The role of short-tongued insects in floral variation across the range of a style-dimorphic plant.

BACKGROUND AND AIMS: Heterostyly and related style polymorphisms are suitable model systems to evaluate the importance of functional pollinators in the maintenance of population variability. In Narcissus papyraceus different functional pollinators, incompatibility system and flower morphology have been proposed to influence the maintenance of polymorphism through their effect on disassortative mating. Here a test is done to find out if the visitation rate of long- versus short-tongued pollinators correlates with the morph ratio and if the latter is related to other flower traits of the species across its main geographic range. METHODS: Floral traits from 34 populations in the south-west of the Iberian Peninsula and in north-west Africa were measured, perianth variation was described and a comparison was made of allometric relationships between sex organs and floral tube. Correlations between pollinator guilds, stigma-anther separation of reciprocal morphs (our proxy for disassortative mating) and morph-ratio variation were analysed. Finally, the incompatibility system of the species in the northern and southern borders of its distribution are described. KEY RESULTS: Flowers from southern populations were significantly larger than flowers from centre and northern populations. The abundance of short-styled plants decreased gradually with increasing distance from the core region (the Strait of Gibraltar), with these disappearing only in the northern range. Although there was a significant difference in stigma-anther separation among populations, morph ratio was not associated with reciprocity or floral tube length. Long-style morph frequency increased with short-tongued pollinator visitation rate. Populations from both edges of the distribution range were self-incompatible and within- and between-morph compatible. CONCLUSIONS: The style morph ratio changed gradually, whereas perianth trait variation showed abrupt changes with two morphotypes across the range. The positive relationship between the visitation rate of short-tongued pollinators and the decrease of the short-style morph supports our initial hypothesis. The results highlight the importance of different pollinators in determining the presence of style polymorphism.

New microsatellite loci for Narcissus papyraceus (Amarillydaceae) and cross-amplification in other congeneric species.

PREMISE OF THE STUDY: Microsatellite loci from a genomic library of the species Narcissus papyraceus were optimized and characterized for studies of population genetics. • METHODS AND RESULTS: Eleven markers that were successfully amplified showed polymorphism when tested on 50 individuals from two populations in southern Spain and northern Morocco. Overall, the number of alleles per locus ranged between 4 and 15. Between 8 and 11 loci successfully amplified in other eight Narcissus species. • CONCLUSIONS: These markers will enable genetic diversity studies of N. papyraceus across its distribution range and conduct paternity analyses among individuals differing in flower morphology.