Ant-repellent sesquiterpene lactones from Eupatorium quadrangularae

The chloroform extract from the leaves of Eupatorium quadrangularae has been systematically fractionated by following biological activity in a bioassay which measures repellency to the leafcutter ant Atta cephalotes (Formicidae, Attini). Several sesquiterpene lactones were isolated, two of which showed significant ant-repellency.     

Filamentous fungi found in Atta sexdens rubropilosa colonies after treatment with different toxic bait formulations

Leaf‐cutting ants maintain a symbiotic relationship with basidiomycetous fungi cultivated as food. Here, we profiled the non‐symbiotic filamentous fungi in laboratory nests of Atta sexdens rubropilosa submitted to treatments with different toxic bait formulations (using the insecticide sulfluramide as the active ingredient). After treatment, several filamentous fungi were found in different nest compartments. Culture‐dependent techniques recovered a total of 93 fungal isolates comprising 10 genera, 11 species and four unidentified fungi. The genus Penicillium was prevalent in both control and insecticide treatments. Overall, the majority of fungal isolates obtained in this study are commonly found in soil. Escovopsis spp., the specialized parasite of the ant‐fungus mutualism was only recorded in the fungus gardens of nests submitted to the toxic treatments. Moreover, no correlation was found regarding the presence of fungi in the different nest compartments (chi‐square, P > 0.4182). This study reveals that Escovopsis spp. is not the only fungus to overgrow the fungus garden of debilitated nests, thus adding more evidence on the possible negative impacts of such alien fungi. As suggested by previous studies, fast‐growing filamentous fungi likely overgrow the fungus garden in such conditions.     

Jacquinonic acid,an ant-repellent triterpenoid from Jacquinia pungens

The isolation and structure elucidation of jacquinonic acid, an ant-repellent triterpenoid from Jacquinia pungens, are described. This compound is a highly functionalized derivative of the oleanane skeleton, which contains both the uncommon C-13, 28 ether linkage and an α,β-unsaturated 3-keto group.     

苜蓿切叶蜂授粉扩散行为及苜蓿种子增产效应的研究

对苜蓿切叶蜂(Megachilerotundata)为苜蓿授粉的田间群体扩散行为和苜蓿种子增产效应研究表明,以授粉后苜蓿种子增产效应为指标,发现苜蓿切叶蜂以蜂箱为中心向四周扩散,随着距离增大,蜂的扩散及授粉效应逐渐降低。但不同方向其扩散及授粉效应不同,以苜蓿种子产量Y≥50g·m^-2为高效区,50g·m^-2>Y≥30g·m^-2为中效区,30g·m^-2>Y≥15g·m^-2为低效区。在高效区和中效区内,东北方向扩散距离最远,分别为50和60m,其次是东和北;在低效区,向北扩散距离最远,可达100m,其次是东北和西北;西、南、西南和东南扩散距离较短。据此做出了高效区、中效区和低效区的苜蓿切叶蜂授粉扩散行为图,由此可直观地看到3个区的范围.     

A monoterpene from Aster bakeranus

The aerial parts of Aster bakeranus afforded 6,7-dihydroxy-6,7-dihydro-cis-ocimene.     

P-hydroxyacetophenone derivatives from senecio graveolens

5-Acetylsalicylaldehyde and 4-hydroxy-3(3'-hydroxyisopentyl) acetophenone were isolated from Senecio graveolens in addition to the already known compounds dihydroeuparin, 4-hydroxy-3-(isopenten-2-yl)acetophenone and 3-hydroxy-2,2-dimethyl-6-acetylchromane.     

Heliangolides from Leucanthemopsis pulverulenta

The structure of hispanolide (4,5-cis-3-oxogermacranolide) and three other related germacranolides, isolated from Leucanthemopsis pulverulenta, have been established by a series of chemical transformations and spectral data.