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Seasonality and the scheduling of life history at different latitudes
Author(s) -
Conover D. O.
Publication year - 1992
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1992.tb03876.x
Subject(s) - biology , ectotherm , seasonality , latitude , ecology , life history theory , seasonal breeder , reproduction , bergmann's rule , life history , growing season , annual cycle , zoology , geodesy , geography
For many ectotherms, the annual cycle is partitioned into ‘growing’ (summer) and ‘non‐growing’ (winter) seasons, and the lengths of these seasons are inversely related across a latitudinal gradient. This pattern of variation has the potential to affect diverse life‐history traits profoundly. A key selective agent is size‐dependent winter mortality which, with increasing latitude, places an increasing premium on attainment of large body size before the first winter of life. Winter body size is determined primarily by two factors: (1) birth date, which defines the beginning of the first growing season and (2) somatic growth rate within the first season. Using examples drawn from the Atlantic silverside, Menidia menidia (L.), and other fishes, I show how latitudinal variation in the scheduling of the spawning season, countergradient variation in the capacity for growth and reproduction, and mode of sex determination (environmental v. genetic) represent adaptations to seasonality.