Evolution of Interactions




Evolution of Interactions

We are particularly fascinated in the evolution of mating systems and how interactions evolve. Our main study animals are fig trees and their wasps and the Afrikaner population (humans).

We have shown that fig wasp mothers regulate the number of sons they produce very carefully in order to minimize competition between their sons. However, if competition between fig wasp males is too intense they will evolve robust morphologies and fighting behavior to fight even with their brothers. Going forward, we want to explore the evolution of virulence because it is claimed to be analogous to sex ratios and sibling rivalry in that competition between parasites can result in higher virulence which can be mitigated by relatedness. Currently we are quantifying the population structure and mating behavior of parasites to get a handle on the relatedness structure of parasitic populations. For these activities we have joined forces with several researchers: Muhammad Ahmed and Bao-Li Qiu looking at Wolbachia in whiteflies, Robin Giblin-Davis looking at the nematodes of fig wasps, Sarah Clift and Pam de Waal looking at Spirocerca lupi, a nematode of dogs. In the future we hope to progress to studying virulence itself.

Studying these population genetic structures and also the mating systems of parasites forms a natural bridge with my interest in the evolution of mating strategies. We study reproductive strategies using theoretical models to predict optimal behaviour and by quantifying the effects of key parameters illustrated in models. We also describe the mating systems of unknown systems and look at the fitness effects of various strategies. Recently we considered the beneficial role of inbreeding and how it is balanced with inbreeding depression; understanding the evolution, causes and consequences of infertility in humans; and quantifying the determinants of fitness through male and female functions in several fig tree species.

In another project we have been looking at the genetic heritage of the Afrikaner population. Here we are particularly interested in racial admixture during the inception of the population and selection in the subsequent 350 years. These data have also revealed interesting links with reproductive strategies in humans.

Dr. Vinet Coetzee is a postdoctoral fellow associated with my group and she is exploring the determinants of facial attractiveness. You should look at her pages as well.



Jaco Greeff

Post-doctoral fellow

Vinet Coetzee

PhD Students

Christoff Erasmus
Meike Wöhr

MSc Students
Bery Flatela
Nico Chung
Karina Pentz


  • Dr Muhammad Z Ahmed : Florida Museum of Natural History, University of Florida
  • Prof Bao-Li Qiu : Department of Entomology, South China Agricultural University
  • Prof Robin M Giblin-Davis : Fort Lauderdale Research and Education Center, University of Florida-IFAS
  • Dr Sarah J Clift : Section Patology, Department of Paraclinical Sciences, University of Pretoria
  • Prof. Willem JH Ferguson : Centre for Environmental Studies, University of Pretoria
  • Dr. Pam J de Waal : Department of Genetics, University of Pretoria
  • Carina Schlebusch & Mattias Jakobsson: Laboratory at the Evolutionary Biology Centre, Uppsala University

On-going projects:

Genetic Heritage of the Afrikaner population
Determinants of human fecundity
Fig-associated nematode diversity and biology
Testing models of optimal sex allocation
The role of trade-offs and selection in optimal fig wasp body shape
Population structure and dynamics of Spirocerca lupi
The mitochondrial genome of Spirocerca lupi
The population genetic structure of fig populations



Last edited by Kishen Mahesh

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