The ecological and taxonomic importance of ¯ower volatiles of Clusia species (Guttiferae) Paulo C. de L. Nogueira a , Volker Bittrich b , George J. Shepherd b , Ariadna V. Lopes c , Anita J. Marsaioli a, * a Instituto de QuõÂmica, UNICAMP, CP 6154, Campinas, 13083-970, SP, Brazil b Departamento de Bota Ãnica, Instituto de Biologia, UNICAMP, CP 6109, Campinas, 13083-970, SP, Brazil c Departamento de Bota Ãnica, Centro de Cie Ãncias Biolo Âgicas, UFPE, Recife, 50670-901, PE, Brazil Received 9 August 1999; received in revised form 30 December 1999 Abstract The chemical composition of ¯oral volatiles of sixteen species of Clusia (Guttiferae) belonging to four dierent taxonomic sec- tions of the genus was investigated. The volatiles were extracted from fresh petals by microhydrodistillation and analysed by GC/ MS. The composition of the volatiles was in part, but not always, related to the taxonomic position of the species, and to a minor extent to the type of pollinator observed on the ¯owers as revealed by clustering analysis. The composition of the volatile compo- nents of female and male ¯owers belonging to the same species (C. grandi¯ora, C. lanceolata, C. paralicola, C. parvi¯ora and C. spiritu-sanctensis) was found to be almost identical. Field bioassays showed the petal extracts to be attractive to pollinating bees. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Clusia spp.; Guttiferae; Floral scents; Pollinators; Taxonomy 1. Introduction The neotropical genus Clusia L. (Guttiferae) com- prises about 250±300 species grouped in a number of more or less natural taxonomic sections (Planchon and Triana, 1860a,b; Engler, 1925; Gustafsson and Bittrich, 1999). Life forms include hemiepiphytes (sometimes stranglers), lianas, shrubs and trees. Recent studies show a high variability in CO 2 uptake patterns in the genus, possibly in part responsible for the success of Clusia in various habitats (Franco et al., 1990). Like other Guttiferae (Clusiaceae), most tissues of the plants contain latex channels and various colours of latex have been reported by plant collectors. While the vast majority of Clusia species are dioecious, a few are known to be hermaphroditic or to include races with hermaphrodite ¯owers. Apomixis is known from C. rosea Jacq. and races of C. minor L. (Maguire, 1976; Hammel, 1986). The genus Clusia is notable for its enormous variety in ¯oral morphology, especially in the androecium (Planchon and Triana, 1860a,b; Engler, 1888), and this morphological variability is paralleled by a great diversity in the reproductive biology (Armbruster, 1984; Bittrich and Amaral, 1996, 1997). Rewards for pollinators include pollen, nectar and often ¯oral resin; in some species, however, the female ¯owers are rewardless and are thus pollinated by ``mistake-pol- lination'' (Correia et al., 1993; Bittrich and Amaral, 1996). Bees of various sizes belonging to several taxo- nomic groups, beetles, hummingbirds, sphingids, and ¯ies have been observed as ¯ower visitors (for a review see Lopes and Machado, 1998). Floral resin is an extre- mely rare reward in angiosperms, and besides in Clusia spp. it is known only from Dalechampia L. (Euphor- biaceae) (Armbruster, 1984) and Clusiella Planch. & Triana (Guttiferae). The chemistry of the ¯oral resin of some Clusia species was recently investigated (de Oli- veira et al., 1996, 1999), and various isoprenylated ben- zophenones were found to be the major components. Floralscentsarefoundinthevastmajorityofanimal- pollinated plants with the exception of ornithophilous ¯owers (Proctor et al., 1996). The scents mostly serve to attract or orient pollinators over long or short distances (Dobson, 1994). Rarely are fragrant essential oils also the reward for pollinating male euglossine bees (Wil- liams, 1983). In the Guttiferae, the latter phenomenon 0031-9422/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0031-9422(00)00213-2 Phytochemistry 56 (2001) 443±452 www.elsevier.com/locate/phytochem * Corresponding author. Tel.: +55-193788-3067; fax: +55-193788- 3023. E-mail address: anita@iqm.unicamp.br (A.J. Marsaioli).