Sakamoto Masaki, Hanazato Takayuki, Tanaka Yoshinari
Institute of Mountain Science, Shinshu University, Suwa, Japan.
Arch Environ Contam Toxicol. 2009 Jul;57(1):68-76. doi: 10.1007/s00244-008-9247-x. Epub 2008 Oct 14.
Pesticides often modify predatory interactions by enhancing (or inhibiting) the development of antipredator morphologies of freshwater cladocerans. In the present study, we assessed the impacts of an insecticide, carbaryl, on the life-history parameters of a polymorphic cladoceran, Bosmina longirostris, and on Bosmina-copepod interaction. In this Bosmina species, all juvenile individuals have the defensive morphology irrespective of presence of predators in juvenile stages, and they lose or maintain such morph compliance with the presence/absence of the predators in adult stages. In the present study, individual somatic growth and population growth rate decreased due to applied carbaryl. Moreover, the animals lost the defensive morphology when their body size was smaller than with no-carbaryl treatment even in the presence of predators, indicating that the insecticide inhibited persistence of the inherent antipredator morphology. Such a chemical disturbance will increase the predation risk to individuals and, in turn, influence the population dynamics of the bosminids through increased mortality.
农药常常通过增强（或抑制）淡水枝角类动物的反捕食形态的发育来改变捕食性相互作用。在本研究中，我们评估了一种杀虫剂西维因对多态性枝角类动物长额象鼻溞的生活史参数以及象鼻溞与桡足类动物相互作用的影响。在这种象鼻溞物种中，所有幼年个体无论在幼体阶段是否存在捕食者都具有防御形态，并且它们会根据成年阶段捕食者的存在与否而失去或保持这种形态。在本研究中，由于施用了西维因，个体的体细胞生长和种群增长率下降。此外，即使在有捕食者存在的情况下，当动物的体型比未施用西维因处理时更小时，它们就会失去防御形态，这表明该杀虫剂抑制了固有的反捕食形态的持续存在。这种化学干扰将增加个体的捕食风险，进而通过增加死亡率影响象鼻溞的种群动态。
