Germán Avila Sakar

Baccalaureate: Facultad de Ciencias, UNAM, México (1991)

Doctorate: The Pennsylvania State University, USA (2000)

Assistant Professor

Department of Biology

The University of Winnipeg

Research Interests

·         Projects

·         Students

·         Publications

·         Student positions in my labPlease inquire

·         Courses

·         Links

When will Ilex glabra flower in the Tusket River basin area (Yarmouth County)? We are following closely the weather and comparing it to last year’s. This way we hope to know when it will flower: last year it flowered when 536 GDD had accumulated, on July 12 (see cross-hairs). It seems that Ilex will flower earlier this year! This graph will be updated on a weekly basis. (Graph last updated: 1 July)

It turns out that I. glabra flowered on July 9 this year.


Research Interests

My research program focuses on the roles of resource allocation in the interrelationships between the evolution of sexual systems and defence against herbivores in flowering plants. One of the questions I am trying to answer is how certain conditions of resource availability may favour the evolution of unisexuality in plants, including changes in the relationship between fitness and the pattern of resource allocation in a plant brought about by herbivory. In addressing this question, I intend to increase our understanding of the physiological mechanisms that regulate allocation of carbon and nutrients, the potential for resource re-allocation in response to environmental stress factors such as herbivory, and the consequences that particular allocation patterns might have on the evolution of defence and sexual systems.

Current Projects

1.      Herbivory in dioecious plant populations of Nova Scotia

2.      Resistance and tolerance to herbivory in Arabidopsis

3.      Evolution of unisexuality in Cucurbita

4.      The shape of the tolerance function in Brassica rapa


GAS and students 2006Current students




Past students


Nicholas Buckley – M. Sc., Biology Graduate Program, Acadia University (2008)


Caroline Tucker – Honours, Biology, Mount Saint Vincent University (2008) (also NSERC, USRA 2007, 2008)

Liam McNeil – Honours, Biology, Mount Saint Vincent University (2006)

Rogelio Cruz Reyes – Honours, Universidad Nacional Autónoma de México (2005)

Carolyn Marshall – Honours, Acadia University (2004, co-supervised with Dr. Ed Reekie)

Deana Sharpe – Directed Studies

Jayne Bellefontaine – Directed Studies

Tessa Protasivich – NSERC-USRA summer research (2005, 2006)

Sarah Surette – NSERC-USRA summer research (2006)


Student positions

Undergraduate positions

· Summer positions – Usually there are opportunities to work on some of the projects in my lab while being funded by an NSERC Undergraduate Student Research Award – please inquire (also, contact Dr. Craig Willis (204)-786-9433).

· Examples of potential honours thesis projects

  • Costs of compensation in plants subjected to herbivory  
  • The vascular architecture of a wild cucurbit.
  • Inter-sexual variation in resistance to herbivory in wild shrubs of Nova Scotia

If you are interested in any of the other projects listed above, please inquire.

Graduate positions

  • Please contact me if you are interested in pursuing either a masters or a doctoral degree working on any aspects of resource allocation in plants, responses of plants to herbivory (resistance, tolerance), plant-pollinator interactions, and evolution of sexual systems of plants (heterostyly, dioecy, monoecy, etc.)

· Partial funding may be possible through a combination of student assistantships and summer salary.

Post-doctoral positions

· Please enquire. Send a brief statement of research interests. I will be happy to support an application for a fellowship from an external funding agency. (e.g. NSERC, Fullbright, etc.)


BIOL 2153 – Biology of Vascular Plants

BIOL 3152 – Flora of Manitoba

BIOL 2403 – Principles of Ecology

Recent Publications

Marshall, C., Avila-Sakar, G. and Reekie, E.G. 2008. Effects of nutrient and CO2 availability on tolerance to herbivory in Brassica rapa. Plant Ecology 196:1-13.

Journal articles:

Avila-Sakar, G., Leist, L.L. and stephenson, A.G. 2006. Effects of the spatial pattern of leaf damage on growth and reproduction: whole plants. International Journal of Plant Sciences 167:1021-1028.

Avila-Sakar, G., Leist, L.L. and stephenson, A.G. 2003. Effects of the spatial pattern of leaf damage on growth and reproduction: nodes and branches. Journal of Ecology 91: 867-879.

Avila-Sakar, G., Simmers, S.M. and stephenson, A.G. 2003. The interrelationships among leaf damage, anther development, and pollen production in Cucurbita pepo ssp. texana (Cucurbitaceae). International Journal of Plant Sciences 164: 395-404.

Avila-Sakar, G., Krupnick, G.A., and Stephenson, A.G. 2001. Growth and sex allocation in Cucurbita pepo ssp. texana: Effects of fruit removal. International Journal of Plant Sciences 162: 1089-1095.

Krupnick, G.A., Avila, G., Brown, K.M., and Stephenson, A.G. 2000. The effects of herbivory on internal ethylene production and sex expression in Cucurbita texana. Functional Ecology 14: 215-225.

Avila-Sakar, G., and Domínguez, C.A. 2000. Parental effects and gender specialization in a tropical heterostylous shrub. Evolution 54: 866-877.

Book chapters:

Domínguez, C.A. y Avila-Sakar, G. 2002. Erythroxylum havanense In Historia natural de Chamela. F.N. Martínez, J.V. Rivera y M.Q. Avendaño (eds.). Instituto de Biología, UNAM, México.

Reekie, E.G. and Avila-Sakar, G. 2005. Contrasting resource requirements of vegetative versus reproductive growth: implications for reproductive allocation. Reekie E.G. and Bazzaz, F.A. (eds.) The Allocation of Resources to Reproduction in Plants. Academic Press, San Diego.



Other Universities

Universidad Nacional Autónoma de México (UNAM)

Dalhousie University - Biology

Acadia University - Biology

MSVU - Biology Department


Collaborators in other universities

Sara V. Good-Avila

Mauricio Quesada

Ed Reekie

Andrew G. Stephenson



The information on this website has been developed by and is at the discretion of Germán Avila Sakar. The information on this site is not published by The University of Winnipeg and therefore The University of Winnipeg cannot accept responsible or liability for any persons who suffer loss, injury or damage from its use. Anyone using the information on this site does so at his or her own risk.