NATURAL SELECTION FOR ENVIRONMENTALLY INDUCED PHENOTYPES IN TADPOLES

Area of Science:

• Ecology
• Evolutionary Biology
• Developmental Biology

Background:

• Phenotypic plasticity is crucial for organisms adapting to changing environments.
• Previous studies show induced phenotypes can outperform others in specific conditions.
• Understanding selection targets and plasticity is key to explaining trait evolution.

Purpose of the Study:

• To investigate phenotypic plasticity and selection targets in Pseudacris triseriata tadpoles.
• To compare tadpole responses in predator-free versus predator-present environments.
• To determine if morphological plasticity aligns with selection pressures.

Main Methods:

• Tadpoles were reared with and without Anax dragonflies for 32 days.
• Selection was measured by regressing growth/survival against morphology and activity.
• Predation trials assessed survival phenotypes in the presence of Anax.

Main Results:

• Selection on tail and body shape differed between environments, acting in opposite directions.
• Tadpoles with specific tail shapes (deep fin, wide muscle) survived better with Anax.
• Tadpoles with narrow tail muscle and shallow fin/deep body grew faster without predators.
• Tail shape plasticity mirrored selection, but body shape showed no plasticity despite strong selection.

Conclusions:

• Pseudacris triseriata tadpoles exhibit tail shape plasticity that aligns with Anax dragonfly selection.
• Body shape plasticity is limited, indicating developmental rigidity or opposing selection.
• Phenotypic plasticity in tail traits may have evolved under intermittent dragonfly predation.
• Developmental constraints may prevent adaptation in body morphology despite predator-induced selection.