Pollination ecology of Petrocoptis grandiflora Rothm. (Caryophyllaceae); a species endemic to the north-west part of the Iberian Peninsula

Petrocoptis grandiflora Rothm. is a species endemic to the Iberian Peninsula with restricted distribution. We studied various aspects of its pollination ecology, nectar characteristics and standing crop, pollinators and nectar-robbers, and the effects of nectar robbing and supplementary pollination on fruit set. The nectar is moderately rich in saccharose (saccharose/hexose ratio 0.54), and is largely consumed by long-tongued bees (Anthophoridae). The incidence of nectar robbing by Xylocopa violncea differed between the four plant populations studied, and it had significant effects on fruit set when the population was simultaneously considered. Supplementary pollination did not improve fruit set significantly.