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The evolution of alternative developmental pathways: footprints of selection on life‐history traits in a butterfly
Author(s) -
AALBERG HAUGEN I. M.,
BERGER D.,
GOTTHARD K.
Publication year - 2012
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2012.02525.x
Subject(s) - biology , selection (genetic algorithm) , life history theory , evolutionary biology , sexual selection , directional selection , butterfly , population , phenotypic plasticity , diapause , trait , sexual dimorphism , developmental plasticity , natural selection , disruptive selection , genetics , heritability , genetic variation , ecology , life history , zoology , gene , larva , demography , plasticity , artificial intelligence , sociology , computer science , thermodynamics , programming language , physics
Developmental pathways may evolve to optimize alternative phenotypes across environments. However, the maintenance of such adaptive plasticity under relaxed selection has received little study. We compare the expression of life‐history traits across two developmental pathways in two populations of the butterfly Pararge aegeria where both populations express a diapause pathway but one never expresses direct development in nature. In the population with ongoing selection on both pathways, the difference between pathways in development time and growth rate was larger, whereas the difference in body size was smaller compared with the population experiencing relaxed selection on one pathway. This indicates that relaxed selection on the direct pathway has allowed life‐history traits to drift towards values associated with lower fitness when following this pathway. Relaxed selection on direct development was also associated with a higher degree of genetic variation for protandry expressed as within‐family sexual dimorphism in growth rate. Genetic correlations for larval growth rate across sexes and pathways were generally positive, with the notable exception of correlation estimates that involved directly developing males of the population that experienced relaxed selection on this pathway. We conclude that relaxed selection on one developmental pathway appears to have partly disrupted the developmental regulation of life‐history trait expression. This in turn suggests that ongoing selection may be responsible for maintaining adaptive developmental regulation along alternative developmental pathways in these populations.