Hare L
Institut National de la Recherche Scientifique-Eau (INRS-Eau), Université du Québec, Sainte-Foy, Canada.
Crit Rev Toxicol. 1992;22(5-6):327-69. doi: 10.3109/10408449209146312.
The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physicochemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.
昆虫从食物和水源中摄取金属的过程被认为是可叠加的。对于某一种特定金属而言，从水和食物中摄取的比例既取决于与每种来源相关的该金属的生物可利用浓度，也取决于金属进入昆虫体内的机制和速率。在了解相关昆虫类群的取食关系的基础上，才应尝试将昆虫体内的痕量金属浓度与昆虫的营养级联系起来。细胞层面存在摄取必需金属（如铜和锌）的途径，而其他非必需金属（如镉）似乎也通过这些途径进入昆虫体内。在细胞内，痕量金属可以与蛋白质结合或储存在颗粒中。金属在昆虫身体组织中的内部分布非常不均匀，其分布模式往往因金属和类群的不同而各异。与昆虫相关的痕量金属既可以结合在其几丁质外骨骼表面，也可以融入身体组织。个体积累的痕量金属量反映了来自溶解态和颗粒态来源的金属流入速率与生物体金属流出速率之间的净平衡。金属的毒性在生物组织的各个层面（细胞、组织、个体、种群和群落）都已得到证实。许多关于金属对水生昆虫毒性影响的文献都基于实验室观察，因此，很难将这些数据外推到自然环境中的昆虫。少数在自然环境中的实验研究表明，痕量金属污染物会影响水生昆虫的分布和数量。昆虫作为自然环境中金属污染生物监测器的潜力在很大程度上尚未得到开发。更好地理解介导痕量金属生物可利用性和交换的物理化学及生物学机制，将有助于开发将昆虫体内痕量金属浓度与其环境中的浓度相关联的通用预测模型。这样的模型将有助于把昆虫用作污染物生物监测器。
