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Based on nuclear ribosomal DNA internal transcribed spacer (ITS) sequences, Thermopsideae is phylogenetically studied within a genistoid background. Analysis reveals that the tribe is not supported as a monophyletic group. Some species of Sophora s.s are nested within it. The central Asian desert Ammopiptanthus forms an isolated clade but is relatively remote to other Thermopsideae members. Piptanthus, Anagyris, Baptisia, and Thermopsis are clustered together into a robust clade. We hence propose that the tribe could either be reduced to just the four 'core genera' with Ammopiptanthus excluded, or, as an alternative, that Thermopsideae could become part of a new Sophoreae s.s. if it is re-circumscribed in the future. Both Piptanthus and Baptisia appear as monophyletic. The genus Anagyris is closer to some east Asian Thermopsis species than to Piptanthus. The east Asian and North American disjunct Thermopsis is not monophyletic. The ITS results suggest a geographical division between the Old World and New World Thermopsis. The east Asian species are clustered with Piptanthus and Anagyris, whereas the North American species are allied to Baptisia. Nonetheless, the only two north-eastern east Asian native Thermopsis species appear to be more related to the North American group than to the east Asian one. The related biogeographical significance has therefore been additionally discussed. (c) 2006 The Linnean Society of London.

Although alkaloids are known feeding deterrents for lepidopteran larvae, including the spruce budworm, Choristoneura fumiferana (Clemens), few studies have investigated their effects on lepidopteran oviposition. Quinolizidine-containing alkaloid extracts and isolated quinolizidine alkaloids were obtained from 2 Chinese plants, Sophora alopecuroides L. and Thermopsis lanceolata Robert Brown, to evaluate their effects on spruce budworm oviposition. Application of extracts from either plant on Parafilm substrate significantly deterred oviposition at dosages as low as 4.7 and 7.9 μg/cm 2 , respectively, in dual-choice bioassays. Of 9 quinolizidine alkaloids produced by these plants, 6 deterred oviposition on Parafilm substrate treated at 7.9 μg/cm 2 or less. The most effective compounds were aloperine (0.3 μg/cm 2 = 1.3 nmol/cm 2 ), sparteine (1.6 μg/cm 2 = 6.8 nmol/cm 2 ), and cytisine (1.6 μg/cm 2 = 8.4 nmol/cm 2 ). Oviposition was deterred also on fresh host foliage, 8-cm twigs of balsam fir, Abies balsamea (L.) Miller, which had been sprayed with either a 1-ml aliquot of alkaloid extract (10 mg/ml) of S. alopecuroides or 1 ml of an aloperine solution (1 mg/ml). There was no effect on longevity of males or females continuously exposed to artificial substrate treated with aloperine or alkaloid extract from S. alopecuroides in no-choice bioassays, nor was the ability of males to inseminate females affected. However, female production of egg masses was inhibited, although clutch size (eggs per egg mass) was not affected. These results are the 1st demonstration of the behaviorally deterring and physiologically inhibiting effects of quinolizidine alkaloids on lepidopteran oviposition.