Pyrethroid Exposure Reduces Growth and Development of Monarch Butterfly (Lepidoptera: Nymphalidae) Caterpillars

Insecticide exposure has been identified as a contributing stressor to the decline in the North American monarch butterfly Danaus plexippus L. (Lepidoptera: Nymphalidae) population. Monarch toxicity data are currently limited and available data focuses on lethal endpoints. This study examined the 72-h toxicity of two pyrethroid insecticides, bifenthrin and β-cyfluthrin, and their effects on growth and diet consumption. The toxicity of bifenthrin to caterpillars was lower than β-cyfluthrin after 72 h. Survival was the most sensitive endpoint for bifenthrin, but diet consumption and caterpillar growth were significantly reduced at sublethal levels of β-cyfluthrin. Using AgDRIFT spray drift assessment, the aerial application of bifenthrin or β-cyfluthrin is predicted to pose the greatest risk to fifth-instar caterpillars, with lethal insecticide deposition up to 28 m for bifenthrin and up to 23 m for β-cyfluthrin from treated edges of fields. Low boom ground applications are predicted to reduce distances of lethal insecticide exposure to 2 m from the treated field edge for bifenthrin and β-cyfluthrin. Growth and survival of fifth-instar monarch caterpillars developing within the margins of a treated field may be significantly impacted following foliar applications of bifenthrin or β-cyfluthrin. These findings provide evidence that pyrethroid insecticides commonly used for soybean pest control are a potential risk to monarch caterpillars in agricultural landscapes

Cardenolide, Potassium, and Pyrethroid Insecticide Combinations Reduce Growth and Survival of Monarch Butterfly Caterpillars (Lepidoptera: Nymphalidae)

The monarch butterfly, Danaus plexippus L., has evolved to be insensitive to milkweed cardenolides via genetic modifications of Na+/K+-ATPase. There is concern for insecticide exposures near agriculture, with little information on monarch caterpillar toxicology. It is unclear how cardenolide insensitivity may affect the sensitivity of monarch caterpillars to pyrethroid insecticides. Additionally, potassium fertilizers may affect monarch caterpillar physiology and cardenolide sequestration. Here, we investigated the growth, survival, and development of caterpillars exposed to the cardenolide ouabain, bifenthrin, and potassium chloride (KCl) alone and in combination. Caterpillars were either exposed to (1) ouabain from third- to fifth-instar stage, (2) KCl at fifth-instar stage, (3) KCl and bifenthrin at fifth-instar stage, or (4) combinations of ouabain at third-instar stage + KCl + bifenthrin at fifth-instar stage. Caterpillar weight, diet consumption, frass, and survival were recorded for the duration of the experiments. It was observed that 1–3 mg ouabain/g diet increased body weight and diet consumption, whereas 50 mg KCl/g diet decreased body weight and diet consumption. Caterpillars feeding on KCl and treated with 0.2 μg/μl bifenthrin consumed significantly less diet compared to individuals provided untreated diet. However, there was no effect on survival or body weight. Combinations of KCl + ouabain did not significantly affect caterpillar survival or body weight following treatment with 0.1 μg/μl bifenthrin. At the concentrations tested, there were no effects observed for bifenthrin sensitivity with increasing cardenolide or KCl concentrations. Further studies are warranted to understand how milkweed-specific cardenolides, at increasing concentrations, and agrochemical inputs can affect monarch caterpillar physiology near agricultural landscapes

LARP7 is a stable component of the 7SK snRNP while P-TEFb, HEXIM1 and hnRNP A1 are reversibly associated

Regulation of the elongation phase of RNA polymerase II transcription by P-TEFb is a critical control point for gene expression. The activity of P-TEFb is regulated, in part, by reversible association with one of two HEXIMs and the 7SK snRNP. A recent proteomics survey revealed that P-TEFb and the HEXIMs are tightly connected to two previously-uncharacterized proteins, the methyphosphate capping enzyme, MEPCE, and a La-related protein, LARP7. Glycerol gradient sedimentation analysis of lysates from cells treated with P-TEFb inhibitors, suggested that the 7SK snRNP reorganized such that LARP7 and 7SK remained associated after P-TEFb and HEXIM1 were released. Immunodepletion of LARP7 also depleted most of the 7SK regardless of the presence of P-TEFb, HEXIM or hnRNP A1 in the complex. Small interfering RNA knockdown of LARP7 in human cells decreased the steady-state level of 7SK, led to an initial increase in free P-TEFb and increased Tat transactivation of the HIV-1 LTR. Knockdown of LARP7 or 7SK ultimately caused a decrease in total P-TEFb protein levels. Our studies have identified LARP7 as a 7SK-binding protein and suggest that free P-TEFb levels are determined by a balance between release from the large form and reduction of total P-TEFb

Measuring the health-related Sustainable Development Goals in 188 countries : a baseline analysis from the Global Burden of Disease Study 2015

Background In September, 2015, the UN General Assembly established the Sustainable Development Goals (SDGs). The SDGs specify 17 universal goals, 169 targets, and 230 indicators leading up to 2030. We provide an analysis of 33 health-related SDG indicators based on the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015). Methods We applied statistical methods to systematically compiled data to estimate the performance of 33 health-related SDG indicators for 188 countries from 1990 to 2015. We rescaled each indicator on a scale from 0 (worst observed value between 1990 and 2015) to 100 (best observed). Indices representing all 33 health-related SDG indicators (health-related SDG index), health-related SDG indicators included in the Millennium Development Goals (MDG index), and health-related indicators not included in the MDGs (non-MDG index) were computed as the geometric mean of the rescaled indicators by SDG target. We used spline regressions to examine the relations between the Socio-demographic Index (SDI, a summary measure based on average income per person, educational attainment, and total fertility rate) and each of the health-related SDG indicators and indices. Findings In 2015, the median health-related SDG index was 59.3 (95% uncertainty interval 56.8-61.8) and varied widely by country, ranging from 85.5 (84.2-86.5) in Iceland to 20.4 (15.4-24.9) in Central African Republic. SDI was a good predictor of the health-related SDG index (r(2) = 0.88) and the MDG index (r(2) = 0.2), whereas the non-MDG index had a weaker relation with SDI (r(2) = 0.79). Between 2000 and 2015, the health-related SDG index improved by a median of 7.9 (IQR 5.0-10.4), and gains on the MDG index (a median change of 10.0 [6.7-13.1]) exceeded that of the non-MDG index (a median change of 5.5 [2.1-8.9]). Since 2000, pronounced progress occurred for indicators such as met need with modern contraception, under-5 mortality, and neonatal mortality, as well as the indicator for universal health coverage tracer interventions. Moderate improvements were found for indicators such as HIV and tuberculosis incidence, minimal changes for hepatitis B incidence took place, and childhood overweight considerably worsened. Interpretation GBD provides an independent, comparable avenue for monitoring progress towards the health-related SDGs. Our analysis not only highlights the importance of income, education, and fertility as drivers of health improvement but also emphasises that investments in these areas alone will not be sufficient. Although considerable progress on the health-related MDG indicators has been made, these gains will need to be sustained and, in many cases, accelerated to achieve the ambitious SDG targets. The minimal improvement in or worsening of health-related indicators beyond the MDGs highlight the need for additional resources to effectively address the expanded scope of the health-related SDGs.Peer reviewe

Toxicology of Chemical Stress to Monarch Butterflies (\u3ci\u3eDanaus plexippus\u3c/i\u3e L.)

Monarch butterfly (Danaus plexippus L.) population declines have caught the attention of the country and prompted nationwide conservation initiatives. The United States Fish and Wildlife Service has identified insecticide exposure and loss of milkweed (Asclepias spp.) reproductive habitat as primary threats to the monarch. In the Midwestern US, milkweed largely occurs around cropland borders where there may be a spatial and temporal overlap of monarch larvae, insecticide usage, and fertilizer applications. In this study, the acute toxicity and sub-lethal effects on growth and diet consumption of two commonly used pyrethroid insecticides, bifenthrin and beta-cyfluthrin, were characterized in fifth instar monarch larvae. While beta-cyfluthrin was more toxic than bifenthrin, foliar applications of formulated products, Baythroid (beta-cyfluthrin) and Brigade 2-EC (bifenthrin), would result in sub-lethal and lethal effects at similar distances from a treated field edge according to the United States Environmental Protection Agency AgDrift model. As monarch larvae consume milkweed leaves they also ingest insecticidal cardenolides, which are antagonized by potassium. We examined the effects of ouabain, a hydrophilic cardenolide, and potassium chloride (KCl), a commonly used potassium fertilizer, in monarch caterpillars following chronic oral exposure. Once effect thresholds of ouabain and KCl were determined, bifenthrin toxicity was compared between different combinations of ouabain and KCl diets. Elevated concentrations of ouabain increased caterpillar growth and decreased development time whereas elevated concentrations of KCl decreased caterpillar growth and diet consumption. There was no difference in bifenthrin toxicity on different diet combinations. Milkweed species contain a variety of cardenolides that vary in concentration and polarity. Toxicity of bifenthrin and effects on detoxification enzymes were characterized in monarchs feeding on tropical milkweed (A. curassavica), a high cardenolide species, and swamp milkweed (A. incarnata), a low cardenolide species. Detoxification gene expression and enzyme activity significantly differed between milkweed species and between solvent control and bifenthrin treated caterpillars on each species. Understanding physiological differences in monarchs developing on different milkweed species is important for maximizing the benefits of habitat restorations among agricultural landscapes. Adviser: Troy D. Anderso

Toxicology of Chemical Stress to Monarch Butterflies (Danaus plexippus L.)

Monarch butterfly (Danaus plexippus L.) population declines have caught the attention of the country and prompted nationwide conservation initiatives. The United States Fish and Wildlife Service has identified insecticide exposure and loss of milkweed (Asclepias spp.) reproductive habitat as primary threats to the monarch. In the Midwestern US, milkweed largely occurs around cropland borders where there may be a spatial and temporal overlap of monarch larvae, insecticide usage, and fertilizer applications. In this study, the acute toxicity and sub-lethal effects on growth and diet consumption of two commonly used pyrethroid insecticides, bifenthrin and beta-cyfluthrin, were characterized in fifth instar monarch larvae. While beta-cyfluthrin was more toxic than bifenthrin, foliar applications of formulated products, Baythroid (beta-cyfluthrin) and Brigade 2-EC (bifenthrin), would result in sub-lethal and lethal effects at similar distances from a treated field edge according to the United States Environmental Protection Agency AgDrift model. As monarch larvae consume milkweed leaves they also ingest insecticidal cardenolides, which are antagonized by potassium. We examined the effects of ouabain, a hydrophilic cardenolide, and potassium chloride (KCl), a commonly used potassium fertilizer, in monarch caterpillars following chronic oral exposure. Once effect thresholds of ouabain and KCl were determined, bifenthrin toxicity was compared between different combinations of ouabain and KCl diets. Elevated concentrations of ouabain increased caterpillar growth and decreased development time whereas elevated concentrations of KCl decreased caterpillar growth and diet consumption. There was no difference in bifenthrin toxicity on different diet combinations. Milkweed species contain a variety of cardenolides that vary in concentration and polarity. Toxicity of bifenthrin and effects on detoxification enzymes were characterized in monarchs feeding on tropical milkweed (A. curassavica), a high cardenolide species, and swamp milkweed (A. incarnata), a low cardenolide species. Detoxification gene expression and enzyme activity significantly differed between milkweed species and between solvent control and bifenthrin treated caterpillars on each species. Understanding physiological differences in monarchs developing on different milkweed species is important for maximizing the benefits of habitat restorations among agricultural landscapes

The Utility of a Bumble Bee (\u3ci\u3eBombus\u3c/i\u3e spp. [Hymenoptera: Apidae]) Brood Test for Evaluating the Effects of Pesticides

Risk assessment for chemicals in the United States relies upon the honey bee (Apis meliffera L. [Hymenoptera: Apidae]) as a surrogate for other bee species. There is uncertainty in extrapolating honey bee toxicity data to bumble bees due to differences in life history strategies, food consumption, and nest structure. Here we evaluated the design of a queenless bumble bee microcolony test that could be considered for generating larval toxicity data. Three microcolony studies were conducted with Bombus impatiens to evaluate the effects of exposure to 1) diflubenzuron in pollen, 2) dimethoate in pollen, and 3) dimethoate in sucrose. Immature drone bee emergence, worker survival, pollen, and sucrose utilization were measured throughout the study duration. For dimethoate, a 10-d chronic adult bumble bee study was also conducted to compare microcolony endpoints to toxicity endpoints on individual adults. Microcolonies exposed to 10 mg diflubenzuron/kg pollen produced fewer adult drones despite no effects on worker survival. Microcolonies treated with dimethoate at ≥3 mg a.i./kg pollen and ≥0.1 mg a.i./kg sucrose solution produced fewer drones. Exposure to dimethoate in the 10-d chronic adult study resulted in direct mortality to the adult workers at ≥0.1 mg a.i./kg diet. Results from the 10-d study suggest direct effects of dimethoate on workers in the microcolony will alter provisioning of diet to the brood, resulting in lower drone production in the microcolony. Our data suggest that the microcolony study is only appropriate to assess brood effects to bumble bees for substances with low toxicity to adults, as demonstrated with diflubenzuron. The microcolony study design is optimal for assessing the effects of substances to larvae when direct effects to adults are not predicted. A test item can be delivered via both the pollen dough and sucrose solution