Toxicity of the insecticide imidacloprid to marine larvae of the hermit crab Coenobita variabilis (Arthropoda/Crustacea) (NESP TWQ 3.1.5, AIMS)

This dataset shows the effects of the insecticide imidacloprid on larval development of the hermit crab Coenobita variabilis. Experiments were conducted in 2017.The aim of this project was to apply a standard ecotoxicology protocol to determine the effects of the insecticide imidacloprid (that has been detected in the Great Barrier Reef catchment area (O'Brien et al., 2016)), on larval development (6-d exposures) of the hermit crab Coenobita variabilis. These toxicity data will enable improved assessment of the risks posed to marine crustaceans for both regulatory purposes and for comparison with other taxa.Methods:Imidacloprid (CAS 138261-41-3) stock solutions were prepared using PESTANAL (Merck) analytical grade product (purity greater than or equal to 99.9%). Stock solutions (100 – 1,000 mg L-1) were prepared by dissolving aliquots of the pure compound in ultrapure water using clean, acid-washed (5% nitric acid) glass screw-top containers. Acetone was used to dissolve the imidacloprid (less than or equal to 0.01 % (v/v) in exposure solutions). Stock solutions were stored refrigerated and in the dark.Tests were conducted as previously described (in van Dam et al, 2018). Broodstock crabs were collected from the Nightcliff seashore (Darwin, Australia – 12°23'8.70"S, 130°50'34.59"E) and maintained in custom-built, flat-bottomed enclosures. Spawning was left to occur naturally and toxicity tests initiated immediately following collection of larvae. Transparent polystyrene cell culture plates (Nunc; Thermo Scientific) were employed as test chambers. Each replicate plate contained six wells with a volume of 13 mL each. Exposures were conducted in a high-precision environmental chamber maintained at 29 ± 1°C, under 80 – 100 µmol quanta m-2s-1 PAR irradiance and a 12h:12h diurnal light:dark cycle. Zoeae were exposed to increasing concentrations of imidacloprid and tested against control (no toxicant) larvae. Zoeae were allocated individually to a well as larvae became cannibalistic once transitioned to megalopae. Five wells within a discrete plate contained analogous treatment solutions. Per test, a total of 18 plates were employed for 5 treatment concentrations and a control group, allowing for 3 replicate plates per treatment. Ten mL of exposure media was added to individual wells before the tests were started by randomly placing a larva from the common pool into each well. Larvae were transferred every 48 h to fresh exposure solutions in clean plates. After 6 d exposure, tests were terminated and individuals scored under a stereo microscope. Quality control criteria (> 70% survival in control group) for test acceptability were met for each test. Treatment effects were quantified by the percentage successful transition to megalopae in treatment groups relative to controls.Following prescribed statistical procedures (OECD, 2006), the R package DRC (R project., 2015, Ritz and Stribig., 2005) was used to model the test data and calculate toxicity estimates. Regression models evaluated included log-logistic and Weibull models of different levels of parametrisation. Model comparisons were conducted using the Akaike Information Criterion (AIC) and models that best described the data were applied to approximate pesticide concentrations eliciting 10 and 50% inhibition of successful transition relative to control animals (EC10 and EC50, respectively). The associated 95% confidence limits were estimated using the delta method.Format:The dataset is summarised in one file named ‘Coenobita variabilis pesticide toxicity data_eAtlas.xlsx’Data Dictionary:The excel spreadsheet has one tab for each pesticide. The last tab of the dataset shows the measured (start and end of test) water quality (WQ) parameters (pH, salinity, dissolved oxygen (DO), and temperature) for each test. For the ‘Imidacloprid_Development tab:Nominal (µg/L) = nominal herbicide concentrations used in the bioassaysMeasured (µg/L) = measured concentrations analysed by The University of QueenslandRep = replicate notation is 1-3No. of stage 1 zoea larvae at start = number of larvae per replicate at start of test No. of megalopae larvae day 6 = number of megalopae observed per replicate at end of testReferences:O’Brien, D. et al. Spatial and temporal variability in pesticide exposure downstream of a heavily irrigated cropping area: application of different monitoring techniques. J. Agric. Food Chem. 64, 3975-3989 (2016).van Dam, J. W. et al. Assessing chronic toxicity of aluminium, gallium and molybdenum in tropical marine waters using a novel bioassay for larvae of the hermit crab Coenobita variabilis. Ecotoxicol Environ Saf 165, 349-356, doi:https://doi.org/10.1016/j.ecoenv.2018.09.025 (2018).OECD. Current Approaches in the Statistical Analysis of Ecotoxicity Data., (OECD Publishing, 2006).R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/. (2015).Ritz, C. & Streibig, J. C. Bioassay analysis using R. Journal of Statistical Software 12, 1-22 (2005).Data Location:This dataset is filed in the eAtlas enduring data repository at: dataesp3\3.1.5_Pesticide-guidelines-GBR

本数据集探究了杀虫剂吡虫啉（imidacloprid）对寄居蟹Coenobita variabilis幼体发育的影响。实验于2017年开展。本研究的目标是采用标准生态毒理学实验规程，测定吡虫啉（该杀虫剂已在大堡礁流域被检出，O'Brien et al., 2016）对寄居蟹Coenobita variabilis幼体进行6天暴露后的发育影响。此类毒性数据可助力优化海洋甲壳动物的风险评估，为监管工作及与其他类群的对比研究提供支撑。

实验方法：
吡虫啉（CAS 138261-41-3）储备液采用PESTANAL（默克（Merck））分析纯产品配制，其纯度不低于99.9%。通过将纯品等分试样溶解于超纯水中，使用经清洁、酸洗（5%硝酸）处理的玻璃螺旋盖容器，配制浓度为100–1000 mg L⁻¹的储备液。实验暴露液中以丙酮作为助溶剂，丙酮体积占比不超过0.01%。储备液需于冷藏、避光条件下储存。
实验参照van Dam等人2018年的方法开展。亲代寄居蟹采集自澳大利亚达尔文市奈特克利夫海滨（12°23'8.70'S, 130°50'34.59'E），并饲养于定制平底养殖围隔中。让其自然产卵，采集幼体后立即启动毒性实验。采用透明聚苯乙烯细胞培养板（Nunc；赛默飞世尔科技（Thermo Scientific））作为实验容器。每个重复板包含6个孔，每孔体积为13 mL。实验在高精度环境舱中开展，环境参数设置为：温度29±1℃，光合有效辐射（PAR）强度80–100 µmol quanta m⁻²s⁻¹，光暗周期为12h:12h。
状幼体（Zoeae）暴露于梯度浓度的吡虫啉，并以无药剂的空白对照组幼体作为对照。由于幼体发育至大眼幼体（megalopae）阶段后会出现同类相食现象，因此每孔单独放置一只幼体。每个独立培养板内的5个孔对应相同的处理液。每个实验共设置5个处理浓度组与1个对照组，总计使用18块培养板，每个处理组设置3个重复板。实验开始前，向每个孔中加入10 mL暴露介质，随后从混合幼体池中随机选取一只幼体放入每孔。每48小时将幼体转移至更换了新鲜暴露液的干净培养板中。
暴露6天后终止实验，在体式显微镜下对个体进行发育评分。所有实验均满足实验可接受性的质控标准（对照组存活率不低于70%）。处理效应通过处理组相较于对照组成功蜕皮至大眼幼体的个体百分比进行量化。
按照经济合作与发展组织（OECD）2006年规定的统计分析流程，使用R包DRC（R项目团队，2015；Ritz与Streibig，2005）对实验数据进行建模并计算毒性评估值。本次评估的回归模型包括不同参数化水平的逻辑对数模型与Weibull模型。模型比较采用赤池信息准则（Akaike Information Criterion, AIC）进行，选取对数据拟合最优的模型，以估算相较于对照组，导致成功蜕皮率受到10%和50%抑制的农药浓度（分别记为EC10和EC50）。采用delta法估算对应的95%置信区间。

数据集格式：
本数据集汇总于名为"Coenobita variabilis pesticide toxicity data_eAtlas.xlsx"的单个文件中。

数据字典：
该Excel表格包含一个工作表对应一种杀虫剂。数据集的最后一个工作表展示了各次实验的实测水质（WQ）参数（pH值、盐度、溶解氧（DO）与温度），涵盖实验起始与结束阶段的数据。针对"Imidacloprid_Development"工作表：
- Nominal (µg/L)：生物测试中使用的标称除草剂浓度
- Measured (µg/L)：由昆士兰大学分析测定的实测浓度
- Rep：重复组编号为1-3
- No. of stage 1 zoea larvae at start：实验开始时每个重复组的Ⅰ期状幼体数量
- No. of megalopae larvae day 6：实验结束（第6天）时每个重复组观测到的大眼幼体数量

参考文献：
1. O’Brien, D. et al. 高灌溉量种植区下游农药暴露的时空差异：不同监测技术的应用. 《农业与食品化学期刊》（J. Agric. Food Chem.）64, 3975-3989 (2016).
2. van Dam, J. W. et al. 利用新型寄居蟹Coenobita variabilis幼体生物测定法评估热带海水中铝、镓与钼的慢性毒性. 《生态毒理与环境安全》（Ecotoxicol Environ Saf）165, 349-356, doi:https://doi.org/10.1016/j.ecoenv.2018.09.025 (2018).
3. 经济合作与发展组织（OECD）. 生态毒理学数据统计分析现行方法. （OECD Publishing, 2006）.
4. R：统计计算语言与环境. 奥地利维也纳：R统计计算基金会. 网址：https://www.R-project.org/. (2015).
5. Ritz, C. & Streibig, J. C. 基于R的生物测定分析. 《统计软件期刊》12, 1-22 (2005).

数据存储位置：
本数据集存储于eAtlas永久性数据存储库中，路径为：dataesp33.1.5_Pesticide-guidelines-GBR