1
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Aljiboury AA, Friedman J. Mating and fitness consequences of variation in male allocation in a wind-pollinated plant. Evolution 2022; 76:1762-1775. [PMID: 35765717 DOI: 10.1111/evo.14544] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/26/2022] [Accepted: 05/04/2022] [Indexed: 01/22/2023]
Abstract
In hermaphrodites, the allocation of resources to each sex function can influence fitness through mating success. A prediction that arises from sex allocation theory is that in wind-pollinated plants, male fitness should increase linearly with investment of resources into male function but there have been few empirical tests of this prediction. In a field experiment, we experimentally manipulated allocation to male function in Ambrosia artemisiifolia (common ragweed) and measured mating success in contrasting phenotypes using genetic markers. We investigated the effects of morphological traits and flowering phenology on male siring success, and on the diversity of mates. Our results provide evidence for a linear relation between allocation to male function, mating, and fitness. We find earlier onset of male flowering time increases reproductive success, whereas later flowering increases the probability of mating with diverse individuals. Our study is among the first empirical tests of the prediction of linear male fitness returns in wind-pollinated plants and emphasizes the importance of a large investment into male function by wind-pollinated plants and mating consequences of temporal variation in sex allocation.
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Affiliation(s)
- Abrar A Aljiboury
- Department of Biology, Syracuse University, Syracuse, New York, 13244
| | - Jannice Friedman
- Department of Biology, Syracuse University, Syracuse, New York, 13244.,Department of Biology, Queen's University, Kingston, Canada, K7L 3N6
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2
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Toji T, Ishimoto N, Itino T. Seasonal change of flower sex ratio and pollinator dynamics in three reproductive ecotypes of protandrous plant. Ecosphere 2020. [DOI: 10.1002/ecs2.3251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Tsubasa Toji
- Department of Science and Technology Graduate School of Medicine, Science and Technology Shinshu University Matsumoto3‐1‐1 AsahiNagano390‐8621Japan
| | - Natsumi Ishimoto
- Faculty of Science Shinshu University Matsumoto3‐1‐1 AsahiNagano390‐8621Japan
| | - Takao Itino
- Faculty of Science Shinshu University Matsumoto3‐1‐1 AsahiNagano390‐8621Japan
- Institute of Mountain Science Shinshu University Matsumoto3‐1‐1 AsahiNagano390‐8621Japan
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3
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Schoen DJ, Johnson MTJ, Wright SI. The ecology, evolution, and genetics of plant reproductive systems. THE NEW PHYTOLOGIST 2019; 224:999-1004. [PMID: 31631365 DOI: 10.1111/nph.16222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Daniel J Schoen
- Department of Biology, McGill University, Montreal, QC, H3A 1B1, Canada
| | - Marc T J Johnson
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
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4
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Ning Y, Wu GJ, Ma H, Guo JL, Zhang MY, Li W, Wang YF, Duoerji SL. Contrasting fine-scale genetic structure of two sympatric clonal plants in an alpine swampy meadow featured by tussocks. PLoS One 2018; 13:e0209572. [PMID: 30576376 PMCID: PMC6303067 DOI: 10.1371/journal.pone.0209572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 12/07/2018] [Indexed: 11/18/2022] Open
Abstract
Tussocks are unique vegetation structures in wetlands. Many tussock species mainly reproduce by clonal growth, resulting in genetically identical offspring distributed in various spatial patterns. These fine-scale patterns could influence mating patterns and thus the long-term evolution of wetland plants. Here, we contribute the first genetic and clonal structures of two key species in alpine wetlands on the Qinghai–Tibet Plateau, Kobresia tibetica and Blysmus sinocompressus, using > 5000 SNPs identified by 2b-RAD sequencing. The tussock-building species, K. tibetica, has a phalanx (clumping) growth form, but different genets could co-occur within the tussocks, indicating that it is not proper to treat a tussock as one genetic individual. Phalanx growth does not necessarily lead to increased inbreeding in K. tibetica. B. sinocompressus has a guerilla (spreading) growth form, with the largest detected clone size being 18.32 m, but genets at the local scale tend to be inbred offspring. Our results highlight that the combination of clone expansion and seedling recruitment facilitates the contemporary advantage of B. sinocompressus, but its evolutionary potential is limited by the input genetic load of the original genets. The tussocks of K. tibetica are more diverse and a valuable genetic legacy of former well-developed wet meadows, and they are worthy of conservation attention.
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Affiliation(s)
- Yu Ning
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
| | - Gao-Jie Wu
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
| | - Hua Ma
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
- Zoige Alpine Wetland Ecosystem Research Station, Zoige, Sichuan, China
| | - Ju-Lan Guo
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
- Zoige Alpine Wetland Ecosystem Research Station, Zoige, Sichuan, China
| | - Man-Yin Zhang
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Wetland Services and Restoration, Chinese Academy of Forestry, Beijing, China
| | - Wei Li
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Wetland Services and Restoration, Chinese Academy of Forestry, Beijing, China
| | - Yi-Fei Wang
- Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China
- Zoige Alpine Wetland Ecosystem Research Station, Zoige, Sichuan, China
- * E-mail:
| | - Suo-Lang Duoerji
- Administration of Zoige Wetland National Nature Preserve, Zoige, Sichuan, China
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5
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Bees are supplementary pollinators of self-compatible chiropterophilous durian. JOURNAL OF TROPICAL ECOLOGY 2018. [DOI: 10.1017/s0266467418000019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Abstract:Nocturnally foraging insects may be supplementary pollinators to chiropterophilous plant species when bats are scarce. Given that insects are much smaller than bats, they may be more effective at transferring pollen for plant species with similar stamen and pistil lengths, such as the ‘Monthong’ durian cultivar. The present study clarifies the role of insects in pollinating the ‘Monthong’ cultivar by examining the floral biology, conducting pollination treatments on 19 trees and observing floral visitors in southern Thailand. Stigmas were receptive by 17h00, and over 50% of ‘Monthong’ anthers had dehisced by 17h30. Several bee species began foraging on flowers during the late afternoon, and the giant honey bee (Apis dorsata) continued to visit throughout the night. Our results show that at 4 wk after pollination, the highest fruit set occurred from hand-crossed pollination (13.5%), followed by open pollination (5.5%), insect pollination (3.3%) and automatic autogamy (2.0%), indicating that this cultivar is highly self-incompatible. Moreover, insects appear to be important pollinators of ‘Monthong’ durian in areas where nectar bats visit infrequently. One bee species in particular,Apis dorsata, commonly foraged on flowers at dusk and appears to be the most effective insect pollinator of durian. Our findings highlight that nocturnally foraging bees are capable of securing pollination for night-blooming plant taxa, even those typically considered to be bat-pollinated.
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6
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Parker AJ, Williams NM, Thomson JD. Geographic patterns and pollination ecotypes inClaytonia virginica. Evolution 2017; 72:202-210. [DOI: 10.1111/evo.13381] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Alison J. Parker
- University of Toronto, Department of Ecology and Evolutionary Biology; Toronto ON M5S 3G5 Canada
| | - Neal M. Williams
- University of California-Davis, Department of Entomology; Davis California 95616
| | - James D. Thomson
- University of Toronto, Department of Ecology and Evolutionary Biology; Toronto ON M5S 3G5 Canada
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7
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Emms SK, Stratton DA, Snow AA. THE EFFECT OF INFLORESCENCE SIZE ON MALE FITNESS: EXPERIMENTAL TESTS IN THE ANDROMONOECIOUS LILY, ZIGADENUS PANICULATUS. Evolution 2017; 51:1481-1489. [PMID: 28568611 DOI: 10.1111/j.1558-5646.1997.tb01471.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/1996] [Accepted: 05/16/1997] [Indexed: 11/26/2022]
Abstract
We studied the relationship between inflorescence size and male fitness in the andromonoecious lily Zigadenus paniculatus, using experimentally manipulated inflorescences to eliminate possible correlations between flower number, resource availability, and other floral traits. Allozyme markers were used to determine the siring success of large versus small plants in 14 arrays of plants, each array containing five large and five small plants. The inflorescence size of small plants was held constant both within and among arrays; the size of large plants was held constant within an array but was varied among arrays. Large plants sired more than half the seeds in 12 of the 14 arrays, and significantly more than half in six of these 12. However, in eight of the arrays, large plants sired significantly fewer seeds than expected on the basis of their size advantage. Furthermore, there was no significant relationship between relative size and relative siring success in comparisons among arrays. A maximum-likelihood model estimated that 28% of seeds were sired by imported pollen, with 95% confidence limits of 13% and 50%. Within these limits, high import rates tended to mask the relative success of large plants in several arrays. These results suggest that the evolution of inflorescence size in Z. paniculatus is at least partly driven by selection for increased male success, assuming genetic variation for flower number. However, the data also support a growing body of evidence that estimates of male fitness in plants can be highly variable. We discuss the sources of this variability and the possible effects of inflorescence design on the relationship between inflorescence size and fitness.
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Affiliation(s)
- S K Emms
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544-1003.,Department of Plant Biology, Ohio State University, 1735 Neil Avenue, Columbus, Ohio, 43210-1293
| | - D A Stratton
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544-1003
| | - A A Snow
- Department of Plant Biology, Ohio State University, 1735 Neil Avenue, Columbus, Ohio, 43210-1293
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8
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Kohn JR, Barrett SCH. POLLEN DISCOUNTING AND THE SPREAD OF A SELFING VARIANT IN TRISTYLOUS EICHHORNIA PANICULATA: EVIDENCE FROM EXPERIMENTAL POPULATIONS. Evolution 2017; 48:1576-1594. [PMID: 28568426 DOI: 10.1111/j.1558-5646.1994.tb02197.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/1993] [Accepted: 12/07/1993] [Indexed: 11/28/2022]
Abstract
Floral traits that increase self-fertilization are expected to spread unless countered by the effects of inbreeding depression, pollen discounting (reduced outcross pollen success by individuals with increased rates of self-fertilization), or both. Few studies have attempted to measure pollen discounting because to do so requires estimating the male outcrossing success of plants that differ in selfing rate. In natural populations of tristylous Eichhornia paniculata, selfing variants of the mid-styled morph are usually absent from populations containing all three style morphs but often predominate in nontrimorphic populations. We used experimental garden populations of genetically marked plants to investigate whether the effects of population morph structure on relative gamete transmission by unmodified (M) and selfing variants (M') of the mid-styled morph could explain their observed distribution. Transmission through ovules and self and outcross pollen by plants of the M and M' morphs were compared under trimorphic, dimorphic (S morph absent), and monomorphic (L and S morphs absent) population structures. Neither population structure nor floral morphology affected female reproductive success, but both had strong effects on the relative transmission of male gametes. The frequency of self-fertilization in the M' morph was consistently higher than that of the M morph under all morph structures, and the frequency of self-fertilization by both morphs increased as morph diversity of experimental populations declined. In trimorphic populations, total transmission by the M and M' morphs did not differ. The small, nonsignificant increase in selfing by the M' relative to the M morph was balanced by decreased outcross siring success, particularly on the S morph. In populations lacking the S morph, male gamete transmission by the M' morph was approximately 1.5 times greater than that by the M morph because of both increased selfing and increased success through outcross pollen donation. Therefore, gamete transmission strongly favored the M' morph only in the absence of the S morph, a result consistent with the distribution of the M' morph in nature. This study indicates that floral traits that alter the selfing rate can have large and context-dependent influences on outcross pollen donation.
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Affiliation(s)
- Joshua R Kohn
- University of California at San Diego, Department of Biology 0116, La Jolla, California, 92093
| | - Spencer C H Barrett
- Department of Botany, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
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9
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Kohn JR, Barrett SCH. EXPERIMENTAL STUDIES ON THE FUNCTIONAL SIGNIFICANCE OF HETEROSTYLY. Evolution 2017; 46:43-55. [PMID: 28564966 DOI: 10.1111/j.1558-5646.1992.tb01983.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/1990] [Accepted: 06/27/1991] [Indexed: 11/27/2022]
Abstract
Heterostyly has been viewed as both an antiselfing device and a mechanism that increases the proficiency of pollen transfer between plants. We used experimental manipulation of the morph structure of garden populations of self-compatible, tristylous Eichhornia paniculata to investigate the function of floral polymorphism. Outcrossing rates (t), levels of intermorph mating (d), and morph-specific male and female reproductive success were compared in replicate trimorphic and monomorphic populations. In trimorphic populations, t and d averaged 0.81 (2 SE = 0.03) and 0.77 (2 SE = 0.03) respectively, with no difference in either parameter among morphs. Ninety-five percent of outcrossed seeds were therefore the result of intermorph fertilizations. Male reproductive success of the long-styled morph was low, especially in comparison with plants of the short-styled morph. Outcrossing rates for each morph were higher in trimorphic than monomorphic populations where t averaged 0.71 (2 SE = 0.01), 0.30 (2 SE = 0.04) and 0.43 (2 SE = 0.1) for the long-, mid-, and short-styled morphs, respectively. Seed set was lower in monomorphic populations, particularly those composed of the L morph, reflecting reduced pollen deposition. Floral polymorphism therefore increased both outcrossing rate and fecundity but the magnitude of the differences varied among morphs. If the ancestral condition in heterostylous groups resembled the L morph, as has been suggested, data from this study suggests that the selective basis for the establishment of floral polymorphism could have been increased pollen transfer rather than higher levels of outcrossing.
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Affiliation(s)
- Joshua R Kohn
- Department of Botany, University of Toronto, Toronto, ON, M5S 3B2, CANADA
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10
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Thomson JD, Thomson BA. DISPERSAL OF ERYTHRONIUM GRANDIFLORUM POLLEN BY BUMBLEBEES: IMPLICATIONS FOR GENE FLOW AND REPRODUCTIVE SUCCESS. Evolution 2017; 43:657-661. [PMID: 28568396 DOI: 10.1111/j.1558-5646.1989.tb04261.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/1988] [Accepted: 12/06/1988] [Indexed: 11/27/2022]
Affiliation(s)
- James D Thomson
- Department of Ecology and Evolution, State University of New York, Stony Brook, NY, 11794.,Rocky Mountain Biological Laboratory, P.O. Box 519, Crested Butte, CO, 81224
| | - Barbara A Thomson
- Department of Ecology and Evolution, State University of New York, Stony Brook, NY, 11794.,Rocky Mountain Biological Laboratory, P.O. Box 519, Crested Butte, CO, 81224
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11
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Mazer SJ, Delesalle VA, Neal PR. RESPONSES OF FLORAL TRAITS TO SELECTION ON PRIMARY SEXUAL INVESTMENT IN SPERGULARIA MARINA: THE BATTLE BETWEEN THE SEXES. Evolution 2017; 53:717-731. [PMID: 28565623 DOI: 10.1111/j.1558-5646.1999.tb05366.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/1998] [Accepted: 12/16/1998] [Indexed: 11/28/2022]
Abstract
Two widespread assumptions underlie theoretical models of the evolution of sex allocation in hermaphroditic species: (1) resource allocations to male and female function are heritable; and (2) there is an intrinsic, genetically based negative correlation between male and female reproductive function. These assumptions have not been adequately tested in wild species, although a few studies have detected either genetic variation in pollen and ovule production per flower or evidence of trade-offs between male and female investment at the whole plant level. It may also be argued, however, that in highly autogamous, perfect-flowered plant taxa that exhibit genetic variation in gamete production, strong stabilizing selection for an efficient pollen:ovule ratio should result in a positive correlation among genotypes with respect to mean ovule and mean pollen production per flower. Here we report the results of a three-generation artificial selection experiment conducted on a greenhouse population of the autogamous annual plant Spergularia marina. Starting with a base population of 1200 individuals, we conducted intense mass selection for two generations, creating four selected lines (high and low ovule production per flower; high and low anther production per flower) and a control line. By examining the direct and correlated responses of several floral traits to selection on gamete production per flower, we evaluated the expectations that primary sexual investment would exhibit heritable variation and that resource-sharing, variation in resource-garnering ability, or developmental constraints mold the genetic correlations expressed among floral organs. The observed direct and correlated responses to selection on male and female gamete production revealed significant heritabilities of both ovule and anther production per flower and a significant negative genetic correlation between them. When plants were selected for increased ovules per flower over two generations, ovule production increased and anther production declined relative to the control line. Among plants selected for decreased anthers per flower, we observed a decline in anther production and an increase in ovule production relative to the control line. In contrast, the lines selected for low ovules per flower and for high anthers per flower exhibited no evidence for significant genetic correlations between male and female primary investment. Correlated responses to selection also indicate a genetically based negative correlation between the production of normal versus developmentally abnormal anthers (staminoid organs); a positive correlation between the production of ovules versus staminoid organs; and a positive correlation between the production of anthers and petals. The negative relationship between male versus female primary investment supports classical sex allocation theory, although the asymmetrical correlated responses to selection indicate that this relationship is not always expressed.
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Affiliation(s)
- Susan J Mazer
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, 93106
| | | | - Paul R Neal
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, 93106
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12
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Mazer SJ, Delesalle VA. TEMPORAL INSTABILITY OF GENETIC COMPONENTS OF FLORAL TRAIT VARIATION: MATERNAL FAMILY AND POPULATION EFFECTS IN SPERGULARIA MARINA (CARYOPHYLLACEAE). Evolution 2017; 50:2509-2515. [PMID: 28565669 DOI: 10.1111/j.1558-5646.1996.tb03637.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/1996] [Accepted: 04/05/1996] [Indexed: 11/28/2022]
Affiliation(s)
- Susan J Mazer
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, 93106
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13
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Xiao CL, Deng H, Xiang GJ, Luguba KE, Guo YH, Yang CF. Sequential stamen maturation and movement in a protandrous herb: mechanisms increasing pollination efficiency and reducing sexual interference. AOB PLANTS 2017; 9:plx019. [PMID: 28698790 PMCID: PMC5499893 DOI: 10.1093/aobpla/plx019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 05/21/2017] [Accepted: 05/24/2017] [Indexed: 06/02/2023]
Abstract
Successive stamen movement directly controls pollen presentation schedules through sequential stamen maturation and changes the extent of herkogamy by altering the positions of sexual organs. However, the implications of such movements in terms of pollination are not well understood. Pollen presentation theory predicts that staggered pollen presentation should be favoured when plants are subject to diminishing returns on pollen transfer. Herkogamy on the other hand, has been interpreted as an adaptive trait that reduces sexual interference in hermaphrodite flowers. In this study, we conducted floral manipulations to determine the function of successive stamen movement in pollen transfer. By artificially manipulating the flowers to present two anthers simultaneously in the floral centre, we attempted to investigate whether changes in the anther presentation strategy affect pollen removal, deposition and the efficiency of pollinators. Compared with the natural treatment, the pollen transfer efficiency of halictid bees decreased significantly when the flowers were manipulated to present two anthers simultaneously. Although the presentation of two anthers simultaneously led to a similar pollen removal rate, there was a significant reduction in pollen deposition on neighbouring stigmas. To evaluate the effect of movement herkogamy on pollen export and deposition and seed set, the flowers were manipulated with or without the movement of stamen bending out from the floral centre. Pollen export decreased significantly when the central anther was moved away from the pistil, and pollen deposition and seed set declined significantly when the five spent anthers were retained on the pistil. Our study provides good support for the pollen presentation theory and provides direct experimental evidence that successive stamen movement could increase pollen transfer efficiency by sequential stamen maturation. Moreover, movement herkogamy promotes pollen export, deposition and seed set, and could therefore be regarded as an effective mechanism to reduce interference between male and female functions.
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Affiliation(s)
- Chang-Long Xiao
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Hui Deng
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Gan-Ju Xiang
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Kadiori Edwin Luguba
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, 430074 Wuhan, China
| | - You-Hao Guo
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Chun-Feng Yang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, 430074 Wuhan, China
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14
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Austen EJ, Weis AE. Estimating selection through male fitness: three complementary methods illuminate the nature and causes of selection on flowering time. Proc Biol Sci 2016; 283:20152635. [PMID: 26911957 DOI: 10.1098/rspb.2015.2635] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Our understanding of selection through male fitness is limited by the resource demands and indirect nature of the best available genetic techniques. Applying complementary, independent approaches to this problem can help clarify evolution through male function. We applied three methods to estimate selection on flowering time through male fitness in experimental populations of the annual plant Brassica rapa: (i) an analysis of mating opportunity based on flower production schedules, (ii) genetic paternity analysis, and (iii) a novel approach based on principles of experimental evolution. Selection differentials estimated by the first method disagreed with those estimated by the other two, indicating that mating opportunity was not the principal driver of selection on flowering time. The genetic and experimental evolution methods exhibited striking agreement overall, but a slight discrepancy between the two suggested that negative environmental covariance between age at flowering and male fitness may have contributed to phenotypic selection. Together, the three methods enriched our understanding of selection on flowering time, from mating opportunity to phenotypic selection to evolutionary response. The novel experimental evolution method may provide a means of examining selection through male fitness when genetic paternity analysis is not possible.
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Affiliation(s)
- Emily J Austen
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2 Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
| | - Arthur E Weis
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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15
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Effects of population size on synchronous display of female and male flowers and reproductive output in two monoecious Sagittaria species. PLoS One 2012; 7:e48731. [PMID: 23119094 PMCID: PMC3485334 DOI: 10.1371/journal.pone.0048731] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 09/28/2012] [Indexed: 11/28/2022] Open
Abstract
Background Flowering synchrony and floral sex ratio have the potential to influence the mating opportunities and reproductive success through female function. Here, we examine the variances in synchronous display of female and male function, ratio of male to female flowers per day and subsequently reproductive output in small populations of two monoecious plants, Sagittaria trifolia and Sagittaria graminea. Methodology/Principal Finding We created plant populations of size 2, 4, 10 and 20 and recorded the daily number of blooming male and female flowers per plant to determine daily floral display, flowering synchrony index and ratio of male to female flowers per day. We also harvested the fruits, counted the seeds and calculated the number of fruits and seeds per flower to measure reproductive success through female function. There is less overlap in flowering time of female and male function in smaller populations than in larger populations. Most importantly, we found that male-biased floral sex ratio and imbalanced display period of female and male function for individual plant can lead to a population-size-dependent ratio of male to female flowers per day. Increasing ratio of male to female flowers per day was generally associated with a greater percentage of fruit production. Conclusions/Significance Our results highlight the importance of flowering synchrony of female and male function and population-size-dependent ratio of male to female flowers per day for female reproductive success. This finding improves our understanding of a mechanism that reduces reproductive success in small populations.
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16
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Narbona E, Ortiz PL, Arista M. Linking self-incompatibility, dichogamy, and flowering synchrony in two Euphorbia species: alternative mechanisms for avoiding self-fertilization? PLoS One 2011; 6:e20668. [PMID: 21674062 PMCID: PMC3107240 DOI: 10.1371/journal.pone.0020668] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 05/08/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Plant species have several mechanisms to avoid selfing such as dichogamy or a self-incompatibility response. Dichogamy in a single flower may reduce autogamy but, to avoid geitonogamy, plants must show flowering synchronization among all their flowers (i.e. synchronous dichogamy). It is hypothesized that one species would not simultaneously show synchronous dichogamy and self-incompatibility because they are redundant mechanisms to reduce selfing; however, this has not been accurately assessed. METHODOLOGY/PRINCIPAL FINDINGS This expectation was tested over two years in two natural populations of the closely related Mediterranean spurges Euphorbia boetica and E. nicaeensis, which completely avoid autogamy by protogyny at the cyathia level. Both spurges showed a high population synchrony (Z<79), and their inflorescences flower synchronously. In E. nicaeensis, there was no overlap among the cyathia in anthesis of successive inflorescence levels and the overlap between sexual phases of cyathia of the same inflorescence level was uncommon (4-16%). In contrast, E. boetica showed a high overlap among consecutive inflorescence levels (74-93%) and between sexual phases of cyathia of the same inflorescence level (48-80%). The flowering pattern of both spurges was consistent in the two populations and over the two successive years. A hand-pollination experiment demonstrated that E. nicaeensis was strictly self-compatible whereas E. boetica was partially self-incompatible. CONCLUSIONS/SIGNIFICANCE We propose that the complex pattern of synchronized protogyny in E. nicaeensis prevents geitonogamous crosses and, consequently, avoids selfing and inbreeding depression. In E. boetica, a high probability of geitonogamous crosses may occur but, alternatively, this plant escapes selfing through a self-incompatibility response. We posit that synchronous dichogamy and physiological self-incompatibility do not co-occur in the same species because each process is sufficiently effective in avoiding self-fertilization.
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Affiliation(s)
- Eduardo Narbona
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain.
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Glaettli M, Barrett SCH. Pollinator responses to variation in floral display and flower size in dioecious Sagittaria latifolia (Alismataceae). THE NEW PHYTOLOGIST 2008; 179:1193-1201. [PMID: 18627490 DOI: 10.1111/j.1469-8137.2008.02532.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In animal-pollinated plants with unisexual flowers, sexual dimorphism in floral traits may be the consequence of pollinator-mediated selection. Experimental investigations of the effects of variation in flower size and floral display on pollinator visitation can provide insights into the evolution of floral dimorphism in dioecious plants. Here, we investigated pollinator responses to experimental arrays of dioecious Sagittaria latifolia in which we manipulated floral display and flower size. We also examined whether there were changes in pollinator visitation with increasing dimorphism in flower size. In S. latifolia, males have larger flowers and smaller floral displays than females. Visitation by pollinators, mainly flies and bees, was more frequent for male than for female inflorescences and increased with increasing flower size, regardless of sex. The number of insect visits per flower decreased with increasing floral display in males but remained constant in females. Greater sexual dimorphism in flower size increased visits to male inflorescences but had no influence on the number of visits to female inflorescences. These results suggest that larger flower sizes would be advantageous to both females and males, and no evidence was found that females suffer from increased flower-size dimorphism. Small daily floral displays may benefit males by allowing extended flowering periods and greater opportunities for effective pollen dispersal.
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Affiliation(s)
- Mélanie Glaettli
- Department of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Canada, M5S 3B2
- Present address: Department of Biology, Institute of Plant Sciences, Altenbergrain 21, University of Bern, 3013 Bern, Switzerland
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Canada, M5S 3B2
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Jordan CY, Harder LD. Manipulation of Bee Behavior by Inflorescence Architecture and Its Consequences for Plant Mating. Am Nat 2006; 167:496-509. [PMID: 16670993 DOI: 10.1086/501142] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Accepted: 11/07/2005] [Indexed: 11/03/2022]
Abstract
Angiosperms display flowers in many three-dimensional arrangements, but the functional significance of this diversity is largely unknown. We examined influences of inflorescence architecture on pollination and mating by quantifying the responses of bumblebees to three architectures and then using these observations as the basis of a model that simulated pollen dispersal. On artificial panicles, racemes, and umbels, each with 12 identical flowers, bees visited one more flower, on average, on umbels than on panicles (with racemes being intermediate). In contrast to this weak response, the consistency of foraging paths among flowers differed strongly among architectures (raceme > panicle > umbel). The simulation model revealed limited differences in self-pollination and pollen export among the three inflorescence designs when all flowers presented and received pollen, because mating differences depended on only the number of flowers visited. In contrast, in simulations of inflorescences on which pollen receipt and presentation were segregated so as to minimize interference among flowers, the consistency of movement paths governed mating. In this case, racemes self-pollinated much less than umbels (with panicles being intermediate), and racemes exported much more pollen than umbels and panicles. These effects have diverse consequences for the evolution of inflorescence architecture, flower design, and sexual segregation.
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Affiliation(s)
- Crispin Y Jordan
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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Castellanos MC, Wilson P, Keller SJ, Wolfe AD, Thomson JD. Anther Evolution: Pollen Presentation Strategies When Pollinators Differ. Am Nat 2006; 167:288-96. [PMID: 16670987 DOI: 10.1086/498854] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2004] [Accepted: 09/28/2005] [Indexed: 11/03/2022]
Abstract
Male-male competition in plants is thought to exert selection on flower morphology and on the temporal presentation of pollen. Theory suggests that a plant's pollen dosing strategy should evolve to match the abundance and pollen transfer efficiency of its pollinators. Simultaneous pollen presentation should be favored when pollinators are infrequent or efficient at delivering the pollen they remove, whereas gradual dosing should optimize delivery by frequent and wasteful pollinators. Among Penstemon and Keckiella species, anthers vary in ways that affect pollen release, and the morphology of dried anthers reliably indicates how they dispense pollen. In these genera, hummingbird pollination has evolved repeatedly from hymenopteran pollination. Pollen production does not change with evolutionary shifts between pollinators. We show that after we control for phylogeny, hymenopteran-adapted species present their pollen more gradually than hummingbird-adapted relatives. In a species pair that seemed to defy the pattern, the rhythm of anther maturation produced an equivalent dosing effect. These results accord with previous findings that hummingbirds can be more efficient than bees at delivering pollen.
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Huang SQ, Tang LL, Sun JF, Lu Y. Pollinator response to female and male floral display in a monoecious species and its implications for the evolution of floral dimorphism. THE NEW PHYTOLOGIST 2006; 171:417-24. [PMID: 16866947 DOI: 10.1111/j.1469-8137.2006.01766.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Pollinator-mediated selection has been hypothesized as one cause of size dimorphism between female and male flowers. Flower number, ignored in studies of floral dimorphism, may interact with flower size to affect pollinator selectivity. In the present study, we explored pollinator response, and estimated pollen receipt and removal, in experimental populations of monoecious Sagittaria trifolia, in which plants were manipulated to display three, six, nine or 12 female or male flowers per plant. In this species, female flowers are smaller but have a more compressed flowering period than males, creating larger female floral displays. Overall, pollinators preferred to visit male rather than female displays of the same size. Both first visit per foraging bout and visitation rates to female displays increased with display size. However, large male displays did not show increased attractiveness to pollinators. A predicted relationship that pollen removal, rather than pollen receipt, is limited by pollinator visitation was confirmed in the experimental populations. The results suggest that the lack of selection on large male displays may affect the evolution of floral dimorphism in this species.
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Pannell JR, Verdú M. THE EVOLUTION OF GENDER SPECIALIZATION FROM DIMORPHIC HERMAPHRODITISM: PATHS FROM HETERODICHOGAMY TO GYNODIOECY AND ANDRODIOECY. Evolution 2006; 60:660-73. [PMID: 16739449 DOI: 10.1554/05-481.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Several different pathways for the evolution of dioecy from hermaphroditism have been invoked and analyzed. These have largely considered either the spread of male- or female-sterility mutations in a monomorphic hermaphroditic population (i.e., the evolution of gynodioecy or androdioecy, respectively) or the gradual divergence in sex allocation of two classes of individuals, one that becomes increasingly male and the other that becomes increasingly female in functional gender (the paradioecy pathway). Here we assess the conditions under which male- or female-sterility mutations may invade and spread in a heterodichogamous population, that is, a dimorphic population composed of protandrous and protogynous individuals. Our model is formally applied to heterodichogamous populations, but the ideas we explore may also apply to the evolution of separate sexes in distylous species, where plants are either long- or short-styled. The model predicts that, under many circumstances, conditions for the evolution of gynodioecy and androdioecy in a heterodichogamous population are the same as those for their evolution from monomorphic populations. However, if one or the other of the two morphs are already somewhat specialized in their functional gender, as might occur if the quality or quantity of seed set is time dependent, the conditions for the invasion of males or females are relaxed. In particular, androdioecy can evolve more easily under such circumstances in heterodichogamous populations than in monomorphic hermaphroditic populations.
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Affiliation(s)
- John R Pannell
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom.
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Manicacci D, Després L. Male and hermaphrodite flowers in the alpine lily Lloydia serotina. ACTA ACUST UNITED AC 2001. [DOI: 10.1139/b01-087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In perennial species that produce only one flower per individual each year, androdicy (coexistence of genetic male and hermaphrodite individuals) may be difficult to distinguish from andromoncy (male and hermaphrodite flowers on the same plant). We show that the alpine lily, Lloydia serotina Rchb., produces functionally male and hermaphroditic flowers. Mean male frequency in 11 populations in the French Alps was 48.5%, ranging from 15.5 to 67.5%. Male flowers do not produce more pollen nor sire more seeds per flower in controlled pollinations than hermaphrodite flowers. Male floral scapes were consistently shorter than those of hermaphrodites. Out of several thousand observed floral scapes, four had two flowers, all with a terminal hermaphroditic flower and an axillary male one. Among 107 bulbs transplanted in pots in 1996, eighteen expressed a different sexual phenotype in 1999 or 2000, and one hermaphrodite produced two flowers of different sexes in 2000. Together, these results suggest that L. serotina is andromoncious throughout its lifetime.Key words: Lloydia serotina, andromoncy, male reproductive success, Liliaceae.
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Sandmeier M, Dajoz I. Flowering Phenology and Gender Variation in Pennisetum typhoides. INTERNATIONAL JOURNAL OF PLANT SCIENCES 2000; 161:81-87. [PMID: 10648197 DOI: 10.1086/314239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Because of the modular structure of pearl millet (an annual grass crop, Poaceae), different tillers of a plant share the same genotype but are subjected to different environmental conditions during their maturation. This allows investigation of the effects of tiller flowering phenology on allocation to resource-producing photosynthetic biomass, sexual functions, and thus tiller gender. All tillers of plants of two families collected from individual maternal plants (represented by 33 and 31 plants each) were analyzed. In both families, allocation to aboveground vegetative biomass decreased as flowering was delayed. On average, late-flowering tillers were 65% smaller than the first ones to flower. The proportion of biomass allocated to reproduction significantly increased with the flowering rank of the tillers, suggesting that translocations of assimilates occurred between early- and late-flowering tillers. In both families, late-flowering tillers produced significantly fewer pollen grains per stamen than early-flowering ones, and female reproductive allocation (expressed as seed mass per tiller) was also affected by flowering phenology. Tillers became increasingly female as flowering phenology progressed. This gender variation is possibly adaptive because pollination efficiency is maximized by plant height. Natural selection may favor a shift toward femaleness to maximize reproductive fitness in small, late-developing tillers.
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Mazer SJ, Delesalle VA. Floral trait variation in Spergularia marina (Caryophyllaceae): ontogenetic, maternal family, and population effects. Heredity (Edinb) 1996. [DOI: 10.1038/hdy.1996.141] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Aizen MA, Basilio A. Within and among flower sex-phase distribution in Alstroemeria aurea (Alstroemeriaceae). ACTA ACUST UNITED AC 1995. [DOI: 10.1139/b95-213] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although dichogamy is a prevailing feature of the angiosperms, the simultaneous change from male to female phases among hermaphrodite flowers within a plant (i.e., synchronous protandry) has been reported for only a few families (e.g., Araliaceae, Umbelliferae). Here we present an example of synchronous protandry at the ramet level in the Alstroemeriaceae. Dichogamy was analyzed in clonal Alstroemeria aurea at the flower, ramet, and at the whole flowering patch level. Alstroemeria aurea is self-compatible but totally dependent on biotic agents for pollen transfer. There was evidence of strong inbreeding depression expressed during seed development. Comparisons of seed set in open-pollinated flowers with those obtained after hand selfing and outcrossing resulted in a selfing rate of 0.3. At the flower level protandry was complete. The male phase lasted about 4 days and the female phase lasted about 3 days. Between the female and male phase, there was an approximately 1-day long "neuter" phase. Flowering ramets produce a terminal inflorescence bearing one or more whorls of flowers. Within a ramet, flowers of the same order opened within a period of 1–2 days, and male and female phases of different flowers did not overlap. When inflorescences held two whorls of flowers, the ramet went through two alternating non-overlapping male–female cycles. Using spatial autocorrelation techniques, we found little evidence for pairs of neighboring ramets expressing the same sexual phase beyond random expectations at any scale ranging between 0.25 to 15 m. By ensuring pollen interchange between flowering ramets, synchronized protandry at the ramet level could be an important feature in reducing selfing in A. aurea. Key words: Alstroemeria aurea, dichogamy, synchronous protandry, inbreeding depression.
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Analytic and simulation models predicting positive genetic correlations between traits linked by trade-offs. Evol Ecol 1991. [DOI: 10.1007/bf02214153] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mazer SJ, Nakamura RR, Stanton ML. Seasonal changes in components of male and female reproductive success in Raphanus sativus L. (Brassicaceae). Oecologia 1989; 81:345-353. [DOI: 10.1007/bf00377082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/1988] [Accepted: 04/28/1989] [Indexed: 10/24/2022]
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Palmer M, Travis J, Antonovics J. Temporal mechanisms influencing gender expression and pollen flow within a self-incompatible perennial, Amianthium muscaetoxicum (Liliaceae). Oecologia 1989; 78:231-236. [DOI: 10.1007/bf00377160] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/1988] [Indexed: 12/01/2022]
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Thomson JD. Effects of variation in inflorescence size and floral rewards on the visitation rates of traplining pollinators ofAralia hispida. Evol Ecol 1988. [DOI: 10.1007/bf02071589] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Pollen success, functional gender and assortative mating in an experimental plant population. Heredity (Edinb) 1987. [DOI: 10.1038/hdy.1987.16] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Thomson JD, Peterson SC, Harder LD. Response of traplining bumble bees to competition experiments: shifts in feeding location and efficiency. Oecologia 1987; 71:295-300. [PMID: 28312259 DOI: 10.1007/bf00377298] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/1985] [Indexed: 10/26/2022]
Abstract
In field experiments, we mapped the regular foraging routes (traplines) of marked bumble bees visiting Aralia hispida. When other bees were removed to create localized "competitive vacuums", the marked bees shifted their feeding activity toward the removal areas. Bees foraging in these competitive vacuums probed more flowers per inflorescence than control bees. One bee's foraging was studied intensively before and after its local competitors were removed. Compared to four nestmates foraging elsewhere, the focal bee's trip times were shorter (p<0.005) and its food collection rate was marginally higher (P=0.064) during the removal, although all the bees foraged similarly before the removal. These observations indicate that traplining bumble bees opportunistically modify their use of space in response to the activities of other bees in a highly competitive environment.
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Affiliation(s)
- J D Thomson
- Ecology and Evolution Department, State University of New York at Stony Brook, 11794, Stony Brook, NY, USA
| | - S C Peterson
- Ecology and Evolution Department, State University of New York at Stony Brook, 11794, Stony Brook, NY, USA
| | - L D Harder
- Ecology and Evolution Department, State University of New York at Stony Brook, 11794, Stony Brook, NY, USA
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Effects of pollen and nitrogen availability on reproduction in a woodland herb, Lysimachia quadrifolia. Oecologia 1985; 67:403-410. [DOI: 10.1007/bf00384947] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/1984] [Indexed: 10/26/2022]
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Sexual reproduction and variation in floral morphology in an ephemeral vernal lily, Eyythronium americanum. Oecologia 1985; 67:286-291. [PMID: 28311326 DOI: 10.1007/bf00384301] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/1985] [Indexed: 10/26/2022]
Abstract
In a riparian population of Erythronium americanum (Liliaceae) in central New Jersey, experimentally self-pollinated plant produced markedly fewer fruit and fewer seeds per fruit than hand-outcrossed and open pollinated plants, even though differences were not evident between pollen tubes that penetrated stigmas from self or foreign pollen. This weak self-compatibility and a positive relation between the percentage of seeds set by outcrossed plants and the distance between pollen donor and recipient plants indicate that this population could be susceptible to inbreeding depression.Limited resources for seed development apparently constrained maximal seed production, based on low seed set (40.6%) by hand-pollinated plants and positive correlations for these plants between plant size and the number and size of seeds set. In contrast, naturally-pollinated plants set a smaller proportion of their ovules, suggesting that limited pollinator service reduced the quantity of seeds produced in this population. Free-foraging bees usually removed more than half of the available pollen in a single visit, so that individual plants probably have few opportunities to disseminate their pollen.Even though sexually reproductive ramets produce only a single flower per year, less than a third of variation in floral morphology is associated with variation in plant size. Within the flower, the sizes of some closely associated structures, such as the style and ovary, and the anthers and filaments, vary essentially independently of one another. Production of nectar and pollen, the ultimate attractors of pollinating insects, was positively correlated with flower size.
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Behavior of bumble bee pollinators of Aralia hispida Vent. (Araliaceae). Oecologia 1982; 54:326-336. [DOI: 10.1007/bf00380001] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/1982] [Indexed: 10/26/2022]
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