E H Graham Centre for Agricultural Innovation (Industry & Investment NSW and Charles Sturt University), Yanco Agricultural Institute, Industry & Investment NSW, Private Mail Bag, Yanco NSW 2703, Australia.
Acta Trop. 2011 Feb;117(2):125-30. doi: 10.1016/j.actatropica.2010.11.002. Epub 2010 Nov 16.
Mosquito-borne arboviruses are a significant health issue in the irrigation areas of south-eastern Australia. Fipronil, a pyrazole insecticide with strong activity against larval Culex species, was tested for its acute effects on Simocephalus elizabethae (Daphniidae) and Polypedilum nubiferum (Chironomidae), two non-target invertebrates associated with Australian rice field mosquito habitats. Technical and formulated fipronil were assessed in the presence or absence of particulate artificial diets in 48 h static bioassays. LC(50) values for neonate S. elizabethae ranged from 11.13 to 19.12 μgl(-1) whilst those for final instar P. nubiferum ranged from 0.89 to 2.18 μgl(-1). Feeding during exposure significantly reduced the susceptibility of P. nubiferum to both technical and formulated fipronil. The effect of feeding was less consistent in Simocephalus bioassays, where much less food was present. We investigated whether adsorption to unconsumed food particles may have limited fipronil bioavailability by using solid-phase microextraction and gas chromatography to measure the available fipronil from fed and unfed systems 24h after establishment. Differences between the systems were not significant (P>0.05). The significantly higher LC(50) values in the fed Polypedilum bioassays do not appear to be a consequence of reduced fipronil bioavailability. Observed differences in toxicity probably reflect increased stresses associated with food deprivation in the unfed bioassays. Our results support published data on the toxicity of fipronil to aquatic invertebrates which suggest that the use of this material as a mosquito larvicide may cause disruption to aquatic ecosystems.
虫媒病毒是澳大利亚东南部灌溉区的一个重大健康问题。吡虫啉是一种具有强烈活性的吡唑类杀虫剂，对幼虫库蚊属具有强烈的活性，本研究测试了其对非靶标水生无脊椎动物伊蚊属若虫（蚤科）和沼蝇属幼虫（摇蚊科）的急性毒性。在存在或不存在颗粒状人工饲料的情况下，用 48 小时静态生物测定法评估了吡虫啉原药和制剂的毒性。新孵化的伊蚊属若虫的 LC50 值范围为 11.13 至 19.12 µgl(-1)，而最后龄期的沼蝇属幼虫的 LC50 值范围为 0.89 至 2.18 µgl(-1)。暴露期间摄食显著降低了沼蝇属对吡虫啉原药和制剂的敏感性。在伊蚊属生物测定中，摄食的影响不太一致，因为食物的量要少得多。我们通过固相微萃取和气相色谱法来测量 24 小时后已消耗和未消耗的食物颗粒中未消耗的吡虫啉的可用性，以调查未消耗的食物颗粒对吡虫啉生物可利用性的吸附作用是否可能限制了吡虫啉的生物有效性。系统之间的差异没有统计学意义（P>0.05）。在有食物的沼蝇属生物测定中，LC50 值显著升高似乎并不是由于吡虫啉生物利用率降低所致。观察到的毒性差异可能反映了在无食物生物测定中与食物剥夺相关的压力增加。我们的研究结果支持了吡虫啉对水生无脊椎动物毒性的已发表数据，表明将该材料用作蚊虫幼虫杀虫剂可能会破坏水生生态系统。
