1
|
Núñez-Hidalgo S, Cascante-Marín A. Selfing in epiphytic bromeliads compensates for the limited pollination services provided by nectarivorous bats in a neotropical montane forest. AOB PLANTS 2024; 16:plae011. [PMID: 38497049 PMCID: PMC10944016 DOI: 10.1093/aobpla/plae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/23/2024] [Indexed: 03/19/2024]
Abstract
Abstract. Plants with specialized pollination systems frequently exhibit adaptations for self-pollination, and this contradictory situation has been explained in terms of the reproductive assurance function of selfing. In the neotropics, several plant lineages rely on specialized vertebrate pollinators for sexual reproduction, including the highly diverse Bromeliaceae family, which also displays a propensity for selfing. Thus far, the scarce evidence on the role of selfing in bromeliads and in other neotropical plant groups is inconclusive. To provide insights into the evolution and persistence of self-fertilization in the breeding systems of Bromeliaceae, we studied four sympatric epiphytic species from the genus Werauhia (Tillandsioideae) in Costa Rica. We documented their floral biology, pollination ecology and breeding systems. We estimated the contribution of selfing by comparing the reproductive success between emasculated flowers requiring pollinator visits and un-manipulated flowers capable of selfing and exposed to open pollination across two flowering seasons. The studied species displayed specialized pollination by nectar-feeding bats as well as a high selfing ability (auto-fertility index values > 0.53), which was attained by a delayed selfing mechanism. Fruit set from natural cross-pollination was low (<26% in both years) and suggested limited pollinator visitation. In line with this, we found a very low bat visitation to flowers using video-camera recording, from 0 to 0.24 visits per plant per night. On the contrary, the contribution of selfing was comparatively significant since 54-80% of the fruit set from un-manipulated flowers can be attributed to autonomous self-pollination. We concluded that inadequate cross-pollination services diminished the reproductive success of the studied Werauhia, which was compensated for by a delayed selfing mechanism. The low negative effects of inbreeding on seed set and germination likely reinforce the persistence of selfing in this bromeliad group. These results suggest that selfing in bat-pollinated bromeliads may have evolved as a response to pollinator limitation.
Collapse
Affiliation(s)
- Stephanie Núñez-Hidalgo
- Sistema de Estudios de Posgrado, Universidad de Costa Rica, San Pedro de Montes de Oca, 11501-2060 San José, Costa Rica
| | - Alfredo Cascante-Marín
- Escuela de Biología y Centro de Investigación en Biodiversidad y Ecología Terrestre (CIBET), Universidad de Costa Rica, San Pedro de Montes de Oca, 11501-2060 San José, Costa Rica
| |
Collapse
|
2
|
Hou M, Opedal ØH, Zhao ZG. Sexually concordant selection on floral traits despite greater opportunity for selection through male fitness. THE NEW PHYTOLOGIST 2024; 241:926-936. [PMID: 37899633 DOI: 10.1111/nph.19370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Pollinators are important drivers of floral trait evolution, yet plant populations are not always perfectly adapted to their pollinators. Such apparent maladaptation may result from conflicting selection through male and female sexual functions in hermaphrodites. We studied sex-specific mating patterns and phenotypic selection on floral traits in Aconitum gymnandrum. After genotyping 1786 offspring, we partitioned individual fitness into sex-specific selfed and outcrossed components and estimated phenotypic selection acting through each. Relative fitness increased with increasing mate number, and more so for male function. This led to greater opportunity for selection through outcrossed male fitness, though patterns of phenotypic selection on floral traits tended to be similar, and with better support for selection through female rather than male fitness components. We detected directional selection through one or more fitness component for larger flower number, larger flowers, and more negative nectar gradients within inflorescences. Our results are consistent with Bateman's principles for sex-specific mating patterns and illustrate that, despite the expected difference in opportunity for selection, patterns of variation in selection across traits can be rather similar for the male and female sexual functions. These results shed new light on the effect of sexual selection on the evolution of floral traits.
Collapse
Affiliation(s)
- Meng Hou
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
- Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 130102, Changchun, China
| | | | - Zhi-Gang Zhao
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
| |
Collapse
|
3
|
Wu Y, Liu G, Sletvold N, Duan X, Tong Z, Li Q. Soil water and nutrient availability interactively modify pollinator-mediated directional and correlational selection on floral display. THE NEW PHYTOLOGIST 2023; 237:672-683. [PMID: 36229922 DOI: 10.1111/nph.18537] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
The individual and combined effects of abiotic factors on pollinator-mediated selection on floral traits are not well documented. To examine potential interactive effects of water and nutrient availability on pollinator-mediated selection on three floral display traits of Primula tibetica, we manipulated pollination and nutrient availability in a factorial experiment, conducted at two common garden sites with different soil water content (natural vs addition). We found that both water and nutrient availability affected floral trait expression in P. tibetica and that hand pollination increased seed production most when both nutrient content and water content were high, indicating joint pollen and resource limitation. We documented selection on all floral traits, and pollinators contributed to directional and correlational selection on plant height and number of flowers. Soil water and nutrient availability interactively influenced the strength of both pollinator-mediated directional and correlational selection, with significant selection observed when nutrient or water availability was high, but not when none or both were added. The results suggest that resource limitation constrains the response of P. tibetica to among-individual variation in pollen receipt, that addition of nutrients or water leads to pollinator-mediated selection and that effects of the two abiotic factors are nonadditive.
Collapse
Affiliation(s)
- Yun Wu
- School of Architecture and Civil Engineering, Xihua University, Chengdu, 610039, China
| | - Guangli Liu
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, 611130, China
| | - Nina Sletvold
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden
| | - Xuyu Duan
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, 611130, China
| | - Zhaoli Tong
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, 650091, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, 650091, China
| | - Qingjun Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, 650091, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, 650091, China
| |
Collapse
|
4
|
Huang X, Chen M, Wang L, Yang M, Yang N, Li Z, Duan Y. Phenotypic Selection in Halenia elliptica D. Don (Gentianaceae), an Alpine Biennial with Mixed Mating System. PLANTS 2022; 11:plants11111488. [PMID: 35684261 PMCID: PMC9183009 DOI: 10.3390/plants11111488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/30/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022]
Abstract
The transition from outcrossing to selfing is a common evolutionary trend in flowering plants, and floral traits change significantly with the evolution of selfing. Whether or not plant traits are subjected to selection remains an open question in species with mixed mating systems. We examined phenotypic selection in two populations of Halenia elliptica with different selfing rates. We found that the pollen–ovule ratio, seed size, plant height, spur length, and pollinator visitation rate in the population with the higher selfing rate were lower than those in the population with the lower selfing rate. Selfing provides reproductive assurance for populations when pollinator service is low, and the floral traits that are associated with selfing syndrome are evident in populations with a higher selfing rate but are subjected to weak selection in each of the two populations with different selfing rates. Directional selection for an early flowering time indicated that late blooming flowers could experience a risk of seed development in alpine environments, and for large plants, selection indicated that seed production could be limited by the available resources. The floral traits that are associated with pollinator attraction and specialization could be subjected to weak selection at the plant level as selfing evolves, and the selective pressures that are independent of pollinators might not change significantly; highlighting the selective biotic and abiotic pressures that shape the morphological traits of plant species and their independence from the mating system.
Collapse
Affiliation(s)
- Xiaojuan Huang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi’an 710069, China;
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Minyu Chen
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Linlin Wang
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Mingliu Yang
- School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China;
| | - Nacai Yang
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Zhonghu Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi’an 710069, China;
- Correspondence: (Z.L.); (Y.D.); Tel.: +86-29-88302411 (Z.L.); +86-87165223231 (Y.D.)
| | - Yuanwen Duan
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
- Yunnan Lijiang Forest Ecosystem National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang 674100, China
- Correspondence: (Z.L.); (Y.D.); Tel.: +86-29-88302411 (Z.L.); +86-87165223231 (Y.D.)
| |
Collapse
|
5
|
Carlson ML, Fulkerson JR. Phenotypic selection on floral traits in the arctic plant
Parrya nudicaulis
(Brassicaceae). Ecol Evol 2022; 12:e8624. [PMID: 35261739 PMCID: PMC8888260 DOI: 10.1002/ece3.8624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 10/20/2021] [Accepted: 10/29/2021] [Indexed: 11/06/2022] Open
Abstract
The evolution of floral traits is often attributed to pollinator‐mediated selection; however, the importance of pollinators as selective agents in arctic environments is poorly resolved. In arctic and subarctic regions that are thought to be pollen limited, selection is expected to either favor floral traits that increase pollinator attraction or promote reproductive assurance through selfing. We quantified phenotypic selection on floral traits in two arctic and two subarctic populations of the self‐compatible, but largely pollinator‐dependent, Parrya nudicaulis. Additionally, we measured selection in plants in both open pollination and pollen augmentation treatments to estimate selection imposed by pollinators in one population. Seed production was found to be limited by pollen availability and strong directional selection on flower number was observed. We did not detect consistently greater magnitudes of selection on floral traits in the arctic relative to the subarctic populations. Directional selection for more pigmented flowers in one arctic population was observed, however. In some populations, selection on flower color was found to interact with other traits. We did not detect consistently stronger selection gradients across all traits for plants exposed to pollinator selection relative to those in the pollen augmentation treatment; however, directional selection tended to be higher for some floral traits in open‐pollinated plants.
Collapse
Affiliation(s)
- Matthew L. Carlson
- Alaska Center for Conservation Science University of Alaska Anchorage Anchorage Alaska USA
- Biological Sciences Department University of Alaska Anchorage Anchorage Alaska USA
| | - Justin R. Fulkerson
- Alaska Center for Conservation Science University of Alaska Anchorage Anchorage Alaska USA
- Biological Sciences Department University of Alaska Anchorage Anchorage Alaska USA
| |
Collapse
|
6
|
Delgado-Dávila R, Martén-Rodríguez S. A test of the reproductive assurance hypothesis in Ipomoea hederacea: does inbreeding depression counteract the benefits of self-pollination? AMERICAN JOURNAL OF BOTANY 2021; 108:2162-2173. [PMID: 34786691 DOI: 10.1002/ajb2.1794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
PREMISE Darwin proposed that self-pollination in allegedly outcrossing species might act as a reproductive assurance mechanism when pollinators or mates are scarce; however, in natural populations, the benefits of selfing may be opposed by seed discounting and inbreeding depression. While empirical studies show variation among species and populations in the magnitude of reproductive assurance, little is known about the counterbalancing effects of inbreeding depression. METHODS By comparing the female reproductive success of emasculated and open-pollinated flowers, we assessed the reproductive assurance hypothesis in two Mexican populations of Ipomoea hederacea. In one population, we assessed temporal variation in reproductive assurance for three years. We evaluated inbreeding depression on seed production, seedling germination, and dry plant mass by contrasting self- and cross-hand pollination treatments in one population for two years. RESULT The contribution of self-pollination to female reproductive success was high and consistent between populations, but there was variation in reproductive assurance across years. Inbreeding depression was absent in the early stages of progeny development, but there was a small negative effect of inbreeding in the probability of germination and the mass of adult progeny. CONCLUSIONS Self-pollination provided significant reproductive assurance in I. hederacea but this contribution was variable across time. The contribution of reproductive assurance is probably reduced by inbreeding depression in later stages of progeny development, but this counter effect was small in the study populations. This study supports the hypothesis that reproductive assurance with limited inbreeding depression is likely an important selective force in the evolution of self-pollination in the genus Ipomoea.
Collapse
Affiliation(s)
- Ruth Delgado-Dávila
- Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
- Laboratorio Nacional de Análisis y Síntesis Ecológica, Escuela Nacional de Estudios Superiores, unidad Morelia, Universidad Nacional Autónoma de México, 58089, Morelia, Michoacán, México
| | - Silvana Martén-Rodríguez
- Laboratorio Nacional de Análisis y Síntesis Ecológica, Escuela Nacional de Estudios Superiores, unidad Morelia, Universidad Nacional Autónoma de México, 58089, Morelia, Michoacán, México
| |
Collapse
|
7
|
Macrì C, Dagnino D, Guerrina M, Médail F, Minuto L, Thompson JD, Casazza G. Effects of environmental heterogeneity on phenotypic variation of the endemic plant Lilium pomponium in the Maritime and Ligurian Alps. Oecologia 2020; 195:93-103. [PMID: 33269409 PMCID: PMC7882563 DOI: 10.1007/s00442-020-04806-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 11/12/2020] [Indexed: 11/29/2022]
Abstract
Geographical limits of species’ distributions are assumed to be coincident with ecological margins, although this assumption might not always be true. Indeed, harsh environments such as Alpine and Mediterranean ecosystems may favour high phenotypic variability among populations, especially those in peripheral sites. Floral traits are often found to be less variable and less affected by environmental heterogeneity than vegetative traits because variation in the former may have negative effects on fitness. For this reason, it is important to quantify variation in floral traits and plant fecundity in study range limits. The objective of the study is to examine phenotypic variation and differences in reproduction in endemic Lilium pomponium in the Maritime and Ligurian Alps in relation to environmental variation across its distribution range. In this species, marginal climatic populations occur both in the peripheral and central geographical locations of the distribution range; hence, geographical and ecological gradients are not concordant. Floral trait variation is related to local environmental conditions with an array of interactions among resource availability, potential pollen limitation and population size that are differentially related to floral traits. Contrary to the general expectation, all central and peripheral populations had similar, moderate seed production with each group limited by different factors acting on different stages of the life-history strategy. Our results are in line with the idea that general expectations are confirmed only when its assumptions are met and that the differences in pollination environment along an environmental gradient may not be the main determinant of the distribution limit.
Collapse
Affiliation(s)
- Carmelo Macrì
- Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), University of Genoa, Corso Europa 26, 16132, Genoa, Italy
| | - Davide Dagnino
- Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), University of Genoa, Corso Europa 26, 16132, Genoa, Italy
| | - Maria Guerrina
- Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), University of Genoa, Corso Europa 26, 16132, Genoa, Italy
| | - Frédéric Médail
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix Marseille Université, Avignon Université, CNRS, IRD, Technopôle de l'Arbois-Méditerranée, BP 80, 13545, Aix-en-Provence Cedex 4, France
| | - Luigi Minuto
- Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), University of Genoa, Corso Europa 26, 16132, Genoa, Italy.
| | - John D Thompson
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 route de Mende, 34293, Montpellier Cedex 5, France
| | - Gabriele Casazza
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix Marseille Université, Avignon Université, CNRS, IRD, Technopôle de l'Arbois-Méditerranée, BP 80, 13545, Aix-en-Provence Cedex 4, France
| |
Collapse
|
8
|
Paterno GB, Silveira CL, Kollmann J, Westoby M, Fonseca CR. The maleness of larger angiosperm flowers. Proc Natl Acad Sci U S A 2020; 117:10921-10926. [PMID: 32366661 PMCID: PMC7245066 DOI: 10.1073/pnas.1910631117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Flower biomass varies widely across the angiosperms. Each plant species invests a given amount of biomass to construct its sex organs. A comparative understanding of how this limited resource is partitioned among primary (male and female structures) and secondary (petals and sepals) sexual organs on hermaphrodite species can shed light on general evolutionary processes behind flower evolution. Here, we use allometries relating different flower biomass components across species to test the existence of broad allocation patterns across the angiosperms. Based on a global dataset with flower biomass spanning five orders of magnitude, we show that heavier angiosperm flowers tend to be male-biased and invest strongly in petals to promote pollen export, while lighter flowers tend to be female-biased and invest more in sepals to insure their own seed set. This result demonstrates that larger flowers are not simple carbon copies of small ones, indicating that sexual selection via male-male competition is an important driver of flower biomass evolution and sex allocation strategies across angiosperms.
Collapse
Affiliation(s)
- Gustavo Brant Paterno
- Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, Rio Grande do Norte, Brazil;
| | - Carina Lima Silveira
- Centro de Biociências, Universidade do Vale do Rio dos Sinos, 93022-750 São Leopoldo, Rio Grande do Sul, Brazil
| | - Johannes Kollmann
- Department of Ecology and Ecosystem Management, Restoration Ecology Research Group, Technical University of Munich, Freising, 85354, Germany
| | - Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Carlos Roberto Fonseca
- Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, Rio Grande do Norte, Brazil;
| |
Collapse
|
9
|
Teixido AL, Valladares F. Heat and drought determine flower female allocation in a hermaphroditic Mediterranean plant family. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:1024-1030. [PMID: 31282088 DOI: 10.1111/plb.13031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 07/03/2019] [Indexed: 06/09/2023]
Abstract
In animal-pollinated hermaphroditic species, larger and xenogamous flowers increase male-biased resource allocation, whereas smaller and selfing flowers invest disproportionally more resources to female function. In Cistaceae, an entomophilous and hermaphroditic Mediterranean family, this pattern generally follows a phylogenetic signal. However, resource allocation to carpels is independent of phylogeny, which suggests trait divergences among closely related species during the diversification into different environmental conditions. We tested this hypothesis across 37 species of Cistaceae along a temperature and precipitation gradient, including semiarid, dry, subhumid and humid sites. We quantified the proportions of dry mass and nutrient investment to carpels and tested the influence of the climatic gradient and site-specific precipitation on the interspecific variation in carpel resource allocation. Lowest and highest percentages of resource allocation to carpels ranged from 1.5-4.2% to 24.2-36.6%, respectively. The proportion of resources comprised in carpels significantly decreased with increasing precipitation/decreasing temperature. Thus, carpels comprised proportionally more resources under drier and hotter conditions, especially in semiarid sites. Our results demonstrate how the extent of climatic constraints is more important than phylogenetic relationships in determining stress-induced differences in carpel resource allocation across species of Cistaceae in a Mediterranean environment. We suggest that allocation of proportionally more resources to carpels in drier and hotter sites lies within a strategy to deal with the most stressful conditions by means of a high reproductive effort.
Collapse
Affiliation(s)
- A L Teixido
- Área de Biodiversidad y Conservación, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Madrid, Spain
| | - F Valladares
- Museo Nacional de Ciencias Naturales, MNCN-CSIC, Madrid, Spain
| |
Collapse
|