A new exposure protocol adapted for wild bees reveals species-specific impacts of the sulfoximine insecticide sulfoxaflor.

Wild bees are crucial pollinators of flowering plants and concerns are rising about their decline associated with pesticide use. Interspecific variation in wild bee response to pesticide exposure is expected to be related to variation in their morphology, physiology, and ecology, though there are still important knowledge gaps in its understanding. Pesticide risk assessments have largely focussed on the Western honey bee sensitivity considering it protective enough for wild bees. Recently, guidelines for Bombus terrestris and Osmia bicornis testing have been developed but are not yet implemented at a global scale in pesticide risk assessments. Here, we developed and tested a new simplified method of pesticide exposure on wild bee species collected from the field in Belgium. Enough specimens of nine species survived in a laboratory setting and were exposed to oral and topical acute doses of a sulfoximine insecticide. Our results confirm significant variability among wild bee species. We show that Osmia cornuta is more sensitive to sulfoxaflor than B. terrestris, whereas Bombus hypnorum is less sensitive. We propose hypotheses on the mechanisms explaining interspecific variations in sensitivity to pesticides. Future pesticide risk assessments of wild bees will require further refinement of protocols for their controlled housing and exposure.

A follow up on the feasibility after national implementation of magnesium sulfate for neuroprotection prior to preterm birth.

INTRODUCTION: The risk for brain injury manifested as cerebral palsy is higher in very preterm born children than in term. Prenatal administration of magnesium sulfate (MgSO4 ) has been shown to be neuroprotective and reduces the proportion of very preterm born children later diagnosed with cerebral palsy. A Swedish national clinical practice guideline was implemented in March 2020, stipulating the administration of a single intravenous dose of 6 g MgSO4 1-24 h prior to delivery before gestational age 32+0, aiming for 90% treatment coverage. The aim of this study was to evaluate the feasibility of this new clinical practice guideline in the first year of its implementation. MATERIAL AND METHODS: Data on MgSO4 treatment were collected by reviewing the medical charts of women who gave birth to live born children in gestational age 22+0-31+6 during the period of March 1, 2020 to February 28, 2021, at five Swedish university hospitals. Women with pre-eclampsia, eclampsia, or high elevated liver enzymes low platelets (HELLP) were excluded. RESULTS: A total of 388 women were eligible and 79% received treatment with MgSO4 . Of the 21% not receiving treatment, 9% did not receive treatment due to lack of knowledge about the clinical practice guideline, 9% were not possible to treat and 3% had missing data. The proportion treated increased from 72% to 87% from the first to the last 3 months. Of those treated, 81% received the drug within the stipulated timeframe (mean 8.7 h, median 3.4 h). CONCLUSIONS: There was a positive trend over time in the proportion of women receiving MgSO4 treatment, but the a priori target of 90% was not reached during the first year of implementation. Our findings indicate that this target could be reached with additional information to clinicians.

Mason bees and honey bees synergistically enhance fruit set in sweet cherry orchards.

Mason bees (Osmia spp.) are efficient fruit tree pollinators that can be encouraged to occupy and breed in artificial nesting material. In sweet cherry orchards, they are occasionally used as an alternative managed pollinator as a replacement for or in addition to honey bees (Apis mellifera). Yet, the lack of practical guidelines on management practices, for example optimal stocking rates, for both mason bee nesting material and honey bees might compromise pollination service provision. In this study, we assessed the relationship between stocking rates (honey bee hives and mason bee nesting material) and the abundance of honey bees and mason bees in 17 sweet cherry (Prunus avium) orchards in Central Germany. We furthermore performed a pollination experiment to explore the interactive effect of mason bees and honey bees on sweet cherry fruit set. In the orchards, both honey bee and mason bee abundance increased with increasing stocking rates of hives or nesting material, respectively. Honey bee abundance increased linearly with stocking rates. In contrast, mason bee abundance asymptoted at 2-3 nesting boxes per ha, beyond which more boxes resulted in little increase in visitation rate. Our pollination experiment demonstrated that orchards were pollen limited, with only 28% of insect-pollinated flowers setting fruit versus 39% of optimally hand-pollinated flowers. Honey bees and mason bees enhanced sweet cherry fruit set, but only when both were present and not when either was present alone in an orchard. Our findings demonstrate that offering nesting material for mason bees and employing honey bee hives can enhance bee abundance in sweet cherry orchards. By increasing honey bee abundance in combination with enhanced mason bee abundance, farmers can substantially boost fruit set and potentially sweet cherry yield. To enhance pollination services, farmers should consider the benefits of increasing pollinator biodiversity as an immediate benefit to improve crop yields.

Intra-specific variation in sensitivity of Bombus terrestris and Osmia bicornis to three pesticides.

There is growing evidence that pesticides may be among the causes of worldwide bee declines, which has resulted in repeated calls for their increased scrutiny in regulatory assessments. One recurring concern is that the current frameworks may be biased towards assessing risks to the honey bee. This paradigm requires extrapolating toxicity information across bee species. Most research effort has therefore focused on quantifying differences in sensitivity across species. However, our understanding of how responses to pesticides may vary within a species is still very poor. Here we take the first steps towards filling this knowledge gap by comparing acute, lethal hazards in sexes and castes of the eusocial bee Bombus terrestris and in sexes of the solitary bee Osmia bicornis after oral and contact exposure to the pesticides sulfoxaflor, Amistar (azoxystrobin) and glyphosate. We show that sensitivity towards pesticides varies significantly both within and across species. Bee weight was a meaningful predictor of pesticide susceptibility. However, weight could not fully explain the observed differences, which suggests the existence of unexplored mechanisms regulating pesticide sensitivity across bee sexes and castes. Our data show that intra-specific responses are an overlooked yet important aspect of the risk assessment of pesticides in bees.

Arterialized collateral capillaries progress from nonreactive to capable of increasing perfusion in an ischemic arteriolar tree.

OBJECTIVE: CCA, outward remodeling of capillaries that anastomose 2 arteriolar trees with different parent feed arteries, may represent a therapeutic target for patients who lack collaterals. ACCs can reperfuse an ischemic tree, but their functional capacity is unknown. Therefore, we determined whether ACCs mature into resistance vessels that regulate blood flow following arterial occlusion. METHODS: We ligated the lateral spinotrapezius feed artery in Balb/C mice, which induces CCA. At days 7 and 21 following occlusion, we measured vasodilation of ACCs using intravital microscopy and blood flow in the ischemic tree using LSF. We determined the presence of ACCs and neurovascular alignment with immunofluorescence. RESULTS: At day 7, ACCs do not vasodilate following muscle contraction and have reduced responses to endothelial- and smooth muscle-dependent agents. By day 21, ACCs exhibit normal vasodilation, accompanied by normalized increases in relative blood flow to the ischemic zone. Although functioning as resistance vessels by regulating blood flow, ACCs do not appear to be innervated. CONCLUSIONS: ACCs mature into resistance vessels that regulate blood flow to the downstream tissue. Therefore, induction of mature ACCs may be a target for reducing ischemia in patients who lack collateral networks.