Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/72254
Type: Artigo de periódico
Title: The pollination mechanism in Trigonidium obtusum Lindl (Orchidaceae : Maxillariinae): Sexual mimicry and trap-flowers
Author: Singer, RB
Abstract: The pollination process in Trigonidium obtusum Lindl. (Epidendroideae: Maxillariinae) is documented. The flowers are pollinated by sexually excited drones of Plebeia droryana (Meliponinae). When attempting to copulate either with sepals or petals, these bees slip on the waxy perianth surface and become trapped in the funnel-like flower tube, Bees trying to escape from the flowers may instead access the space between the column and lip, fixing the pollinarium on their scutellum. Pollinarium-bearing bees may pollinate the flowers when repeating the above-mentioned steps, leaving pollinia on the concave stigmatic surface, thus effecting pollination. Recently removed pollinaria are too broad to enter the stigma but they begin to dehydrate and within 40 min of removal are small enough to fit the stigmatic cavity. This mechanism prevents insect-mediated self-pollination and promotes cross-pollination. Preliminary evidence based on experiments with cultivated plants suggests that they are self-compatible but that fruit set is pollinator-dependent. The data obtained are discussed in a phylogenetic context. It is suggested that the pseudocopulatory syndrome in Trigonidium could have evolved from rewardless (food advertising) ancestors. Pseudocopulation in the context of the long flowering period of this orchid species (about 7 months) is understandable since the eusocial Plebeia bees produce fertile individuals several times a year. (C) 2002 Annals of Botany Company.
Subject: Trigonidium
Maxillaria
Maxillariinae
pollination
pseudocopulation
Plebeia
Meliponinae
Country: Inglaterra
Editor: Oxford Univ Press
Rights: fechado
Identifier DOI: 10.1093/aob/mcf021
Date Issue: 2002
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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