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Welcome!

Welcome to my personal webpages at the University of Amsterdam.
I am assistant professor in Population Biology at the Institute for Biodiversity and Ecosystem Dynamics, headed by prof.dr. Maurice W. Sabelis.
Currently, I am supervising four PhD students:

• Eva van den Broek (thesis defence: January 2014)
• Pedro Branco
• Paulien de Bruijn
• Bram Knegt

One of my PhD students graduated in 2013:

• Mathias Spichtig (thesis defence: 2013)

Two of my PhD students graduated in 2010:

• Nicola Tien
• Beata Sznajder

Please do refer to the information on my research, teaching activities and publications, which can be accessed through the navigation bar at the top of this page.

• Overview of the Department of Population Biology

Research

Brief summary of research
Generally, I am interested in evolution by multi-level selection and have worked on projects related to: effects of learning on the evolution of exploitation strategies of mite predators (with Beata Sznajder; PhD awarded September 2010), evolution of diapause (with Annemarie Kroon, postdoc), communicating the nature of danger in thrips (with Paulien de Bruijn; ongoing PhD project), and evolution of the interaction between cytoplasmic bacteria and the animal hosts they infect (with Filipa Vala and Hans Breeuwer).
My research focus is in the combined experimental and theoretical study of evolutionary dynamics (i.e., feedbacks between evolutionary and ecological processes, and the role of genetic factors in determining these dynamics). Over the last years, I have focused on 1) the evolution of specialization in herbivorous arthropods, and 2) the evolution of altruism in humans.

Specialization is a widespread biological phenomenon, particularly among herbivorous arthropods, and its evolutionary explanation therefore poses important questions. I applied adaptive dynamics theory to study the role of foraging behaviour in the evolution of specialization. Adaptive host-plant selection was found to strongly facilitate the evolution of specialization, mainly through the process of evolutionary branching. Experimentally, I studied the foraging behaviour of spider mites, to assess the degree in which such animals can express adaptive host-plant preference. Mites learn their performance on a host plant and this allows them to select the host plant on which they have higher fitness - adaptive learning. This is an example of the foraging behaviour that promotes the evolution of specialization in the developed theory. With Sara Magalhaes and Isabelle Olivieri, I studied patterns of local adaptation to new host plants using experimental evolution. With Nicola Tien (PhD awarded November 2010), I studied the evolutionary genetics of life-history traits of spider mites.
Explaining the evolution and maintenance of cooperation among unrelated individuals is one of the fundamental problems in biology and the social sciences. Over the last years, a collaboration project was set up with Aljaz Ule, Eva van den Broek, Arno Riedl and Arthur Schram (Experimental Economics, UvA) to study the interactive evolution of social norms and cooperation. We have conducted a large-scale internet experiment in The Netherlands to explore the boundary conditions for altruistic punishment to maintain cooperation. The observed economics of altruistic punishment suggests that the scope for altruistic punishment as a means to maintain human cooperation is limited. Current work focuses on the role of group competition and on the interaction of relations (e.g., friendship networks) and cooperation (with Mathias Spichtig).
My expertise in both theory and experiments on specialization has in recent years led to collaboration with the group of Jef Huisman (Aquatic Microbiology, University of Amsterdam) on the evolution of specialization and life-historytraits in phytoplankton and their herbivores (with Maayke Stomp and Jef Huisman). This collaboration is ongoing with the daily supervisor of one of the PhD students of Jef Huisman (Pedro Branco) on evolution of ecological stochiometric relationships in phytoplankton and zooplankton.

Teaching

I am involved in the following courses and other teaching activities:

Bachelor programme Biology

• Course: "Evolutionary Biology - theory" (for biologists)
• Course: "Evolutionary Biology - practice" (for biologists)
• Course: "Evolution and Behaviour" (for biologists; from 2011)
• Course: "Animal Cognition" (for psychobiologists)
  
• Literature thesis supervision
  
• Bachelor thesis supervision

Master programme Biological Sciences

• Coordinator of the MSc track General Biology
  
• Courses: "Evolutionary Dynamics" , "Masterclasses in Ecology & Evolution"
• Supervision of MSc projects and literature theses
  

PhD courses

• "Evolutionary Dynamics"

Committees

• Chairman Education Committee Psychobiology (2008-present)
• Member Education Team Biology (2008-present)
  

Resources for the PhD Course "Evolutionary Dynamics" 2012

• Lecture General Intro
  
• Lecture Intro Adaptive Dynamics
• Lecture Fitness Function AD
  
• Exercises
• Lecture Mathematical Recipes AD
• Lecture Experimental test AD
• Lecture AD & Adaptive Speciation
• Lecture Canonical Equation AD
• Lecture Canonical Equation AD contd.
  
• Lecture Counterintuitive Outcomes AD
  

• Lecture General Intro

• Lecture Intro Adaptive Dynamics

• Lecture Fitness Function AD

• Exercises

• Lecture Mathematical Recipes AD

• Lecture Experimental test AD

• Lecture AD & Adaptive Speciation

• Lecture Canonical Equation AD

• Lecture Canonical Equation AD contd.

• Lecture Counterintuitive Outcomes AD

For information or reprint requests, please do not hesitate to send me an e-mail!

Publication list

1.    Sabelis M.W., Van Baalen M., Bruin J., Egas M., Jansen V.A.A., Janssen A. & Pels B. (1999), The evolution of overexploitation and mutualism in plant-herbivore-predator interactions and its impact on population dynamics. In: Theoretical Approaches to Biological Control, B.A. Hawkins & H.V. Cornell (eds.), Cambridge University Press, Cambridge. Pp 259-282.

2.    Sabelis M.W., Van Baalen M., Bakker F.M., Bruin J., Drukker B., Egas M., Janssen A.R.M., Lesna I.K., Pels B., Van Rijn P.C.J. & Scutareanu P. (1999), The evolution of direct and indirect plant defence against herbivorous arthropods. In: Herbivores: between Plants and Predators, H. Olff, V.K. Brown & R.H. Drent (eds), Blackwell Scientific Publications, Oxford. Pp 109-166.

3.    Van der Wal R., Egas M., Van der Veen A. & Bakker J. (2000). Effects of resource competition and herbivory on plant performance along a productivity gradient. Journal of Ecology 88:317-330.

4.    Egas M. & Sabelis M.W. (2001). Adaptive learning of host preference in a herbivorous arthropod. Ecology Letters 4:190-195.

5.    Chatzivasileiadis E.A., Egas M. & Sabelis M.W. (2001). Resistance to 2-tridecanone in Tetranychus urticae: effects of induced resistance, cross-resistance and heritability. Experimental and Applied Acarology 25:717-730.

6.    Egas M., Vala F. & Breeuwer J.A.J. (2002). On the evolution of cytoplasmic incompatibility in haplodiploid species. Evolution 56:1101-1109.

7.    Sabelis M.W., Van Baalen M., Pels B., Egas M. & Janssen A. (2002). Evolution of exploitation and defence in plant-herbivore-predator interactions. In: The Adaptive Dynamics of Infectious Diseases: In Pursuit of Virulence Management, U. Dieckmann, J.A.J. Metz, M.W. Sabelis & K. Sigmund (eds.), Cambridge University Press, Cambridge. Pp 297-321.

8.    Magowski W., Egas M., Bruin J. & Sabelis M.W. (2003). Intraspecific variation in induction of feeding preference and performance in a herbivorous mite. Experimental and Applied Acarology 29:13-25.

9.    Egas M., Norde D.-J. & Sabelis M.W. (2003). Adaptive learning in arthropods: spider mites learn to distinguish food quality. Experimental and Applied Acarology 30: 233-247.

10.  Egas M., Dieckmann U. & Sabelis M.W. (2004). Evolution restricts the coexistence of specialists and generalists – the role of trade-off structure. American Naturalist 163: 518-531.

11.  Vala F., Egas M., Breeuwer J.A.J. & Sabelis, M.W. (2004). Wolbachia affects mating and oviposition behavior of its spider mite host. Journal of Evolutionary Biology 17: 692-700.

12.  Egas M., Sabelis M.W., Vala F. & Lesna I. (2004). Adaptive speciation in agricultural pests. In: Adaptive Speciation, U. Dieckmann, J.A.J. Metz, M. Doebeli & D. Tautz (eds.), Cambridge University Press, Cambridge. Pp 249-263.

13.  Parvinen K. & Egas M. (2004). Dispersal and the evolution of specialisation in a two-habitat type metapopulation. Theoretical Population Biology 66: 233-248.

14.  Kroon A., Veenendaal R.L., Bruin J., Egas M. & Sabelis M.W. (2004). Predation risk affects diapause induction in the spider mite Tetranychus urticae. Experimental and Applied Acarology 34: 307-314.

15.  Egas M. (2005). Evolution of specialization and ecological character displacement: metabolic plasticity matters. In: Current Themes in Theoretical Biology: A Dutch Perspective (eds. Th.A.C. Reydon, L. Hemerik), Springer, Dordrecht, pp 281-304.

16.  Kroon A., Veenendaal R.L., Egas M., Bruin J. & Sabelis M.W. (2005). Diapause incidence in the two-spotted spider mite increases due to predator presence, not due to selective predation. Experimental and Applied Acarology 35: 73-81.

17.  Egas M., Sabelis M.W. & Dieckmann U. (2005). Evolution of specialization and ecological character displacement along a gradient of plant quality. Evolution 59(3): 507-520.

18.  De Bruijn P.J.A., Egas M., Janssen A. & Sabelis M.W. (2006). Pheromone-induced priming of a defensive response in Western Flower Thrips. Journal of Chemical Ecology 32: 1599-1603.

19.  Rueffler C., Egas M. & Metz J.A.J. (2006). Evolutionary predictions should be based on individual-level traits. American Naturalist 168: E148-E162.

20.  Xue H., Egas M. & Yang X. (2007). Development of a positive preference-performance relationship in an oligophagous beetle: adaptive learning? Entomologia experimentalis et applicata 125: 119-124.

21.  Egas M. & Riedl A. (2008). The economics of altruistic punishment and the maintenance of cooperation. Proceedings of the Royal Society London B Biological Sciences 275: 871-878.

22. Stomp, M., Van Dijk M.A., Van Overzee H.M.J., Wortel M., Sigon C.A.M., Egas M., Hoogveld H., Gons H.J. & Huisman J. (2008). The time scale of phenotypic plasticity, and its impact on competition in fluctuating environments. American Naturalist 172: E169-E185.

23. Kroon, A., Veenendaal R.L., Bruin J., Egas M. & Sabelis M.W. (2008). “Sleeping with the enemy” – Predator-induced diapause in a mite. Naturwissenschaften 95: 1195-1198.

24. Magalhaes, S., Blanchet E., Egas M. & Olivieri I. (2009). Are adaptation costs necessary to build up a local adaptation pattern? BMC Evolutionary Biology 9: 182.

25. Tien, N.S.H., Sabelis M.W. & Egas, M. (2009). The heritability of defense and life-history traits in the two-spotted spider mite. Evolutionary Ecology Research 11: 1271-1281.

26.  Bijleveld, A.I., Egas, M., Van Gils, J.A., & Piersma, T. (2010) Beyond the information centre hypothesis: communal roosting for information on food, predators, travel companions and mates? OIKOS 119: 277-285.

27.  Sznajder, B., Sabelis M.W. & Egas M. (2010). Response of predatory mites to a herbivore-induced plant volatile: genetic variation for context-dependent behaviour. Journal of Chemical Ecology 36: 680-688.

28.  Tien, N.S.H., Sabelis M.W. & Egas, M. (2010). The maintenance of genetic variation for oviposition rate in two-spotted spider mites: inferences from artificial selection. Evolution 64: 2547–2557.

29.  Van Veelen, M., Garcia J., Sabelis M.W., & Egas M. (2010). Call for a return to rigour in models. Nature 467: 661.

30.  Branco, P., Stomp, M., Egas, M. & Huisman, J. (2010). Evolution of nutrient uptake reveals a trade-off in the ecological stoichiometry of plant-herbivore interactions. American Naturalist 176: E162-E176.

31.  Tien, N.S.H., Sabelis M.W. & Egas, M. (2011). Ambulatory dispersal in Tetranychus urticae: An artificial selection experiment on propensity to disperse yields no response. Experimental and Applied Acarology 53: 349–360.

32.  Sznajder, B., Sabelis M.W. & Egas M. (2011). The interplay between genetic and learned components of behavioural traits. Journal of Plant Interactions 6(2): 77-80.

33.  Tien, N.S.H., Massourakis, G., Sabelis M.W. & Egas, M. (2011). Mate choice promotes inbreeding avoidance in Tetranychus urticae. Experimental and Applied Acarology 54:119-124.

34.  Sznajder, B., Sabelis M.W. & Egas M. (2011). Innate responses of the predatory mite Phytoseiulus persimilis to a herbivore-induced plant volatile. Experimental and Applied Acarology 54:125-138.

35.  Konijnendijk, N., Mrosso H.D.J., Joyce D.A., Egas M., & Seehausen O. (2011) Community genetics reveal elevated levels of sympatric gene flow among morphologically similar but not among morphologically dissimilar species of Lake Victoria cichlid fish. International Journal of Evolutionary Biology, Article ID 616320, 12 pages, doi:10.4061/2011/616320

36.  Magalhaes, S., Blanchet E., Egas M. & Olivieri I. (2011). Environmental effects on the detection of adaptation. Journal of Evolutionary Biology 24: 2653–2662.

37. Van Veelen, M., Garcia J., Sabelis M.W., & Egas M. (2012). Group selection and inclusive fitness are not equivalent; the Price equation vs. models and statistics. Journal of Theoretical Biology 299: 64-80.

38.  Sznajder, B., Sabelis M.W. & Egas M. (2012). How adaptive learning affects evolution: reviewing theory on the Baldwin effect. Evolutionary Biology 39: 301-310, doi:10.1007/s11692-011-9155-2

39.  Molleman, L., Van den Broek E., & Egas M. (2013). Personal experience and reputation interact in human decisions to help reciprocally. Proceedings of the Royal Society London B Biological Sciences 280: 20123044, DOI: 10.1098/rspb.2012.3044.

40.  Egas, M., Kats, R., van der Sar, X., Reuben, E., & Sabelis, M.W. (2013) Human altruism by lethal group competition. Scientific Reports 3: 1373, DOI: 10.1038/srep01373.

41.  Sato, Y., Sabelis M.W., Egas M. & Faraji F. (2013). Alternative phenotypes for male mating behaviour in the two-spotted spider mite. Experimental and Applied Acarology 61:31-41, DOI 10.1007/s10493-013-9673-y

42.  Sato, Y., Egas M., Sabelis M.W. & Mochizuki A. (2013). Male-Male Aggression Peaks at Intermediate Relatedness in a Social Spider Mite. Ecology and Evolution 3:2661-2669, doi: 10.1002/ece3.661

43.  Egas, M., Sabelis M.W. & Dieckmann U. (in press). Evolution of specialization and ecological character displacement along a gradient of plant quality. (Invited book chapter in: Elements of Adaptive Dynamics; eds. J.A.J. Metz, U. Dieckmann)

Secondary literature

Menken S. & Egas M. (2002). Nieuwe soort zoekt nieuwe soort. Natuur & Techniek 70 (3): 36-39.

Egas M. (2002). Spintmijten leren foerageren -nieuw licht op de evolutie van waardplantspecialisatie en gastheerrasvorming. Entomologische Berichten 62(3-4): 66-72.

Egas M., Dieckmann U. & Sabelis M.W. (2004). Evolution restricts the coexistence of specialists and generalists - the role of trade-off structure. IIASA Interim Report IR-04-004 , available at http://www.iiasa. ac.at/Research/ADN/Publications.html .

Egas M. & Riedl A. (2005). The economics of altruisticpunishment and the demise of cooperation. Tinbergen Institute Discussion Paper 05065, available at http://www.tinbergen.nl/discussionpapers/05065.pdf.

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