Abstract
Plant reproductive systems present a gradient of gender ranging from unisexuality to hermaphrodism. This variability in sex expression can be found within species and has been found to be influenced by external factors such as resource levels. The sexual strategy selected will depend not only on the number of pollen grains and seeds an individual can produce but also on the chance of success of this production. Production depends on trade-offs between female and male functions of hermaphrodites according to resource level and subsequent fate is influenced by selfing, inbreeding depression and competition among offspring. The goal of this study is to determine how interactions between these key parameters, resources availability, selfing and density-dependent competition within offspring influence the evolution of reproductive systems. We showed with a theoretical approach that (i) a change in resource level at the population level affects sexual strategies only in certain conditions; (ii) density-dependent seedling mortality disadvantages females compared to hermaphrodites and interacts strongly with resource level.





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References
Alcantara JM, Rey PJ, Valera F et al (1997) Temporal pattern of seed dispersal of Wild Olive (Olea europaea var sylvestris): its effect on intraspecific competition. Lagascalia 19:583–590
Alcantara JM, Rey PJ, Valera F et al (2000) Factors shaping the seedfall pattern of a bird-dispersed plant. Ecology 81:1937–1950
Ashman TL (1992) The relative importance of inbreeding and maternal sex in determining progeny fitness in Sidalcea oregana ssp. spicata, a gynodioecious plant. Evolution 46:1862–1874
Ashman TL (1994) Reproductive allocation in hermaphrodite and female plants of Sildalcea oregana ssp. spicata (Malvaceae) using four currencies. Am J Bot 81:433–438
Ashman TL (1999) Determinants of sex allocation in a gynodioecious wild strawberry: implications for the evolution of dioecy and sexual dimorphism. J Evol Biol 12:648–661
Ashman TL (2006) The evolution of separate sexes: a focus on the ecological context. In: Barrett SCH, Harder LD (eds) The ecology and evolution of flowers. Oxford University Press, Oxford, pp 419–465
Bailey MF, Delph LF, Lively CM (2003) Modeling gynodioecy: novel scenarios for maintaining polymorphism. Am Nat 161:762–776
Barrett SCH (1992) Gender variation and the evolution of dioecy in Wurmbea dioica (Liliaceae). J Evol Biol 5:423–444
Beverton RJH, Holt SJ (1957) On the dynamics of exploited fish populations. Fishery Investigations Series II. Ministry of Agriculture, Fisheries and Food and Fisheries, London
Brunet J (1992) Sex allocation in hermaphroditic plants. Trend Ecol Evol 7:79–84
Cadet C, Metz JAJ, Klinkhamer PGL (2004) Size and the not-so-single sex: disentangling the effects of size and budget on sex allocation in hermaphrodites. Am Nat 164:779–792
Campbell DR (2000) Experimental tests of sex-allocation theory in plants. Trend Ecol Evol 15:227–232
Case AL, Ashman TL (2007) An experimental test of the effects of resources and sex ratio on maternal fitness and phenotypic selection in gynodioecious Fragaria virginiana. Evolution 61:1900–1911
Case AL, Barrett SCH (2004) Environmental stress and the evolution of dioecy: Wurmbea dioica (Colchicaceae) in Western Australia. Evol Ecol 18:145–164
Charlesworth B, Charlesworth D (1978) A model for the evolution of dioecy and gynodioecy. Am Nat 112:975–997
Charlesworth D, Charlesworth B (1981) Allocation of resources to male and female functions in hermaphrodites. Biol J Linn Soc 15:57–74
Charnov EL (1979) Simultaneous hermaphroditism and sexual selection. Proc Natl Acad Sci USA 76:2480–2484
Charnov EL, Smith JM, Bull JJ (1976) Why be an hermaphrodite? Nature 263:125–126
Cheplick GP (1992) Sibling competition in plants. J Ecol 80:567–575
Cheptou P-O, Imbert E, Lepart J et al (2000) Effects of competition on lifetime estimates of inbreeding depression in the outcrossing plant Crepis sancta (Asteraceae). J Evol Biol 13:522–531
Costich DE (1995) Gender specialization across a climatic gradient: experimental comparison of monoecious and dioecious Ecballium. Ecology 76:1036–1050
Costish DE, Galan F (1988) The ecology of monoecious and dioecious subspecies of Ecballium elaterium (L.) Richard (Cucurbitaceae). I. Geographic distribution and its relationship to climatic conditions in Spain. Lagascalia 15:697–710
Darwin CR (1877) Polygamous, dioecious, and gyno-dioecious plants, the different forms of flower on plants of the same species. Murray, London, pp 278–309
De Laguerie P, Olivieri I, Gouyon P-H (1993) Environmental effects on fitness-sets shape and evolutionarily stable strategies. J Theor Biol 163:113–125
Debusshe M, Isenmann P (1994) Bird-dispersed seed rain and seedling establishment in patchy Mediterranean vegetation. Oikos 69:414–426
Delph LF (1990a) The evolution of gender dimorphism in New Zealand Hebe (Scrophulariaceae) species. Evol Trends Plants 4:85–97
Delph LF (1990b) Sex-differential resource allocation patterns in the subdioecious shrub Hebe subalpina. Ecology 71:1342–1351
Delph LF, Carroll SB (2001) Factors affecting relative seed fitness and female frequency in a gynodioecious species, Silene acaulis. Evol Ecol Res 3:487–505
Delph LF, Lloyd DG (1991) Environmental and genetic-control of gender in the dimorphic shrub Hebe subalpina. Evolution 45:1957–1964
Delph LF, Wolf DE (2005) Evolutionary consequences of gender plasticity in genetically dimorphic breeding systems. New Phytol 166:119–128
Dorken ME, Mitchard ETA (2008) Phenotypic plasticity of hermaphrodite of separate sexes: an experimental test of the sex-differential plasticity hypothesis using Sagittaria latifolia (Alismataceae). Evolution 62:971–978
Eckhart V (1992) Resource compensation and the evolution of gynodyoecy in Phacelia linearis (Hydrophyllaceae). Evolution 46:1313–1328
Eppley SM, Pannell JR (2009) Inbreeding depression in dioecious populations of the plant Mercurialis annua: comparisons between outcrossed progeny and the progeny of self-fertilized feminized males. Heredity 102:600–608
Escarre J, Houssard C, Thompson JD (1994) An experimental study of the role of seedling density and neighbor relatedness in the persistence of Rumex acetosella in an old-field succession. Can J Bot 72:1273–1281
Guillon J-M, Julliard R, Leturque H (2006) Evolution of habitat-dependent sex allocation in plants: superficially similar to, but intrinsically different from animals. J Evol Biol 19:500–512
Herrera CM, Jordano P, Lopez-Soria L, Amat J (1994) Recruitment of a mast-fruiting, bird-dispersed tree: bridging frugivore activity and seedling establishment. Ecol Monogr 64:315–344
Hesse E, Pannell JR (2011) Sexual dimorphism in androdioecious Mercurialis annua, a wind-pollinated herb. Int J Plant Sci 172:49–59
Humeau L, Pailler T, Thompson JD (1999) Cryptic dioecy and leaky dioecy in endemic species of Dombeya (Sterculiaceae) on La Réunion. Am J Bot 86:1437–1447
Humeau L, Pailler T, Thompson JD (2000) Variation in gender and flower-size dimorphism in the dioecious tree Dombeya ciliata, an endemic to La Réunion island. Biotropica 32:463–472
Kelley SE (1989a) Experimental studies of the evolutionary significance of sexual reproduction. V. A field test of the sib-competition lottery hypothesis. Evolution 43:1054–1065
Kelley SE (1989b) Experimental studies of the evolutionary significance of sexual reproduction. VI. A greenhouse test of the sib-competition hypotheses. Evolution 43:1066–1074
Klinkhamer PGL, De Jong TJ, Metz H (1997) Sex and size on cosexual plants. Trends Ecol Evol 12:260–265
Litrico I, Pailler T, Thompson JD (2005) Gender variation and primary succession in a tropical woody plant, Antirhea borbonica (Rubiaceae). J Ecol 93:705–715
Lloyd DG (1975) The maintenance of gynodioecy and androdioecy in angiosperms. Genetica 45:1–15
Lloyd DG, Bawa KS (1984) Modification of the gender of seed plants in varying conditions. Evol Biol 17:255–338
Olson MS (2001) Patterns of fruit production in the subdioecious plant Astilbe biternata (Saxifragaceae). J Ecol 89:600–607
Pannell JR (2000) A hypothesis for the evolution of androdioecy: the joint influence of reproductive assurance and local mate competition in a metapopulation. Evol Ecol 14:195–211
Pannell JR, Dorken ME, Pujol B, Berjano R (2008) Gender variation and transitions between sexual systems in Mercurialis annua (Euphorbiaceae). Int J Plant Sci 169:129–139
Pausas JG, Bonet A, Maestre FT et al (2006) The role of the perch effect on the nucleation process in Mediterranean semi-arid oldfields. Acta Oecologica 29:346–352
Ramsey M, Vaughton G (2001) Sex expression and sexual dimorphism in subdioecious Wurmbea dioica (colchicaceae). Int J Plant Sci 162:589–597
Ribbens E, Silander JA, Pacala SW (1994) Seedling recruitment in forests: calibrating models to predict patterns of tree seedling dispersion. Ecology 75:1794–1806
Sakai AK, Weller SG (1991) Ecological aspects of sex expression in subdioecious Schiedea globosa (Caryophyllaceae). Am J Bot 78:1280–1288
Shaw RG, Antonovics J (1986) Density-dependence in Salvia lyrata. A herbaceous perennial: the effects of experimental alteration of seed densities. J Ecol 74:797–813
Shykoff JA, Kolokotronis SO, Collin CL et al (2003) Effects of male sterility on reproductive traits in gynodioecious plants: a meta-analysis. Oecologia 135:1–9
Verdú M, García-Fayos P (2003) Frugivorous birds mediate sex-biased facilitation in a dioecious nurse plant. J Veg Sci 14:35–42
Weller SG, Sakai AK, Wagner WL et al (1990) Evolution of dioecy in Schiedea (Caryophyllaceae: Alsinoideae) in the Hawaiian Islands: biogeographical and ecological factors. Syst Bot 15:266–276
Wolf DE, Takebayashi N (2004) Pollen limitation and the evolution of androdioecy from dioecy. Am Nat 163:122–137
Wolfe LM, Shmida A (1995) Regulation of gender and flowering behavior in a sexually dimorphic desert shrub (Ochradenus baccatus Delile [Resedaceae]). Israel J Plant Sci 43:325–337
Wolfe LM, Shmida A (1997) The ecology of sex expression in a gynodioecious Israeli desert shrub (Ochradenus baccatus). Ecology 78:101–110
Wolfram Research, Inc (2003) Mathematica, version 5.0, Champaign, IL
Acknowledgments
We thank the CEFE-CNRS, the University of La Réunion and the “Région de La Reunion” for financial support, John Thompson and Eric Imbert for useful comments on this manuscript.
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Isabelle Litrico and Sandrine Maurice: equal contribution.
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Litrico, I., Maurice, S. Resources, competition and selfing: their influence on reproductive system evolution. Evol Ecol 27, 923–936 (2013). https://doi.org/10.1007/s10682-012-9613-z
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DOI: https://doi.org/10.1007/s10682-012-9613-z

