Armament Imbalances: Match and Mismatch in Plant-Pollinator Traits of Highly Specialized Long-Spurred Orchids

MORÉ, M.; AMORIM, F.W.; BENITEZ-VIEYRA, S.; MEDINA, A.M.; SAZIMA, M; COCUCCI, A.A.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2012 vol. 7 p. 41878 - 41879

1932-6203

Background: Some species of long-spurred orchids achieve pollination by a close association with long-tongued hawkmoths. Among them, severalHabenariaspecies present specialized mechanisms, where pollination success depends on the attachment of pollinaria onto the heads of hawkmoths with very long proboscises. However, in the Neotropical region such moths are less abundant than their shorter-tongued relatives and are also prone to population fluctuations. Both factors may give rise to differences in pollinator-mediated selection on floral traits through time and space.Methodology/Principal Findings:We characterized hawkmoth assemblages and estimated phenotypic selection gradients on orchid spur lengths in populations of three South AmericanHabenariaspecies. We examined the match between hawkmoth proboscis and flower spur lengths to determine whether pollinators may act as selective agents on flower morphology. We found significant directional selection on spur length only inHabenaria gourlieana, where most pollinators had proboscises longer than the mean of orchid spur length.Conclusions/Significance: Phenotypic selection is dependent on the mutual match between pollinator and flower morphologies. However, our findings indicate that pollinator-mediated selection may vary through time and space according to local variations in pollinator assemblages.