- a workshop organised by the European Research Training Network ModLife -


Nonequilibrium populations and stochastic environments get increasing attention in life history evolution. The aim of the workshop is to discuss this issue both from theoretical and empirical points of view. One empirical system of interest, around which part of the workshop will be organised, is the side-blotched lizard, where two distinct life-history strategies coexist in a nonequilibrium population (see Sinervo et al. in Nature 406(2000)985-988).

We envisage a workshop with a flexible structure, where we can discuss models and empirical research in pretty much detail, and everyone is encouraged to be as technical as necessary for an in-depth understanding. In this spirit, follow-ups and more detailed accounts are welcome even if the problem has been presented at a previous ModLife workshop. Open problems could also be discussed, and there will be time for private discussions.


General information

Place: University of Turku (Finland)

Time: 12 - 15 September 2002

12 September (Thursday): evening program
13 - 14 September: scientific program
15 September (Sunday): leaving

Lectures will be held in Seminar Room MS-3 on the 3rd floor of the Natural Science Building II (T6 on the campus map)

Accommodation: Hotel Centro, Yliopistonkatu 12a, 20100 Turku (phone: +358-2-469 0469)


Financial support: Human Potential Programme of the European Commission, with additional funding from the STADYCS research consortium of the Academy of Finland

Useful links:

The town of Turku
Map of Turku


Time schedule for 13-14 September:

morning session: 9:00 - 13:00 with a coffee break at about 10:30

lunch break: 13:00 - 14:30

afternoon session: 14:30 - 17:00 with a coffee break at about 15:30

dinner: 19:00


Program (* see abstract below)

I would like to keep the program as flexible as possible in order to facilitate discussions both during lectures and in small working groups. To this end, presentations are not constrained by a rigid time schedule, and we can reorganise the program on the spot as needed. By and large, we shall treat nonequilibrium populations on Friday and stochastic environments on Saturday.

Friday 13 September, morning session

Barry Sinervo*: TBA (on the side-blotched lizard (Uta stansburiana) system)

Barry Sinervo & Tom van Dooren: Predicting developmental genetics from population dynamics: Polymorphic lizards as an example

Jon Brommer*: Natal effects in Ural owls living on a cyclically fluctuating prey


 Friday 13 September, afternoon session

Tom van Dooren & Claus Rueffler: Environmental feedback and evolution in simple life history models with non-equilibrium population dynamics

Kalle Parvinen*: Evolution of dispersal with cyclic local population dynamics

Mats Gyllenberg: On the concept of attractor for dynamical systems describing communities of structured populations

Ulf Dieckmann: Invasion fitness in slightly fluctuating environments


Saturday 14 September, morning session

Hans Metz: Small noise approximations for the invasion dynamics of new mutants in populations with density dependent dynamics in stochastically fluctuating environments

Martijn Egas: Evolutionary coexistence of specialists and generalists revisited

Eva Kisdi*: Evolution of diversity in stochastic environments


Saturday 14 September, afternoon session

Patsy Haccou & Vladimir Vatutin*: Establishment success and extinction risk in autocorrelated environments

Jean Clobert: TBA (on the effect of density dependence, environmental and demographic stochasticity on persistence time of spiders on the Bahamas)

Hans Metz: A different model to explain delayed germination

Else Fjerdingstad: Tetrahymena thermophila and the evolution of dispersal


List of participants (¤ Friday only)

Jon Brommer (University of Helsinki)
Jean Clobert (University of Pierre et Marie Curie, Paris)
Ulf Dieckmann (IIASA)
Martijn Egas (IIASA)
Bruno Ernande (IIASA)
Else Fjerdingstad (University of Pierre et Marie Curie, Paris)
Patrick Fitze (University of Pierre et Marie Curie, Paris)
Stefan Geritz ¤ (University of Turku)
Mats Gyllenberg ¤ (University of Turku)
Patsy Haccou (University of Leiden)
Eva Kisdi (University of Turku)
Hans (JAJ) Metz (University of Leiden)
Kalle Parvinen ¤ (University of Turku)
Claus Rueffler (University of Leiden)
Barry Sinervo ¤ (University of California)
Thomas Tully (Ecole Normale Superieure, Paris)
Tom van Dooren (University of Leiden)


Abstracts (where given; in alphabetic order)

Jon Brommer: Natal effects in Ural owls living on a cyclically fluctuating prey

In the boreal zone, the populations of voles fluctuate in large-amplitude, multi-annual cycles. Voles are the Ural owl's main food supply. I will present an overview of how the vole cycle interacts with the owl's life history.

Patsy Haccou & Vladimir Vatutin: Establishment success and extinction risk in autocorrelated environments.

We consider establishment success (and extinction risk of small populations) in fluctuating environments, by means of an inhomogeneous branching process model. In this model it is assumed that individuals reproduce asexually during discrete reproduction periods. Within each period individuals reproduce independently and have random numbers of offspring. Expected numbers of offspring vary over reproduction periods due to random environmental changes. Previous simulation results indicated that there is a positive autocorrelation between the establishment probabilities of invaders in successive reproduction periods when environmental states are independently distributed. This result was never formally proved. We proved that this is indeed true, regardless of the form of the distribution of environmental states or the offspring distribution (under a monotonicity condition, which holds for biologically realistic models). Furthermore, we proved that it is also true for positively autocorrelated environmental states. We showed by a counterexample that in environments with a strong negative autocorrelation establishment probabilities can be negatively autocorrelated. This was further examined through simulations. Our results imply that in independent, positively autocorrelated and weakly negatively autocorrelated environments the probability of success of invasion in different independently varying sites is the highest, followed by sequential invasion. For environments with a strong negative autocorrelation, sequential invasion has the highest probability of success. Effects of autocorrelation were further examined with simulations. From the results it appears that the expected length of Śruns of bad lucką is the most crucial factor for establishment success.

Eva Kisdi: Evolution of diversity in stochastic environments

Environmental stochasticity leads to frequency-dependent selection under most regimes of population regulation, and thus can facilitate the evolution of diversity either by evolutionary branching or by the evolution of mixed strategies. By reviewing three models, I show that (i) how the ESS under weak stochasticity differs from the stable environment optimum, (ii) sufficiently strong environmental stochasticity can lead to evolutionary branching or to the evolution of mixed life history strategies, but (iii) environmental stochasticity can hinder branching in the well-known Lotka-Volterra competition model.

Kalle Parvinen: Evolution of dispersal with cyclic local population dynamics

In this paper a general deterministic discrete-time metapopulation model with a finite number of habitat patches is analysed within the framework of adaptive dynamics. We study a general model and prove analytically that (i) if the resident populations state is a fixed point, then the resident strategy with no migration is an evolutionarily stable strategy, (ii) a mutant population with no migration can invade any resident population in a fixed point state, (iii) in the uniform migration case the strategy not to migrate is attractive under small mutational steps so that selection favours low migration. Some of these results have been previously observed in simulations, but here they are proved analytically in a general case. If the resident population is in a two-cyclic orbit, then the situation is different. In the uniform migration case the invasion behaviour depends both on the type of the residents attractor and the survival probability during migration. If the survival probability during migration is low, then the system evolves towards low migration. If the survival probability is high enough, then evolutionary branching can happen and the system evolves to a situation with several coexisting types. In the case of out-of-phase attractor, evolutionary branching can happen with significantly lower survival probabilities than in the in-phase attractor case. Most results in the two-cyclic case are obtained by numerical simulations. Also, when migration is not uniform we observe in numerical simulations in the two-cyclic orbit case selection for low migration or evolutionary branching depending on the survival probability during migration.

Barry Sinervo

Understanding population regulation is a fundamental goal of ecological and evolutionary studies. Population regulation must arise from effects of interactions between individuals on rate of reproduction and progeny survival. Interactions will be intense at high density, but weak at low density. The recent discovery of a genetic basis for population regulation of side-blotched lizards facilitates study of density effects. Lizards carry a genetic color marker for alternative reproductive strategies that have cascading effects on progeny survival. Laboratory breeding studies demonstrate that the color marker and associated reproductive attributes are due to a single gene. This genetic linkage has profound implications for the evolution of population regulation. Intersexual ontogenetic conflict arises when an allele's fitness optimum differs between the sexes. I present the first evidence of ontogenetic conflict from a wild population of the side-blotched lizard, Uta stansburiana, showing that genes for male body-size confer high or low fitness depending on sex of the progeny. Thus, selection on female traits during the course of the female density and frequency cycle is antagonized by selection on male traits during the male rock-paper-scissors cycle. I describe the spatial and temporal scale of strong selection on female traits in the side-blotch lizard. The female density cycle is driven by natural selection in small neighborhoods and the cycle is synchronized by strong natural selection on progeny mass on later clutches, when progeny density peaks. However, in alternate years of the cycle, progeny density is well below carrying capacity and progeny enjoy high survival, thereby allowing the lizards to overshoot the adult carrying capacity in the next generation. The male cycle is perpetual because a two-point attractor in the two-year female cycle perturbs the male game away from its single-point attractor. The high reproductive rate of the female cycle allows the female game to establish a stable two-point attractor in female frequency.


For more information, contact Eva Kisdi (