Generalists, specialists, and the evolution of phenotypic plasticity in sympatric populations of distinct species

TY - JOUR

T1 - Generalists, specialists, and the evolution of phenotypic plasticity in sympatric populations of distinct species

AU - Van Tienderen, P.H.

N1 - Reporting year: 1997 Metis note: 2250; CTE; PVP; file:///L:/Endnotedatabases/NIOOPUB/pdfs/Pdfs1997/VanTienderen_2250.pdf

PY - 1997

Y1 - 1997

N2 - The evolution of phenotypic plasticity is studied in a model with two reproductively isolated ''species'' in a coarse- grained environment, consisting of two types of habitats. A quantitative genetic model for selection was constructed, in which habitats differ in the optimal value for a focal trait, and with random dispersal among habitats. The main interest was to study the effects of different selection regimes. Three cases were investigated: (1) without any limits to plasticity; (2) without genetic variation for plasticity; and (3) with a fitness cost for phenotypically plastic reactions. in almost all cases a generalist strategy to exploit both habitats emerged. Without any limits to plasticity, optimal adaptive reactions evolved. Without any genetic variation for plasticity, a compromise strategy with an intermediate, fixed phenotype evolved, whereas in the presence of costs a plastic compromise between the demands of the habitats and the costs associated with plasticity was found. Specialization and phenotypic differentiation was only found when selection within habitats was severe and optimal phenotypes for different habitats were widely different. Under soft selection (local regulation of population numbers in each habitat) the specialists coexisted; under hard selection (global regulation of population numbers) one specialist outcompeted the other. The prevalent evolutionary outcome of compromises rather than specialization implies that costs or constraints are not necessarily detectable as local adaptation in transplantation or translocation experiments. [KEYWORDS: phenotypic plasticity; quantitative genetics; reaction norms; specialization Reaction norms; environment interaction; character displacement; quantitative genetics; plantago-lanceolata;selection; defenses]

AB - The evolution of phenotypic plasticity is studied in a model with two reproductively isolated ''species'' in a coarse- grained environment, consisting of two types of habitats. A quantitative genetic model for selection was constructed, in which habitats differ in the optimal value for a focal trait, and with random dispersal among habitats. The main interest was to study the effects of different selection regimes. Three cases were investigated: (1) without any limits to plasticity; (2) without genetic variation for plasticity; and (3) with a fitness cost for phenotypically plastic reactions. in almost all cases a generalist strategy to exploit both habitats emerged. Without any limits to plasticity, optimal adaptive reactions evolved. Without any genetic variation for plasticity, a compromise strategy with an intermediate, fixed phenotype evolved, whereas in the presence of costs a plastic compromise between the demands of the habitats and the costs associated with plasticity was found. Specialization and phenotypic differentiation was only found when selection within habitats was severe and optimal phenotypes for different habitats were widely different. Under soft selection (local regulation of population numbers in each habitat) the specialists coexisted; under hard selection (global regulation of population numbers) one specialist outcompeted the other. The prevalent evolutionary outcome of compromises rather than specialization implies that costs or constraints are not necessarily detectable as local adaptation in transplantation or translocation experiments. [KEYWORDS: phenotypic plasticity; quantitative genetics; reaction norms; specialization Reaction norms; environment interaction; character displacement; quantitative genetics; plantago-lanceolata;selection; defenses]

KW - NIOO/CTE/PVP

U2 - 10.2307/2411189

DO - 10.2307/2411189

M3 - Article

SN - 0014-3820

VL - 51

SP - 1372

EP - 1380

JO - Evolution

JF - Evolution

IS - 5

ER -