University of Calgary

Lawrence David Harder

  • Professor
  • Ecology & Evolutionary Biology

Currently Teaching

Research Interests

My research seeks explanations for the remarkable diversity of floral design and display that characterizes angiosperms. I expect that much of this diversity represents differences in reproductive function, so that my specific research projects address the roles of design and display in particular pollination and mating environments. Clearly this objective is too large to be applied individually to all 250,000 angiosperm species, so I adopt a conceptual approach, often supplemented by formal mathematical theory, which is guided by my empirical experience with pollinator behaviour and reproduction by diverse species. At the moment, some of my projects address: the function of the 3-dimensional arrangement of flowers on flowering stalks and constraints on its evolution; changes in the reproductive characteristics of individual plants during the flowering season as means of promoting female and male success; the allocation of resources, especially carbon, to reproduction and its allocation to competing reproductive functions; and whether characteristic features of being a plant affect selection on traits that influence mating success.

Graduate Students

Clocher, Ilona M.Sc. Selection on allocation gradients within inflorescences of Delphinium glaucum
Hensel, Lisa Ph.D. The influences of plant characteristics on the operation and intensity of sexual selection in angiosperms
Sawich, Lauren M.Sc. The effect of population size/density on reproductive success and resource allocation in the rewardless orchid Cypripedium parviflorum
     
     

Kulbaba, Mason

PDF

Ecology and evolution of plant mating, and hawkmoth foraging

Selected Publications

  • Google Scholar Link
  • Harder, L.D., M.A. Aizen and S.A. Richards. 2016. The population ecology of male gametophytes: the link between pollination and seed production. Ecology Letters 19:497–509.
  • Harder, L.D., M. A. Aizen, S.A. Richards, M.A. Joseph and J.W. Busch. 2016.  Diverse ecological relations of male gametophyte populations in stylar environments. American Journal of Botany 103:484–497.
  • Ida, T. Y., L. D. Harder, and G. Kudo. 2015. The consequences of demand-driven seed provisioning for sexual differences in reproductive investment in Thalictrum occidentale (Ranunculaceae). Journal of Ecology 103:269-280.
  • Schreiber, S.J., J.A. Rosenheim, N.M. Williams and L.D. Harder. 2015. Evolutionary and ecological consequences of multiscale variation in pollen receipt for seed production. American Naturalist. 185: E14-E29.
  • Harder, L.D. and P. Prusinkiewicz. 2013. The interplay between inflorescence development and function as the crucible of architectural diversity. Annals of Botany 112: 1477-1493.
  • Ida, T.Y., L.D. Harder and G. Kudo. 2013. Demand-driven resource investment in annual seed production by a perennial angiosperm precludes resource limitation. Ecology 94: 51–61. 
  • Morales, C.L., A. Traveset and L.D. Harder. 2013. Sterile flowers increase pollinator attraction and promote outcrossing in the Mediterranean herb Leopoldia comosa. Annals of Botany 111:103-111. 
  • Ishii, H.S., and L.D. Harder. 2012. Phenological associations of gender with floral morphology and integration in protandrous Delphinium glaucum. Journal of Ecology 100:1029–1038.
  • Harder, L.D., N. Hobbhahn and S.A. Richards. 2012. How depressed? Estimates of inbreeding effects during seed development depend on reproductive conditions. Evolution 66:1375-1386.
  • Internicola, A.I. and L.D. Harder. 2012. Bumble bee learning selects for both early and long flowering in food-deceptive plants. Proceedings of the Royal Society, B 279:1538-1543.
  • Hargreaves, A.L., L.D. Harder, and S.D. Johnson. 2012. Floral traits mediate the vulnerability of aloes to pollen theft and inefficient pollination by bees. Annals of Botany 109:761–772.
  • Ida, T.Y., L.D. Harder and G. Kudo. 2012. Effects of defoliation and shading on the physiological cost of reproduction in silky locoweed, Oxytropis sericea. Annals of Botany 109:237-246.
  • Johnson, S.D., P.M. Burgoyne, L.D. Harder and S. Dötterl.  2011.  Mammal pollinators lured by the scent of a parasitic plant. Proceedings of the Royal Society of London, B 278:2303-2310.
  • Garibaldi, L.A., M.A. Aizen, A.M. Klein, S.A. Cunningham and L.D. Harder. 2011. Global growth and stability in agricultural yield decrease with pollinator dependence. Proceedings of the National Academy of Sciences, U.S.A. 108:5909–5914.
  • Hargreaves A. L., L. D. Harder and S. D. Johnson. 2010. Native pollen thieves reduce the reproductive success of a hermaphroditic plant, Aloe maculata. Ecology 91:1693-1703.
  • Harder, L. D. and M. A. Aizen.2010.Floral adaptation and diversification under pollen limitation.Philosophical Transactions of the Royal Society, B 365:529-543.
  • Harder, L. D. and S. D. Johnson. 2009. Darwin’s beautiful contrivances: evolutionary and functional evidence for floral adaptation. New Phytologist 183:530-545.
  • Aizen, M. A. and L. D. Harder. 2009. The global stock of domesticated honey bees is increasing at a lower rate than agricultural pollination demands. Current Biology 19:915–918.
  • Hargreaves, A. L., L. D. Harder and S. D. Johnson. 2009. Consumptive emasculation: the ecological and evolutionary consequences of pollen theft. Biological Reviews 84:259-276.
  • Harder, L. D., and S. D. Johnson. 2008. Function and evolution of aggregated pollen in angiosperms. International Journal of Plant Sciences 169:59-78.
  • Harder, L. D., S. A. Richards and M. B. Routley. 2008. Effects of reproductive compensation, gamete discounting and reproductive assurance on mating-system diversity in hermaphrodites. Evolution 62:157-172.
  • Aizen, M. A., and L. D. Harder. 2007. Expanding the limits of the pollen-limitation concept: effects of pollen quantity and quality. Ecology 88:271-281.
  • Prusinkiewicz, P., Y. Erasmus, B. Lane, L. D. Harder and E Coen. 2007. Evolution and development of inflorescence architectures. Science 316:1452-1456.
  • Harder, L.D. and M.B. Routley. 2006. Pollen and ovule fates and reproductive performance by flowering plants. In L.D. Harder and S.C.H. Barrett (editors), Ecology and Evolution of Flowers. pp. 61-80. Oxford University Press.
  • Jordan, C.Y., and L.D. Harder. 2006. Manipulation of bee behavior by inflorescence architecture and its consequences for plant mating. American Naturalist 167:496-509.
 

Harder, L.D. and S.C.H. Barrett (editors). 2006. Ecology and Evolution of Flowers. Oxford University Press.
http://www.eeb.utoronto.ca/eef/index.htm

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