ADAPTIVE GENETIC VARIATION IN GROWTH AND DEVELOPMENT OF TADPOLES OF THE HYBRIDOGENETIC RANA ESCULENTA COMPLEX

Area of Science:

• Amphibian ecology
• Evolutionary genetics
• Quantitative genetics

Background:

• The sexual species Rana lessonae and the hybridogenetic frog Rana esculenta exhibit different distributions, suggesting varied adaptive capabilities.
• Understanding adaptive plasticity is crucial for predicting species' responses to environmental heterogeneity.

Purpose of the Study:

• To investigate phenotypic and quantitative genetic variation in tadpole responses to varying food levels.
• To compare adaptive abilities and phenotypic plasticity between Rana lessonae and Rana esculenta.

Main Methods:

• Utilized a half-sib design to partition variance components in tadpole traits.
• Assessed growth rate, larval period, and body size at metamorphosis under two distinct food conditions.
• Analyzed sire x food interactions and environmental correlations to infer plasticity.

Main Results:

• Rana lessonae exhibited significant phenotypic variation and adaptive plasticity in growth rate, larval period, and body size.
• Rana esculenta showed less phenotypic variation, particularly in larval period, and lacked phenotypic plasticity in key traits.
• Additive genetic variance was moderate for larval period and body size in Rana lessonae, and high for body size in Rana esculenta.

Conclusions:

• Rana lessonae possesses greater adaptive genetic variation, enabling better coping with heterogeneous environments.
• Rana esculenta's limited plasticity may constrain its ability to adapt to changing environmental conditions.
• Differences in adaptive strategies highlight the evolutionary divergence between sexual and hybridogenetic anuran lineages.