Eristalis (Diptera: Syrphidae) Flower Flies are Potential Non-host Vectors of the Common Trypanosome Bee Parasite, Crithidia Bombi

Abstract Flowers can be transmission platforms for parasites that impact bee health, yet bees share floral resources with other pollinator taxa, such as flies, that could be hosts or non-host vectors (i.e., mechanical vectors) of parasites. Here, we assessed whether the fecal-orally transmitted gut parasite of bees, Crithidia bombi, can infect Eristalis tenax flower flies. We also investigated the potential for two confirmed solitary bee hosts of C. bombi, Osmia lignaria and Megachile rotundata, as well as two flower fly species, Eristalis arbustorum and E. tenax, to transmit the parasite at flowers. We found that C. bombi did not replicate (i.e., cause an active infection) in E. tenax flies. However, 93% of inoculated flies defecated live C. bombi in their first fecal event, and all contaminated fecal events contained C. bombi at concentrations sufficient to infect bumble bees. Flies and bees defecated inside the corolla (flower) more frequently than other plant locations, and flies defecated at volumes comparable to or greater than bees. Our results demonstrate that Eristalis flower flies are not hosts of C. bombi, but they may be mechanical vectors of this parasite at flowers. Thus, flower flies may amplify or dilute C. bombi in bee communities.

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Eristalis flower flies can be mechanical vectors of the common trypanosome bee parasite, Crithidia bombi

Scientific Reports ◽

10.1038/s41598-021-95323-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Abby E. Davis ◽

Kaitlin R. Deutsch ◽

Alondra M. Torres ◽

Mesly J. Mata Loya ◽

Lauren V. Cody ◽

...

Keyword(s):

Theoretical Work ◽

Floral Resources ◽

Active Infection ◽

Osmia Lignaria ◽

Crithidia Bombi ◽

Large Populations ◽

Bee Health ◽

The Common ◽

Flower Flies ◽

Bee Communities

AbstractFlowers can be transmission platforms for parasites that impact bee health, yet bees share floral resources with other pollinator taxa, such as flies, that may be hosts or non-host vectors (i.e., mechanical vectors) of parasites. Here, we assessed whether the fecal-orally transmitted gut parasite of bees, Crithidia bombi, can infect Eristalis tenax flower flies. We also investigated the potential for two confirmed solitary bee hosts of C. bombi, Osmia lignaria and Megachile rotundata, as well as two flower fly species, Eristalis arbustorum and E. tenax, to transmit the parasite at flowers. We found that C. bombi did not replicate (i.e., cause an active infection) in E. tenax flies. However, 93% of inoculated flies defecated live C. bombi in their first fecal event, and all contaminated fecal events contained C. bombi at concentrations sufficient to infect bumble bees. Flies and bees defecated inside the corolla (flower) more frequently than other plant locations, and flies defecated at volumes comparable to or greater than bees. Our results demonstrate that Eristalis flower flies are not hosts of C. bombi, but they may be mechanical vectors of this parasite at flowers. Thus, flower flies may amplify or dilute C. bombi in bee communities, though current theoretical work suggests that unless present in large populations, the effects of mechanical vectors will be smaller than hosts.

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

Parasitology ◽

10.1017/s0031182020001018 ◽

2020 ◽

Vol 147 (12) ◽

pp. 1290-1304 ◽

Cited By ~ 1

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.

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Noncrop Habitat Use by Wild Bees (Hymenoptera: Apoidea) in a Mixed-Use Agricultural Landscape

Environmental Entomology ◽

10.1093/ee/nvaa001 ◽

2020 ◽

Vol 49 (2) ◽

pp. 502-515 ◽

Cited By ~ 1

Author(s):

Brianne Du Clos ◽

Francis A Drummond ◽

Cynthia S Loftin

Keyword(s):

United States ◽

Floral Resources ◽

Northeastern United States ◽

Wild Bees ◽

Wild Bee ◽

Lowbush Blueberry ◽

Mixed Use ◽

Abundance And Diversity ◽

Bee Communities ◽

Bee Abundance

Abstract Homogeneous, agriculturally intense landscapes have abundant records of pollinator community research, though similar studies in the forest-dominated, heterogeneous mixed-use landscape that dominates the northeastern United States are sparse. Trends of landscape effects on wild bees are consistent across homogeneous agricultural landscapes, whereas reported studies in the northeastern United States have not found this consistency. Additionally, the role of noncrop habitat in mixed-use landscapes is understudied. We assessed wild bee communities in the mixed-use lowbush blueberry (Vaccinium angustifolium Ait.) production landscape of Maine, United States at 56 sites in eight land cover types across two regional landscapes and analyzed effects of floral resources, landscape pattern, and spatial scale on bee abundance and species richness. Within survey sites, cover types with abundant floral resources, including lowbush blueberry fields and urban areas, promoted wild bee abundance and diversity. Cover types with few floral resources such as coniferous and deciduous/mixed forest reduced bee abundance and species richness. In the surrounding landscape, lowbush blueberry promoted bee abundance and diversity, while emergent wetland and forested land cover strongly decreased these measures. Our analysis of landscape configuration revealed that patch mixing can promote wild bee abundance and diversity; however, this was influenced by strong variation across our study landscape. More surveys at intra-regional scales may lead to better understanding of the influence of mixed-use landscapes on bee communities.

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Diversified Farming in a Monoculture Landscape: Effects on Honey Bee Health and Wild Bee Communities

Environmental Entomology ◽

10.1093/ee/nvaa031 ◽

2020 ◽

Vol 49 (3) ◽

pp. 753-764 ◽

Cited By ~ 1

Author(s):

Ashley L St. Clair ◽

Ge Zhang ◽

Adam G Dolezal ◽

Matthew E O’Neal ◽

Amy L Toth

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Natural Habitat ◽

Colony Growth ◽

Nutritional State ◽

Floral Resources ◽

Fruit And Vegetable ◽

Wild Bee ◽

Bee Conservation ◽

Bee Communities

Abstract In the last century, a global transformation of Earth’s surface has occurred due to human activity with extensive agriculture replacing natural ecosystems. Concomitant declines in wild and managed bees are occurring, largely due to a lack of floral resources and inadequate nutrition, caused by conversion to monoculture-based farming. Diversified fruit and vegetable farms may provide an enhanced variety of resources through crops and weedy plants, which have potential to sustain human and bee nutrition. We hypothesized fruit and vegetable farms can enhance honey bee (Hymenoptera: Apidae, Apis mellifera Linnaeus) colony growth and nutritional state over a soybean monoculture, as well as support a more diverse wild bee community. We tracked honey bee colony growth, nutritional state, and wild bee abundance, richness, and diversity in both farm types. Honey bees kept at diversified farms had increased colony weight and preoverwintering nutritional state. Regardless of colony location, precipitous declines in colony weight occurred during autumn and thus colonies were not completely buffered from the stressors of living in a matrix dominated with monocultures. Contrary to our hypothesis, wild bee diversity was greater in soybean, specifically in August, a time when fields are in bloom. These differences were largely driven by four common bee species that performed well in soybean. Overall, these results suggest fruit and vegetable farms provide some benefits for honey bees; however, they do not benefit wild bee communities. Thus, incorporation of natural habitat, rather than diversified farming, in these landscapes, may be a better choice for wild bee conservation efforts.

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The nectar alkaloid, gelsemine, does not affect offspring performance of a native solitary bee, Osmia lignaria (Megachilidae)

Ecological Entomology ◽

10.1111/j.1365-2311.2007.00974.x ◽

2008 ◽

Vol 33 (2) ◽

pp. 298-304 ◽

Cited By ~ 22

Author(s):

SUSAN E. ELLIOTT ◽

REBECCA E. IRWIN ◽

LYNN S. ADLER ◽

NEAL M. WILLIAMS

Keyword(s):

Solitary Bee ◽

Offspring Performance ◽

Osmia Lignaria

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DNA fingerprinting analysis in the solitary bee Megachile rotundata: variability and nest mate genetic relationships

Genome ◽

10.1139/g92-103 ◽

1992 ◽

Vol 35 (4) ◽

pp. 681-688 ◽

Cited By ~ 24

Author(s):

Alain Blanchetot

Keyword(s):

Genetic Variability ◽

Dna Fingerprinting ◽

Genetic Relationships ◽

Globin Gene ◽

Hypervariable Region ◽

Enzyme Polymorphism ◽

Solitary Bee ◽

Megachile Rotundata ◽

Wide Range ◽

Oligonucleotide Sequence

The most conventional approach for evaluating genetic variability in an insect population involves assessing the degree of enzyme polymorphism. Hymenoptera display a relatively low level of genetic variability compared with most insect species. DNA probes consisting of tandemly repeated sequences are powerful tools for detecting polymorphisms when employed to develop DNA fingerprinting (DNAfp) profiles in a wide range of organisms. This report describes genetic variability in the solitary bee species Megachile rotundata as assessed by DNAfp using the Ml3 sequence and a synthetic oligonucleotide sequence homologous to a hypervariable region of the α-globin gene. DNAfp comparisons among offspring were used to analyze genealogical structure in M. rotundata nests. The results indicate that polyandry, by a large number of males, is not a common phenomenon in M. rotundata bee species. In the present analysis, it is likely that the broods raised in single nests are mostly the offspring of one singly mated female. However, the data does not preclude that for certain nests two males could have been involved in the mating process.Key words: Megachile rotundata, DNA fingerprinting, M13 sequence, α-globin hypervariable sequence, intra-nest genetic relationships.

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