Original Article

Population Ecology

, Volume 50, Issue 1, pp 3-8

First online:

Variation in juvenile growth rates among and within latitudinal populations of the medaka

  • Kazunori YamahiraAffiliated withDepartment of Environmental Science, Faculty of Science, Niigata University Email author 
  • , Kenichi TakeshiAffiliated withDepartment of Environmental Science, Faculty of Science, Niigata University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

In ectotherms, lower temperatures at high latitudes would theoretically reduce annual growth rates of individuals. If slower growth and resulting smaller body size reduce fitness, individuals at high latitudes may evolve compensatory growth. This study compares individual growth rates among and within 12 latitudinal populations of the medaka (Oryzias latipes). Growth rates during juvenile stage were measured in a common, temperature-controlled (28°C) environment. The results revealed that juvenile growth rates differed significantly among the populations. Growth rates were, moreover, significantly correlated with latitudes of source populations, such that higher-latitude individuals grew faster. Significant variation in growth rates among full-sib families within populations was also demonstrated. The results strongly suggest that higher-latitude O. latipes have acquired a greater capacity for growth as an adaptation to shorter growing seasons (which would reduce annual growth rates), thus refuting probability processes, i.e., genetic drift, founder, or bottleneck effects, as a cause of the among-population variation.

Keywords

Adaptation Full-sib Genetic variation Latitude Oryzias latipes Sesonality