Laboratory for Sensory Ecology, Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
University of Michigan Biological Station, Pellston, MI, 49769, USA.
Arch Environ Contam Toxicol. 2019 Oct;77(3):452-460. doi: 10.1007/s00244-019-00664-3. Epub 2019 Aug 26.
The adoption of genetically modified (GM) crops has occurred rapidly in the United States. The transfer of GM corn byproducts from agricultural fields to nearby streams after harvest is significant and occurs well into the post-harvest year. These corn leaves, stems, and cobs then become a detrital food source for organisms, such as shredders in the stream ecosystem. Considering that the nontarget effects of Bt corn have been observed in some terrestrial organisms, we assessed whether Bt toxins affect an important aquatic organism, juvenile F. rusticus crayfish. Juvenile crayfish were fed six distinct diet treatments: two varieties of Bt corn, two non-Bt controls of herbicide tolerant corn, and two controls: fish gelatin and river detritus. Juveniles were fed these diets while housed in flow-through artificial streams that received natural stream water from a local source. Specific growth rate and survivorship of the crayfish were measured throughout the study. Juveniles fed corn diets grew significantly less and had reduced survival compared with juveniles fed fish gelatin or river detritus diets. Furthermore, juveniles fed one Bt variety of corn (VT Triple Pro) exhibited significantly less growth than those fed one of the herbicide tolerant varieties (Roundup Ready 2). Our study shows that corn inputs to streams may be detrimental to the growth and survivorship of juvenile crayfish and that certain Bt varieties may exacerbate these negative effects. These effects on crayfish will have repercussions for the entire ecosystem, because crayfish are conduits of energy between many trophic levels.
美国的转基因（GM）作物已经迅速普及。收获后，GM 玉米副产品从农田转移到附近溪流的情况非常严重，并且会持续到收获后的一年。这些玉米的叶子、茎和玉米芯随后成为溪流生态系统中碎屑食物源，如生物碎屑分解者。考虑到 Bt 玉米在一些陆地生物中已经观察到非靶标效应，我们评估了 Bt 毒素是否会影响一种重要的水生生物——幼年 F. rusticus 小龙虾。幼年小龙虾被喂食六种不同的饮食处理：两种转基因玉米、两种抗除草剂的非转基因玉米和两种对照：鱼明胶和河流碎屑。在流经人工溪流的过程中，幼年小龙虾被喂食这些饮食，这些溪流接收了来自当地的天然溪流水源。在整个研究过程中，测量了小龙虾的特定生长率和存活率。与喂食鱼明胶或河流碎屑饮食的小龙虾相比，喂食玉米饮食的小龙虾生长明显减少，存活率降低。此外，喂食一种 Bt 玉米品种（VT Triple Pro）的小龙虾生长速度明显低于喂食一种抗除草剂玉米品种（Roundup Ready 2）的小龙虾。我们的研究表明，流入溪流的玉米可能会对幼年小龙虾的生长和存活率产生不利影响，并且某些 Bt 品种可能会加剧这些负面影响。这些对小龙虾的影响将对整个生态系统产生影响，因为小龙虾是许多营养级之间能量的渠道。
