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How adaptive plasticity evolves when selected against

How adaptive plasticity evolves when selected against
How adaptive plasticity evolves when selected against

Adaptive plasticity allows organisms to cope with environmental change, thereby increasing the population's long-term fitness. However, individual selection can only compare the fitness of individuals within each generation: if the environment changes more slowly than the generation time (i.e., a coarse-grained environment) a population will not experience selection for plasticity even if it is adaptive in the long-term. How does adaptive plasticity then evolve? One explanation is that, if competing alleles conferring different degrees of plasticity persist across multiple environments, natural selection between genetic lineages could select for adaptive plasticity (lineage selection). We show that adaptive plasticity can evolve even in the absence of such lineage selection. Instead, we propose that adaptive plasticity in coarse-grained environments evolves as a by-product of inefficient short-term natural selection: populations that rapidly evolve their phenotypes in response to selective pressures follow short-term optima, with the result that they have reduced long-term fitness across environments. Conversely, populations that accumulate limited genetic change within each environment evolve long-term adaptive plasticity even when plasticity incurs short-term costs. These results remain qualitatively similar regardless of whether we decrease the efficiency of natural selection by increasing the rate of environmental change or decreasing mutation rate, demonstrating that both factors act via the same mechanism. We demonstrate how this mechanism can be understood through the concept of learning rate. Our work shows how plastic responses that are costly in the short term, yet adaptive in the long term, can evolve as a by-product of inefficient short-term selection, without selection for plasticity at either the individual or lineage level.

1553-734X
e1006260
Rago, Alfredo
12ff6af9-c7dc-4eb2-9bdf-43c876c19737
Kouvaris, Kostas
ced6ce72-5863-4af8-82f6-dea1576b9d23
Uller, Tobias
05ac1f63-5fd6-490d-8f9f-f7d3ed62b948
Watson, Richard
ce199dfc-d5d4-4edf-bd7b-f9e224c96c75
Rago, Alfredo
12ff6af9-c7dc-4eb2-9bdf-43c876c19737
Kouvaris, Kostas
ced6ce72-5863-4af8-82f6-dea1576b9d23
Uller, Tobias
05ac1f63-5fd6-490d-8f9f-f7d3ed62b948
Watson, Richard
ce199dfc-d5d4-4edf-bd7b-f9e224c96c75

Rago, Alfredo, Kouvaris, Kostas, Uller, Tobias and Watson, Richard (2019) How adaptive plasticity evolves when selected against. PLoS computational biology, 15 (3), e1006260. (doi:10.1371/journal.pcbi.1006260).

Record type: Article

Abstract

Adaptive plasticity allows organisms to cope with environmental change, thereby increasing the population's long-term fitness. However, individual selection can only compare the fitness of individuals within each generation: if the environment changes more slowly than the generation time (i.e., a coarse-grained environment) a population will not experience selection for plasticity even if it is adaptive in the long-term. How does adaptive plasticity then evolve? One explanation is that, if competing alleles conferring different degrees of plasticity persist across multiple environments, natural selection between genetic lineages could select for adaptive plasticity (lineage selection). We show that adaptive plasticity can evolve even in the absence of such lineage selection. Instead, we propose that adaptive plasticity in coarse-grained environments evolves as a by-product of inefficient short-term natural selection: populations that rapidly evolve their phenotypes in response to selective pressures follow short-term optima, with the result that they have reduced long-term fitness across environments. Conversely, populations that accumulate limited genetic change within each environment evolve long-term adaptive plasticity even when plasticity incurs short-term costs. These results remain qualitatively similar regardless of whether we decrease the efficiency of natural selection by increasing the rate of environmental change or decreasing mutation rate, demonstrating that both factors act via the same mechanism. We demonstrate how this mechanism can be understood through the concept of learning rate. Our work shows how plastic responses that are costly in the short term, yet adaptive in the long term, can evolve as a by-product of inefficient short-term selection, without selection for plasticity at either the individual or lineage level.

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More information

Accepted/In Press date: 18 January 2019
e-pub ahead of print date: 8 March 2019
Published date: March 2019

Identifiers

Local EPrints ID: 430064
URI: http://eprints.soton.ac.uk/id/eprint/430064
ISSN: 1553-734X
PURE UUID: 35bd6211-1445-476e-b136-ac0cd6c42665
ORCID for Alfredo Rago: ORCID iD orcid.org/0000-0002-7925-4331

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Date deposited: 11 Apr 2019 16:30
Last modified: 19 Jul 2019 16:36

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