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Vol. 51 No. 3, 2012
Phenotypic Plasticity in Larval Development of Six Amphibian Species in Stressful Natural Environments
Tali Goldberg1, Eviatar Nevo1, and Gad Degani2,3,*
1Institute of Evolution, Faculty of Sciences and Science Education, University of Haifa, Haifa 31905, Israel
2MIGAL – Galilee Technology Center, PO Box 831, Kiryat Shmona 11016, Israel
3School of Science and Technology, Tel-Hai Academic College, Upper Galilee 12210, Israel
Tali Goldberg, Eviatar Nevo, and Gad Degani (2012)
Phenotypic plasticity is known as the capacity to change in response to
different environmental conditions, and if these changes imply
reversible transformations, it is known as phenotypic flexibility. This
plasticity includes changes in behavior, physiology, morphology,
growth, life history, and demography, and can be expressed either
within the lifespan of a single individual or across generations.
Plasticity in amphibian species, which breed in extreme conditions at
the southern frontier of their distributions, allows an individual to
prolong the larval period and maximize its size at metamorphosis when
conditions are favorable. Plasticity may allow tadpoles to avoid
mortality in a desiccating habitat by accelerating metamorphosis and
reducing their size at metamorphosis. This study examined 6 species of
amphibian larvae over several years that grew and completed
metamorphosis at 14 ephemeral and permanent breeding sites in a
Mediterranean climate. The aim of the current study was to test the
ability of these 6 species to undergo phenotypic changes in larval size
and the course of metamorphosis relative to time, in response to
various water-quality parameters. Of the 6 species tested, the
salamander was the only species that occupied all types of breeding
sites that were sampled and showed significant differences in growth
rates and sizes of tadpoles during metamorphosis by comparison between
individuals from different pools. Five other species mainly inhabited
ephemeral pools. There was no significant difference in the timing of
metamorphosis, but for some species there was a significant difference
in the final size of the tadpoles. In 2 poorly fed, completely dark,
and very shallow breeding sites, we found Salamandra infraimmaculata larvae for longer periods and with a smaller size at metamorphosis.
Key words: Amphibians, Ephemeral habitat, Permanent habitat, Larval growth.
*Correspondence: Tel: 972-5-5586706. Fax: 972-4-6944980. E-mail:gad@migal.org.il
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