Leaf litter resource quality induces morphological changes in wood frog (Lithobates sylvaticus) metamorphs

Area of Science:

• Ecology
• Evolutionary Biology
• Amphibian Biology

Background:

• Resource conditions before metamorphosis influence later phenotypes in organisms with complex life cycles.
• Resource quantity effects are known, but the impact of resource quality (chemistry) on amphibian development is less understood.
• Plant community composition changes may alter wetland resource quality.

Purpose of the Study:

• To test the hypothesis that variation in resource quality induces a gradient of morphological effects on anuran metamorphs.
• To investigate how different leaf litter species, representing diverse wetland plant communities, affect wood frog (Lithobates sylvaticus) morphology.

Main Methods:

• Outdoor mesocosm experiment manipulating leaf litter quality for larval wood frogs.
• Eleven distinct leaf litter treatments from open- and closed-canopy wetland plant species were used.
• Mass-adjusted morphological dimensions of metamorphs were measured and analyzed in relation to litter characteristics.

Main Results:

• Significant, graded morphological responses were observed across most mass-adjusted dimensions.
• Hindlimb dimensions and gut mass correlated positively with litter nutrient content and decomposition rate.
• Forelimb length and head width correlated positively with phenolic acids and dissolved organic carbon; limb length/width related to larval period duration.

Conclusions:

• Leaf litter species composition, not just presence/absence or canopy type, drives specific morphological changes in metamorphs.
• Resource quality, particularly plant chemistry, plays a crucial role in shaping amphibian development and morphology.
• Changes in wetland plant communities will have species-specific impacts on amphibian metamorphosis, contingent on litter composition.