See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/323449472 Breeding system and pollination of Gesneria pauciflora (Gesneriaceae), a threatened Caribbean species Article in Flora - Morphology Distribution Functional Ecology of Plants · February 2018 DOI: 10.1016/j.flora.2018.02.009 CITATIONS READS 0 62 3 authors: Mervin Perez Elvia Melendez-Ackerman University of Puerto Rico at Rio Piedras University of Puerto Rico at Rio Piedras 9 PUBLICATIONS 13 CITATIONS 83 PUBLICATIONS 1,154 CITATIONS SEE PROFILE SEE PROFILE Omar A. Monsegur-Rivera U.S. Fish and Wildlife Service 4 PUBLICATIONS 2 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: NSF-CREST-CATEC at University of Puerto Rico View project Ecosystem services loss due to impacts of hurricanes Irma and María in San Juan residential trees View project All content following this page was uploaded by Mervin Perez on 26 February 2019. The user has requested enhancement of the downloaded file. Flora 242 (2018) 8–15 Contents lists available at ScienceDirect Flora journal homepage: www.elsevier.com/locate/flora Breeding system and pollination of Gesneria pauciflora (Gesneriaceae), a T threatened Caribbean species ⁎ Mervin E. Péreza, , Elvia J. Meléndez-Ackermana,b, Omar A. Monsegur-Riverac a Environmental Sciences Department, College of Natural Science, University of Puerto, Rico-Río-Piedras, Puerto Rico b Center for Applied Tropical Ecology and Conservation, College of Natural Science, University of Puerto, Rico-Río Piedras Campus, Puerto Rico c Caribbean Ecological Services Field Office, Fish and Wildlife Service, Boquerón, Puerto Rico ARTICLE INFO ABSTRACT Edited by Fei-Hai Yu Knowledge of plant breeding systems may be critical to facilitate recovery of species considered at risk. Gesneria fl fl Keywords: pauci ora is a threatened, rupiculous, and riverine species with oral-traits that suggest a hummingbird-polli- Autofertility nation system. Because these habitat-pollinator conditions have been linked to pollinator-independent re- Florivory productive systems, we expected a breeding system that provides reproductive assurance. We assessed the Hummingbirds breeding system and potential vulnerabilities during pollination phase using field observations and pollination Pollen limitation experiments, to determine pollinator dependency and the existence of strategies for reproductive assurance. Self-compatibility Gesneria pauciflora was pollinated by two hummingbird species but visitation rates were low, probably due to Reproductive assurance low nectar rewards. Fruit set and seed production were significantly higher in flowers when pollen was artifi- cially delivered (self- and cross-pollination) compared to when it was not (control and autogamy), suggesting that reproduction is pollen-limited. Gesneria pauciflora is self-compatible, with some seeds produced via au- tonomous selfing without any effects of pollination mechanism on seed germination rates. Florivory by the native plume-moth Postplatyptilia caribica was observed, but its incidence was low (12%). Our findings are consistent with theory on the evolution of plant breeding systems on islands, and contribute to the understanding of the evolution of breeding systems in Caribbean gesneriads. Overall, data do not show immediate vulner- abilities to this listed species at the pollination phase, and autogamy may represent reproductive assurance counteracting unpredictable environmental factors that influence its reproduction. However, its capacity for selfing is small relative to other tubular Puerto Rican Gesneria which may explain its rare status. 1. Introduction led to recommendations for management of their habitat as well as their plant-pollinator interactions to improve fruit and seed production. Information on breeding systems may be critical for the develop- However, not all endangered or threatened species have an obligate ment of successful strategies to facilitate recovery in rare, endemic, pollination interaction but instead exhibit mixed pollination systems threatened, or endangered plant species (Cao et al., 2006; Pino-Torres that may reduce their vulnerability (Yates and Ladd, 2004). The en- and Koptur, 2009; Robertson et al., 2004; Rodríguez-Pérez, 2005). dangered herbs Helianthemum marifolium Mill. and H. caput-felis Boiss. Breeding systems may influence processes at the reproductive stage that are both self-compatible species that produce fruit and seeds in self- in turn influence the type of mating (selfing vs. outcrossing), the like- pollinated and outcrossed flowers (Rodríguez-Pérez, 2005); the en- lihood of fruit and seed production, and plant fitness. For example, demic herb Petrocoptis viscosa Rothm, has an autonomous facultative Astrophytum asterias (Zucc.) Lem., a self-incompatible endangered self-pollination system that has the potential for outcrossing (Navarro cactus with a restricted distribution range, has a reproductive system and Guitián, 2002); and the endangered climbing vine species Jacque- that is highly dependent on the availability and effectiveness of its montia reclinata House ex Small, is predominantly outcrossing but is pollinators (Strong and Williamson, 2007). The same phenomenon has also capable of producing fruits and seeds via late autogamy (Pino- been shown for the threatened shrub Tetratheca juncea Sm. (Gross et al., Torres and Koptur, 2009). Thus, the observed variability in breeding 2003) and the endemic perennial shrub Polygala vayredae Costa (Castro, system mechanisms across rare and endemic species may also be ac- 2009; Castro et al., 2008). All of which faced reproductive constraints companied by variation in their reproductive capacity and in their due to low biotic visitation rates and high pollinator dependence, which demographic vulnerability. ⁎ Corresponding author. E-mail address: [email protected] (M.E. Pérez). https://doi.org/10.1016/j.flora.2018.02.009 Received 27 October 2017; Received in revised form 25 February 2018; Accepted 27 February 2018 Available online 28 February 2018 0367-2530/ © 2018 Elsevier GmbH. All rights reserved. M.E. Pérez et al. Flora 242 (2018) 8–15 Plants may exhibit a reduction in fitness during the pollination (i.e. changes in the hydrology due to water extraction) (U.S. Fish and phase due to variation in biotic and abiotic factors, or by human-dis- Wildlife Services, 1995). The study of this species’ reproductive biology turbance impacts through a variety of mechanisms. Large-scale dis- and ecology are identified as recovery actions in the “Recovery Plan for turbance events such as selective logging, metal soil contamination, G. pauciflora” (U.S. Fish and Wildlife Services, 1998). However, we lack wetland creation, may reduce the availability of pollinators and in- information on its reproductive biology, potential pollinators, and on crease pollen limitation, but also diminish pollen loads on stigmas and vulnerabilities experienced during the pollination phase. Gesneria pau- in the process reduce outcrossing (Eckert et al., 2009). Likewise, forest ciflora is a rupiculous and riverine species that may experience periodic patch isolation (habitat fragmentation) can reduce pollinator network disturbances. Assuming that G. pauciflora’s breeding system behaves in connectivity and increase vulnerability in outcrossing species by redu- similar ways to other rupiculous gesneriads, we hypothesized that the cing plant fitness (Vanbergen et al., 2014). Changes in climate (i.e. species may exhibit an autonomous breeding system for reproductive temperature and precipitation) by inducing early or late flowering assurance. Herein we address the information gaps in its reproductive events (Hamann, 2004; Iler and Inouye, 2013; Menzel et al., 2006) can biology by asking the following questions: What are the main pollinator lead to mismatches in plant-pollinator interaction that in turn may (s) of G. pauciflora? Is fruit or seed production influenced by the type of decrease fruit production (Hegland et al., 2009). Other vulnerabilities pollination (self- vs. cross)? Is the breeding system of G. pauciflora during the pollination phase may result from antagonist processes such different to those reported for other Gesneria species on Puerto Rico? as flower herbivory, in which pollinator' visitation rates might decrease Our goal was to carry out a comprehensive study to evaluate the re- due to a reduction in flower attractiveness, nectar production and de- productive biology of G. pauciflora focusing on events occurring at the layed flowering (McArt et al., 2014; Schiestl et al., 2014). Given the pollination stage. We also compared the breeding system characteristics tight link between pollination and plant fitness, it is important to of G. pauciflora to those reported for other Gesneria species in the evaluate the factors that influence pollination success directly or in- Caribbean to explore the ecological and evolutionary context of G. directly, especially for rare and endangered species as a way to gather pauciflora’s breeding system. information that may help improve natural seed production, seedling recruitment, and long-term population persistence. 2. Materials and methods For plants endemic to insular systems, the evolution of breeding systems may be influenced by ecological conditions that may char- 2.1. Study site acterize island ecosystems (Barrett, 1996; Charlesworth, 2006). This hypothesis, also known as Baker’s rule (Baker, 1955; Barrett, 1996), The Maricao State Forest