Effects of contaminants of emerging concern on Megaselia scalaris (Lowe, Diptera: Phoridae) and its microbial community

Proc. Natl. Acad. Sci. U.S.A.

Dudley

et al. 2017

Self Cite

Many countries are utilizing reclaimed wastewater for agriculture because drought, rising temperatures, and expanding human populations are increasing water demands. Unfortunately, wastewater often contains biologically active, pseudopersistent pharmaceuticals, even after treatment. Runoff from farms and output from wastewater treatment plants also contribute high concentrations of pharmaceuticals to the environment. This study assessed the effects of common pharmaceuticals on an agricultural pest, Trichoplusia ni (Lepidoptera: Noctuidae). Larvae were reared on artificial diets spiked with contaminants of emerging concern (CECs) at environmentally relevant concentrations. Trichoplusia ni showed increased developmental time and mortality when reared on artificial diets containing antibiotics, hormones, or a mixture of contaminants. Mortality was also increased when T. ni were reared on tomatoes grown hydroponically with the same concentrations of antibiotics. The antibiotic-treated plants translocated ciprofloxacin through their tissues to roots, shoots, and leaves. Microbial communities of T. ni changed substantially between developmental stages and when exposed to CECs in their diets. Our results suggest that use of reclaimed wastewater for irrigation of crops can affect the developmental biology and microbial communities of an insect of agricultural importance.

Section: Discussionsupporting

confidence: 67%

Contaminants of emerging concern affect Trichoplusia ni growth and development on artificial diets and a key host plant

Pennington

Proc. Natl. Acad. Sci. U.S.A.

Dudley

et al. 2017

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“…We used a DNA extraction protocol based on Engel et al 2013 (58), Pennington et al 2017 (59), and Rothman et al 2019 (60). We first surface sterilized individual bees using a 0.1% sodium hypochlorite wash followed by three rinses with ultrapure water.…”

Section: Methodsmentioning

confidence: 99%

The direct and indirect effects of environmental toxicants on the health of bumble bees and their microbiomes

Russell

Leger

et al. 2020

Preprint

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Bumble bees (Bombus spp.) are important and widespread insect pollinators, but the act of foraging on flowers can expose them to harmful pesticides and environmental chemicals such as oxidizers and heavy metals. How these compounds directly influence bee survival and indirectly affect bee health via the gut microbiome is largely unknown. As the toxins and toxicants in floral nectar and pollen take many forms, we explored the genomes of core bumblebee microbes (Using RAST) for their potential to detoxify cadmium, copper, selenium, the neonicotinoid pesticide imidacloprid, and hydrogen peroxide - which have all been identified in floral nectar and pollen. We then exposed Bombus impatiens workers to varying concentrations of these chemicals spiked into their diet and identified the direct effects on bee survival. Using field realistic doses, we further explored indirect effects on bee microbiomes. We found multiple genes in core gut microbes that have the potential to aid in detoxifying harmful chemicals. We also found that while the chemicals are largely toxic at levels within and above field-realistic concentrations, the field-realistic concentrations - except for imidacloprid - altered the composition of the bee microbiome, potentially causing gut dysbiosis. Overall, our study shows that environmental chemicals found in floral nectar and pollen can directly cause bee mortality, and at field-realistic levels, likely have indirect, deleterious effects on bee health via their influence on the bee microbiome.

“…We used a modified DNA extraction protocol based on the study by Engel and colleagues () and Pennington and and colleagues (; ). Using sterile technique, we dissected whole guts out of each bee and placed them into 96‐well bead‐beating plates (Qiagen, Valencia, CA) containing 50–100 μl of 0.1 mm glass beads, one 3.4 mm steel‐chrome bead (Biospec, Bartlesville, OK), and Qiagen lysis buffer, then homogenized the mixture with a Qiagen Tissuelyser at 30 Hz for 6 min.…”

Section: Methodsmentioning

confidence: 99%

The bumble bee microbiome increases survival of bees exposed to selenate toxicity

Environmental Microbiology

Leger

Graystock

et al. 2019

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Summary Bumble bees are important and widespread insect pollinators who face many environmental challenges. For example, bees are exposed to the metalloid selenate when foraging on pollen and nectar from plants growing in contaminated soils. As it has been shown that the microbiome of animals reduces metalloid toxicity, we assayed the ability of the bee microbiome to increase survivorship against selenate challenge. We exposed uninoculated or microbiota‐inoculated Bombus impatiens workers to a field‐realistic dose of 0.75 mg l−1 selenate and found that microbiota‐inoculated bees survive slightly but significantly longer than uninoculated bees. Using 16S rRNA gene sequencing, we found that selenate exposure altered gut microbial community composition and relative abundance of specific core bacteria. We also grew two core bumble bee microbes – Snodgrassella alvi and Lactobacillus bombicola – in selenate‐spiked media and found that these bacteria grew in the tested concentrations of 0.001–10 mg l−1 selenate. Furthermore, the genomes of these microbes harbour genes involved in selenate detoxification. The bumble bee microbiome slightly increases survivorship when the host is exposed to selenate, but the specific mechanisms and colony‐level benefits under natural settings require further study.