scholarly journals Short communication: First data on the prevalence and distribution of pathogens in bumblebees (Bombus terrestris and Bombus pascuorum) from Spain

2017 ◽  
Vol 15 (1) ◽  
pp. e05SC01 ◽  
Author(s):  
Clara Jabal-Uriel ◽  
Raquel Martín-Hernández ◽  
Concepcion Ornosa ◽  
Mariano Higes ◽  
Eduardo Berriatua ◽  
...  
Keyword(s):  
Bombus Terrestris ◽  
Infection Prevalence ◽  
Pollination Services ◽  
Pathogen Diversity ◽  
Nosema Bombi ◽  
Crithidia Bombi ◽  
Pathogen Prevalence ◽  
Area North ◽  
Estimate Prevalence ◽  
Ecological Differences

Bumblebees provide pollination services not only to wildflowers but also to economically important crops. In the context of the global decline of pollinators, there is an increasing interest in determining the pathogen diversity of bumblebee species. In this work, wild bumblebees of the species Bombus terrestris and Bombus pascuorum from northern and southern Spain were molecularly screened to detect and estimate prevalence of pathogens. One third of bumblebees were infected: while viruses only infected B. pascuorum, B. terrestris was infected by Apicystis bombi, Crithidia bombi and Nosema bombi. Ecological differences between host species might affect the success of the pathogens biological cycle and consequently infection prevalence. Furthermore, sex of the bumblebees (workers or males), sampling area (north or south) and altitude were important predictors of pathogen prevalence. Understanding how these factors affect pathogens distribution is essential for future conservation of bumblebee wild populations.

scholarly journals The potential for parasite spill-back from commercial bumblebee colonies: a neglected threat to wild bees?

2021 ◽  
Author(s):  
Callum D. Martin ◽  
Michelle T. Fountain ◽  
Mark J. F. Brown
Keyword(s):  
Bombus Terrestris ◽  
Experimental Period ◽  
Early Spring ◽  
Early Summer ◽  
Potential Threat ◽  
Wild Bees ◽  
Pollination Services ◽  
Crop Species ◽  
Crithidia Bombi ◽  
Low Prevalence

AbstractCommercially-reared bumblebee colonies provide pollination services to numerous crop species globally. These colonies may harbour parasites which can spill-over to wild bee species. However, the potential for parasites to spread from wild to commercial bumblebees, which could then lead to parasite spill-back, is poorly understood. To investigate this, parasite-free commercial Bombus terrestris audax colonies, which are used commercially for strawberry pollination, were placed into seasonal strawberry crops for either 6- or 8-week blocks across two key time periods, early spring and early summer. Bumblebees were removed from colonies weekly and screened for the presence of parasites. In the early spring placement, only one parasite, the highly virulent neogregarine Apicystis bombi, was detected at a low prevalence (0.46% across all bees screened). In contrast, all colonies placed in the crop in the early summer became infected. A trypanosome, Crithidia bombi, and A. bombi were the most prevalent parasites across all samples, reaching peak prevalence in screened bees of 39.39% and 18.18% respectively at the end of the experimental period. The prevalence of A. bombi was greater than most UK records from wild bumblebees, suggesting that commercial colonies could enhance levels of A. bombi infection in wild bees through spill-back. Studies on larger geographical scales with different commercial colony densities are required to fully assess spill-back risk. However, seasonal management, to minimise spill-back opportunities, and treatment of commercial colonies to prevent infection, could be implemented to manage the potential risks of parasite spill-back to wild bees.Implications for insect conservation Our results show that commercial bumblebee populations do pick up infections, most likely from wild bees, and that these infections can reach prevalences where they may pose a threat to wild bees via parasite spill-back. More research is required to clarify the extent of this potential threat.

The swift parrot Lathamus discolor (Psittacidae), social bees (Apidae), and native insects as pollinators of Eucalyptus globulus ssp. globulus (Myrtaceae)

2004 ◽  
Vol 52 (3) ◽  
pp. 371 ◽  
Author(s):  
A. B. Hingston ◽  
B. M. Potts ◽  
P. B. McQuillan
Keyword(s):  
Eucalyptus Globulus ◽  
Seed Set ◽  
Bombus Terrestris ◽  
Pollination Services ◽  
Social Bees ◽  
Single Flower ◽  
Fitness Benefits ◽  
The Cost ◽  
Effective Pollinator ◽  
Better Than

It has been argued that the production of sufficient nectar to attract bird pollinators would evolve if the fitness benefits accruing from pollination services by birds, compared with insects, outweighed the cost of increased allocation of photosynthate to nectar. This hypothesis implies that the pollination services provided by birds must be considerably better than those provided by insects with which the plant has evolved. Consistent with this, we found that the endangered native swift parrot Lathamus discolor (Shaw) was a very effective pollinator of the native tree Eucalyptus globulus Labill. in Tasmania, facilitating an average of 76% of the maximum possible seed set for open-pollinated flowers in just one visit to a flower, whereas single flower visits by native insects did not facilitate any seed production. Flowers visited once by either species of introduced social bees, the honeybee Apis mellifera L. or the bumblebee Bombus terrestris (L.), produced less than 7% of the maximum possible seed set for open-pollinated flowers. Hence, easily managed social bees appear to be poor substitutes for bird pollinators in commercial seed orchards of this tree. We propose three possible reasons why this largely bird-pollinated tree has not evolved characters that deter insects from removing nectar.

Horizontal transmission success of Nosema bombi to its adult bumble bee hosts: effects of dosage, spore source and host age

Parasitology ◽  
2007 ◽  
Vol 134 (12) ◽  
pp. 1719-1726 ◽  
Author(s):  
S. T. RUTRECHT ◽  
J. KLEE ◽  
M. J. F. BROWN
Keyword(s):  
Bombus Terrestris ◽  
Horizontal Transmission ◽  
Fold Increase ◽  
Population Heterogeneity ◽  
Host Susceptibility ◽  
Bumble Bee ◽  
Host Age ◽  
Transmission Success ◽  
Nosema Bombi ◽  
Evolutionary Epidemiology

SUMMARYParasite transmission dynamics are fundamental to explaining the evolutionary epidemiology of disease because transmission and virulence are tightly linked. Horizontal transmission of microsporidian parasites, e.g. Nosema bombi, may be influenced by numerous factors, including inoculation dose, host susceptibility and host population heterogeneity. Despite previous studies of N. bombi and its bumble bee hosts, neither the epidemiology nor impact of the parasite are as yet understood. Here we investigate the influence N. bombi spore dosage (1000 to 500 000 spores), spore source (Bombus terrestris and B. lucorum isolates) and host age (2- and 10-day-old bees) have on disease establishment and the presence of patent infections in adult bumble bees. Two-day-old bees were twice as susceptible as their 10-day-old sisters, and a 5-fold increase in dosage from 100 000 to 500 000 spores resulted in a 20-fold increase in the prevalence of patent infections. While intraspecific inoculations were 3 times more likely to result in non-patent infections there was no such effect on the development of patent infections. These results suggest that host-age and dose are likely to play a role in N. bombi's evolutionary epidemiology. The relatively low levels of horizontal transmission success are suggestive of low virulence in this system.

scholarly journals Pollination services enhanced with urbanization despite increasing pollinator parasitism

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160561 ◽  
Author(s):  
Panagiotis Theodorou ◽  
Rita Radzevičiūtė ◽  
Josef Settele ◽  
Oliver Schweiger ◽  
Tomás E. Murray ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Urban Areas ◽  
Negative Effects ◽  
Pollination Services ◽  
Pollination Success ◽  
Flower Visitation ◽  
Visitation Rates ◽  
Crithidia Bombi ◽  
Agricultural Areas

Animal-mediated pollination is required for the reproduction of the majority of angiosperms, and pollinators are therefore essential for ecosystem functioning and the economy. Two major threats to insect pollinators are anthropogenic land-use change and the spread of pathogens, whose effects may interact to impact pollination. Here, we investigated the relative effects on the ecosystem service of pollination of (i) land-use change brought on by agriculture and urbanization as well as (ii) the prevalence of pollinator parasites, using experimental insect pollinator-dependent plant species in natural pollinator communities. We found that pollinator habitat (i.e. availability of nesting resources for ground-nesting bees and local flower richness) was strongly related to flower visitation rates at the local scale and indirectly influenced plant pollination success. At the landscape scale, pollination was positively related to urbanization, both directly and indirectly via elevated visitation rates. Bumblebees were the most abundant pollinator group visiting experimental flowers. Prevalence of trypanosomatids, such as the common bumblebee parasite Crithidia bombi, was higher in urban compared with agricultural areas, a relationship which was mediated through higher Bombus abundance. Yet, we did not find any top-down, negative effects of bumblebee parasitism on pollination. We conclude that urban areas can be places of high transmission of both pollen and pathogens.

Infection with the trypanosome Crithidia bombi and expression of immune-related genes in the bumblebee Bombus terrestris

2010 ◽  
Vol 34 (7) ◽  
pp. 705-709 ◽  
Author(s):  
Helge Schlüns ◽  
Ben M. Sadd ◽  
Paul Schmid-Hempel ◽  
Ross H. Crozier
Keyword(s):  
Bombus Terrestris ◽  
Crithidia Bombi ◽  
Immune Related Genes

scholarly journals Agri-environment nectar chemistry suppresses parasite social epidemiology in an important pollinator

2021 ◽  
Author(s):  
Arran J. Folly ◽  
Hauke Koch ◽  
Iain W. Farrell ◽  
Philip C. Stevenson ◽  
Mark J.F. Brown
Keyword(s):  
Disease Management ◽  
Social Epidemiology ◽  
Management Strategies ◽  
Infection Intensity ◽  
Population Level ◽  
Biodiversity Loss ◽  
Infection Prevalence ◽  
Disease Epidemiology ◽  
Nosema Bombi ◽  
First Time

Emergent infectious diseases are a principal driver of biodiversity loss globally. The population and range declines of a suite of North American bumblebees, a group of important pollinators, have been linked to emergent infection with the microsporidian Nosema bombi. Previous work has shown that phytochemicals in pollen and nectar can negatively impact parasites in individual bumblebees, but how this relates to social epidemiology and by extension whether plants can be effectively used as disease management strategies remains unexplored. Here we show that caffeine, identified in the nectar of Sainfoin, a constituent of agri-environment schemes, significantly reduced N. bombi infection intensity in individual bumblebees and, for the first time, that such effects impact social epidemiology, with colonies reared from wild caught queens having lower prevalence and intensity of infection. Furthermore, infection prevalence was lower in foraging bumblebees from these colonies, suggesting a likely reduction in population-level transmission. Our results demonstrate that phytochemicals can impact pollinator disease epidemiology and that planting strategies, which increase floral abundance to support biodiversity could be co-opted as disease management strategies.

Immunocompetence in workers of a social insect, Bombus terrestris L., in relation to foraging activity and parasitic infection

2000 ◽  
Vol 78 (6) ◽  
pp. 1060-1066 ◽  
Author(s):  
Claudie Doums ◽  
Paul Schmid-Hempel
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Intestinal Parasite ◽  
Bombus Terrestris ◽  
Parasitic Infection ◽  
General Mechanism ◽  
Immune Defence ◽  
Foraging Activity ◽  
Natural Conditions ◽  
Crithidia Bombi

The immune system is a general mechanism that reduces the fitness cost of parasitism. In this study, we examined variation in immune responses under natural conditions in the bumblebee Bombus terrestris. Using 14 colonies reared in the field, we compared the immune response to an artificial implant between workers that could or could not forage (86 control and 91 nonforaging workers). Foraging activity was prevented by cutting a large part of the wings. As expected, control workers had lower immune responses than nonforaging workers in 10 of 14 colonies. Overall, the treatment effect was significant even though weak, suggestive of a trade-off between immune defence and foraging activity. We also examined the environmental factors that might covary with the immune response in workers. The immune response significantly decreased in workers that were naturally infected by the intestinal parasite Crithidia bombi and increased with a measure of colony success, the maximum number of workers. These correlations suggest that the strength of immune responses reflects individual, and hence colony condition.

Single-clone and mixed-clone infections versus host environment in Crithidia bombi infecting bumblebees

Parasitology ◽  
1998 ◽  
Vol 117 (4) ◽  
pp. 331-336 ◽  
Author(s):  
B. IMHOOF ◽  
P. SCHMID-HEMPEL
Keyword(s):  
Bombus Terrestris ◽  
Infection Intensity ◽  
Parasite Prevalence ◽  
Mixed Genotype ◽  
Host Environment ◽  
Crithidia Bombi ◽  
The Family ◽  
Single Clone ◽  
Parasite Evolution ◽  
Host Heterogeneity

Current theories assume that adaptive parasite evolution explains variation in the level of virulence and parasite success. In particular, mixed-genotype infections by parasites should generally be more virulent, and faster multiplying strains more successful, either because fixed strategies have evolved or because parasites facultatively alter virulence in response to co-infecting competitors. We compared several measures of parasite success and virulence between single-clone and mixed-clone infections of 2 strains of the trypanosome Crithidia bombi in its bumblebee host, Bombus terrestris. Contrary to expectation, we could not find differences between single-clone and mixed-clone infections in parasite prevalence, infection success, duration and clearance rate. However, a clearly significant effect of colony on infection intensity was present, and the colony effect emerged in virtually all other measures. We thus conclude that host environment as defined by the family (colony) genotype and thus host heterogeneity are more important in determining parasite virulence than the parasite characteristics. This does not invalidate modern theories of parasite evolution but suggests that variation in both hosts and parasites must be taken into account in more detail.

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