| 1. |
- Gekière, Antoine, et al.
(författare)
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Poison or Potion : Effects of Sunflower Phenolamides on Bumble Bees and Their Gut Parasite
- 2022
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Ingår i: Biology. - : MDPI AG. - 2079-7737. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- 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 studies suggested it could be due to phenolamides, a group of compounds commonly found in flowering plants. We, therefore, decided to assess separately the impacts of sunflower pollen and its phenolamides on a bumble bee and its gut parasite. We fed Crithidia-infected and -uninfected microcolonies of Bombus terrestris either with a diet of willow pollen (control), a diet of sunflower pollen (natural diet) or a diet of willow pollen supplemented with sunflower phenolamides (supplemented diet). We measured several parameters at both microcolony (i.e., food collection, parasite load, brood development and stress responses) and individual (i.e., fat body content and phenotypic variation) levels. As expected, the natural diet had detrimental effects on bumble bees but surprisingly, we did not observe any reduction in parasite load, probably because of bee species-specific outcomes. The supplemented diet also induced detrimental effects but by contrast to our a priori hypothesis, it led to an increase in parasite load in infected microcolonies. We hypothesised that it could be due to physiological distress or gut microbiota alteration induced by phenolamide bioactivities. We further challenged the definition of medicinal effects and questioned the way to assess them in controlled conditions, underlining the necessity to clearly define the experimental framework in this research field.
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| 2. |
- Gérard, Maxence, 1991-, et al.
(författare)
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Elevated developmental temperatures impact the size and allometry of morphological traits of the bumblebee Bombus terrestris
- 2023
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 226:8
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Tidskriftsartikel (refereegranskat)abstract
- The impact of global warming on wild bee decline threatens the pollination services they provide. Exposure to temperatures above optimal during development is known to reduce adult body size but how it affects the development and scaling of body parts remains unclear. In bees, a reduction in body size and/or a reduction in body parts, such as the antennae, tongue and wings, and how they scale with body size (i.e. their allometry) could severely affect their fitness. To date, it remains unclear how temperature affects body size and the scaling of morphological traits in bees. To address this knowledge gap, we exposed both males and workers of Bombus terrestris to elevated temperature during development and assessed the effects on (i) the size of morphological traits and (ii) the allometry between these traits. Colonies were exposed to optimal (25°C) or stressful (33°C) temperatures. We then measured the body size, wing size, antenna and tongue length, as well as the allometry between these traits. We found that workers were smaller and the antennae of both castes were reduced at the higher temperature. However, tongue length and wing size were not affected by developmental temperature. The allometric scaling of the tongue was also affected by developmental temperature. Smaller body size and antennae could impair both individual and colony fitness, by affecting foraging efficiency and, consequently, colony development. Our results encourage further exploration of how the temperature-induced changes in morphology affect functional traits and pollination efficiency.
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| 3. |
- Gérard, Maxence, 1991-, et al.
(författare)
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Exposure to elevated temperature during development affects bumblebee foraging behavior
- 2022
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 33:4, s. 816-824
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Tidskriftsartikel (refereegranskat)abstract
- 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 behavior remains unexplored. Here, we assessed how exposure to elevated temperatures during development affects the foraging behavior and morphology of workers from commercial and wild Bombus terrestris colonies. Workers reared at 33 °C had a higher visiting rate and shorter visiting time than those reared at 27°C. In addition, far fewer workers reared at 33 °C engaged in foraging activities and this is potentially related to the drastic reduction in the number of individuals produced in colonies exposed to 33 °C. The impact of elevated developmental temperature on wild colonies was even stronger as none of the workers from these colonies performed any foraging trips. We also found that rearing temperature affected wing size and shape. Our results provide the first evidence that colony temperature can have striking effects on bumblebee foraging behavior. Of particular importance is the drastic reduction in the number of workers performing foraging trips, and the total number of foraging trips made by workers reared in high temperatures. Further studies should explore if, ultimately, these observed effects of exposure to elevated temperature during development lead to a reduction in pollination efficiency.
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| 4. |
- Gérard, Maxence, et al.
(författare)
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Impact of crop exposure and agricultural intensification on the phenotypic variation of bees
- 2022
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Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 338
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Tidskriftsartikel (refereegranskat)abstract
- 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 phenotypic modifications could affect the functionality of traits from taxa that are in decline but that are keystone species in many ecosystems. In this study, we assessed the impact of environmental drivers and agricultural intensification on two crucial pollinator species: the honeybee (Apis mellifera) and the buff-tailed bumblebee (Bombus terrestris). Among eight countries representing four major European biogeographical regions [i.e., Boreal (Sweden and Estonia), Atlantic (Ireland and United Kingdom), Continental (Germany and Switzerland) and Mediterranean (Spain and Italy)] and two type of crops (i.e., apple orchards and oilseed rape) we assessed how landscape structure, latitude and pesticide management could impact their wing morphology. Two sampling sessions were conducted: the first one when the hives/nests were settled on the field (T0) and a second sampling session after the potential effect of agricultural intensification (T1). Using a dataset of more than 7238 wings, we measured the wing size, shape and asymmetry. We observed that, in several countries, a shift in most of the morphological traits occurred between T0 and T1. When focusing on the drivers of phenotypic variation in T1, the levels of significance for some potential drivers were sometimes high, while most of the variation remained unexplained. The latitude and, more rarely, grassland cover were found to partly explain the wing modifications. In light of these results, we conclude that phenotypic shifts can occur in a very short period, after encountering new field conditions. Further studies should be conducted to better understand which alternative drivers could explain morphological changes in the agro-ecosystem after crop exposition, as well as the potential consequences of these changes on foraging performance or pollination efficiency.
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| 5. |
- Gérard, Maxence, et al.
(författare)
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Impact of landscape fragmentation and climate change on body size variation of bumblebees during the last century
- 2021
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 44:2, s. 255-264
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Tidskriftsartikel (refereegranskat)abstract
- 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 developing faster) or the selection of larger individuals in fragmented habitats (e.g. large individuals more capable of reaching distant patches). We assessed the relationship between temperature and landscape fragmentation with mean body size during the last century, within four European regions (Austria, Belgium, England and above the Arctic circle in Scandinavia) and among queens of five bumblebee species. At the regional scale, we first analysed the variation over time of body size and the two hypothesised drivers, temperature and landscape fragmentation. Then, at the local landscape scale, we tested whether body size varied according to these drivers irrespective of the region. At the regional level, we observed a statistically clear increase of queen body size corresponding to an increase of landscape fragmentation (i.e. in Belgium and England). There was no increase of size when fragmentation did not increase (i.e. in Austria and above the Arctic Circle). Temperature also increased through time in all regions. At the local landscape scale, we found that all species were impacted by changes in both climate and landscape fragmentation but show different trends. The body size of the two largest species significantly increased at landscape level with higher fragmentation while body size of the two smallest species decreased with higher fragmentation. We highlight that, in a context of global changes, landscape fragmentation can also be a major driver of body size clines. Depending on the dispersal abilities of species, larger species could be positively selected for and overcome landscape fragmentation.
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| 6. |
- Gerard, Maxence, et al.
(författare)
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Patterns of size variation in bees at a continental scale : does Bergmann's rule apply?
- 2018
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Ingår i: Oikos. - : Wiley-Blackwell. - 0030-1299 .- 1600-0706. ; 127:8, s. 1095-1103
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Tidskriftsartikel (refereegranskat)abstract
- 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. Nevertheless, no comprehensive studies of species assemblages at a phylogenetically larger scale have been carried out even if they could identify the traits and the ecological conditions that generate different patterns of latitudinal size variation. We aimed to test Bergmann's rule for wild bees by assessing relationships between body size and latitude at continental and community levels. We tested our hypotheses for bees showing different life history traits (i.e. sociality and nesting behaviour). We used 142 008 distribution records of 615 bee species at 50 x 50 km (CGRS) grids across the West Palearctic. We then applied generalized least squares fitted linear model (GLS) to assess the relationship between latitude and mean body size of bees, taking into account spatial autocorrelation. For all bee species grouped, mean body size increased with higher latitudes, and so followed Bergmann's rule. However, considering bee genera separately, four genera were consistent with Bergmann's rule, while three showed a converse trend, and three showed no significant cline. All life history traits used here (i.e. solitary, social and parasitic behaviour; ground and stem nesting behaviour) displayed a Bergmann's cline. In general there is a main trend for larger bees in colder habitats, which is likely to be related to their thermoregulatory abilities and partial endothermy, even if a 'season length effect' (i.e. shorter foraging season) is a potential driver of the converse Bergmann's cline particularly in bumblebees.
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| 7. |
- Gérard, Maxence, 1991-, et al.
(författare)
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Resilience of bumblebee foraging behavior despite colony size reduction
- 2023
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Ingår i: Frontiers in insect science. - : Frontiers Media SA. - 2673-8600. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Foraging behavior is driven by diverse factors, notably life history traits. Foraging strategies are particularly complex among eusocial species such as bumblebees, because they depend primarily on the needs of the colony, rather than on individual's needs. Colony size, i.e. the number of workers in a colony vary a lot among eusocial insects. While a large colony can be adaptive, several drivers can strongly decrease colony size, like pesticides or high temperatures. In this study, we used the bumblebee Bombus terrestris to assess if workers adapted their foraging behavior to such rapid decreases in colony size. We conducted the foraging experiments with two plant species commonly used by bumblebees: Borago officinalis and Echium plantagineum. Several foraging parameters were measured: foraging time, number of foraging trips, number of workers foraging, handling time and visiting rate. Despite a drastic reduction in colony size, nearly all the foraging behavior parameters were unaffected by the colony size reduction. Colonies that were subject to a large decrease in workers instead displayed high resilience and behavioral plasticity by quickly increasing the proportion of foragers. Ultimately, further research should assess if this consistency in foraging behavior also allows bumblebee colonies to maintain both the efficiency of the resources collection and pollination.
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| 8. |
- Gérard, Maxence, et al.
(författare)
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Short-term exposure to heatwave-like temperatures affects learning and memory in bumblebees
- 2022
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28:14, s. 4251-4259
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Tidskriftsartikel (refereegranskat)abstract
- 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 elevated ambient temperatures impair cognition but whether and how heat affects the cognitive abilities of invertebrates remains unclear. Cognitive skills in bees are essential for their survival as, to supply the hive with nutrition, workers must be able to learn and remember the location of the most rewarding floral resources. Here, we investigate whether temperature-related cognitive impairments could be a driver of bee declines by exploring the effect of short-term increases in ambient temperature on learning and memory. We found that, in comparison to bees that were tested at 25°C (a temperature that they would typically experience in summer), bees that were exposed to 32°C (a temperature that they will becoming increasingly exposed to during heatwave events) were significantly worse at forming an association between a coloured light and a sucrose reward and that their capacity to remember this association after just 1 h was abolished. This study provides novel experimental evidence that even just a few hours of exposure to heatwave-like temperatures can severely impair the cognitive performance of insects. Such temperature-induced cognitive deficits could play an important role in explaining recent and future bee population declines.
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| 9. |
- Ghisbain, Guillaume, et al.
(författare)
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A worthy conservation target? Revising the status of the rarest bumblebee of Europe
- 2021
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 14:5, s. 661-674
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Tidskriftsartikel (refereegranskat)abstract
- 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 bumblebee species recorded only from the highest altitudes of the Sierra Nevada (Spain), Bombus reinigiellus (Rasmont, 1983). The species has the smallest range of any European bumblebee, along with a restricted diet and an inability to disperse because of its isolated montane distribution, making it an appropriate conservation target. However, through an integrative taxonomic approach including genetics, morphometrics and semio-chemistry, we demonstrate the conspecificity of this taxon with one of the most common and widespread bumblebee species of Europe, Bombus hortorum (L. 1761). We assign a subspecies status to this endemic taxon (Bombus hortorum reinigiellus comb. nov.) shown to be different in colour and morphology but also in wing shape and relative wing size compared to the other conspecific subspecies.Following our taxonomic revision, we reassessed the IUCN conservation status of Bombus hortorum both at the continental and Spanish scale. We then propose how historic climatic oscillations of the last Ice age could explain such a phenotypic divergence in a post-glacial refugium and highlight the critical role of establishing unambiguous taxonomic revision prior to any conservation assessment.
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| 10. |
- Ghisbain, Guillaume, et al.
(författare)
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Expanding insect pollinators in the Anthropocene
- 2021
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Ingår i: Biological Reviews. - : Wiley. - 1464-7931 .- 1469-185X. ; 96:6, s. 2755-2770
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Tidskriftsartikel (refereegranskat)abstract
- 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 expansion. Here, we review the factors and traits that have allowed a fraction of the pollinating entomofauna to take advantage of global environmental change. Sufficient mobility, high resistance to acute heat stress, and inherent adaptation to warmer climates appear to be key traits that allow pollinators to persist and even expand in the face of climate change. An overall flexibility in dietary and nesting requirements is common in expanding species, although niche specialization can also drive expansion under specific contexts. The numerous consequences of wild and domesticated pollinator expansions, including competition for resources, pathogen spread, and hybridization with native wildlife, are also discussed. Overall, we show that the traits and factors involved in the success stories of expanding pollinators are mostly species specific and context dependent, rendering generalizations of 'winning traits' complicated. This work illustrates the increasing need to consider expansion and its numerous consequences as significant facets of global changes and encourages efforts to monitor the impacts of expanding insect pollinators, particularly exotic species, on natural ecosystems.
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| 11. |
- Guiraud, Marie, et al.
(författare)
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Higher developmental temperature increases queen production and decreases worker body size in the bumblebee Bombus terrestris
- 2021
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Ingår i: Journal of Hymenoptera Research. - : Pensoft Publishers. - 1070-9428 .- 1314-2607. ; 88, s. 39-49
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Tidskriftsartikel (refereegranskat)abstract
- 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 are affected when temperatures rise above optimal rearing temperature. It has become imperative to understand how heat stress affects the life history traits of insect pollinators as well as how changes in life history interact with other traits like morphology. For example, a decrease in the number of foraging workers could be balanced by producing larger workers, able to forage at longer distances and gather more resources. Here, we investigated the impact of temperature on colony production and body size in the bumblebee Bombus terrestris. Colonies were exposed to two temperatures: 25 degrees C, which is around the optimal temperature for larval development and 33 degrees C, which is slightly above the set-point that is considered stressful for bumblebees. Although the production of males and workers wasn't significantly affected by these different temperatures, queen production and reproductive investment were much higher for colonies placed in 33 degrees C than in 25 degrees C. We also found that, in agreement with the temperature-size rule, workers were significantly smaller in the higher temperature. The decrease in worker body size could affect resource collection and pollination if their foraging distance and the quantity of food they are taking back to the colony decreases. While in our controlled conditions the bumblebees were fed ad libitum, the decrease of resource collection in field conditions could prevent colonies from producing as many queens as in our study. Together with the decrease of worker body size, our results suggest that elevated temperatures could ultimately have a negative impact on bumblebee colony fitness. Indeed, smaller workers are known to have weaker flight performance which could affect foraging performance and consequently colony development.
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| 12. |
- Hill, Luke, et al.
(författare)
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Bumblebee cognitive abilities are robust to changes in colony size
- 2023
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 77:2
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Tidskriftsartikel (refereegranskat)abstract
- Eusocial insect colonies act as a superorganism, which can improve their ability to buffer the negative impact of some anthropogenic stressors. However, this buffering effect can be affected by anthropogenic factors that reduce their colony size. A reduction in colony size is known to negatively affect several parameters like brood maintenance or thermoregulation, but the effects on behaviour and cognition have been largely overlooked. It remains unclear how a sudden change in group size, such as that which might be caused by anthropogenic stressors, affects individual behaviour within a colony. In this study, the bumblebee Bombus terrestris was used to study the effect of social group size on behaviour by comparing the associative learning capabilities of individuals from colonies that were unmanipulated, reduced to a normal size (a colony of 100 workers) or reduced to a critically low but functional size (a colony of 20 workers). The results demonstrated that workers from the different treatments performed equally well in associative learning tasks, which also included no significant differences in the learning capacity of workers that had fully developed after the colony size manipulation. Furthermore, we found that the size of workers had no impact on associative learning ability. The learning abilities of bumblebee workers were thus resilient to the colony reduction they encountered. Our study is a first step towards understanding how eusocial insect cognition can be impacted by drastic reductions in colony size. Significance statement While anthropogenic stressors can reduce the colony size of eusocial insects, the impact of this reduction is poorly studied, particularly among bumblebees. We hypothesised that colony size reduction would affect the cognitive capacity of worker bumblebees as a result of fewer social interactions or potential undernourishment. Using differential conditioning, we showed that drastic reductions in colony size have no effect on the associative learning capabilities of the bumblebee Bombus terrestris and that this was the same for individuals that were tested just after the colony reduction and individuals that fully developed under the colony size reduction. We also showed that body size did not affect learning capabilities. This resilience could be an efficient buffer against the ongoing impacts of global change.
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| 13. |
- Leclercq, N., et al.
(författare)
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A comparative analysis of crop pollinator survey methods along a large-scale climatic gradient
- 2022
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 329
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Tidskriftsartikel (refereegranskat)abstract
- 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 community of pollinator species for each crop, and to determine how it is influenced by the different survey methods used, as well as by climatic variables at larger geographic scales. Here, we surveyed wild bees using a standardised protocol at an unprecedented scale including 62 commercial apple orchards in Western and Central Europe (i) to validate recent findings on pollinator community divergence as measured by common survey methods (netting and pan trapping) using conventional and alternative biodiversity metrics (phylogenetic and functional diversity), and (ii) to investigate the impact of climatic variation on the patterns observed. Our results confirm the significant divergence in pollinator communities measured using the two common methods at the larger, sub-continental scale, and we provide evidence for a significant influence of climate on the magnitude of pollinator community divergence (beta diversity and its turnover component) be-tween survey methods, particularly when comparing colder to warmer sites and regions. We also found that warmer sites are more dissimilar than colder sites in terms of species composition, functional traits, or phylo-genetic affinities. This result probably stems from the comparatively larger species pool in Southern Europe and because apple flowers are accessible to a wide spectrum of pollinator species; hence, two distant survey localities in Southern Europe are more likely to differ significantly in their pollinator community. Collectively, our results demonstrate the spatially-varying patterns of pollinator communities associated with common survey methods along a climate gradient and at the sub-continental scale in Europe.
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| 14. |
- Lhomme, Patrick, et al.
(författare)
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Diversification Pattern of the Widespread Holarctic Cuckoo Bumble Bee, Bombus flavidus (Hymenoptera: Apidae) : The East Side Story
- 2021
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Ingår i: Insect Systematics and Diversity. - : Oxford University Press (OUP). - 2399-3421. ; 5:2, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- 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 separate species allied with B. flavidus have been suggested, until recently, recognition of two species, a Nearctic Bombus fernaldae (Franklin) and Palearctic B. flavidus, was favored. Limited genetic data, however, suggested that even these could be a single widespread species. We addressed the species status of this lineage using an integrative taxonomic approach, combining cytochrome oxidase I (COI) and nuclear sequencing, wing morphometrics, and secretions used for mate attraction, and explored patterns of color polymorphism that have previously confounded taxonomy in this lineage. Our results support the conspecificity of fernaldae and flavidus; however, we revealed a distinct population within this broader species confined to eastern North America. This makes the distribution of the social parasite B. flavidus the broadest of any bumble bee, broader than the known distribution of any nonparasitic bumble bee species. Color polymorphisms are retained across the range of the species, but may be influenced by local mimicry complexes. Following these results, B. flavidusEversmann, 1852 is synonymized with Bombus fernaldae (Franklin, 1911) syn. nov. and a subspecific status, Bombus flavidus appalachiensisssp. nov., is assigned to the lineage ranging from the Appalachians to the eastern boreal regions of the United States and far southeastern Canada.
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| 15. |
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| 16. |
- Moradinour, Zahra, 1989-, et al.
(författare)
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Exposure to elevated temperature during development affects eclosion and morphology in the temperate Pieris napi butterfly (Lepidoptera Pieridae)
- 2023
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Ingår i: Journal of Thermal Biology. - 0306-4565 .- 1879-0992. ; 118
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Tidskriftsartikel (refereegranskat)abstract
- Global warming has been identified as one of the main drivers of population decline in insect pollinators. One aspect of the insect life cycle that would be particularly sensitive to elevated temperatures is the developmental transition from larva to adult. Temperature-induced modifications to the development of body parts and sensory organs likely have functional consequences for adult behaviour. To date, we have little knowledge about the effect of sub-optimal temperature on the development and functional morphology of different body parts, particularly sensory organs, in ectothermic solitary pollinators such as butterflies. To address this knowledge gap, we exposed the pupae of the butterfly Pieris napi to either 23 degrees C or 32 degrees C and measured the subsequent effects on eclosion, body size and the development of the wings, proboscis, eyes and antennae. In comparison to individuals that developed at 23 degrees C, we found that exposure to 32 degrees C during the pupal stage increased mortality and decreased time to eclose. Furthermore, both female and male butterflies that developed at 32 degrees C were smaller and had shorter proboscides, while males had shorter antennae. In contrast, we found no significant effect of rearing temperature on wing and eye size or wing deformity. Our findings suggest that increasing global temperatures and its corresponding co-stressors, such as humidity, will impact the survival of butterflies by impairing eclosion and the proper development of body and sensory organs.
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| 17. |
- Ndungu, Nelly, et al.
(författare)
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Can the shape of the wing help in the identification of African stingless bee species? (Hymenoptera: Apidae: Meliponini) : Wing geometric morphometrics: a tool for african stingless bee taxonomy
- 2023
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Ingår i: International Journal of Tropical Insect Science. - : Springer Science and Business Media LLC. - 1742-7584 .- 1742-7592. ; 43:2, s. 749-759
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Tidskriftsartikel (refereegranskat)abstract
- Stingless bees are important pollinators of wild and cultivated plants, and they produce medicinal honey. However, their taxonomy and systematics are still debated and would benefit a continent-wide revision. Here, we explore the potential of wing shape in delineation and classification of Afrotropical Meliponini using geometric morphometrics. We sampled 749 specimens from nine countries of sub-Saharan Africa, belonging to the genera Meliponula (n = 8), Dactylurina (n = 2) and Plebeina (n = 1). Specimens collected from Kenya were used as standards to assess similar species collected from other eight African countries. Eleven landmarks were plotted on the right forewing of each specimen to conduct multivariate analyses and group/specimen classification. Our results show that seven out of eleven African stingless bee species were reliably discriminated using wing shape, however, there was overlap in the remaining four species, namely Meliponula cameroonensis, Meliponula ferruginea, Meliponula togoensis and Meliponula erythra. In conclusion geometric morphometrics represent a promising taxonomic tool that can be applied to identify African stingless bee species.
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| 18. |
- Reverte, Sara, et al.
(författare)
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Intraspecific size shifts in generalist bumblebees and flowers lead to low functional consequences
- 2023
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Ingår i: Ecosphere. - 2150-8925. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- Body size is a trait that can affect plant–pollinator interaction efficiency and plant reproductive success. We explored the impact of intraspecific size shifts on the interactions between pollinators and flowering plants under controlled conditions. We considered two development conditions leading to the production of large and small individual flowers of Borago officinalis and Echium plantagineum. We also used the natural variability of worker size within bumblebee colonies to isolate small and large workers. We performed a fully crossed experiment with the two flower sizes of each plant species and the two sizes of bumblebee workers. Our results show that the size of both partners did not affect bee foraging behavior in most of the evaluated parameters and both bee sizes were equally efficient in depositing pollen. Significant differences were found only in pollen deposition across the life of a flower in small flowers of B. officinalis, with the greatest quantity of pollen deposited by small bees. We did not find a relationship between pollinator size and plant fitness. Our results suggest that generalist plant–pollinator interactions may be resilient to future potential mismatches in the size of the partners but remain to be tested if they are still resilient under the new environmental conditions resulting from global changes.
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| 19. |
- Schatz, Bertrand, et al.
(författare)
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Pollinator conservation in the context of global changes with a focus on France and Belgium
- 2021
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 112
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Tidskriftsartikel (refereegranskat)abstract
- 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 to counter the substantial worldwide risk of pollinator loss. As our perception of the situation is rapidly changing, as a result of the steady accumulation of international and national reports as well as new scientific findings, we propose here to provide an updated overview of pollinator conservation globally. We present the key messages and the proposed solutions found in international reports and assessments, how European countries have interpreted these solutions proposed in the context of existing international frameworks. Next, we analyze how scientific research is addressing the issue of pollinator conservation through different international, European and national programs. The analysis of the keywords used in published scientific articles also allows us to characterize how the scientific community has engaged with this issue over time. Finally, we focus on how France and Belgium have reacted to the observed decline of pollinators, and examine their national interpretations, conservation actions and research contributions.
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| 20. |
- Sculfort, Ombeline, et al.
(författare)
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Specialized Metabolites in Floral Resources : Effects and Detection in Buff-Tailed Bumblebees
- 2021
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- 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 (taste). While numerous studies have investigated the detection of pollen macronutrients in bees and their impact on bee health and reproductive success, only a few studies have described the gustatory responses of bees toward specialized metabolites. In addition, these studies mostly focused on the response to nectar and neglected pollen, which is the main food resource for both bee imagines and larvae. Whether bees have the ability to detect specialized toxic metabolites in pollen and then rapidly adapt their foraging behavior to avoid them is very little studied. In this study, we tested whether pollen specialized metabolites affect bumblebees at both the micro-colony and individual levels (i.e., bioassays using supplemented pollen), and whether foragers detect these specialized metabolites and potentially display an avoidance behavior (i.e., preference tests using supplemented syrup). Bumblebees were fed with either amygdalin-, scopolamine- or sinigrin-supplemented pollen diets in ratios that mimic 50%, 100%, and 200% of naturally occurring concentrations. We found no effect of these specialized metabolites on resource collection, reproductive success and stress response at the micro-colony level. At the individual level, bumblebees fed on 50%-amygdalin or 50%-scopolamine diets displayed the highest scores for damage to their digestive systems. Interestingly, during the preference tests, the solution with 50%-scopolamine displayed a phagostimulatory activity, whereas solution with 50%-amygdalin had a deterrent effect and could trigger an active avoidance behavior in bumblebees, with a faster proboscis retraction. Our results suggest that regulation of toxin intake is not as well-established and effective as the regulation of nutrient intake in bees. Bees are therefore not equally adapted to all specialized pollen metabolites that they can come into contact with.
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| 21. |
- Vanderplanck, Maryse, et al.
(författare)
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Monitoring bee health in European agroecosystems using wing morphology and fat bodies
- 2021
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Ingår i: One Ecosystem. - : Pensoft Publishers. - 2367-8194. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Current global change substantially threatens pollinators, which directly impacts the pollination services underpinning the stability, structure and functioning of ecosystems. Amongst these threats, many synergistic drivers, such as habitat destruction and fragmentation, increasing use of agrochemicals, decreasing resource diversity, as well as climate change, are known to affect wild and managed bees. Therefore, reliable indicators for pollinator sensitivity to such threats are needed. Biological traits, such as phenotype (e.g. shape, size and asymmetry) and storage reserves (e.g. fat body size), are important pollinator traits linked to reproductive success, immunity, resilience and foraging efficiency and, therefore, could serve as valuable markers of bee health and pollination service potential.
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