scholarly journals No evidence of effects or interaction between the widely used herbicide, glyphosate, and a common parasite in bumble bees

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12486
Author(s):  
Edward A. Straw ◽  
Mark J.F. Brown
Keyword(s):  
Chronic Exposure ◽  
Multiple Stressors ◽  
Bombus Terrestris ◽  
Bumble Bees ◽  
Acute Exposure ◽  
Bumble Bee ◽  
Term Survival ◽  
Crithidia Bombi ◽  
Bee Health ◽  
Acute And Chronic Exposure

Background Glyphosate is the world’s most used pesticide and it is used without the mitigation measures that could reduce the exposure of pollinators to it. However, studies are starting to suggest negative impacts of this pesticide on bees, an essential group of pollinators. Accordingly, whether glyphosate, alone or alongside other stressors, is detrimental to bee health is a vital question. Bees are suffering declines across the globe, and pesticides, including glyphosate, have been suggested as being factors in these declines. Methods Here we test, across a range of experimental paradigms, whether glyphosate impacts a wild bumble bee species, Bombus terrestris. In addition, we build upon existing work with honey bees testing glyphosate-parasite interactions by conducting fully crossed experiments with glyphosate and a common bumble bee trypanosome gut parasite, Crithidia bombi. We utilised regulatory acute toxicity testing protocols, modified to allow for exposure to multiple stressors. These protocols are expanded upon to test for effects on long term survival (20 days). Microcolony testing, using unmated workers, was employed to measure the impacts of either stressor on a proxy of reproductive success. This microcolony testing was conducted with both acute and chronic exposure to cover a range of exposure scenarios. Results We found no effects of acute or chronic exposure to glyphosate, over a range of timespans post-exposure, on mortality or a range of sublethal metrics. We also found no interaction between glyphosate and Crithidia bombi in any metric, although there was conflicting evidence of increased parasite intensity after an acute exposure to glyphosate. In contrast to published literature, we found no direct impacts of this parasite on bee health. Our testing focussed on mortality and worker reproduction, so impacts of either or both of these stressors on other sublethal metrics could still exist. Conclusions Our results expand the current knowledge on glyphosate by testing a previously untested species, Bombus terrestris, using acute exposure, and by incorporating a parasite never before tested alongside glyphosate. In conclusion our results find that glyphosate, as an active ingredient, is unlikely to be harmful to bumble bees either alone, or alongside Crithidia bombi.

scholarly journals Microbiome Structure Influences Infection by the Parasite Crithidia bombi in Bumble Bees

2018 ◽  
Vol 84 (7) ◽  
Author(s):  
Blair K. Mockler ◽  
Waldan K. Kwong ◽  
Nancy A. Moran ◽  
Hauke Koch
Keyword(s):  
Gut Microbiota ◽  
Bombus Terrestris ◽  
Bacterial Load ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Bacterial Populations ◽  
Important Species ◽  
Content Type ◽  
Crithidia Bombi ◽  
Microbiome Diversity

ABSTRACT Recent declines in bumble bee populations are of great concern and have prompted critical evaluations of the role of pathogen introductions and host resistance in bee health. One factor that may influence host resilience when facing infection is the gut microbiota. Previous experiments with Bombus terrestris , a European bumble bee, showed that the gut microbiota can protect against Crithidia bombi , a widespread trypanosomatid parasite of bumble bees. However, the particular characteristics of the microbiome responsible for this protective effect have thus far eluded identification. Using wild and commercially sourced Bombus impatiens , an important North American pollinator, we conducted cross-wise microbiota transplants to naive hosts of both backgrounds and challenged them with a Crithidia parasite. As with B. terrestris , we find that microbiota-dependent protection against Crithidia operates in B. impatiens . Lower Crithidia infection loads were experimentally associated with high microbiome diversity, large gut bacterial populations, and the presence of Apibacter , Lactobacillus Firm-5, and Gilliamella spp. in the gut community. These results indicate that even subtle differences between gut community structures can have a significant impact on a microbiome's ability to defend against parasite infections. IMPORTANCE Many wild bumble bee populations are under threat due to human activity, including through the introduction of pathogens via commercially raised bees. Recently, it was found that the bumble bee gut microbiota can help defend against a common parasite, Crithidia bombi , but the particular factors contributing to this protection are unknown. Using both wild and commercially raised bees, we conducted microbiota transplants to show that microbiome diversity, total gut bacterial load, and the presence of certain core members of the microbiota may all impact bee susceptibility to Crithidia infection. Bee origin (genetic background) was also a factor. Finally, by examining this phenomenon in a previously uninvestigated bee species, our study demonstrates that microbiome-mediated resistance to Crithidia is conserved across multiple bumble bee species. These findings highlight how intricate interactions between hosts, microbiomes, and parasites can have wide-ranging consequences for the health of ecologically important species.

scholarly journals Olfactory coding in the antennal lobe of the bumble bee Bombus terrestris

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcel Mertes ◽  
Julie Carcaud ◽  
Jean-Christophe Sandoz
Keyword(s):  
Honey Bees ◽  
Antennal Lobe ◽  
Bombus Terrestris ◽  
Bumble Bees ◽  
Foraging Strategies ◽  
Bumble Bee ◽  
Carbon Chain Length ◽  
Olfactory Coding ◽  
Major Transitions

AbstractSociality is classified as one of the major transitions in evolution, with the largest number of eusocial species found in the insect order Hymenoptera, including the Apini (honey bees) and the Bombini (bumble bees). Bumble bees and honey bees not only differ in their social organization and foraging strategies, but comparative analyses of their genomes demonstrated that bumble bees have a slightly less diverse family of olfactory receptors than honey bees, suggesting that their olfactory abilities have adapted to different social and/or ecological conditions. However, unfortunately, no precise comparison of olfactory coding has been performed so far between honey bees and bumble bees, and little is known about the rules underlying olfactory coding in the bumble bee brain. In this study, we used in vivo calcium imaging to study olfactory coding of a panel of floral odorants in the antennal lobe of the bumble bee Bombus terrestris. Our results show that odorants induce reproducible neuronal activity in the bumble bee antennal lobe. Each odorant evokes a different glomerular activity pattern revealing this molecule’s chemical structure, i.e. its carbon chain length and functional group. In addition, pairwise similarity among odor representations are conserved in bumble bees and honey bees. This study thus suggests that bumble bees, like honey bees, are equipped to respond to odorants according to their chemical features.

scholarly journals Cross-infectivity of honey and bumble bee-associated parasites across three bee families

Parasitology ◽  
2020 ◽  
Vol 147 (12) ◽  
pp. 1290-1304 ◽  
Author(s):  
Lyna Ngor ◽  
Evan C. Palmer-Young ◽  
Rodrigo Burciaga Nevarez ◽  
Kaleigh A. Russell ◽  
Laura Leger ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Bumble Bees ◽  
Floral Resources ◽  
Bumble Bee ◽  
Broad Host Range ◽  
Osmia Lignaria ◽  
Social Bees ◽  
Crithidia Bombi ◽  
Halictus Ligatus ◽  
Parasite Replication

AbstractRecent declines of wild pollinators and infections in honey, bumble and other bee species have raised concerns about pathogen spillover from managed honey and bumble bees to other pollinators. Parasites of honey and bumble bees include trypanosomatids and microsporidia that often exhibit low host specificity, suggesting potential for spillover to co-occurring bees via shared floral resources. However, experimental tests of trypanosomatid and microsporidial cross-infectivity outside of managed honey and bumble bees are scarce. To characterize potential cross-infectivity of honey and bumble bee-associated parasites, we inoculated three trypanosomatids and one microsporidian into five potential hosts – including four managed species – from the apid, halictid and megachilid bee families. We found evidence of cross-infection by the trypanosomatids Crithidia bombi and C. mellificae, with evidence for replication in 3/5 and 3/4 host species, respectively. These include the first reports of experimental C. bombi infection in Megachile rotundata and Osmia lignaria, and C. mellificae infection in O. lignaria and Halictus ligatus. Although inability to control amounts inoculated in O. lignaria and H. ligatus hindered estimates of parasite replication, our findings suggest a broad host range in these trypanosomatids, and underscore the need to quantify disease-mediated threats of managed social bees to sympatric pollinators.

scholarly journals Bumble bees (Hymenoptera: Apidae: Bombus terrestris) collecting honeydew from the giant willow aphid (Hemiptera: Aphididae)

2019 ◽  
Vol 68 ◽  
pp. 75-83 ◽  
Author(s):  
Sydney A. Cameron ◽  
Sarah A. Corbet ◽  
James B. Whitfield
Keyword(s):  
Leaf Litter ◽  
Bombus Terrestris ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Ambient Conditions ◽  
Floral Nectar ◽  
Phloem Sap ◽  
Evaporative Concentration ◽  
Large Numbers ◽  
Leaf Surfaces

Only rarely have bumble bees (Bombus) been observed collecting honeydew from aphids (Aphididae) feeding on phloem sap. This behavior may be rare because the percentage of sugar in honeydew egested from aphids is generally well below the sugar concentration in floral nectars preferred by bumble bees. Nonetheless, in August 2018, near St. Buryan, Penzance, Cornwall, UK (56.0602N; -5.6034W) we observed large numbers of wild Bombusterrestris (Linnaeus) collecting honeydew from a colony of the giant willow aphid Tuberolachnussalignus Gmelin feeding on the stems of the willow Salixalba. Unlike aphid-tending ants, who glean fresh honeydew directly from the aphid anal opening, the bumble bees were collecting honeydew from leaf litter below the aphid colony. We hypothesized that honeydew collected from exposed ground surfaces was more concentrated due to evaporation under ambient conditions than that released directly from the anus (fresh honeydew). We thus monitored sugar concentrations of fresh honeydew and compared them with the concentrations of the crop contents of worker bumble bees foraging from the leaf litter. Our data show that the concentration of sugar in fresh honeydew was as much as 10% w/w lower than that collected from leaf surfaces, as measured from the crop contents of foragers. The unusually hot, dry weather in Cornwall may have enhanced evaporative concentration of honeydew while restricting floral nectar sources, thus favoring honeydew collection by B.terrestris, a generalist bumble bee forager.

scholarly journals Effect of garlic extract on mortality and biochemical parameters of fresh water fishes Heteropneustes fossilis against Cypermethrin

2019 ◽  
Vol 9 (2) ◽  
pp. 14-19
Author(s):  
Akanksha Singh ◽  
Kaneez Zahra
Keyword(s):  
Chronic Exposure ◽  
Biochemical Parameters ◽  
Chronic Toxicity ◽  
Garlic Extract ◽  
Acute Exposure ◽  
Exposure Level ◽  
Heteropneustes Fossilis ◽  
Blood Samples ◽  
Acute And Chronic Exposure ◽  
Remarkable Reduction

To find out the effect of garlic extract (GE) on mortality different concentrations of GE (1ml/l, 2ml/l, 5ml/l & 10ml/l) were administered along with the LC50 values of cypermethrin after 24, 48, 72 & 96 h exposures and 10 ml/l of GE was found to be effective at which no mortality occurred. To analyze the effect of GE on biochemical parameters after acute exposure of cypermethrin, fishes were divided into 4 groups of 10 fishes each. Ist group served as control, IInd, IIIrd and IVth group were treated with toxicant (24h LC50), GE (10ml/l) and toxicant + GE respectively. Same protocol was employed using 48-96 h LC50 values & 10ml/l GE. For chronic toxicity experiments fishes were divided into 4 groups of 10 fishes each. Ist group taken as control, IInd group contained 1/10th of 96 h LC50 of CYP, IIIrd group contained 10ml/l GE and in IVth group GE (10ml/l) + CYP (1/10th of 96 h LC50) for 15 days. Experiments were also carried out after 30 and 45 days exposure by same protocol. After acute and chronic exposure periods blood samples were collected, centrifuged and serum was separated to analyze biochemical parameters. Increased level of SGOT, SGPT, ALP, ACP, Creatinine, and Blood Glucose were observed during both acute and chronic exposure. Activity of Total protein was found to be decreased following acute and chronic exposure. Level of Uric acid increased in acute exposure but decreased during chronic exposure. However, garlic extract supplementation showed a remarkable reduction to these changes and all the parameters tends to become normalize. Our data indicate that garlic is a powerful antioxidant against cypermethrin induced toxicity. Keywords: Cypermethrin, Garlic extract, Heteropneustus fossilis, LC50.

scholarly journals Activation of host constitutive immune defence by an intestinal trypanosome parasite of bumble bees

Parasitology ◽  
2003 ◽  
Vol 126 (3) ◽  
pp. 253-260 ◽  
Author(s):  
M. J. F. BROWN ◽  
Y. MORET ◽  
P. SCHMID-HEMPEL
Keyword(s):  
Immune System ◽  
Bombus Terrestris ◽  
Parasitic Infection ◽  
Bumble Bees ◽  
Host Immune System ◽  
Immune Defence ◽  
Important Species ◽  
Crithidia Bombi ◽  
Resource Stress ◽  
Host Parasite

Many parasites, including important species that affect humans and livestock, must survive the harsh environment of insect guts to complete their life-cycle. Hence, understanding how insects protect themselves against such parasites has immediate practical implications. Previously, such protection has been thought to consist mainly of mechanical structures and the action of lectins. However, recently it has become apparent that gut infections may interact with the host immune system in more complex ways. Here, using bumble bees, Bombus terrestris and their non-invasive gut trypanosome, Crithidia bombi, as a model system we investigated the effects of parasitic infection, host resources and the duration of infections on the host immune system. We found that infection doubled standing levels of immune defence in the haemolymph (the constitutive pro-phenoloxidase system), which is used as a first, general defence against parasites. However, physical separation of the parasite from the haemolymph suggests the presence of a messenger system between the gut and the genes that control the pro-phenoloxidase system. Surprisingly, we found no direct effect of host resource-stress or duration of the infection on the immune system. Our results suggest a novel and tactical response of insects to gut infections, demonstrating the complexity of such host–parasite systems.

scholarly journals Geographic profiling applied to testing models of bumble-bee foraging

2008 ◽  
Vol 6 (32) ◽  
pp. 307-319 ◽  
Author(s):  
Nigel E Raine ◽  
D. Kim Rossmo ◽  
Steven C Le Comber
Keyword(s):  
Spatial Data ◽  
Bombus Terrestris ◽  
Experimental Studies ◽  
Bumble Bees ◽  
Foraging Strategies ◽  
Bumble Bee ◽  
Statistical Tool ◽  
Foraging Patterns ◽  
Geographic Profiling ◽  
Gp Model

Geographic profiling (GP) was originally developed as a statistical tool to help police forces prioritize lists of suspects in investigations of serial crimes. GP uses the location of related crime sites to make inferences about where the offender is most likely to live, and has been extremely successful in criminology. Here, we show how GP is applicable to experimental studies of animal foraging, using the bumble-bee Bombus terrestris . GP techniques enable us to simplify complex patterns of spatial data down to a small number of parameters (2–3) for rigorous hypothesis testing. Combining computer model simulations and experimental observation of foraging bumble-bees, we demonstrate that GP can be used to discriminate between foraging patterns resulting from (i) different hypothetical foraging algorithms and (ii) different food item (flower) densities. We also demonstrate that combining experimental and simulated data can be used to elucidate animal foraging strategies: specifically that the foraging patterns of real bumble-bees can be reliably discriminated from three out of nine hypothetical foraging algorithms. We suggest that experimental systems, like foraging bees, could be used to test and refine GP model predictions, and that GP offers a useful technique to analyse spatial animal behaviour data in both the laboratory and field.

scholarly journals Evidence for and against deformed wing virus spillover from honey bees to bumble bees: a reverse genetic analysis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Olesya N. Gusachenko ◽  
Luke Woodford ◽  
Katharin Balbirnie-Cumming ◽  
Eugene V. Ryabov ◽  
David J. Evans
Keyword(s):  
Honey Bees ◽  
Reverse Genetics ◽  
Bombus Terrestris ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Major Contributor ◽  
Reverse Genetic ◽  
Colony Losses ◽  
Deformed Wing Virus ◽  
Resistance To Infection

Abstract Deformed wing virus (DWV) is a persistent pathogen of European honey bees and the major contributor to overwintering colony losses. The prevalence of DWV in honey bees has led to significant concerns about spillover of the virus to other pollinating species. Bumble bees are both a major group of wild and commercially-reared pollinators. Several studies have reported pathogen spillover of DWV from honey bees to bumble bees, but evidence of a sustained viral infection characterized by virus replication and accumulation has yet to be demonstrated. Here we investigate the infectivity and transmission of DWV in bumble bees using the buff-tailed bumble bee Bombus terrestris as a model. We apply a reverse genetics approach combined with controlled laboratory conditions to detect and monitor DWV infection. A novel reverse genetics system for three representative DWV variants, including the two master variants of DWV—type A and B—was used. Our results directly confirm DWV replication in bumble bees but also demonstrate striking resistance to infection by certain transmission routes. Bumble bees may support DWV replication but it is not clear how infection could occur under natural environmental conditions.

scholarly journals Managed bumble bees are viable as pollinators in netted kiwifruit orchards

2018 ◽  
Vol 71 ◽  
pp. 214-220 ◽  
Author(s):  
Brian T. Cutting ◽  
Lisa J. Evans ◽  
Ludivine I. Paugam ◽  
Heather M. McBrydie ◽  
Linley K. Jesson ◽  
...  
Keyword(s):  
Seed Set ◽  
Bombus Terrestris ◽  
Theoretical Calculations ◽  
Predictive Modelling ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Bee Pollination ◽  
Flower Visitation ◽  
Stocking Rates ◽  
Effective Pollinators

Protected cropping can increase orchard productivity; however, enclosed environments can be disruptive to pollinators. Bumble bees (Bombus terrestris) forage under covers, but industries lack guidelines for using them as pollinators. Here conservative stocking rates for bumble bees in covered kiwifruit orchards were identified using empirical manipulation of bee density and theoretical calculations based on bee behaviour. Bumble bee pollination at two bee densities (24 and 72 colonies/ha) was assessed within two fully netted sections (1/25 ha each) in a Gold3 kiwifruit orchard. Predictive modelling was used to estimate total bees required for pollination while actual pollination in the two blocks was measured directly. There was no difference in flower visitation rate between stocking densities but a 20% increase in seed set was found at high bee density. It was estimated that 90% of a Gold3 crop could be pollinated by 914 foraging bees/ha, or between 22 and 48 colonies/ha at the strengths used in this study. Bumble bees are effective pollinators in protected cropping environments and provide a viable tool for managed pollination under nets. A theoretical approach to refining stocking rates is a good option when manipulating pollinator densities is not possible.

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