Pratt Corin, Pope Tom W, Powell Glen, Rossiter John T
Division of Biology, Faculty of Natural Sciences, Imperial College London, Wye Campus, Ashford, Kent, TN25 5AH, UK.
J Chem Ecol. 2008 Mar;34(3):323-9. doi: 10.1007/s10886-007-9421-z. Epub 2008 Feb 13.
Brassica nigra plants, characterized by high levels of sinigrin, and artificial aphid diets to which sinigrin was selectively added were used to rear the crucifer specialist, Brevicoryne brassicae. Aphids were provided as a food source to two species of polyphagous ladybird, Adalia bipunctata and Coccinella septempunctata. First instar A. bipunctata were unable to survive when fed with B. brassicae reared on B. nigra or diets containing 0.2% sinigrin, but when fed with aphids reared on diets containing 0% sinigrin, survival rates were high. By contrast, first instar C. septempunctata were able to survive when fed with aphids reared on B. nigra or artificial diets containing up to 1% sinigrin. However, the presence of sinigrin in the aphid diet decreased larval growth and increased the time necessary for larvae to reach second instar for this species of ladybird. These results indicate that the presence of sinigrin in the diet of B. brassicae makes this aphid unsuitable as a food source for A. bipunctata but not for C. septempunctata, although for this ladybird species, there appear to be costs associated with feeding on aphids that contain this secondary metabolite.
以高含量黑芥子硫苷为特征的黑芥植株，以及选择性添加了黑芥子硫苷的人工蚜虫饲料，被用于饲养十字花科专食性害虫——甘蓝蚜。蚜虫作为食物来源被提供给两种多食性瓢虫，即二斑瓢虫和七星瓢虫。用在黑芥上饲养的甘蓝蚜或含有0.2%黑芥子硫苷的饲料饲养的甘蓝蚜喂食时，二斑瓢虫一龄幼虫无法存活，但用含有0%黑芥子硫苷的饲料饲养的蚜虫喂食时，存活率很高。相比之下，用在黑芥上饲养的蚜虫或含有高达1%黑芥子硫苷的人工饲料饲养的蚜虫喂食时，七星瓢虫一龄幼虫能够存活。然而，蚜虫饲料中黑芥子硫苷的存在会降低这种瓢虫幼虫的生长速度，并延长幼虫发育到二龄所需的时间。这些结果表明，甘蓝蚜饲料中黑芥子硫苷的存在使得这种蚜虫不适宜作为二斑瓢虫的食物来源，但对七星瓢虫而言并非如此，尽管对于这种瓢虫来说，取食含有这种次生代谢物的蚜虫似乎存在代价。
