Distant populations of a Xanthosoma (Araceae) species have different floral scents but the same cyclocephaline beetle pollinators

Abstract

ABSTRACT We report on the reproductive biology, pollinators, and thermogenesis of the widely distributed Araceae species, Xanthosoma striatipes. We analyzed the floral scent in one population and compared it to a previous study. Xanthosoma striatipes was studied at three sites in Brazil, São Paulo, Minas Gerais and Maranhão. The results showed constancy of the reproductive biology and main pollinator species across sites. The pollinators at all three sites sites were two species of cyclocephaline scarabs, Cyclocephala atricapilla and C. ohausiana. The scent composition of the strongly scented inflorescences of plants of a site in São Paulo differed from plants recently studied in Central Brazil. Of the 39 and 23 compounds detected, in the present and the previous study, respectively, only seven compounds, were in common. We discuss that the two main constituents identified in samples at both sites, the aromatic compound methyl salicylate and the terpenoid (E)-4,8-dimethyl-1,3,7-nonatriene, alone seem to be sufficient for the attraction of the beetles. However, it is also possible that different compounds are involved in attracting the same beetle species to plants of the different populations.

Keywords

• beetle behavior
• cyclocephaline scarabs
• floral scent
• GCMS-analyses
• thermogenesis