Nutritional stress exacerbates impact of a novel insecticide on solitary bees' behaviour, reproduction and survival.

Pesticide exposure and food stress are major threats to bees, but their potential synergistic impacts under field-realistic conditions remain poorly understood and are not considered in current pesticide risk assessments. We conducted a semi-field experiment to examine the single and interactive effects of the novel insecticide flupyradifurone (FPF) and nutritional stress on fitness proxies in the solitary bee Osmia bicornis. Individually marked bees were released into flight cages with monocultures of buckwheat, wild mustard or purple tansy, which were assigned to an insecticide treatment (FPF or control) in a crossed design. Nutritional stress, which was high in bees foraging on buckwheat, intermediate on wild mustard and low on purple tansy, modulated the impact of insecticide exposure. Within the first day after application of FPF, mortality of bees feeding on buckwheat was 29 times higher compared with control treatments, while mortality of FPF exposed and control bees was similar in the other two plant species. Moreover, we found negative synergistic impacts of FPF and nutritional stress on offspring production, flight activity, flight duration and flower visitation frequency. These results reveal that environmental policies and risk assessment schemes that ignore interactions among anthropogenic stressors will fail to adequately protect bees and the pollination services they provide.

Pharmacokinetic analysis of ziconotide (SNX-111), an intrathecal N-type calcium channel blocking analgesic, delivered by bolus and infusion in the dog.

BACKGROUND AND PURPOSE: Ziconotide is a peptide that blocks N-type calcium channels and is antihyperalgesic after intrathecal (IT) delivery. We here characterize the spinal kinetics of IT bolus and infused ziconotide in dog. EXPERIMENTAL APPROACH: Male beagle dogs (N= 5) were prepared with chronic IT lumbar injection and cerebrospinal fluid (LCSF) sampling catheters connected to vest-mounted pumps. Each dog received the following: 1) IT bolus ziconotide (10 µg + 1 µCi (3) H-inulin); 2) IT infusion for 48 hours of ziconotide (1 µg/100 µL/hour); 3) IT infusion for 48 hours of ziconotide (5 µg/100 µL/hour); and 4) intravenous injection of ziconotide (0.1 mg/kg). After IT bolus, LCSF ziconotide and inulin showed an initial peak and biphasic (distribution/elimination) clearance (ziconotide T(1/2-α/ß) = 0.14 and 1.77 hours, and inulin T(1/2-α/ß) = 0.16 and 3.88 hours, respectively). The LCSF : plasma ziconotide concentration ratio was 20,000:1 at 30 min and 30:1 at eight hours. IT infusion of 1 and then 5 µg/hour resulted in LCSF concentrations that peaked by eight hours and remained stable at 343 and 1380 ng/mL, respectively, to the end of the 48-hour infusions. Terminal elimination T(1/2) after termination of continuous infusion was 2.47 hours. Ziconotide LCSF : cisternal CSF : plasma concentration ratios after infusion of 1 and 5 µg/hour were 1:0.017:0.001 and 1:0.015:0.003, respectively. IT infusion of ziconotide at 1 µg/hour inhibited thermal skin twitch by 24 hours and produced modest trembling, ataxia, and decreased arousal. Effects continued through the 48-hour infusion period, increased in magnitude during the subsequent 5 µg/hour infusion periods, and disappeared after drug clearance. CONCLUSIONS AND IMPLICATIONS: After IT bolus or infusion, ziconotide displays linear kinetics that are consistent with a hydrophilic molecule of approximately 2500 Da that is cleared slightly more rapidly than inulin from the LCSF. Behavioral effects were dose dependent and reversible.

No evidence for impaired solitary bee fitness following pre-flowering sulfoxaflor application alone or in combination with a common fungicide in a semi-field experiment.

Pesticide exposure is considered a major driver of pollinator decline and the use of neonicotinoid insecticides has been restricted by regulatory authorities due to their risks for pollinators. Impacts of new alternative sulfoximine-based compounds on solitary bees and their potential interactive effects with other commonly applied pesticides in agriculture remain unclear. Here, we conducted a highly replicated full-factorial semi-field experiment with the solitary bee Osmia bicornis, an important pollinator of crops and wild plants in Europe, and Phacelia tanacetifolia as a model crop. We show that spray applications of the insecticide sulfoxaflor (product Closer) and the fungicide azoxystrobin (product Amistar), both alone and combined, had no significant negative impacts on adult female survival or the production, mortality, sex ratio and body size of offspring when sulfoxaflor was applied five days before crop flowering. Our results indicate that for O. bicornis (1) the risk of adverse impacts of sulfoxaflor (Closer) on fitness is small when applied at least five days before crop flowering and (2) that azoxystrobin (Amistar) has a low potential of exacerbating sulfoxaflor effects under field-realistic conditions.

Flowering resources modulate the sensitivity of bumblebees to a common fungicide.

Bees are exposed to various stressors, including pesticides and lack of flowering resources. Despite potential interactions between these stressors, the impacts of pesticides on bees are generally assumed to be consistent across bee-attractive crops, and regulatory risk assessments of pesticides neglect interactions with flowering resources. Furthermore, impacts of fungicides on bees are rarely examined in peer-reviewed studies, although these are often the pesticides that bees are most exposed to. In a full-factorial semi-field experiment with 39 large flight cages, we assessed the single and combined impacts of the globally used azoxystrobin-based fungicide Amistar® and three types of flowering resources (Phacelia, buckwheat, and a floral mix) on Bombus terrestris colonies. Although Amistar is classified as bee-safe, Amistar exposure through Phacelia monocultures reduced adult worker body mass and colony growth (including a 55% decline in workers and an 88% decline in males), while the fungicide had no impact on colonies in buckwheat or the floral mix cages. Furthermore, buckwheat monocultures hampered survival and fecundity irrespective of fungicide exposure. This shows that bumblebees require access to complementary flowering species to gain both fitness and fungicide tolerance and that Amistar impacts are flowering resource-dependent. Our findings call for further research on how different flowering plants affect bees and their pesticide tolerance to improve guidelines for regulatory pesticide risk assessments and inform the choice of plants that are cultivated to safeguard pollinators.

Sulfoxaflor insecticide and azoxystrobin fungicide have no major impact on honeybees in a realistic-exposure semi-field experiment.

Exposure to pesticides is considered a major threat to bees and several neonicotinoid insecticides were recently banned in cropland within the European Union in light of evidence of their potential detrimental effects. Nonetheless, bees remain exposed to many pesticides whose effects are poorly understood. Recent evidence suggests that one of the most prominent replacements of the banned neonicotinoids - the insecticide sulfoxaflor - harms bees and that fungicides may have been overlooked as a driver of bee declines. Realistic-exposure studies are, however, lacking. Here, we assess the impact of the insecticide Closer (active ingredient: sulfoxaflor) and the widely used fungicide Amistar (a.i.: azoxystrobin) on honeybees in a semi-field study (10 flight cages containing a honeybee colony, for each of three treatments: Closer, Amistar, control). The products were applied according to label instructions either before (Closer) or during (Amistar) the bloom of purple tansy. We found no significant effects of Closer or Amistar on honeybee colony development or foraging activity. Our study suggests that these pesticides pose no notable risk to honeybees when applied in isolation, following stringent label instructions. The findings on Closer indicate that a safety-period of 5-6 days between application and bloom, which is only prescribed in a few EU member states, may prevent its impacts on honeybees. However, to conclude whether Closer and Amistar can safely be applied, further realistic-exposure studies should examine their effects in combination with other chemical or biological stressors on various pollinator species.

Fungicide and insecticide exposure adversely impacts bumblebees and pollination services under semi-field conditions.

Sulfoximines, the next generation systemic insecticides developed to replace neonicotinoids, have been shown to negatively impact pollinator development and reproduction. However, field-realistic studies on sulfoximines are few and consequences on pollination services unexplored. Moreover, the impacts of other agrochemicals such as fungicides, and their combined effects with insecticides remain poorly investigated. Here, we show in a full factorial semi-field experiment that spray applications of both the product Closer containing the insecticide sulfoxaflor and the product Amistar containing the fungicide azoxystrobin, negatively affected the individual foraging performance of bumblebees (Bombus terrestris). Insecticide exposure further reduced colony growth and size whereas fungicide exposure decreased pollen deposition. We found indications for resource limitation that might have exacerbated pesticide effects on bumblebee colonies. Our work demonstrates that field-realistic exposure to sulfoxaflor can adversely impact bumblebees and that applications before bloom may be insufficient as a mitigation measure to prevent its negative impacts on pollinators. Moreover, fungicide use during bloom could reduce bumblebee foraging performance and pollination services.

Complement depletion with humanized cobra venom factor in a mouse model of age-related macular degeneration.

The effect of complement depletion with humanized cobra venom factor (CVF) on retinal lesion development/neovascularization was determined in a mouse model of wet age-related macular degeneration (AMD). Mice were treated with the humanized CVF protein HC3-1496 prior to, and once daily for 28 days after laser coagulation surgery of the retina. CVF transgenic mice exhibiting permanently low levels of serum complement activity and PBS-treated mice served as positive and negative controls, respectively. Fluorescein isothiocyanate (FITC)-dextran funduscopy after laser surgery indicated the presence of lesions in all mice that underwent laser surgery. In HC3-1496-treated mice as well as CVF transgenic mice smaller lesions were seen after 8 days. Measurement of lesion sizes by histopathological examination of eyes after 28 days revealed a significant reduction of lesion area and volume in both HC3-1496-treated animals and CVF transgenic animals compared to PBS-treated control animals. Systemic complement depletion with a complement depletor, such as the humanized CVF protein HC3-1496, represents a promising therapeutic concept for patients with wet AMD.

14-day repeat-dose oral toxicity evaluation of oxazyme in rats and dogs.

Oxazyme (OC4) is an orally administered formulation that has as an active component a recombinant mutant form of Bacillus subtilis oxalate decarboxylase (OxDC) enzyme C383S, designed to degrade dietary oxalate in the stomach. Fourteen-day repeat-dose studies were conducted in rats and dogs to evaluate toxicity and determine a no observed adverse effect level (NOAEL). Animals were administered OC4 by oral gavage twice daily for 14 consecutive days. Reversibility, progression, and delayed appearance of any observed changes were evaluated in a subset of animals that underwent a recovery of 7 days following 14 days of control or test-article. There were no test-article-related adverse effects or deaths in either species. Results indicate that the NOAEL under the conditions used in the studies was 720.8 mg/kg/d in rats and 187.2 mg/kg/d in dogs, the high dose tested in each species.