Complexity of Bumble Bee Marking Pheremones: Biochemical, Ecological and Systematical Interpretations

Male bumble bee labial gland marking pheromone blends from 18 species belonging to three genera (Bombus, Pyrobombus and Alpinobombus) are compared from biochemical, ecological and systematical points of view. General chemical similarities within the genera have been found and also distinct characteristics for each species. Male spatial, temporal, mechanical and marking pheromonal premating species-isolating mechanisms are compared between species in a subalpine/alpine area. Species which utilize the same mating habitat usually differ greatly by virtue of their mechanical, pheromonal and, to some extent, temporal characteristics. These mechanisms enhance species discrimination and counteract hybridization

Studies on Natural Odoriferous Compounds XXII

A comparison is made between methods for the isolation/enrichment of biologically active odors from Ophrys orchids. The main techniques discussed here are: 1. Direct odor collection (“direct headspace”), 2. Low temperature trapping, 3. Adsorption by enfleurage or by packed precolumn, 4. Strippiug of volatiles in the GC inlet system, 5. Solvent extraction, 6. Steam distillation. The organoleptic examination of thin-layer chromatographic and gas chromatographic fractions has been employed in this work and is briefly described. The further analyses of Ophrya odors were carried out by capillary gas chromatography-mass spectrometry. Four of the isolation methods are preferred. Two of these are accumulation methods (2 and 3), and the other two (4 and 5) give a cross section of the volatile constituents. Any of the six possible combinations of two of these four methods give good results depending on the main objectives of isolation. Characteristics/advantages of the six possible combinations between two of the methods are discussed