés comme des déserts de bio‑ diversité. Pourtant, une certaine biodiversité existe en ville et les pratiques de gestion émergentes dans les milieux urbains peuvent aider à son maintien. C'est notamment le cas pour les abeilles sauvages (super‑famille des Apoidés Apiformes) où des études de plus en plus nombreuses montrent qu'une biodiversité non négligeable d'abeilles peut être présente dans les centres urbains denses. Nous relayons ici les résultats de certains de ces articles qui, avec des méthodes et des intensités de piégeages différents, montrent tous que les villes peuvent héberger des assemblages relativement diversifiés d'abeilles sauvages. Nous apportons également de nouvelles données sur la faune d'abeilles de Paris intra‑muros. Lors d'une campagne de terrain de deux ans dans sept localités de Paris nous avons capturé 360 spécimens d'abeilles sauvages appartenant à 51 espèces différentes. Cette nouvelle campagne porte la richesse spécifique de Paris intramuros à 67 espèces. Bien que cet assemblage ne regroupe que 6.9 % des espèces de la faune Française et montre des caractéristiques d'une communauté affaiblie (faible abondance d'espèces cleptoparasites, sur‑dominance d'espèces de la famille des Halictidae), certaines des localités Parisiennes échantillonnées présentent une diversité d'espèces relativement élevée, qu'il est important de préserver afin de garantir la pérennité des com‑ munautés de pollinisateurs dans le contexte actuel de croissance des milieux urbains. Des pratiques de gestions émergentes au sein des villes comme l'implantation massive d'abeilles domestiques (près de 700 ruches dans Paris intramuros), pourraient néanmoins fragiliser ces communautés

Seasonal dynamics of competition between honey bees and wild bees in a protected Mediterranean scrubland

International audienceDue to the widespread use of pesticides and the lack of floral resources in many agricultural landscapes, beekeepers have moved numerous honey bee colonies in protected areas which could shelter an important diversity of wild bees. Here, we investigated the seasonal dynamics of the competition between honey bees and wild bees through a two-year study of plant-bee networks in a Mediterranean protected area. We recorded the visitation rates of four bee groups: honey bees, small wild bees, large wild bees and bumblebees. Our study reveals that the competition for floral resources induced by honey bees is especially strong during the early spring and then decreases along the season for all groups of wild bees. We observed a competitive exclusion of all groups of wild bees illustrated by an avoidance of well-flowered plant species in presence of honey bees. As a consequence, we detected a rewiring of large and small bee floral preferences linked to the presence of honey bees. In presence of honey bees, Rosmarinus officinalis and Cistus albidus were significantly less visited by large bees. This study underlines the need to mitigate the establishment of numerous honey bee colonies in protected areas as honey bees could strongly affect the foraging activity of wild bees

Wild pollinator activity negatively related to honey bee colony densities in urban context

International audienceAs pollinator decline is increasingly reported in natural and agricultural environments, cities are perceived as shelters for pollinators because of low pesticide exposure and high floral diversity throughout the year. This has led to the development of environmental policies supporting pollinators in urban areas. However, policies are often restricted to the promotion of honey bee colony installations, which resulted in a strong increase in apiary numbers in cities. Recently, competition for floral resources between wild pollinators and honey bees has been highlighted in semi-natural contexts, but whether urban beekeeping could impact wild pollinators remains unknown. Here, we show that in the city of Paris (France), wild pollinator visitation rates are negatively correlated to honey bee colony densities present in the surrounding landscape (500m-slope =-0.614; p = 0.001-and 1000m-slope =-0.489; p = 0.005). Regarding the morphological groups of wild pollinators, large solitary bee and beetle visitation rates were negatively affected by honey bee colony densities within a 500m buffer (slope =-0.425, p = 0.007 and slope =-0.671, p = 0.002, respectively) and bumblebee visi-tation rates were negatively affected by honey bee colony density within a 1000m buffer (slope =-0.451, p = 0.012). Further, lower interaction evenness in plant-pollinator networks was observed with high honey bee colony density within a 1000m buffer (slope =-0.487, p = 0.008). Finally, honey bees tended to focus their foraging activity on managed rather than wild plant species (student t-test, p = 0.001) whereas wild pollinators equally visited managed and wild species. We advocate responsible practices mitigating the introduction of high density of honey bee colonies in urban environments. Further studies are however needed to deepen our knowledge about the potential negative interactions between wild and domesticated pollinators

Land cover composition, local plant community composition and honeybee colony density affect wild bee species assemblages in a Mediterranean biodiversity hot-spot

International audienceIdentifying environmental drivers which structure wild bee species assemblages appears essential in a context of worldwide pollinator decline. During a two-year survey, we studied wild bee species assemblages in an 85km 2 protected area dominated by Mediterranean scrubland, the Calanques National Park, located in southern France. Our objectives were (i) to assess the composition of the wild bee species assemblages, and (ii) to explore the effect of a) land cover composition (anthropogenic zone, low scrubland, forest and rocky land cover), b) local plant community composition, and c) honeybee colony density on wild bee species assemblages. On 17 circular 100m 2 plots, we collected 541 specimens belonging to 87 wild bee species. We found that large bee species were significantly influenced by land cover composition within a 1000m radius. More specifically, we observed that the presence of a diversified land cover composition within a 1000m radius maximized large wild bee species richness, whereas large bee abundance and richness were negatively affected by honeybee colony density. Small wild bee species were structured by the local plant community composition within 100m 2 plots and by land cover composition within a 1000m radius. Their occurrence were related to the local composition of plants growing on deep soils in scrublands. The Calanques National Park, which is the only European park located at the interface with a large city and consequently suffers from anthropic pressure, encompasses several types of land cover which are beneficial for a wide diversity of bees. However, we would like to raise awareness among park managers regarding beekeeping activities within this territory which includes diverse types of land cover favorable for wild bee species

Révision du genre Pelecocera Meigen, 1822 (Diptera: Syrphidae) en France: taxonomie, écologie et distribution

International audienceThe occurrence and distribution of the various species of the genus Pelecocera Meigen, 1822 (Diptera: Syrphidae) occurring in France are revised and a new species, Pelecocera garrigae Lair & Nève, 2022 sp. nov., is described from Mediterranean France. Distribution and ecological data of the six French species of Pelecocera are provided and an identification key is given to all these species. Sequences of the cytochrome c oxidase subunit I (COI) from all European Pelecocera species support the morphological species concept, except for Pelecocera scaevoides (Fallén, 1817). The binomen Pelecocera lugubris Perris, 1839 is recovered to name the Pelecocera lusitanica (Mik, 1898) of authors in France.Les données concernant les six espèces du genre Pelecocera Meigen, 1822 (Diptera, Syrphidae) appartenant à la faune de France ont été révisées, et une nouvelle espèce, Pelecocera garrigae Lair & Nève, 2022, est décrite de la zone méditerranéenne de France. La distribution et l'écologie des six espèces française du genre Pelecocera sont discutées, et une clé de détermination illustrée est fournie. Les séquences de la cytochrome oxydase sous-unité I (COI) de toutes les espèces européenne de Pelecocera confirment le concept morphologique des espèces, sauf pour Pelecocera scaevoides (Fallén, 1817). Le nom Pelecocera lusitanica (Mik, 1898) est reconnu comme synonyme junior et donc invalide de Pelecocera lugubris Perris, 1839, au moins pour les populations françaises