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Simón-Porcar V, Escudero M, Santos-Gally R, Sauquet H, Schönenberger J, Johnson SD, Arroyo J. Convergent evolutionary patterns of heterostyly across angiosperms support the pollination-precision hypothesis. Nat Commun 2024; 15:1237. [PMID: 38336937 PMCID: PMC10858259 DOI: 10.1038/s41467-024-45118-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 01/12/2024] [Indexed: 02/12/2024] Open
Abstract
Since the insights by Charles Darwin, heterostyly, a floral polymorphism with morphs bearing stigmas and anthers at reciprocal heights, has become a model system for the study of natural selection. Based on his archetypal heterostylous flower, including regular symmetry, few stamens and a tube, Darwin hypothesised that heterostyly evolved to promote outcrossing through efficient pollen transfer between morphs involving different areas of a pollinator's body, thus proposing his seminal pollination-precision hypothesis. Here we update the number of heterostylous and other style-length polymorphic taxa to 247 genera belonging to 34 families, notably expanding known cases by 20%. Using phylogenetic and comparative analyses across the angiosperms, we show numerous independent origins of style-length polymorphism associated with actinomorphic, tubular flowers with a low number of sex organs, stamens fused to the corolla, and pollination by long-tongued insects. These associations provide support for the Darwinian pollination-precision hypothesis as a basis for convergent evolution of heterostyly across angiosperms.
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Affiliation(s)
- Violeta Simón-Porcar
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, E-41080, Sevilla, Spain.
- School of Life Sciences, University of KwaZulu-Natal, P Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.
| | - Marcial Escudero
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, E-41080, Sevilla, Spain
| | | | - Hervé Sauquet
- National Herbarium of New South Wales, Royal Botanic Gardens and Domain Trust, Sydney, NSW, Australia
| | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030, Vienna, Austria
| | - Steven D Johnson
- School of Life Sciences, University of KwaZulu-Natal, P Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Juan Arroyo
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, E-41080, Sevilla, Spain.
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Wang B, Tong ZY, Xiong YZ, Wang XF, Scott Armbruster W, Huang SQ. The evolution of flower-pollinator trait matching, and why do some alpine gingers appear to be mismatched? ANNALS OF BOTANY 2023; 132:1073-1088. [PMID: 37751161 PMCID: PMC10809048 DOI: 10.1093/aob/mcad141] [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: 07/09/2023] [Accepted: 09/20/2023] [Indexed: 09/27/2023]
Abstract
BACKGROUND AND AIMS Morphological matching between flower and pollinator traits has been documented in diverse plant lineages. Indeed, the matching of corolla tube length and pollinator tongue length has been cited repeatedly as a classic case of coevolution. However, there are many possible evolutionary routes to trait matching. Our aim here is both to review the evolutionary mechanisms of plant-pollinator trait matching and to investigate a specific case of trait matching/mismatching in a genus of alpine gingers. METHODS Roscoea gingers with long corolla tubes in the western Himalayas have pollinators with correspondingly long tongues, but the match between corolla tube and pollinator tongue lengths is not seen in the eastern Himalayas. Six floral traits were measured, including corolla tube depth, an internal trait controlling pollinator access to nectar. We calculated coefficients of variation and phylogenetically controlled correlation patterns of these traits in six Roscoea species in order to gain possible insights into stabilizing selection and modularization of these traits. KEY RESULTS The distal (nectar-containing) portion of the corolla tube exhibited lower coefficients of variations than did the basal portion. This is consistent with the hypothesis that pollinators mediate stabilizing selection on the distal, but not basal, portion of the corolla tube. This result, combined with phylogenetic data, suggests that the elevated liquid level of nectar in the distal tube evolved subsequent to dispersal into the eastern Himalayan region and loss of long-tongue pollinators. After accounting for phylogeny, corolla tube length, anther length, style length and labellum width were all intercorrelated. Corolla-tube depth was not part of this covariational module, however, suggesting separate adaptation to short-tongued pollinators. CONCLUSIONS The reduction in functional corolla tube depth in the Roscoea appears to be related to the loss of long-tongued pollinators associated with dispersal to the eastern Himalayas and pollination by short-tongued pollinators. The apparent mismatch between floral tubes and pollinator tongues is a case of cryptic trait matching between flowers and pollinators, underscoring the importance of combining floral anatomy with pollination ecology in assessing plant-pollinator trait matching.
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Affiliation(s)
- Bo Wang
- State Key Laboratory of Hybrid Rice, The College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ze-Yu Tong
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Ying-Ze Xiong
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Xiao-Fan Wang
- State Key Laboratory of Hybrid Rice, The College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - W Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO12DY, UK
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
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3
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Zhang L, Li P, Zhang X, Li J. Two floral forms in the same species-distyly. PLANTA 2023; 258:72. [PMID: 37656285 DOI: 10.1007/s00425-023-04229-6] [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: 04/23/2023] [Accepted: 08/23/2023] [Indexed: 09/02/2023]
Abstract
MAIN CONCLUSION This paper reviews the progress of research on the morphology, physiology and molecular biology of distyly in plants. It will help to elucidate the mysteries of distyly in plants. Distyly is a unique representative type of heterostyly in plants, primarily characterized by the presence of long style and short style within the flowers of the same species. This interesting trait has always fascinated researchers. With the rapid development of molecular biology, the molecular mechanism for the production of dimorphic styles in plants is also gaining ground. Researchers have been studying plant dimorphic styles from various perspectives. The researchers are gradually unravelling the mechanisms by which plants produce distyly traits. This paper reviews advances in the study of plant dimorphic style characteristics, mainly in terms of the morphology, physiology and molecular biology of plants with dimorphic styles. The aim is to provide a theoretical basis for the study of the mechanism of distyly formation in plants.
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Affiliation(s)
- Lu Zhang
- College of Landscape and Tourism, Hebei Agricultural University, No. 289 Lingyusi Street, P. O. Box 28, Baoding, 071000, Hebei, China
| | - Ping Li
- College of Landscape and Tourism, Hebei Agricultural University, No. 289 Lingyusi Street, P. O. Box 28, Baoding, 071000, Hebei, China.
| | - Xiaoman Zhang
- College of Landscape and Tourism, Hebei Agricultural University, No. 289 Lingyusi Street, P. O. Box 28, Baoding, 071000, Hebei, China.
| | - Jinfeng Li
- College of Landscape and Tourism, Hebei Agricultural University, No. 289 Lingyusi Street, P. O. Box 28, Baoding, 071000, Hebei, China
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Xiang GJ, Lázaro A, Dai XK, Xia J, Yang CF. Pollinator Proboscis Length Plays a Key Role in Floral Integration of Honeysuckle Flowers ( Lonicera spp.). PLANTS (BASEL, SWITZERLAND) 2023; 12:1629. [PMID: 37111853 PMCID: PMC10144162 DOI: 10.3390/plants12081629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 06/19/2023]
Abstract
Pollinator-mediated selection is supposed to influence floral integration. However, the potential pathway through which pollinators drive floral integration needs further investigations. We propose that pollinator proboscis length may play a key role in the evolution of floral integration. We first assessed the divergence of floral traits in 11 Lonicera species. Further, we detected the influence of pollinator proboscis length and eight floral traits on floral integration. We then used phylogenetic structural equation models (PSEMs) to illustrate the pathway through which pollinators drive the divergence of floral integration. Results of PCA indicated that species significantly differed in floral traits. Floral integration increased along with corolla tube length, stigma height, lip length, and the main pollinators' proboscis length. PSEMs revealed a potential pathway by which pollinator proboscis length directly selected on corolla tube length and stigma height, while lip length co-varied with stigma height. Compared to species with short corolla tubes, long-tube flowers may experience more intense pollinator-mediated selection due to more specialized pollination systems and thus reduce variation in the floral traits. Along elongation of corolla tube and stigma height, the covariation of other relevant traits might help to maintain pollination success. The direct and indirect pollinator-mediation selection collectively enhances floral integration.
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Affiliation(s)
- Gan-Ju Xiang
- College of Life Science, Yangtze University, Jingzhou 434025, China
| | - Amparo Lázaro
- Global Change Research Group, Mediterranean Institute of Advanced Studies (IMEDEA; UIB-CSIC), 07190 Esporles, Balearic Islands, Spain
- Department of Biology, Ecology Area, University of the Balearic Islands, 07190 Palma, Balearic Islands, Spain
| | - Xiao-Kang Dai
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Jing Xia
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan 430074, China
| | - Chun-Feng Yang
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China
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Simón‐Porcar VI, Muñoz‐Pajares AJ, de Castro A, Arroyo J. Direct evidence supporting Darwin's hypothesis of cross-pollination promoted by sex organ reciprocity. THE NEW PHYTOLOGIST 2022; 235:2099-2110. [PMID: 35596603 PMCID: PMC9546006 DOI: 10.1111/nph.18266] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/09/2022] [Indexed: 05/28/2023]
Abstract
The floral phenotype plays a main role in the attraction and fit of pollinators. Both perianth traits and the positioning of sex organs can be subjected to natural selection and determine nonrandom mating patterns in populations. In stylar-polymorphic species, the Darwinian hypothesis predicts increased mating success between individuals with sex organs at equivalent heights (i.e. with higher reciprocity). We used paternity analyses in experimental populations of a stylar-dimorphic species. By comparing the observed mating patterns with those expected under random mating, we tested the effects of sex organ reciprocity and perianth traits on mating success. We also analysed phenotypic selection on perianth traits through female and male functions. The (dis)similarity of parental perianth traits had no direct effects on the mating patterns. Sex organ reciprocity had a positive effect on mating success. Narrow floral tubes increased this effect in upper sex organs. Perianth traits showed little signs of phenotypic selection. Female and absolute fitness measures resulted in different patterns of phenotypic selection. We provide precise empirical evidence of the Darwinian hypothesis about the functioning of stylar polymorphisms, demonstrating that mating patterns are determined by sex organ reciprocity and only those perianth traits which are critical to pollinator fit.
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Affiliation(s)
| | - A. Jesús Muñoz‐Pajares
- Department of GeneticsUniversity of GranadaE‐18071GranadaSpain
- Research Centre in Biodiversity and Genetic Resources (CIBIO)Campus Agrário de Vairão4485‐661VairãoPortugal
| | - Alejandra de Castro
- Department of Plant Biology and EcologyUniversity of SevilleE‐41080SevilleSpain
| | - Juan Arroyo
- Department of Plant Biology and EcologyUniversity of SevilleE‐41080SevilleSpain
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Kato M, Watanabe H, Hoshino Y. Evaluation of pollen tube growth ability in Petunia species having different style lengths. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2022; 39:85-92. [PMID: 35937536 PMCID: PMC9300434 DOI: 10.5511/plantbiotechnology.21.1113a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/13/2021] [Indexed: 06/15/2023]
Abstract
Pollen tube growth is essential for the fertilization process in angiosperms. When pollen grains arrive on the stigma, they germinate, and the pollen tubes elongate through the styles of the pistils to deliver sperm cells into the ovules to produce the seeds. The relationship between the growth rate and style length remains unclear. In previous studies, we developed a liquid pollen germination medium for observing pollen tube growth. In this study, using this medium, we examined the pollen tube growth ability in Petunia axillaris subsp. axillaris, P. axillaris subsp. parodii, P. integrifolia, and P. occidentalis, which have different style lengths. Petunia occidentalis had the longest pollen tubes after 6 h of culture but had a relatively shorter style. Conversely, the pollination experiments revealed that P. axillaris subsp. parodii, which had the longest style, produced the longest pollen tubes in vivo. The results revealed no clear relationship between the style lengths and the growth rate of pollen tubes in vitro. Interspecific pollinations indicated that the styles affected pollen tube growth. We concluded that, in vitro, the pollen tubes grow without being affected by the styles, whereas, in vivo, the styles significantly affected pollen tube growth. Furthermore, interspecific pollination experiments implied that the pollen tube growth tended to be suppressed in the styles of self-incompatibility species. Finally, we discussed the pollen tube growth ability in relation to style lengths.
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Affiliation(s)
- Miyako Kato
- Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Kita 11, Nishi 10, Kita-ku, Sapporo, Hokkaido 060-0811, Japan
| | - Hitoshi Watanabe
- Center for Environment, Health and Field Sciences, Chiba University, 6-2-1 Kashiwano-ha, Kashiwa, Chiba 277-0882, Japan
| | - Yoichiro Hoshino
- Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Kita 11, Nishi 10, Kita-ku, Sapporo, Hokkaido 060-0811, Japan
- Field Science Center for Northern Biosphere, Hokkaido University, Kita 11, Nishi 10, Kita-ku, Sapporo, Hokkaido 060-0811, Japan
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7
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Dellinger AS. Pollination syndromes in the 21 st century: where do we stand and where may we go? THE NEW PHYTOLOGIST 2020; 228:1193-1213. [PMID: 33460152 DOI: 10.1111/nph.16793] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/31/2020] [Indexed: 06/12/2023]
Abstract
Pollination syndromes, recurring suites of floral traits appearing in connection with specific functional pollinator groups, have served for decades to organise floral diversity under a functional-ecological perspective. Some potential caveats, such as over-simplification of complex plant-animal interactions or lack of empirical observations, have been identified and discussed in recent years. Which of these caveats do indeed cause problems, which have been solved and where do future possibilities lie? I address these questions in a review of the pollination-syndrome literature of 2010 to 2019. I show that the majority of studies was based on detailed empirical pollinator observations and could reliably predict pollinators based on a few floral traits such as colour, shape or reward. Some traits (i.e. colour) were less reliable in predicting pollinators than others (i.e. reward, corolla width), however. I stress that future studies should consider floral traits beyond those traditionally recorded to expand our understanding of mechanisms of floral evolution. I discuss statistical methods suitable for objectively analysing the interplay of system-specific evolutionary constraints, pollinator-mediated selection and adaptive trade-offs at microecological and macroecological scales. I exemplify my arguments on an empirical dataset of floral traits of a neotropical plant radiation in the family Melastomataceae.
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8
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Ganguly S, Barua D. High herkogamy but low reciprocity characterizes isoplethic populations of Jasminum malabaricum, a species with stigma-height dimorphism. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:899-909. [PMID: 32352185 DOI: 10.1111/plb.13127] [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: 11/29/2019] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
Studies of floral polymorphisms have focused on heterostyly, while stigma-height dimorphism has received considerably less attention. Few studies have examined the reproductive biology of species with stigma-height dimorphism to understand how factors influencing mate availability and pollen transfer are related to morph ratios in populations. Floral morphological traits, especially herkogamy and reciprocity, pollinator visitation, breeding system and spatiotemporal mate availability, are known to affect inter-morph pollination and morph ratios in species with stigma-height dimorphism. In this study, we investigated the presence of stigma-height dimorphism and estimated morph ratios in four naturally occurring populations of Jasminum malabaricum. We quantified morph- and population-specific differences in the abovementioned factors in these populations to understand the observed morph ratios. The positions of anthers and stigmas were characteristic of stigma-height dimorphism, the first report of this polymorphism in the genus. All study populations were isoplethic, implying equal fitness of both morphs. Herkogamy was higher in the short-styled morph, while reciprocity was higher between the long-styled stigma and short-styled anthers. Long- and short-tongued pollinators were common floral visitors, and we observed no differences between morphs in spatiotemporal mate availability or pollinator visitation. Neither morph exhibited self- or heteromorphic incompatibility. The short-styled stigma had lower reciprocity but likely receives sufficient inter-morph pollen from long-tongued pollinators, and also by avoiding self-pollination due to higher herkogamy. These results highlight the importance of sufficient effective pollinators and floral morphological features, particularly herkogamy, in maintaining isoplethy in species with stigma-height dimorphism.
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Affiliation(s)
- S Ganguly
- Department of Biology, Indian Institute of Science Education and Research, Pune, India
| | - D Barua
- Department of Biology, Indian Institute of Science Education and Research, Pune, India
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Matias R, Pérez-Barrales R, Consolaro H. Patterns of variation in distylous traits and reproductive consequences in Erythroxylum species and populations. AMERICAN JOURNAL OF BOTANY 2020; 107:910-922. [PMID: 32462680 DOI: 10.1002/ajb2.1478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Distylous species possess two floral morphs with reciprocal positioning of stigmas and anthers that is hypothesized to promote disassortative pollination. Theoretical models predict equal morph frequencies, but many populations depart from the expected 1:1 ratio, a pattern that often correlates with asymmetric mating between morphs and/or presence of a weak incompatibility system. Variation in reciprocity can also affect the likelihood of disassortative pollination and, hence, reproductive fitness. METHODS We described variation in incompatibility systems and morph ratio in four Erythroxylum species to test if greater deviations from 1:1 ratios occur in populations of self-compatible species. Using adaptive inaccuracy, we described upper and lower organ reciprocity in species and populations and assessed the relationship of reciprocity to population means and coefficients of variation for fruit set to test if reciprocity could predict female reproductive success. RESULTS Morphs occurred in 1:1 ratios in most populations of three Erythroxylum species with distylous self-incompatibility. In self-compatible E. campestre populations showed an excess of the long-styled morph, the short-styled morph, or were monomorphic for the short-styled morph. We detected deviations from reciprocity, with total inaccuracy ranging between 9.39% and 42.94%, and inaccuracy values were lowest in low organs. Across populations, we found a positive relationship between inaccuracy and the coefficient of variation of fruit set. CONCLUSIONS Erythroxylum species showed variation in the distylous syndrome, with changes in the incompatibility system that corresponded with deviations from 1:1 morph ratio, and variation in reciprocity that correlated with variation in female reproductive fitness.
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Affiliation(s)
- Raphael Matias
- Graduate Program in Botany, University of Brasília, Brasília, Distrito Federal, Brazil
- Academic Areas Department, Federal Institute of Goiás, Águas Lindas, Goiás, Brazil
| | | | - Hélder Consolaro
- Biotechnology Institute, Federal University of Catalão, Catalão, Goiás, Brazil
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Benitez‐Vieyra S, Pérez‐Alquicira J, Sazatornil FD, Domínguez CA, Boege K, Pérez‐Ishiwara R, Fornoni J. Evolutionary transition between bee pollination and hummingbird pollination in
Salvia
: Comparing means, variances and covariances of corolla traits. J Evol Biol 2019; 32:783-793. [DOI: 10.1111/jeb.13480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 03/19/2019] [Accepted: 04/15/2019] [Indexed: 01/15/2023]
Affiliation(s)
- Santiago Benitez‐Vieyra
- Instituto Multidisciplinario de Biología Vegetal Universidad Nacional de Córdoba, CONICET Córdoba Argentina
| | - Jessica Pérez‐Alquicira
- Departamento de Botánica y Zoología CONACYT – Laboratorio Nacional de Identificación y Caracterización Vegetal Centro Universitario de Ciencias Biológicas y Agropecuarias Universidad de Guadalajara Zapopan Mexico
- Departamento de Ecología Evolutiva Instituto de Ecología Universidad Nacional Autónoma de México Ciudad de México México
| | - Federico D. Sazatornil
- Instituto Multidisciplinario de Biología Vegetal Universidad Nacional de Córdoba, CONICET Córdoba Argentina
| | - César A. Domínguez
- Departamento de Ecología Evolutiva Instituto de Ecología Universidad Nacional Autónoma de México Ciudad de México México
| | - Karina Boege
- Departamento de Ecología Evolutiva Instituto de Ecología Universidad Nacional Autónoma de México Ciudad de México México
| | - Rubén Pérez‐Ishiwara
- Departamento de Ecología Evolutiva Instituto de Ecología Universidad Nacional Autónoma de México Ciudad de México México
| | - Juan Fornoni
- Instituto Multidisciplinario de Biología Vegetal Universidad Nacional de Córdoba, CONICET Córdoba Argentina
- Departamento de Ecología Evolutiva Instituto de Ecología Universidad Nacional Autónoma de México Ciudad de México México
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11
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Development of G: a test in an amphibious fish. Heredity (Edinb) 2018; 122:696-708. [PMID: 30327484 DOI: 10.1038/s41437-018-0152-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/16/2018] [Accepted: 09/24/2018] [Indexed: 01/06/2023] Open
Abstract
Heritable variation in, and genetic correlations among, traits determine the response of multivariate phenotypes to natural selection. However, as traits develop over ontogeny, patterns of genetic (co)variation and integration captured by the G matrix may also change. Despite this, few studies have investigated how genetic parameters underpinning multivariate phenotypes change as animals pass through major life history stages. Here, using a self-fertilizing hermaphroditic fish species, mangrove rivulus (Kryptolebias marmoratus), we test the hypothesis that G changes from hatching through reproductive maturation. We also test Cheverud's conjecture by asking whether phenotypic patterns provide an acceptable surrogate for patterns of genetic (co)variation within and across ontogenetic stages. For a set of morphological traits linked to locomotor (jumping) performance, we find that the overall level of genetic integration (as measured by the mean-squared correlation across all traits) does not change significantly over ontogeny. However, we also find evidence that some trait-specific genetic variances and pairwise genetic correlations do change. Ontogenetic changes in G indicate the presence of genetic variance for developmental processes themselves, while also suggesting that any genetic constraints on morphological evolution may be age-dependent. Phenotypic correlations closely resembled genetic correlations at each stage in ontogeny. Thus, our results are consistent with the premise that-at least under common environment conditions-phenotypic correlations can be a good substitute for genetic correlations in studies of multivariate developmental evolution.
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Wu Y, Zhong T, Zhang ZQ, Li QJ. Pollinator-mediated selection on floral traits varies in space and between morphs in Primula secundiflora. AOB PLANTS 2018; 10:ply059. [PMID: 30393517 PMCID: PMC6205359 DOI: 10.1093/aobpla/ply059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
Elucidating how variation in selection shapes the evolution of flowers is key to understanding adaptive differentiation processes. We estimated pollinator-mediated selection through female function in L-morph (long-style and short-anther phenotype) and S-morph (short-style and long-anther phenotype) flowers among four Primula secundiflora populations with different pollinator assemblages. Variation in pollinator assemblage strongly contributed to differences in reproductive success among populations and between morphs of the primrose species. A wider corolla tube width was selected in the bumblebee-dominated populations, whereas shorter corolla tube length and wider corolla tube width were selected in the syrphid fly-dominated populations. Morph-specific variation in pollinator-mediated selection on corolla tube length was detected in the syrphid fly-dominated populations. A shorter corolla tube was selected in the L-morph flowers. However, similar selective pressure on this trait was not observed in the S-morph flowers. These results show that variation in pollinator assemblage leads to variation in selection in space and between morphs. The findings highlight the potential forces of different pollinator agents in driving floral evolution in this primrose species.
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Affiliation(s)
- Yun Wu
- School of Civil Engineering, Architecture and Environment, Xihua University, Chengdu, China
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tao Zhong
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, China
| | - Zhi-Qiang Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Qing-Jun Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
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13
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Pérez-Barrales R, Abarca CA, Santos-Gally R, Schiestl FP, Arroyo J. The function of the floral corona in the pollination of a Mediterranean style dimorphic daffodil. PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20 Suppl 1:118-127. [PMID: 29105981 DOI: 10.1111/plb.12657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Narcissus papyraceus is a style dimorphic species with two floral forms, with anthers at similar height and stigmas above (long-styled L) and below (short-styled S) the anther level. The species is self-incompatible, but intra- and inter-morph compatible. Populations are either dimorphic (including both morphs) in the region of the Strait of Gibraltar, or L-monomorphic (with only L plants) in the inland of the Iberian Peninsula. This variation correlates with the most common floral visitors, being primarily long-tongued and short-tongued pollinators, respectively, a rare condition in Mediterranean plants. The maintenance of S-flowers relies on long-tongued insects, as only those deliver pollen to short-styled stigmas. Narcissus flowers present a long and narrow tube, at the bottom of which nectar accumulates, and a floral corona, which has been proposed as an important trait for the attraction of pollinators. Here we tested the importance of the corona on pollination of L and S flowers. We described UV reflectance patterns of the corona and tepals, and characterised VOCs in intact flowers and flowers with trimmed coronas. We also conducted a field experiment in the dimorphic and monomorphic region to estimate the importance of corona removal on seed production in stands with solitary plants and in groups to control for compatible pollen limitation. Reflectance was higher in the tepals than the corona, although both traits presented a reflectance peak around 450 nm wavelength. L- and S-flowers produced similar volatiles, regardless of the manipulation of the corona. Across dimorphic and monomorphic regions, S-flowers with the corona removed suffered a reduction in seed production of ca. 50%, while seed production remained similar in L flowers both with the corona intact and removed. Plants in solitary stands suffered a strong reduction in seed production, which was more pronounced in the monomorphic region. Our results suggest that the corona in Narcissus is more important for the pollination of S-flowers, which generally have lower seed production compared to L-flowers. Taken together, these results suggest that the floral corona indirectly plays an important role for maintenance of the polymorphism.
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Affiliation(s)
- R Pérez-Barrales
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - C A Abarca
- Unidad Lerma Departamento de Ecología Evolutiva, Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana, Mexico City, México
| | - R Santos-Gally
- CONACYT-Departamento de Ecología Evolutiva, Instituto de Ecología, UNAM, Mexico City, México
| | - F P Schiestl
- Institute of Systematic Botany, University of Zurich, Zurich, Switzerland
| | - J Arroyo
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Sevilla, Spain
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Laphitz RML, Ezcurra C, Vidal-Russell R. Cryptic species in the Andean hemiparasite Quinchamalium chilense (Schoepfiaceae: Santalales). SYST BIODIVERS 2017. [DOI: 10.1080/14772000.2017.1404504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Rita M Lopez Laphitz
- Departamento de Botánica, Instituto de Investigaciones en Biodiversidad y Medioambiente, CONICET-UNComahue, Quintral 1250, S. C. de Bariloche, 8400 Río Negro, Argentina
| | - Cecilia Ezcurra
- Departamento de Botánica, Instituto de Investigaciones en Biodiversidad y Medioambiente, CONICET-UNComahue, Quintral 1250, S. C. de Bariloche, 8400 Río Negro, Argentina
| | - Romina Vidal-Russell
- Departamento de Botánica, Instituto de Investigaciones en Biodiversidad y Medioambiente, CONICET-UNComahue, Quintral 1250, S. C. de Bariloche, 8400 Río Negro, Argentina
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15
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Heywood JS, Michalski JS, McCann BK, Russo AD, Andres KJ, Hall AR, Middleton TC. Genetic and environmental integration of the hawkmoth pollination syndrome in Ruellia humilis (Acanthaceae). ANNALS OF BOTANY 2017; 119:1143-1155. [PMID: 28334177 PMCID: PMC5604580 DOI: 10.1093/aob/mcx003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 01/11/2017] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS The serial homology of floral structures has made it difficult to assess the relative contributions of selection and constraint to floral integration. The interpretation of floral integration may also be clouded by the tacit, but largely untested, assumption that genetic and environmental perturbations affect trait correlations in similar ways. In this study, estimates of both the genetic and environmental correlations between components of the hawkmoth pollination syndrome are presented for chasmogamous flowers of Ruellia humilis , including two levels of control for serial homology. METHODS A greenhouse population for quantitative genetic analysis was generated by a partial diallel cross between field-collected plants. An average of 634 chasmogamous flowers were measured for each of eight floral traits that contribute to the hawkmoth syndrome. Genetic correlations (across parents) and environmental correlations (across replicate flowers) were estimated by restricted maximum likelihood. KEY RESULTS Stigma height, anther height and floral tube length were very tightly integrated in their responses to both genetic and environmental perturbations. The inclusion of floral disc width as a control for serial homology suggests this integration is an adaptive response to correlational selection imposed by pollinators. In contrast, integration of non-homologous traits was low. Furthermore, when comparisons between the dimensions of serially homologous structures were excluded, the genetic and environmental correlation matrices showed little congruence. CONCLUSIONS The results suggest that hawkmoths have imposed strong correlational selection on floral traits involved in the deposition and removal of pollen, and that this is a consequence of stabilizing selection on the relative positions of stigmas and anthers in the face of substantial flower size variation. Low integration of other floral traits, and conflicting patterns of genetic and environmental correlations among these traits, suggest weak or no correlational selection within the range of variability expressed within a population.
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16
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Esteve-Altava B. In search of morphological modules: a systematic review. Biol Rev Camb Philos Soc 2016; 92:1332-1347. [DOI: 10.1111/brv.12284] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Borja Esteve-Altava
- Department of Comparative Biomedical Sciences; Royal Veterinary College; Hawkshead Lane, North Mymms Hatfield Hertfordshire AL9 7TA UK
- Department of Anatomy; College of Medicine, Howard University; 520 W Street, NW, Numa Adams Building Washington DC 20059 USA
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Gómez JM, Torices R, Lorite J, Klingenberg CP, Perfectti F. The role of pollinators in the evolution of corolla shape variation, disparity and integration in a highly diversified plant family with a conserved floral bauplan. ANNALS OF BOTANY 2016; 117:889-904. [PMID: 26884512 PMCID: PMC4845802 DOI: 10.1093/aob/mcv194] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 09/17/2015] [Accepted: 10/14/2015] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Brassicaceae is one of the most diversified families in the angiosperms. However, most species from this family exhibit a very similar floral bauplan. In this study, we explore the Brassicaceae floral morphospace, examining how corolla shape variation (an estimation of developmental robustness), integration and disparity vary among phylogenetically related species. Our aim is to check whether these floral attributes have evolved in this family despite its apparent morphological conservation, and to test the role of pollinators in driving this evolution. METHODS Using geometric morphometric tools, we calculated the phenotypic variation, disparity and integration of the corolla shape of 111 Brassicaceae taxa. We subsequently inferred the phylogenetic relationships of these taxa and explored the evolutionary lability of corolla shape. Finally, we sampled the pollinator assemblages of every taxon included in this study, and determined their pollination niches using a modularity algorithm. We explore the relationship between pollination niche and the attributes of corolla shape. KEY RESULTS Phylogenetic signal was weak for all corolla shape attributes. All taxa had generalized pollination systems. Nevertheless, they belong to different pollination niches. There were significant differences in corolla shape among pollination niches even after controlling for the phylogenetic relationship of the plant taxa. Corolla shape variation and disparity was significantly higher in those taxa visited mostly by nocturnal moths, indicating that this pollination niche is associated with a lack of developmental robustness. Corolla integration was higher in those taxa visited mostly by hovering long-tongued flies and long-tongued large bees. CONCLUSIONS Corolla variation, integration and disparity were evolutionarily labile and evolved very recently in the evolutionary history of the Brassicaceae. These floral attributes were strongly related to the pollination niche. Even in a plant clade having a very generalized pollination system and exhibiting a conserved floral bauplan, pollinators can drive the evolution of important developmental attributes of corolla shape.
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Affiliation(s)
- José M Gómez
- Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (EEZA-CSIC), Almería, Spain, Department of Ecology,
| | - Ruben Torices
- Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (EEZA-CSIC), Almería, Spain, Centre for Functional Ecology, Department of Life Science, University of Coimbra, Coimbra, Portugal and
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18
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Fornoni J, Ordano M, Pérez-Ishiwara R, Boege K, Domínguez CA. A comparison of floral integration between selfing and outcrossing species: a meta-analysis. ANNALS OF BOTANY 2016; 117:299-306. [PMID: 26578721 PMCID: PMC4724042 DOI: 10.1093/aob/mcv166] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 09/10/2015] [Accepted: 09/16/2015] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Floral integration is thought to be an adaptation to promote cross-fertilization, and it is often assumed that it increases morphological matching between flowers and pollinators, increasing the efficiency of pollen transfer. However, the evidence for this role of floral integration is limited, and recent studies have suggested a possible positive association between floral integration and selfing. Although a number of explanations exist to account for this inconsistency, to date there has been no attempt to examine the existence of an association between floral integration and mating system. This study hypothesized that if pollinator-mediated pollen movement among plants (outcrossing) is the main factor promoting floral integration, species with a predominantly outcrossing mating system should present higher levels of floral integration than those with a predominantly selfing mating system. METHODS A phylogenetically informed meta-analysis of published data was performed in order to evaluate whether mating system (outcrossing vs. selfing) accounts for the variation in floral integration among 64 species of flowering plants. Morphometric floral information was used to compare intra-floral integration among traits describing sexual organs (androecium and gynoecium) and those corresponding to the perianth (calix and corolla). KEY RESULTS The analysis showed that outcrossing species have lower floral integration than selfing species. This pattern was caused by significantly higher integration of sexual traits than perianth traits, as integration of the latter group remained unchanged across mating categories. CONCLUSIONS The results suggest that the evolution of selfing is associated with concomitant changes in intra-floral integration. Thus, floral integration of sexual traits should be considered as a critical component of the selfing syndrome.
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Affiliation(s)
- Juan Fornoni
- Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, Ciudad Universitaria 04510, México Distrito Federal, México and
| | - Mariano Ordano
- Fundación Miguel Lillo, Miguel Lillo 251, San Miguel de Tucumán T4000JFE, Tucumán, Argentina, and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Rubén Pérez-Ishiwara
- Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, Ciudad Universitaria 04510, México Distrito Federal, México and
| | - Karina Boege
- Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, Ciudad Universitaria 04510, México Distrito Federal, México and
| | - César A Domínguez
- Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, Ciudad Universitaria 04510, México Distrito Federal, México and
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19
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Wanderley AM, Galetto L, Machado ICS. Functional decoupling between flowers and leaves in the Ameroglossum pernambucense complex can facilitate local adaptation across a pollinator and climatic heterogeneous landscape. J Evol Biol 2015; 29:528-40. [PMID: 26663030 DOI: 10.1111/jeb.12802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/09/2015] [Accepted: 11/29/2015] [Indexed: 11/30/2022]
Abstract
Decoupling between floral and leaf traits is expected in plants with specialized pollination systems to assure a precise flower-pollinator fit, irrespective of leaf variation associated with environmental heterogeneity (functional modularity). Nonetheless, developmental interactions among floral traits also decouple flowers from leaves regardless of selection pressures (developmental modularity). We tested functional modularity in the hummingbird-pollinated flowers of the Ameroglossum pernambucense complex while controlling for developmental modularity. Using two functional traits responsible for flower-pollinator fit [floral tube length (TL) and anther-nectary distance (AN)], one floral trait not linked to pollination [sepal length (SL), control for developmental modularity] and one leaf trait [leaf length (LL)], we found evidence of flower functional modularity. Covariation between TL and AN was ca. two-fold higher than the covariation of either of these traits with sepal and leaf lengths, and variations in TL and AN, important for a precise flower-pollinator fit, were smaller than SL and LL variations. Furthermore, we show that previously reported among-population variation of flowers associated with local pollinator phenotypes was independent from SL and LL variations. These results suggest that TL and AN are functionally linked to fit pollinators and sufficiently decoupled from developmentally related floral traits (SL) and vegetative traits (LL). These results support previous evidences of population differentiation due to local adaptation in the A. pernambucense complex and shed light on the role of flower-leaf decoupling for local adaptation in species distributed across biotic and abiotic heterogeneous landscapes.
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Affiliation(s)
- A M Wanderley
- Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - L Galetto
- Departamento de Diversidad Biológica y Ecología, Facultad de Ciencias Exactas, Físicas y Naturales, Instituto Multidisciplinario de Biología Vegetal (CONICET - UNC), Universidad Nacional de Córdoba (UNC), Córdoba, Argentina
| | - I C S Machado
- Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Pernambuco, Recife, PE, Brazil.,Departamento de Botânica, Universidade Federal de Pernambuco, Recife, PE, Brazil
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20
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Villellas J, Doak DF, García MB, Morris WF. Demographic compensation among populations: what is it, how does it arise and what are its implications? Ecol Lett 2015; 18:1139-1152. [DOI: 10.1111/ele.12505] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/12/2015] [Accepted: 08/04/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Jesús Villellas
- Department of Ecology and Genetics; Uppsala University; Uppsala 75236 Sweden
| | - Daniel F. Doak
- Environmental Studies Program; University of Colorado Boulder; Boulder CO 80309 USA
| | - María B. García
- Pyrenean Institute of Ecology (IPE-CSIC); Apdo. 13034 50080 Zaragoza Spain
| | - William F. Morris
- Department of Ecology and Genetics; Uppsala University; Uppsala 75236 Sweden
- Department of Biology; Duke University; Box 90338 Durham NC 27708-0338 USA
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21
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Mikolajewski DJ, Rüsen L, Mauersberger R, Johansson F, Rolff J. Relaxed predation results in reduced phenotypic integration in a suite of dragonflies. J Evol Biol 2015; 28:1354-63. [PMID: 26009809 DOI: 10.1111/jeb.12658] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/11/2015] [Accepted: 05/14/2015] [Indexed: 12/13/2022]
Abstract
Although changes in magnitude of single traits responding to selective agents have been studied intensively, little is known about selection shaping networks of traits and their patterns of covariation. However, this is central for our understanding of phenotypic evolution as traits are embedded in a multivariate environment with selection affecting a multitude of traits simultaneously rather than individually. Here, we investigate inter- and intraspecific patterns of trait integration (trait correlations) in the larval abdomen of dragonflies as a response to a change in predator selection. Species of the dragonfly genus Leucorrhinia underwent a larval habitat shift from predatory fish to predatory dragonfly-dominated lakes with an associated relaxation in selection pressure from fish predation. Our results indicate that the habitat-shift-induced relaxed selection pressure caused phenotypic integration of abdominal traits to be reduced. Intraspecific findings matched patterns comparing species from both habitats with higher abdominal integration in response to predatory fish. This higher integration is probably a result of faster burst swimming speed. The abdomen holds the necessary morphological machinery to successfully evade predatory fish via burst swimming. Hence, abdominal traits have to function in a tight coordinated manner, as maladaptive variation and consequently nonoptimal burst swimming would cause increased mortality. In predatory dragonfly-dominated lakes, no such strong link between burst swimming and mortality is present. Our findings highlight the importance of studying multivariate trait relationships as a response to selection for understanding patterns of phenotypic diversification.
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Affiliation(s)
- D J Mikolajewski
- Institut für Biologie, Freie Universität Berlin, Berlin, Germany
| | - L Rüsen
- Institut für Biologie, Freie Universität Berlin, Berlin, Germany
| | - R Mauersberger
- Förderverein Feldberg-Uckermärkische Seenlandschaft e.V., Templin, Germany
| | - F Johansson
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - J Rolff
- Institut für Biologie, Freie Universität Berlin, Berlin, Germany.,Berlin-Brandenburg Institute of Advanced Biodiversity Research, Berlin, Germany
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22
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Diggle PK. Modularity and intra-floral integration in metameric organisms: plants are more than the sum of their parts. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130253. [PMID: 25002698 DOI: 10.1098/rstb.2013.0253] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Within-individual variation in virtually every conceivable morphological and functional feature of reiterated structures is a pervasive feature of plant phenotypes. In particular, architectural effects, regular, repeatable patterns of intra-individual variation in form and function that are associated with position are nearly ubiquitous. Yet, flowers also are predicted to be highly integrated. For animal-pollinated plants, the coordination of multiple organs within each flower is required to achieve the complex functions of pollinator attraction and orientation, pollen donation and pollen receipt. To the extent that pollinators may select for multiple independent functions, phenotypic integration within flowers may also be modular. That is, subsets of floral structures may be integrated but vary independently of other subsets of structures that are themselves integrated. How can phenotypic integration and modularity be understood within the context of architectural effects? This essay reviews recent research on patterns of floral integration and modularity and explores the potential for spatial and temporal changes in the selective environment of individual flowers to result in positional variation in patterns of morphological integration.
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Affiliation(s)
- Pamela K Diggle
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043, USA
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Leme da Cunha N, Fischer E, Lorenz-Lemke AP, Barrett SCH. Floral variation and environmental heterogeneity in a tristylous clonal aquatic of the Pantanal wetlands of Brazil. ANNALS OF BOTANY 2014; 114:1637-49. [PMID: 25180289 PMCID: PMC4416129 DOI: 10.1093/aob/mcu181] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/28/2014] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS The balance between stochastic forces and frequency-dependent mating largely governs style morph frequencies in heterostylous populations. In clonal species, deviations from equal morph ratios often result from founder events and unfavourable conditions for sexual reproduction. The aim of this study was to investigate whether different flooding regimes, because of their influence on sexual vs. clonal reproduction, are associated with regional variation in morph frequencies and floral trait differentiation in populations of the clonal, tristylous, aquatic Eichhornia azurea (Pontederiaceae) in the Pantanal wetlands of Brazil. METHODS Style morph frequencies were sampled from 73 populations distributed across four flooding regimes differing in depth and duration. Measurements of flower size, sex-organ dimension, pollen size and pollen production were made in selected populations, and pollinator assemblages and their functional traits were recorded. KEY RESULTS Most populations of E. azurea were tristylous (78 %), but the majority exhibited uneven morph ratios. The frequency of the mid-styled morph was significantly lower than that of the long- and short-styled morphs. Morph evenness was positively associated with population size but not with flooding regime. There were significant phenotypic differences among flooding regimes for all floral traits, including populations with reduced flower size, sex-organ length and smaller pollen. Pollinator assemblages varied with flood duration. CONCLUSIONS The similar morph structure and evenness of populations, regardless of flooding regime, suggest that sexual reproduction and clonal dispersal are sufficiently common to prevent the signature of founder events from dominating in a region. However, the pervasive occurrence of biased morph ratios in most populations suggests that many are in a non-equilibrium state. The reduced frequency of the mid-styled morph in trimorphic and dimorphic populations may be associated with the weak self-incompatibility of this morph resulting in selfing and inbreeding depression. Clonality in E. azurea and the weak self-incompatibility of the mid-styled morph may make it more vulnerable to geitonogamous selfing.
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Affiliation(s)
- Nicolay Leme da Cunha
- Programa de Pós-Graduação em Ecologia e Conservação, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, Mato Grosso do Sul, Brazil
| | - Erich Fischer
- Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, Mato Grosso do Sul, Brazil
| | - Aline P Lorenz-Lemke
- Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, Mato Grosso do Sul, Brazil
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S 3B2, Canada
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González AV, Murúa MM, Pérez F. Floral integration and pollinator diversity in the generalized plant-pollinator system of Alstroemeria ligtu (Alstroemeriaceae). Evol Ecol 2014. [DOI: 10.1007/s10682-014-9746-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Armbruster WS, Pélabon C, Bolstad GH, Hansen TF. Integrated phenotypes: understanding trait covariation in plants and animals. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130245. [PMID: 25002693 PMCID: PMC4084533 DOI: 10.1098/rstb.2013.0245] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Integration and modularity refer to the patterns and processes of trait interaction and independence. Both terms have complex histories with respect to both conceptualization and quantification, resulting in a plethora of integration indices in use. We review briefly the divergent definitions, uses and measures of integration and modularity and make conceptual links to allometry. We also discuss how integration and modularity might evolve. Although integration is generally thought to be generated and maintained by correlational selection, theoretical considerations suggest the relationship is not straightforward. We caution here against uncontrolled comparisons of indices across studies. In the absence of controls for trait number, dimensionality, homology, development and function, it is difficult, or even impossible, to compare integration indices across organisms or traits. We suggest that care be invested in relating measurement to underlying theory or hypotheses, and that summative, theory-free descriptors of integration generally be avoided. The papers that follow in this Theme Issue illustrate the diversity of approaches to studying integration and modularity, highlighting strengths and pitfalls that await researchers investigating integration in plants and animals.
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Affiliation(s)
- W Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO12DY, UK Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Christophe Pélabon
- Center for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Geir H Bolstad
- Center for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Thomas F Hansen
- Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, PO Box 1066, 0316 Oslo, Norway
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