Os constituintes voláteis das secreções cefálicas de 11 espécies brasileiras de abelhas sem ferrão da linha Tetragonisca -Tetragona foram analisados. Foram identificados 145 compostos, por cromatografia gasosa e espectrometria de massas, dentre os quais 72 ésteres, 22 álcoois, 16 ácidos carboxílicos, 13 terpenos, 8 aldeídos, 4 compostos aromáticos, 2 lactonas e 1 diidropirano. As relações estruturais, origem e a distribuição detes compostos são discutidas. Com respeito à composição qualitativa e quantitativa, cada espécie mostra um buquê de odores, os quais são obtidos a partir de componentes poucos específicos. Em algumas espécies proximamente relacionadas foram observadas similaridades no buquê de odores. As fragmentações no espectro de massas de ésteres graxos e dos ésteres insaturados derivatizados com DMDS são discutidas em detalhes.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.

The nest of the stingless bee,Trigona (Tetragonisca) angustula, is guarded by bees positioned in the nest entrance and others hovering in front of it. Hovering guard bees track returning foragers sideways along the last 10 cm in front of the nest, but intercept and incapacitate nest intruders by clinging with mandibles to wings and legs. When attacked by the cleptobiotic stingless beeLestrimelitta limao, the colony strengthens its aerial defense with hundreds of additional hoverers. To test our hypothesis that this reaction is due to interspecific chemical communication based on kairomone effects, we presented synthetic cephalic volatiles of both species at the nest entrance and counted the number of bees leaving the nest and taking up hovering positions. We conclude that guard bees recognizeL. limao by the major terpenoids of their volatile cephalic secretions, geranial, neral (=citral) and 6-methyl-5-hepten-2-one; other components may fine-tune this recognition. The effect of chemical stimuli is not significantly enhanced by combination with a dummy ofL. limao. Guard bees, we hypothesize, respond to this kairomone by secreting a species specific alarm pheromone; a major component of this pheromone, benzaldehyde, recruits additional bees to defend the nest.

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Workers in Relation to Reproduction in the Stingless Bee, Scaptotrigona postica (Hymenoptera: Apidae: Trigonini). -Entomol. Gener. 15 (2): 091-101; Stuttgart 1990. -[Article].The volatile composition of head extracts from drones [0"0"], queens [��] and workers [I;SI;S] was analysed in the neotropical trigonine, Scaptotrigona postica (Latreille 1811). A total of 129 compounds could be identified. The chemical composition of 0" and � volatile bouquets in stingless bees is described here for the first time. Sex and caste specific patterns of the cephalic volatiles are discussed. The possible role of pheromones in meliponid reproduction is outlined with emphasis on sex pheromone functions. In a field biotest the attractiveness for 0"0" of artificial scent mixtures, reflecting the main compounds of the cephalic volatiles found in ��, was evaluated. A mixture of secondary alcohols was shown to attract the 0"0" of a lek aggregation. The chemical composition of the cephalic extracts and also assumed I;S, � and 0" pheromone functions are discussed.