Mommaerts Veerle, Sterk Guido, Smagghe Guy
Faculty of Sciences, Department of Biology, Free University of Brussels, Brussels, Belgium.
Ecotoxicology. 2006 Aug;15(6):513-21. doi: 10.1007/s10646-006-0087-z. Epub 2006 Aug 4.
This study examined the lethal and sublethal effects on the beneficial insect Bombus terrestris by two classes of insect growth regulators (IGRs) that are commercially used in agriculture to control pest insects. Three juvenile hormones analogues (JHAs) (pyriproxyfen, fenoxycarb and kinoprene) and two ecdysone agonists or moulting accelerating compounds (MACs) (tebufenozide and methoxyfenozide) were tested. The bumblebee workers were exposed to the insecticides via three different routes of exposure: dermally by topical contact, and orally via the drinking sugar water or the pollen. In the first series of experiments the IGRs were applied at their respective maximum field recommended concentration (MFRC). These risk hazard tests showed that the tested IGRs caused no acute toxicity on the workers, and any compound had an adverse effect on reproduction (production of males). In addition, larval development was followed in the treated nests compared with the controls. After application of the two MACs and the JHA fenoxycarb no adverse effects were observed on larval development. However, in the nests where the workers were exposed to the JHAs pyriproxyfen and kinoprene higher numbers of dead larvae were scored. These larvae were third and fourth instars, implying a lethal blockage of development before metamorphosis. In a second test, a series of dilutions was made for kinoprene, and these results revealed that only the MFRC caused a toxic effect on the larval development. On the other hand, kinoprene at lower concentrations (0.0650 mg ai/l) had a stimulatory effect on brood production. It was remarkable that ovaries of such treated dominant workers were longer and contained more eggs than in the controls. In a last experiment, the cuticular uptake was determined for a JHA and MAC to evaluate to what extent worker bees accumulate these classes of IGRs. Cuticular uptake ranged from 34 to 83% at 24 h after topical application. Overall, the obtained results indicate that the tested IGRs at their recommended concentration are safe to be used in combination with B. terrestris.
本研究考察了农业上用于防治害虫的两类昆虫生长调节剂（IGRs）对有益昆虫熊蜂的致死和亚致死效应。测试了三种保幼激素类似物（JHAs）（吡丙醚、苯氧威和烯虫炔酯）以及两种蜕皮激素激动剂或蜕皮加速化合物（MACs）（虫酰肼和甲氧虫酰肼）。熊蜂工蜂通过三种不同的接触途径接触这些杀虫剂：经皮局部接触、通过饮用糖水或花粉口服。在第一系列实验中，IGRs以各自的最大田间推荐浓度（MFRC）施用。这些风险危害测试表明，所测试的IGRs对工蜂没有急性毒性，且任何化合物对繁殖（雄性产生）都有不利影响。此外，与对照相比，跟踪了处理过的蜂巢中的幼虫发育情况。施用两种MACs和保幼激素苯氧威后，未观察到对幼虫发育有不利影响。然而，在工蜂接触保幼激素吡丙醚和烯虫炔酯的蜂巢中，记录到死亡幼虫数量更多。这些幼虫为三龄和四龄幼虫，这意味着在变态前发育出现致死性阻滞。在第二项测试中，对烯虫炔酯进行了一系列稀释，这些结果表明只有MFRC对幼虫发育产生毒性作用。另一方面，较低浓度（0.0650毫克有效成分/升）的烯虫炔酯对育雏有刺激作用。值得注意的是，与对照相比，经过此类处理的优势工蜂的卵巢更长且含有更多卵子。在最后一项实验中，测定了一种保幼激素和一种MAC的表皮吸收情况，以评估工蜂积累这类IGRs的程度。局部施用后24小时，表皮吸收范围为34%至83%。总体而言，所得结果表明，所测试的IGRs在推荐浓度下与熊蜂联合使用是安全的。
