MOVEMENT PATTERNS OF CETONIA BEETLES (SCARABAEIDAE) AMONG FLOWERING VIBURNUM-OPULUS (CAPRIFOLIACEAE) - OPTION FOR LONG-DISTANCE POLLEN DISPERSAL IN A TEMPERATE SHRUB

The movement patterns of flower-visiting Cetonia (Coleoptera, Scarabae idae) were studied in central Sweden over 4 years, providing the first quantitative study of beetle pollination behaviour conducted in a tem perate zone. The beetles were marked individually and tracked througho ut their visits to Viburnum opulus L. (Caprifoliaceae), a partly beetl e-pollinated shrub displaying large umbel-like, creamy-white blossoms. Beetle abundance differed greatly between study years. Of marked beet les observed on V. opulus flowers, an average of 26% returned each yea r. The beetles performed frequent inter-plant flights, and showed fide lity to particular V. opulus individuals at the study site. Furthermor e, they preferred V. opulus to other plants flowering concomitantly an d showed considerable constancy in this habit. Movements were mostly b etween individuals from unshaded locations with high inflorescence and flower number. Normally, the beetles flew on average about 4 times th e horizontal nearest-neighbour distance between flowering V. opulus (c . 18 m). From these observations it is concluded that Cetonia beetles are powerful long-distance dispersal agents for V. opulus pollen, perh aps leading to an enhanced gene flow not possible with the plant's oth er pollinators.