Sexual Dimorphism in Catasetum Orchids: Forcible Pollen Emplacement and Male Flower Competition

  title={Sexual Dimorphism in Catasetum Orchids: Forcible Pollen Emplacement and Male Flower Competition},
  author={Gustavo As Romero and Charles Edward Nelson},
  pages={1538 - 1540}
Orchids of the Neotropical genus Catasetum have sexually dimorphic flowers; that is, male and female flowers are distinctly different in shape and color. Male flowers forcibly attach a large pollinarium onto euglossine bees. Euglossa bees leave the male flower in response to pollinarium emplacement by Catasetum ochraceum and subsequently avoid male but not female flowers. This evidence suggests that sexual dimorphism promotes pollination. The aversion of the bee to pollinarium attachment and… 

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Univcrsity colleagues were especially helpful. R. L. DressIer identified the bees. P. L. Romero provided invaluablc assistance in the field

    m m Costa Rica; Romero (5) for C. oebraceum

      ITc hieh polien-donation success suggested for Catastum in

      • 1981

      Forcible emplacement and attachment of pollinarium is characteristic of Catasetum, except for the C. dor alliance (1)