Department of Entomology, University of California, 92521, Riverside, California.
J Chem Ecol. 1991 May;17(5):973-87. doi: 10.1007/BF01395603.
Acidic fogs with a pH of 2.0 and duration of 2 hr did not reduce the efficacy ofBacillus thuringiensis var.Kurstaki (Berliner). Therefore, the impact of UV radiation was investigated on the interactions between (1) levels of the antibacterial linear furanocoumarins psoralen, bergapten, and xanthotoxin inApium graveolens (L.) occurring following a 2.0 pH acidic fog episode, (2) the noctuidSpodoptera exigua (Hübner), and (3) a sublethal dosage of the microbial pathogenB. thuringiensis var.Kurstaki. Mean time to pupation in the absence of UV radiation (survival was too low to conduct this analysis for insects exposed to UV) was significantly extended by the addition of either psoralens orB. thuringiensis. Larvae developing on diets containingB. thuringiensis plus psoralens required nearly 40% longer to pupate than controls, but their effects were additive as the interaction was not significant. Although the mean times to adult emergence were significantly different, time spent in the pupal stage did not vary significantly between treatments, indicating that increases in larval developmental time were responsible for the observed decrease in developmental rate. Mean time to mortality, a weighted average time of death, was not significantly affected by any of the treatments. In a 2 × 2 × 2 factorial analysis, all main effects (linear furanocoumarins.B. thuringiensis, UV radiation) reduced survival significantly, as did the three-way interaction. Thus, antagonistic interactions with psoralens that would reduce the effectiveness ofB. thuringiensis in the field were not observed. When pairs of main effects were nested within the two levels (presence and absence) of the third factor, several two-way interactions were found. Interestingly, the activity ofB. thuringiensis and the psoralens, individually or in combination, was enhanced by exposure to UV radiation. Implications of this research are discussed for both natural and agricultural ecosystems.
酸性雾 pH 值为 2.0,持续时间为 2 小时,并未降低苏云金芽孢杆菌 var.Kurstaki (Berliner) 的功效。因此,研究了紫外线辐射对以下方面的相互作用的影响:(1)在 pH 值为 2.0 的酸性雾事件后,Apium graveolens (L.) 中存在的抗细菌线性呋喃香豆素补骨脂素、佛手柑内酯和黄樟素的水平;(2)夜蛾属昆虫 Spodoptera exigua (Hübner);(3)微生物病原体苏云金芽孢杆菌 var.Kurstaki 的亚致死剂量。在没有紫外线辐射的情况下(由于暴露在紫外线中的昆虫的存活率太低,无法进行此分析),添加补骨脂素或苏云金芽孢杆菌均可显著延长化蛹时间。在含有苏云金芽孢杆菌和补骨脂素的饮食中发育的幼虫化蛹时间几乎延长了 40%,但它们的作用是相加的,因为相互作用不显著。尽管成虫出现的平均时间有显著差异,但处理之间的蛹期时间没有显著差异,这表明幼虫发育时间的增加是观察到发育率下降的原因。死亡率的平均时间,即加权平均死亡时间,没有受到任何处理的显著影响。在 2 × 2 × 2 析因分析中,所有主要效应(线性呋喃香豆素、苏云金芽孢杆菌、紫外线辐射)均显著降低了存活率,三个因素的三向相互作用也是如此。因此,没有观察到与补骨脂素的拮抗相互作用,这种相互作用会降低苏云金芽孢杆菌在田间的效果。当两对主要效应嵌套在第三个因素的两个水平(存在和不存在)内时,发现了几个双向相互作用。有趣的是,苏云金芽孢杆菌和补骨脂素单独或组合使用的活性,在暴露于紫外线辐射时会增强。本文讨论了这项研究对自然和农业生态系统的意义。