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The volatile constituents of cephalic secrections of 11 Brazilian social stingless bee species of the Tetragonisca - Tetragona line have been analysed. By gas chromatography/mass spectrometry 145 compounds could be identified which include 72 esters, 22 alcohols, 16 carboxylic acids, 13 terpenoids, 8 aldehydes, 7 ketones, 4 aromatic compounds, 2 lactones and 1 dihydropyran. Structural relations, origin, and distribution of these compounds are discussed. With respect to qualitative and quantitative composition, each species shows a specific odour pattern which is made up by less specific components. To a certain extent, closely related species show some similarities in the odour bouquets. The mass spectrometric fragmentation patterns of typical wax type esters and DMDS derivatives of unsaturated esters are discussed in detail.

A swampy nest site of the sweat beeAugochloropsis caerulans(Vachal, 1903) in southern Brazil is reported. The bees colonized small earth mounds scattered throughout a water-covered area. Although the substrate of these mounds has high organic matter content, the risk of microbial infestation seems not to be enhanced owing to permanent water saturation. The nests are shallow and can be found 3 cm above the water table. Each nest consists of a cluster of vertically oriented cells on pillars in an oval shaped cavity. The specific nest architecture is thought to mitigate microbial infestation of the brood and to prevent water excess. Nests ofA. caerulansare not restricted to water-saturated substrates, but the specific nest architecture presumably enables the bee to propagate in such habitats. [ABSTRACT FROM PUBLISHER]