Summary
I developed a model for seed size variation among plants assuming that the pollen captured per flower depends on both the allocation to pollen capture mechanisms per flower and the number of flowers on each plant. I showed that the optimal seed size increases with (1) the total resource allocation to reproduction, (2) decreasing outcross pollen availability, (3) decreasing probability of seedling establishment and (4) decreasing selfing rate. However, optimal seed size does not depend on the total resource allocation if the total number of pollen grains captured by a plant increases linearly with its flower number. In addition, the optimal seed size is not always positively correlated with the optimal resource allocation to pollen capture mechanisms per flower. I discussed implications of the results for seasonal decline in seed size and seed size variations among populations, such as alutitudinal variation.
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References
Ågren, J. (1989) Seed size and number inRubus chamaemorus: between-habitat variation, and effects of defoliation and supplemental pollination.J. Ecol. 77 1080–92.
Bell, G. (1985) On the function of flowers.Proc. Royal Soc. London B 224 223–65.
Cavers, P.B. and Steel, M.G. (1984) Patterns of change in seed weight over time on individual plants.Am. Nat. 124 324–35.
Chaplin, S.J. and Walker, J.L. (1982) Energetic constraints and adaptive significance of the floral display of a forest milkweed.Ecology 63 1857–70.
Christy, E.J. and Sharitz, R.R. (1980) Characteristics of three populations of a swamp annual under different temperature regimes.Ecology 61 454–60.
Eckhart, V.M. (1992) Spatio-temporal variation in abundance and variation in foraging behavior of the pollinators of gynodioeciousPhacelia linearis (Hydrophyllaceae).Oikos 64 573–86.
Escarré, J. and Thompson, J.D. (1991) The effects of successional habitat variation and time of flowering on seed production inRumex acetosella.J. Ecol. 79 1099–12.
Fuller, W., Hance, C.E. and Hutchings, M.J. (1983) Within-season fluctuations in mean fruit weight inLeontodon hispidus L.Ann. Bot. 51 545–9.
Geber, M.A. (1985) The relationship of plant size to self-pollination inMertensia ciliata.Ecology 66 762–72.
Haig, D. and Westoby, M. (1988) Inclusive fitness, seed resources, and maternal care. InPlant reproductive ecology: patterns and strategies (J. Lovett Doust and L. Lovett Doust eds) pp. 60–79. Oxford University Press, New York.
Heithaus, E.R., Stashko, E. and Anderson, P.K. (1982) Cumulative effects of plant—animal interactions on seed production byBauhinia ungulata, a neotropical legume.Ecology 63 1294–302.
Herrera, C.M. (1988) The fruiting ecology ofOsyris quadripartita: individual variation and evolutionary potential.Ecology 69 233–49.
Janzen, D.H. (1977) Variation in seed size within a crop of a Costa RicanMucuna andreana (Leguminosae).Am. J. Bot. 64 347–9.
Kane, M. and Cavers, P.B. (1992) Patterns of seed weight distribution and germination with time in a weedy biotype of proso millet (Panicum miliaceum).Can. J. Bot. 70 562–7.
Kang, H. and Primack, R.B. (1991) Temporal variation of flower and fruit size in relation to seed yield in celandine poppy (Chelidonium majus; Papaveraceae).Am. J. Bot. 78 711–22.
Klinkhamer, P.G.L., de Jong, T.J. and de Bruyn, G.-J. (1989) Plant size and pollinator visitation inCynoglossum officinale.Oikos 54 201–4.
Lalonde, R.G. (1988) A text of McGinley and Charnov's multiple resource pool hypothesis.Evol. Ecol. 2 316–20.
Lalonde, R.G. (1991) Optimal offspring provisioning when resources are not predictable.Am. Nat. 138 680–6.
Lalonde, R.G. and Roitberg, B.D. (1989) Resource limitation and offspring size and number trade-offs inCirsium arvense (Asteraceae).Am. J. Bot. 76 1107–13.
McGinley, M.A. and Charnov, E.L. (1988) Multiple resources and the optimal balance between size and number of offspring.Evol. Ecol. 2 77–84.
McWilliams, E.L., Landers, R.Q. and Mahlstede, J.P. (1968) Variation in seed weight and germination in populations ofAmaranthus retroflexus L.Ecology 49 290–6.
Marshall, D.L., Fowler, N.L. and Levin, D.A. (1985) Plasticity in yield components in natural populations of three species ofSesbania.Ecology 66 753–61.
Melzack, R.N. and Watts, D. (1982) Variations in seed weight, germination, and seedling vigour in the yew (Taxus baccata, L.) in England.J. Biogeogr 9 55–63.
Michaels, H.J., Benner, B., Hartgerink, A.P., Lee, T.D. and Rice, S. (1988) Seed size variation: magnitude, distribution, and ecological correlates.Evol. Ecol. 2 157–66.
Morse, D.H. (1986) Inflorescence choice and time allocation by insects foraging on milkweed.Oikos 46 229–36.
Pellmyr, O. (1987) Temporal patterns of ovule allocation, fruit set, and seed predation inAnemonopsis macrophylla (Ranunculaceae).Bot. Mag. Tokyo 100 175–83.
Piper, J.G. and Waite, S. (1988) The gender role of flowers of broad leaved Helleborine,Epipactis helleborine (L.) Crantz (Orchidaceae).Funct. Ecol. 2 35–40.
Roach, D.A. (1986) Timing of seed production and dispersal inGeranium carolinianum: effects on fitness.Ecology 67 572–6.
Sakai, S. (1993) Allocation to attractive structures in animal-pollinated flowers.Evolution 47 1711–20.
Sakai, S. (1995) Evolutionarily stable selfing rates of hermaphroditic plants in competing and delayed selfing modes with allocation to attractive structures.Evolution in press.
Sakai, S. and Sakai, A. (1995) Flower size-dependent variation in seed size: theory and a test.Am. Nat. in press.
Schimpf, D.J. (1977) Seed weight ofAmaranthus retroflexus in relation to moisture and length of growing season.Ecology 58 450–3.
Schmitt, J., Niles, J. and Wulff, R.D. (1992) Norms of reaction of seed traits to maternal environments inPlantago lanceolata.Am. Nat. 139 451–66.
Smith, C.C. and Fretwell, S.D. (1974) The optimal balance between size and number of offspring.Am. Nat. 108 499–506.
Stamp, N.E. (1990) Production and effect of seed size in a grassland annual (Erodium brachycarpum, Geraniaceae).Am. J. Bot. 77 874–82.
Stanton, M.L., Bereczky, J.K. and Hasbrouck, H.D. (1987) Pollination thoroughness and maternal yield regulation in wild radish,Raphanus raphanistrum (Brassicaceae).Oecologia 74 68–76.
Stromberg, J.C. and Patten, D.T. (1990) Variation in seed size of a southwestern riparian tree, Arizona walnut (Juglans major).Am. Midl. Nat. 124 269–77.
Thompson, J.N. and Pellmyr, O. (1989) Origins of variance in seed number and mass: interaction of sex expression and herbivory inLomatium salmoniflorum.Oecologia 79 395–402.
Werner, P.A. and Platt, W.J. (1976) Ecological relationships of co-occurring goldenrods (Solidago: Compositae).Am. Nat. 110 959–71.
Whelan, R.J. and Goldingay, R.L. (1989) Factors affecting fruit-set inTelopea speciosissima (Proteaceae): the importance of pollen limitation.J. Ecol. 77 1123–34.
Winn, A.A. (1985) Effects of seed size and microsite on seedling emergence ofPrunella vulgaris in four habitats.J. Ecol. 73 831–40.
Winn, A.A. and Gross, K.L. (1993) Latitudinal variation in seed weight and flower number inPrunella vulgaris.Oecologia 93 55–62.
Winn, A.A. and Werner, P.A. (1987) Regulation of seed yield within and among populations ofPrunella vulgaris.Ecology 68 1224–33.
Wolf, L.L., Hainsworth, F.R., Mercier, T. and Benjamin, R. (1986) Seed size variation and pollinator uncertainty inIpomopsis aggregata (Polemoniaceae).J. Ecol. 74 361–71.
Wolfe, L.M. (1992) Why does the size of reproductive structures decline through time inHydrophyllum appendiculatum (Hydrophyllaceae)?: developmental constraints vs. resource limitation.Am. J. Bot. 79 1286–90.
Wyatt, R. (1980) The reproductive biology ofAsclepias tuberosa. I. Flower number, arrangement, and fruitset.New Phytol. 85 119–31.
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Sakai, S. A model for seed size variation among plants. Evol Ecol 9, 495–507 (1995). https://doi.org/10.1007/BF01237831
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DOI: https://doi.org/10.1007/BF01237831