Interactions in the evolution of dispersal distance and emigration probability [Elektronische Ressource] / vorgelegt von Andreas Gros

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Biologie

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Publié par	julius-maximilians-universitat_wurzburg
Publié le	01 janvier 2008
Nombre de lectures	18
Langue	Deutsch

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Interactions in the evolution of dispersal
distance and emigration probability
Dissertation zur Erlangung des
naturwissenschaftlichen Doktorgrades
der Bayerischen Julius-Maximilians-Universität Würzburg
vorgelegt von
Andreas Gros
(geboren in Addis Abeba)
Würzburg, Mai 2008Eingereicht am: ....................................................
Mitglieder der Promotionskommission:
Vorsitzender: Prof. Dr. Martin J. Müller
Gutachter: Prof. Dr. Hans Joachim Poethke
Gutachter: Prof. Dr. Dieter Tautz
Tag des Promotionskolloquiums: ....................................
Doktorurkunde ausgehändigt am: ...................................Ich versichere hiermit ehrenwörtlich, dass die Dissertation von mir selbständig,
ohne unerlaubte Beihilfe und nur mit Hilfe der angegebenen Quellen und Hilfsmit-
tel angefertigt ist.
Hiermit erkläre ich, dass ich mich anderweitig einer Doktorprüfung ohne Erfolg
nicht unterzogen habe.Contents
0 General introduction 7
0.1 Chapter 1 - “Evolution of local adaptations in dispersal strategies” . 10
0.2 Chapter 2 - “The eﬀect of kin-competition and population density
on the evolution of dispersal under distance dependent costs” . . . . 12
0.3 Chapter 3 - “Evolution of sex-biased dispersal: the role of sex-
speciﬁc dispersal costs, demographic stochasticity, and inbreeding” . 14
0.4 Chapter 4 - “Evolution of sex-biased dispersal under asymmetric
competition and demographic stochasticity” . . . . . . . . . . . . . 16
1 Evolution of spatial pattern in dispersal strategies 19
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.2 Material and Methods . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2 How dispersal propensity and distance depend on the capability
to assess population-density 31
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3 Evolutionofsex-biaseddispersal: theroleofsex-speciﬁcdispersal
costs, demographic stochasticity, and inbreeding 51
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.2 The model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.3 Individual-based simulations . . . . . . . . . . . . . . . . . . . . . . 56
3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
3.5 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
56 CONTENTS
4 Sex-speciﬁc spatio-temporal variability in reproductive success
promotes the evolution of sex-biased dispersal 65
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2 The model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
4.5 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Bibliography 77
Zusammenfassung 91
List of publications 97
Curriculum Vitae 99
Anteilsbeschreibung 101
Acknowledgements 103Chapter 0
General introduction
In this thesis I use mathematical and computer simulation methods to investigate
certain aspects of the evolution of dispersal strategies of plants and animals. In
very general terms, dispersal is a process by which species spread over a given
landscape. The ability to colonize new habitats or to escape from unfavourable
conditionsisakey element inspecies survival. Thelossofspecies asaconsequence
of changes in environmental conditions and its eﬀects on biodiversity emphasize
the importance of research on the evolution of dispersal strategies.
Following thedeﬁnitionofHoward(1960),Iassume dispersaltobe “the permanent
movement an individual makes from its birth site to the place where it reproduces
or would have reproduced had it survived and found a mate.” This is one of the
most commonly used deﬁnitions of natal dispersal. It was extended by Johnson
and Gaines (1990), who state that an “additional type of movement is breeding
dispersal, or the movement from one homerange to another between attempts at
reproduction, disregarding whether reproduction is successful.” (see also Green-
wood and Harvey, 1982). Like in Johnson and Gaines (1990), I consider no min-
imum distance requirement for dispersal, because this would just be an arbitrary
limitation.
Ithereforeconsider twotypesofdispersal: nataldispersal, theemigrationfromthe
natal habitat, and breeding dispersal. In this thesis, breeding dispersal happens
after natal dispersal. In principle breeding dispersal could also happen after a
breeding attempt in the natal habitat, but this case is not considered in this
thesis.
While natal dispersal is always only the ﬁrst step of leaving the natal habitat,
breeding dispersal can consist of multiple dispersal moves between habitats that
individuals perform in order to ﬁnd a suitable habitat for reproduction. In this8 General introduction
thesis, mating and breeding in animals happens always in the (ﬁnal) habitat they
occupy after optional dispersal. For philopatric (non-dispersing) individuals the
natal habitat is also the breeding habitat.
The investigation of the spatial distribution of species by Charles Darwin and
Alfred Russel Wallace in the 19th century (see Darwin, 1859; Wallace, 1877,1887)
was the starting point of scientiﬁc research on the spread of species. Kew (1893)
investigated the dispersal of fresh-water and land Mollusca and was one of the
ﬁrst to report on various dispersal vectors, e.g. insects, batrachians, birds and
humans (for a review see Packard, 1896). In the early 20th century Pearson and
Blakeman (1906) and Brownlee (1911) started to work on mathematical models
about random migration, which were later taken up by geneticists (e.g. Fisher,
1937; Haldane, 1948). The ﬁrst to deliver a broad mathematical discussion of the
spread and growth of species was Skellam (1951), acknowledging the developing
ﬁeld of evolutionary genetics.
However,itwasHamilton(1964)whoﬁrstformalizedthenotionofgeneticselection
on traits that were not necessarily beneﬁcial to the individual itself, but to its kin,
making it possible to mathematically study the evolution of social behaviour and
dispersalstrategiesthatwereimpossibletodescribewiththepreviouslyestablished
models. This concept of kin-selection (see below) was applied to investigate the
evolution of dispersal strategies by Hamilton and May (1977).
After theoretical works that either considered dispersal probability (Hamilton and
May, 1977; Comins et al., 1980; Comins, 1982; Motro, 1983; Travis and Dytham,
1998;GandonandMichalakis, 1999;Cadetetal.,2003)ordispersaldistance(Skel-
lam, 1951; Kitching, 1971; Hovestadt et al., 2001; Murrell et al., 2002; Rousset
and Gandon, 2002; Levin et al., 2003), the processes driving the evolution of both
characters are well understood. However, these studies did not consider possible
interactions in the evolution of both, dispersal probability and dispersal distance.
In this thesis I investigate interactions in the concurrent evolution of dispersal
probability and dispersal distance.
Such interactions can be of various kind and they can be determined by various
factors.
For example, if environmental changes lower local habitat quality, it can become
necessary to emigrate from the natal patch to search for a better habitat for
reproduction. Yet, depending on the spatial extent of the habitat deterioration it
can take longer time and farther distances to reach a better habitat. Therefore,
as long as the distances the individuals are capable of dispersing are too short to
reachbetterpatches,theslightestdispersalmortalitywillselectagainstemigration,9
so that dispersal probability will most likely remain low. Only when mutation
and selection result in the evolution of dispersers capable of moving suﬃciently
long distances to reach good quality habitat, selection will favor higher dispersal
probabilities. Hence, in this example there is an interaction between dispersal
distance and emigration propensity.
Iinvestigatethenatureofsuchinteractionsandtheeﬀectofdiﬀerent factorswhich
can inﬂuence either emigration probability, dispersal distance, or both.
The evolution of dispersal strategies is shaped by costs and beneﬁts of dispersal,
which in turn can be determined by various factors. Costs of dispersal comprise
dispersal mortality, which may be aﬀected by factors like time and distance spent
on dispersal, but also metabolic investment into the ability to disperse (e.g. bigger
muscles, longer wings, higher fat storage) (Jenkins et al., 2007). This metabolic
investment often happens at the expense of fertility (Mole and Zera, 1993; Lan-
gellotto et al., 2000; Zera and Harshman, 2001). Another cost factor is the time
spent on dispersal that an individual cannot spend on reproduction (Hanski et al.,
2006). Hence, dispersal c