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Makowski H, Lamb K, Galloway LF. Support for Baker's law: Facultative self-fertilization ability decreases pollen limitation in experimental colonization. AMERICAN JOURNAL OF BOTANY 2024; 111:e16351. [PMID: 38812263 DOI: 10.1002/ajb2.16351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 05/31/2024]
Abstract
PREMISE The ability to self-fertilize is predicted to provide an advantage in colonization because a single individual can reproduce and establish a next generation in a new location regardless of the density of mates. While there is theoretical and correlative support for this idea, the strength of mate limitation as a selective agent has not yet been delineated from other factors that can also select for self-fertilization in colonization of new habitats. We used known mating-system variation in the American bellflower (Campanula americana) to explore how plants' ability to self-fertilize can mitigate density-dependent reproduction and impact colonization success. METHODS We created experimental populations of single individuals or a small number of plants to emulate isolated colonization events. These populations were composed of plants that differed in their ability to self-fertilize. We compared pollen limitation of the single individuals to that of small populations. RESULTS Experimental populations of plants that readily self-fertilize produced consistent seed numbers regardless of population size, whereas plants with lower ability to self-fertilize had density-dependent reproduction with greater seed production in small populations than in populations composed of a single individual. CONCLUSIONS We experimentally isolated the effect of mate limitation in colonization and found that it can select for increased self-fertilization. We show the benefit of self-fertilization in colonization, which helps to explain geographic patterns of self-fertilization and shows support for Baker's law, a long-held hypothesis in the field of mating-system evolution.
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Affiliation(s)
- Hanna Makowski
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, 22904, Virginia, USA
- Black Rock Forest, 65 Reservoir Road, Cornwall, New York, 12518, USA
| | - Keric Lamb
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, 22904, Virginia, USA
| | - Laura F Galloway
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, 22904, Virginia, USA
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Buide ML, Del Valle JC, Prado-Comesaña A, Narbona E. The effects of pollination, herbivory and autonomous selfing on the maintenance of flower colour variation in Silenelittorea. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:275-284. [PMID: 33179369 DOI: 10.1111/plb.13209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/30/2020] [Indexed: 05/23/2023]
Abstract
Intraspecific flower colour variation has been generally proposed to evolve as a result of selection driven by biotic or abiotic agents. In a polymorphic population of Silene littorea with pink- and white-flowered plants, we studied pollinators, analysed flower colour perception and tested for differences in pollinator visitation. We also experimentally analysed pollinator limitation in fruit and seed set, and the degree of autonomous selfing. The incidence of florivory and leaf herbivory was compared over 3-4 years. Silene littorea is mainly pollinated by bees and butterflies. Pollinators preferred pink flowers, which did not show pollinator limitation. On the contrary, white flowers showed pollinator limitation in fruit set. White-flowered plants had less floral display and higher levels of florivory than pink plants. Flower colour morphs of S. littorea can reproduce in the absence of pollinators by autonomous selfing, setting 20% and 12% of fruit and seeds in the pink morph and 27% and 20% in the white morph, respectively. Fruit set of white flowers produced by autonomous selfing did not differ from open-pollinated flowers. In conclusion, S. littorea is pollinated by insects of different orders that more frequently visit pink flowers, which is reflected in pollinator limitation of fruit set in white flowers. Moreover, this species has a mixed mating system in which both colour morphs can reproduce in the absence of pollinators by autonomous selfing, although white flowers mainly produce fruits by autogamy. We suggest that reproductive assurance by autonomous selfing helps to maintain flower colour polymorphism in this population.
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Affiliation(s)
- M L Buide
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
| | - J C Del Valle
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
| | - A Prado-Comesaña
- Department of Analytical and Food Chemistry, University of Vigo, Vigo, Spain
| | - E Narbona
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
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Martín-Gómez JJ, Rewicz A, Rodríguez-Lorenzo JL, Janoušek B, Cervantes E. Seed Morphology in Silene Based on Geometric Models. PLANTS 2020; 9:plants9121787. [PMID: 33339395 PMCID: PMC7766405 DOI: 10.3390/plants9121787] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/26/2020] [Accepted: 12/11/2020] [Indexed: 01/09/2023]
Abstract
Seed description in morphology is often based on adjectives such as “spherical”, “globular”, or “reniform”, but this does not provide a quantitative method. A new morphological approach based on the comparison of seed images with geometric models provides a seed description in Silene species on a quantitative basis. The novelty of the proposed method is based in the comparison of the seed images with geometric models according to a cardioid shape. The J index is a measurement that indicates the seed percentage of similarity with a cardioid or cardioid-derived figures used as models. The seeds of Silene species have high values of similarity with the cardioid and cardioid-derived models (J index superior to 90). The comparison with different figures allows species description and differentiation. The method is applied here to seeds of 21 species and models are proposed for some of them including S. diclinis, an endangered species. The method is discussed in the context of previous comparison with the measures used in traditional morphometric analysis. The similarity of seed images with geometric figures opens a new perspective for the automatized taxonomical evaluation of samples linking seed morphology to functional traits in endangered Silene species.
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Affiliation(s)
| | - Agnieszka Rewicz
- Department of Biogeography, Paleoecology and Nature Conservation, Faculty of Biology and Environmental Protection, University of Lodz, 1/3 Banacha Str., 90-237 Lodz, Poland;
| | - José Luis Rodríguez-Lorenzo
- Plant Developmental Genetics, Institute of Biophysics v.v.i, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic; (J.L.R.-L.); (B.J.)
| | - Bohuslav Janoušek
- Plant Developmental Genetics, Institute of Biophysics v.v.i, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic; (J.L.R.-L.); (B.J.)
| | - Emilio Cervantes
- IRNASA-CSIC, Cordel de Merinas 40, 37008 Salamanca, Spain;
- Correspondence:
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Rocha OJ, Gómez C, Hamrick JL, Trapnell DW, Smouse PE, Macaya G. Reproductive consequences of variation in flowering phenology in the dry forest tree Enterolobium cyclocarpum in Guanacaste, Costa Rica. AMERICAN JOURNAL OF BOTANY 2018; 105:2037-2050. [PMID: 30548976 DOI: 10.1002/ajb2.1205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 09/06/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY Flowering initiation, duration and magnitude, and degree of flowering synchrony within a population can affect the reproductive fitness of individuals. We examined the flowering phenology within a population of the tropical dry forest Guanacaste tree (Enterolobium cyclocarpum) to gauge the impact of phenological variation among trees on fruit production and progeny vigor. METHODS We monitored the flowering phenology of 93 trees weekly during 2005, 2006, and 2007, using a scale based on the percentage of the crown with open flowers. We also monitored fruit production for each tree in 2005, 2006, 2007, and 2008. Finally, we evaluated the relationship between phenological variation and progeny performance. KEY RESULTS Ten measures of flowering phenology and synchrony among flowering trees, based on the number of weeks when anthesis of the crown exceeded 50%, were used to develop four phenological profiles. These profiles were correlated with significant differences in fruit production and progeny vigor. Trees with flowers in >50% of their crown for at least 2 weeks produced more fruits and more vigorous progeny than trees with other profiles. Trees also tended to produce the same phenological profile among years than predicted by chance. CONCLUSIONS Guanacaste trees vary significantly in the initiation of anthesis, duration and magnitude of flowering, and degree of synchrony among trees. Trees also tend to maintain the same flowering profile among years. Finally, the flowering behavior of E. cyclocarpum leads to significant differences in fruit and seed production, germination, and early progeny growth.
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Affiliation(s)
- Oscar J Rocha
- Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA
- Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria "Rodrigo Facio", San Pedro de Montes de Oca, San José, Costa Rica
| | - Carlos Gómez
- Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria "Rodrigo Facio", San Pedro de Montes de Oca, San José, Costa Rica
| | - James L Hamrick
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
| | - Dorset W Trapnell
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
| | - Peter E Smouse
- DEENR, Rutgers University, 14 College Farm Road, New Brunswick, NJ, 08901-8551, USA
| | - Gabriel Macaya
- Centro de Investigación en Biología Celular y Molecular, Universidad de Costa Rica, Ciudad Universitaria "Rodrigo Facio", San Pedro de Montes de Oca, San José, Costa Rica
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Tsuji K, Ohgushi T. Florivory indirectly decreases the plant reproductive output through changes in pollinator attraction. Ecol Evol 2018; 8:2993-3001. [PMID: 29531712 PMCID: PMC5838046 DOI: 10.1002/ece3.3921] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 01/07/2018] [Accepted: 01/16/2018] [Indexed: 11/28/2022] Open
Abstract
Species often interact indirectly with each other via their traits. There is increasing appreciation of trait-mediated indirect effects linking multiple interactions. Flowers interact with both pollinators and floral herbivores, and the flower-pollinator interaction may be modified by indirect effects of floral herbivores (i.e., florivores) on flower traits such as flower size attracting pollinators. To explore whether flower size affects the flower-pollinator interaction, we used Eurya japonica flowers. We examined whether artificial florivory decreased fruit and seed production, and also whether flower size affected florivory and the number of floral visitors. The petal removal treatment (i.e., artificial florivory) showed approximately 50% reduction in both fruit and seed set in natural pollination but not in artificial pollination. Furthermore, flower size increased the number of floral visitors, although it did not affect the frequency of florivory. Our results demonstrate that petal removal indirectly decreased 75% of female reproductive output via decreased flower visits by pollinators and that flower size mediated indirect interactions between florivory and floral visitors.
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Affiliation(s)
- Kaoru Tsuji
- Center of Ecological ResearchKyoto UniversityOtsuShigaJapan
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Sapir Y, Karoly K, Koelling VA, Sahli HF, Knapczyk FN, Conner JK. Effect of expanded variation in anther position on pollinator visitation to wild radish, Raphanus raphanistrum. ANNALS OF BOTANY 2017; 120:665-672. [PMID: 28531293 PMCID: PMC5714124 DOI: 10.1093/aob/mcx041] [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: 11/26/2016] [Revised: 02/04/2017] [Accepted: 03/17/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND AIMS Plant-pollinator interactions shape the evolution of flowers. Floral attraction and reward traits have often been shown to affect pollinator behaviour, but the possible effect of efficiency traits on visitation behaviour has rarely been addressed. Anther position, usually considered a trait that influences efficiency of pollen deposition on pollinators, was tested here for its effect on pollinator visitation rates and visit duration in flowers of wild radish, Raphanus raphanistrum . METHODS Artificial selection lines from two experiments that expanded the naturally occurring phenotypic variation in anther position were used. In one experiment, plant lines were selected either to increase or to decrease anther exsertion. The other experiment decreased anther dimorphism, which resulted in increased short stamen exsertion. The hypothesis was that increased exsertion would increase visitation of pollen foragers due to increased visual attraction. Another hypothesis was that exsertion of anthers above the corolla would interfere with nectar foragers and increase the duration of visit per flower. KEY RESULTS In the exsertion selection experiment, increased exsertion of both short and long stamens resulted in an increased number of fly visits per plant, and in the dimorphism experiment bee visits increased with increased short stamen exsertion. The duration of visits of nectar feeders declined significantly with increasing long stamen exsertion, which was opposite to the hypothesis. CONCLUSIONS Until now, anther position was considered to be an efficiency trait to enhance pollen uptake and deposition. Anther position in wild radish is shown here also to have an ecological significance in attracting pollen foragers. This study suggests an additional adaptive role for anther position beyond efficiency, and highlights the multiple ecological functions of floral traits in plant-pollinator interactions.
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Affiliation(s)
- Yuval Sapir
- The Botanical Garden, School of Plant Sciences and Food Security, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Keith Karoly
- Biology Department, Reed College, 3203 S.E. Woodstock Boulevard, Portland, OR 97202, USA
| | - Vanessa A Koelling
- Biology Department, Reed College, 3203 S.E. Woodstock Boulevard, Portland, OR 97202, USA
| | - Heather F Sahli
- Kellogg Biological Station and Department of Plant Biology, Michigan State University, 3700 East Gull Lake Drive, Hickory Corners, MI 49060, USA
| | - Frances N Knapczyk
- Kellogg Biological Station and Department of Plant Biology, Michigan State University, 3700 East Gull Lake Drive, Hickory Corners, MI 49060, USA
| | - Jeffrey K Conner
- Kellogg Biological Station and Department of Plant Biology, Michigan State University, 3700 East Gull Lake Drive, Hickory Corners, MI 49060, USA
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Jadeja S, Tenhumberg B. Phytophagous insect oviposition shifts in response to probability of flower abortion owing to the presence of basal fruits. Ecol Evol 2017; 7:8770-8779. [PMID: 29152176 PMCID: PMC5677471 DOI: 10.1002/ece3.3426] [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: 01/18/2017] [Revised: 08/22/2017] [Accepted: 08/25/2017] [Indexed: 11/09/2022] Open
Abstract
Phytophagous insects use a wide range of indicators or associated cues to avoid laying eggs in sites where offspring survival is low. For insects that lay eggs in flowers, these unsuitable sites may be created by the host plant's resource allocation to flowers. In the sequentially flowering host plant, Yucca glauca, late‐opening distal flowers are more likely to be aborted in the presence of already‐initiated basal fruits because they are strong resource sinks. If flowers are aborted, all eggs of the phytophagous insect, Tegeticula yuccasella, within the flower die. We used the phytophagous insect T. yuccasella that lays eggs in and pollinates host plant Y. glauca flowers to test the hypothesis that phytophagous insect females are less likely to invest eggs in host plant flowers if basal fruits are present because they are more likely to be aborted. We also investigated potential predictors of arrival of T. yuccasella at inflorescences at the onset of flowering. These factors may influence a phytophagous insect's decisions to select oviposition sites. We carried out a behavioral experiment using wild‐caught T. yuccasella females on manipulated inflorescences with distal flowers with basal fruits and without fruits. As potential predictors of T. yuccasella arriving at inflorescences, we used floral display size and day of onset of flowering. In support of our hypothesis, our experimental results showed that T. yuccasella was significantly less likely to oviposit in distal flowers on inflorescences with basal fruits. We also found that T. yuccasella arrival was higher at inflorescences with larger floral display size and earlier in the flowering season. These findings uncover a novel indicator of unsuitable oviposition sites—the presence of basal fruits, that phytophagous insects use to make oviposition decisions. Further, our study contributes to the growing body of evidence that shows that females prefer sites that increase the probability of survival of their offspring.
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Affiliation(s)
- Shivani Jadeja
- School of Biological Sciences; University of Nebraska; Lincoln NE USA
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Burkhardt A, Ridenhour BJ, Delph LF, Bernasconi G. The contribution of a pollinating seed predator to selection on Silene latifolia females. J Evol Biol 2011; 25:461-72. [PMID: 22168583 DOI: 10.1111/j.1420-9101.2011.02436.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Interactions, antagonistic or mutualistic, can exert selection on plant traits. We explored the role of Hadena bicruris, a pollinating seed predator, as a selective agent on its host, the dioecious plant Silene latifolia. We exposed females from artificial-selection lines (many, small flowers (SF) vs. few, large flowers (LF)) to this moth. Infestation did not differ significantly between lines, but the odds of attacked fruits aborting were higher in SF females. We partitioned selection between that caused by moth attack and that resulting from all other factors. In both lines, selection via moth attack for fewer, smaller flowers contrasted with selection via other factors for more flowers. In LF females, selection via the two components was strongest and selection via moth attack also favoured increased fruit abortion. This suggests that the moths act as more of a selective force on flower size and number via their predating than their pollinating role.
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Affiliation(s)
- A Burkhardt
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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Forrest JRK, Ogilvie JE, Gorischek AM, Thomson JD. Seasonal change in a pollinator community and the maintenance of style length variation in Mertensia fusiformis (Boraginaceae). ANNALS OF BOTANY 2011; 108:1-12. [PMID: 21515606 PMCID: PMC3119607 DOI: 10.1093/aob/mcr093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/09/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS In sub-alpine habitats, patchiness in snowpack produces marked, small-scale variation in flowering phenology. Plants in early- and late-melting patches are therefore likely to experience very different conditions during their flowering periods. Mertensia fusiformis is an early-flowering perennial that varies conspicuously in style length within and among populations. The hypothesis that style length represents an adaptation to local flowering time was tested. Specifically, it was hypothesized that lower air temperatures and higher frost risk would favour short-styled plants (with stigmas more shielded by corollas) in early-flowering patches, but that the pollen-collecting behaviour of flower visitors in late-flowering patches would favour long-styled plants. METHODS Floral morphology was measured, temperatures were monitored and pollinators were observed in several matched pairs of early and late populations. To evaluate effects of cold temperatures on plants of different style lengths, experimental pollinations were conducted during mornings (warm) and evenings (cool), and on flowers that either had or had not experienced a prior frost. The effectiveness of different pollinators was quantified as seed set following single visits to plants with relatively short or long styles. KEY RESULTS Late-flowering populations experienced warmer temperatures than early-flowering populations and a different suite of pollinators. Nectar-foraging bumble-bee queens and male solitary bees predominated in early populations, whereas pollen-collecting female solitary bees were more numerous in later sites. Pollinators differed significantly in their abilities to transfer pollen to stigmas at different heights, in accordance with our prediction. However, temperature and frost sensitivity did not differ between long- and short-styled plants. Although plants in late-flowering patches tended to have longer styles than those in early patches, this difference was not consistent. CONCLUSIONS Seasonal change in pollinator-mediated selection on style length may help maintain variation in this trait in M. fusiformis, but adaptation to local flowering time is not apparent. The prevalence of short styles in these populations requires further explanation.
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Affiliation(s)
- Jessica R K Forrest
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.
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Berjano R, Arista M, Ortiz PL, Talavera S. Persistently low fruiting success in the Mediterranean pipevine Aristolochia baetica (Aristolochiaceae): a multi-year study. PLANT BIOLOGY (STUTTGART, GERMANY) 2011; 13 Suppl 1:109-117. [PMID: 21134094 DOI: 10.1111/j.1438-8677.2010.00396.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Low fruit set is common in many plant species and may be caused by a variety of factors, such as predation, resource limitation or deficient pollination, or it may be an evolutionary strategy. In this paper, we investigate factors that affect fruit set in Aristolochia baetica (Aristolochiaceae), a Mediterranean pipevine found in southwest Spain. Fruit production was monitored in two populations over 4 years (2002-2005), and the causes of flower or fruit loss were determined. Experimental hand-pollinations were performed, and germinated pollen grains on the stigmas of open-pollinated flowers were quantified. Fruit set was always very low (4-14%). Floral abscission initially reduced reproductive output by more than 50%; then herbivory (6-12%) and fruit abortion (8-26%) caused further reductions. Given that the number of efficiently pollinated flowers was always higher than that of ripe fruits, and that xenogamous hand-pollination did not increase fruit set in relation to open-pollination, the final fruit production of A. baetica seems not to be pollen-limited. Fruit abortion of effectively pollinated flowers supports the idea that resource availability limits fruit set. In A. baetica, fruit abortion could lead to mate selection of the best quality fruits. Moreover, the initiated fruits that finally abort could also satiate predators, contributing to increase progeny fitness.
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Affiliation(s)
- R Berjano
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain.
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Vargas P, Ornosa C, Ortiz-Sánchez FJ, Arroyo J. Is the occluded corolla ofAntirrhinumbee-specialized? J NAT HIST 2010. [DOI: 10.1080/00222930903383552] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Varga S, Kytöviita MM. Gender dimorphism and mycorrhizal symbiosis affect floral visitors and reproductive output in Geranium sylvaticum. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2010.01708.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Cosacov A, Nattero J, Cocucci AA. Variation of pollinator assemblages and pollen limitation in a locally specialized system: the oil-producing Nierembergia linariifolia (Solanaceae). ANNALS OF BOTANY 2008; 102:723-34. [PMID: 18765440 PMCID: PMC2712377 DOI: 10.1093/aob/mcn154] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 06/17/2008] [Accepted: 07/14/2008] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Few studies have examined the dynamics of specialist plant-pollinator interactions at a geographical scale. This knowledge is crucial for a more general evolutionary and ecological understanding of specialized plant-pollinator systems. In the present study, variations in pollinator activity, assemblage composition and pollen limitation were explored in the oil-producing species Nierembergia linariifolia (Solanaceae). METHODS Pollen limitation in fruit and seed production was analysed by supplementary hand pollination in five wild populations. Pollinator activity and identity were recorded while carrying out supplementary pollination to assess the effect of pollinators on the degree of pollen limitation. In two populations, pollen limitation was discriminated into quantitative and qualitative components by comparing supplementation and hand cross-pollination in fruit set and seed set. The effect of flower number per plant on the number of flowers pollinated per visitor per visit to a plant was examined in one of these populations as a possible cause of low-quality pollination by increasing geitonogamy. RESULTS AND CONCLUSIONS Although pollen limitation was evident along time and space, differences in magnitude were detected among populations and years that were greatly explained by pollinator activity, which was significantly different across populations. Floral display size had a significant effect on the visitation rate per flower. Limitation by quality clearly affected one population presumably due to a high proportion of geitonogamous pollen. The great inter-population variation in plant-pollinator interaction (both in pollinator assemblages composition and pollinator activity) and fitness consequences, suggests that this system should be viewed as a mosaic of locally selective processes and locally specialized interactions.
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Affiliation(s)
- Andrea Cosacov
- Laboratorio de Biología Floral, IMBIV (CONICET-UNCba), Casilla de Correo 495, CP 5000, Córdoba, Argentina.
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Buide ML. Disentangling the causes of intrainflorescence variation in floral traits and fecundity in the hermaphrodite Silene acutifolia. AMERICAN JOURNAL OF BOTANY 2008; 95:490-497. [PMID: 21632374 DOI: 10.3732/ajb.95.4.490] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Inflorescence architecture directly determines variations in floral traits and fecundity. Disentangling these patterns of variation is crucial to understanding intraplant variation, which sometimes is directly attributed to competition for resources with developing fruits. The dichasial cymes of Silene acutifolia were experimentally manipulated in the field to analyze whether the declines in petal size, ovule number, fruit set, and seed/ovule ratio along the inflorescence are constrained by ontogenetic development or are phenotypically plastic in response to environmental changes. At the same time, the level of pollen deficit was measured on different positions of the dichasia. The results showed clearly that all measured variables were more influenced by architecture than by resource competition with developing fruits; the removal of central (basal) and primary lateral flowers in the dichasia did not increase either the measures of floral characters or fecundity. On the other hand, although most of the decline in fecundity was due to architectural effects, there was also a pollen limitation, dependent to some degree on inflorescence position, which was probably due to lower pollen availability in the population when secondary flowers are in the female phase.
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Affiliation(s)
- M Luisa Buide
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide 41013 Sevilla, Spain
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