Ecological Research

, Volume 24, Issue 1, pp 47–55

Floral traits variation, legitimate pollination, and nectar robbing in Polygala vayredae (Polygalaceae)

Original Article


The variation of floral morphology and its effect on the flower visitors of Polygala vayredae Costa (Polygalaceae), a narrow endemic species from the Oriental pre-Pyrenees, were examined. First, to account for the main floral reward (i.e., nectar), the relationship between the dimensions of the nectar gland and nectar production was investigated. Second, floral traits variation was assessed within and between the three most representative populations of the species. Finally, the role of several floral traits in the female fitness was evaluated. Furthermore, as nectar robbing was highly frequent, preferences of robbers for specific floral traits and their impact on legitimate pollinations were also evaluated. The flowers of this species are characterized by significant variations in floral characteristics and nectar rewards. A significant and positive correlation between the nectar gland dimensions and nectar production per flower was observed, with the gland dimensions being a good measure to infer the rewards offered by the flowers of P. vayredae. In general, corolla traits were significant and positively correlated with each other. Nectar was revealed to be an important trait in flower–visitor interactions, with legitimate pollinations being primarily influenced by this floral reward. Negative correlations between robbing frequency and legitimate pollinations were observed in two of the studied populations, and positive correlations between flower size and robbing frequency were observed in one population. An indirect negative selection over phenotypic floral traits mediated by nectar robbers is proposed.


Floral morphology Endemic species Nectar rewards Nectar robbers Phenotypic selection 


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Copyright information

© The Ecological Society of Japan 2008

Authors and Affiliations

  • Sílvia Castro
    • 1
    • 2
    • 3
  • Paulo Silveira
    • 1
  • Luis Navarro
    • 2
  1. 1.CESAM and Department of BiologyUniversity of AveiroAveiroPortugal
  2. 2.Department of Plant Biology and Soil Sciences, Faculty of BiologyUniversity of VigoVigoSpain
  3. 3.Department of Botany, Faculty of ScienceCharles UniversityPragueCzech Republic

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