Pollen limitation and specialist pollination of Rhytidophyllum lomense (Gesneriaceae) in Topes de Collantes, Cuba

Abstract

The pollinator contribution to the reproductive success of species is made from the transfer of pollen, through the visit rate, which varies according to the expression of certain floral features. Rhytidophyllum lomense (Gesnerieae) is an endemic species of Cuba with tubular flowers and other characteristics that allow to predict the pollination syndrome by hummingbirds. Other species of the tribe with this corolla design, show low reproductive success. The study was directed to three questions: Does the floral design of R. lomense correspond to a specialist pollination system? Are there high levels of pollen limitation associated with the inefficiency of the specialist pollinator? and how does floral biology and reproductive assurance mechanisms determine reproductive success? The studies were carried out in three populations and 11 variables were used to describe the floral morphology. Direct observations were made to the flowers to determine the pollinators. The autogamy capacity was calculated through the self-fertilization index and, as pollinator efficiency measures, the indexes of pollen limitation, fruits/flowers and seeds/ovules were calculated. Chlorostilbon ricordii is the only R. lomense pollinator in concordance to its floral biology. The low visit rate of the hummingbird and the values of the calculated indexes show low efficiency of the pollinator. In addition, the low value of the index of self-fertility and the high levels of hercogamy and dicogamy do not show that R. lomense is in a period of transition a mechanism of reproductive assurance such as self-fertilization.\n\nCitation: Díaz-Suárez, L., Faife-Cabrera, M., Díaz-Álvarez, E., Torres-Roche, E.M. & Toledo-Sotolongo, A. 2020. Limitación de polen y polinización especialista de Rhytidophyllum lomense (Gesneriaceae) en Topes de Collantes, Cuba. Revista Jard. Bot. Nac. Univ. Habana 41: 131-140.\n\nArticle history: Received: 23 November 2018. Accepted: 25 August 2019. Online: 28 December 2020. Editor: José Angel García-Beltrán.