Low maize pollen collection and low pesticide risk to honey bees in heterogeneous agricultural landscapes

Urbanowicz, Christine; Baert, Nicolas; Bluher, Sarah E.; Böröczky, Katalin; Ramos, M.M. Gómez; McArt, Scott H.

doi:10.1007/s13592-019-00655-2

Cited by 17 publications

(15 citation statements)

References 48 publications

(85 reference statements)

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“…We attempted to standardize bee size as much as possible within a microcolony, but limitations due to the number and size of bees eclosing from source colonies on any given day meant that there was variation in the size of individual bees and the average weight of microcolonies. We initially fed bees a mixture of a standard diet of honey bee collected pollen (CC Pollen Company High Desert Fresh Raw Bee Pollen Granules) that was determined to be pesticide-free 72 and 30% sucrose solution, while they acclimated to the microcolony for two-six days and established a dominance hierarchy 47,69 . After this period, one bee typically develops into a pseudoqueen capable of laying eggs.…”

Section: Methodsmentioning

confidence: 99%

Pollen defenses negatively impact foraging and fitness in a generalist bee (Bombus impatiens: Apidae)

Brochu

Dyke

Milano

et al. 2020

Sci Rep

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Plants may benefit from limiting the community of generalist floral visitors if the species that remain are more effective pollinators and less effective pollenivores. Plants can reduce access to pollen through altered floral cues or morphological structures, but can also reduce consumption through direct pollen defenses. We observed that Eucera (Peponapis) pruinosa, a specialist bee on Cucurbita plants, collected pure loads of pollen while generalist honey bees and bumble bees collected negligible amounts of cucurbit pollen, even though all groups of bees visited these flowers. Cucurbit flowers have no morphological adaptations to limit pollen collection by bees, thus we assessed their potential for physical, nutritional, and chemical pollen traits that might act as defenses to limit pollen loss to generalist pollinators. Bumble bee (Bombus impatiens) microcolonies experienced reduced pollen consumption, mortality, and reproduction as well as increased stress responses when exposed to nutritional and mechanical pollen defenses. These bees also experienced physiological effects of these defenses in the form of hindgut expansion and gut melanization. chemical defenses alone increased the area of gut melanization in larger bees and induced possible compensatory feeding. Together, these results suggest that generalist bumble bees avoid collecting cucurbit pollen due to the physiological costs of physical and chemical pollen defenses.

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Section: Methodsmentioning

confidence: 99%

Pollen defenses negatively impact foraging and fitness in a generalist bee (Bombus impatiens: Apidae)

Brochu

Dyke

Milano

et al. 2020

Sci Rep

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“…We prepared bee bread slides using the palynological methods outlined in Urbanowicz et al (2019). For the uncapped nectar samples, we subsampled 0.5 ml of nectar, added 1 ml of 40°C DI water, vortexed for 30 s, centrifuged for 10 min at 6K rpm, and decanted the supernatant.…”

Section: Knapweed Pollen Identificationmentioning

confidence: 99%

Honey bees and wild pollinators differ in their preference for and use of introduced floral resources

Urbanowicz

Muñiz

McArt

2020

Ecology and Evolution

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Introduced plants may be important foraging resources for honey bees and wild pollinators, but how often and why pollinators visit introduced plants across an entire plant community is not well understood. Understanding the importance of introduced plants for pollinators could help guide management of these plants and conservation of pollinator habitat. We assessed how floral abundance and pollinator preference influence pollinator visitation rate and diversity on 30 introduced versus 24 native plants in central New York. Honey bees visited introduced and native plants at similar rates regardless of floral abundance. In contrast, as floral abundance increased, wild pollinator visitation rate decreased more strongly for introduced plants than native plants. Introduced plants as a group and native plants as a group did not differ in bee diversity or preference, but honey bees and wild pollinators preferred different plant species. As a case study, we then focused on knapweed (Centaurea spp.), an introduced plant that was the most preferred plant by honey bees, and that beekeepers value as a late‐summer foraging resource. We compared the extent to which honey bees versus wild pollinators visited knapweed relative to coflowering plants, and we quantified knapweed pollen and nectar collection by honey bees across 22 New York apiaries. Honey bees visited knapweed more frequently than coflowering plants and at a similar rate as all wild pollinators combined. All apiaries contained knapweed pollen in nectar, 86% of apiaries contained knapweed pollen in bee bread, and knapweed was sometimes a main pollen or nectar source for honey bees in late summer. Our results suggest that because of diverging responses to floral abundance and preferences for different plants, honey bees and wild pollinators differ in their use of introduced plants. Depending on the plant and its abundance, removing an introduced plant may impact honey bees more than wild pollinators.

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“…Twice weekly, we provided the bees with pollen balls (~5 g) made from a mixture of ground "High Desert" pollen granules (CC Pollen Inc.; Phoenix, AZ, USA) removed from honey bee corbicula and 30% (w /v ) sucrose solution. To confirm there were little to no pesticides in the pollen, we screened a sample of the pollen granules for 267 pesticides using liquid chromatography/mass spectrometry (LC-MS/MS) using the methods outlined by Urbanowicz et al (2019).…”

Section: Hive Acquisition and Maintenancementioning

confidence: 99%

Synergistic effects of three sterol biosynthesis inhibiting fungicides on the toxicity of a pyrethroid and neonicotinoid insecticide to bumble bees

et al. 2019

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Understanding how different pesticides influence bee health is inhibited by a limited knowledge about the interactions between different compounds to which bees are simultaneously exposed. Although research has demonstrated synergistic effects of some sterol biosynthesis inhibiting (SBI) fungicides on the toxicity of certain insecticides to bees, a high degree of variability exists in the relatively few SBI fungicide-insecticide interactions tested. Furthermore, most research has been conducted on honey bees, Apis mellifera , limiting our understanding of pesticide synergisms in native wild bees. We tested the effects of the SBI fungicides difenoconazole, myclobutanil, and fenhexamid on acute contact toxicity of the insecticides thiamethoxam (neonicotinoid) and bifenthrin (pyrethroid) to the common eastern bumble bee, Bombus impatiens. Based on range-finding trials, we selected a single dosage of each pesticide, with insecticides approximating LD20 values and fungicides approximating their maximum sublethal levels. We found that the triazole SBI fungicide difenoconazole interacted synergistically with bifenthrin, with a maximum synergy ratio of 1.48, while the triazole myclobutanil interacted synergistically with both bifenthrin and thiamethoxam, with maximum synergy ratios of 11.0 and 2.38, respectively. However, the hydroxyanilide SBI fungicide fenhexamid did not exhibit a synergistic effect on either insecticide. Our results suggest that certain SBI fungicides, and potentially those from particular SBI classes, may be particularly harmful to bumble bee health when co-exposure to insecticides occurs, despite their low toxicity when experienced in isolation.

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Low maize pollen collection and low pesticide risk to honey bees in heterogeneous agricultural landscapes

Cited by 17 publications

References 48 publications

Pollen defenses negatively impact foraging and fitness in a generalist bee (Bombus impatiens: Apidae)

Pollen defenses negatively impact foraging and fitness in a generalist bee (Bombus impatiens: Apidae)

Honey bees and wild pollinators differ in their preference for and use of introduced floral resources

Synergistic effects of three sterol biosynthesis inhibiting fungicides on the toxicity of a pyrethroid and neonicotinoid insecticide to bumble bees

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