Premium
Contemporary egg size divergence among sympatric grayling demes with common ancestors
Author(s) -
Gregersen F.,
Haugen T. O.,
Vøllestad L. A.
Publication year - 2008
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/j.1600-0633.2007.00264.x
Subject(s) - tributary , sympatric speciation , grayling , sympatry , biology , competition (biology) , ecology , divergence (linguistics) , interspecific competition , geography , linguistics , philosophy , arctic , cartography
This study documents divergence in egg size that has occurred over less than 25 generations among sympatric demes of European grayling ( Thymallus thymallus ) from Lake Lesjaskogsvatnet in Norway. A cluster analysis identified two clusters of tributaries: one of small, warm tributaries (SW) and the other of large, cold tributaries (LC). Spawning occurs more regularly and up to 4 weeks earlier in SW tributaries compared with that in LC ones. We explored numerous mixed models predicting egg size from year (random effect), basin and tributary (fixed effects), and female length. The most supported model estimated length‐adjusted egg size to be larger in SW tributaries compared with that in LC tributaries. Combinations of density‐dependent (competition for food/space) and density‐independent (temperature) factors along with phenotypic plasticity and maternal effects are discussed as potential differentiation sources. We suggest high temperatures (increased metabolism) to reinforce the selective advantage of large eggs under conditions with highly density‐dependent fry interactions.