Predator-induced phenotypic plasticity within- and across-generations: a challenge for theory?

Area of Science:

• Ecology
• Evolutionary Biology
• Environmental Science

Background:

• The environment can induce non-genetic phenotypic changes that persist across multiple generations.
• Theory suggests predictable environmental variation favors both within- and across-generation adaptive responses.
• Empirical evidence testing this dual-response prediction is currently lacking.

Purpose of the Study:

• To investigate the relationship between within- and across-generation plasticity.
• To evaluate the influence of predator cues on the life-history traits of Daphnia ambigua.
• To determine the duration and induction timing of predator-induced transgenerational effects.

Main Methods:

• Exposure of Daphnia ambigua to predator cues during embryonic development.
• Measurement of life-history traits, including maturation time and reproductive output.
• Quantification of cues that activate transgenerational plasticity, including those from injured conspecifics.

Main Results:

• Predator exposure induced earlier maturation and increased reproductive output in Daphnia ambigua.
• These transgenerational effects were detectable up to two generations post-exposure.
• A negative correlation was observed between within- and across-generation responses to predator cues, indicating opposite effects.

Conclusions:

• Transgenerational plasticity can manifest as opposing within- and across-generation responses to environmental cues.
• Current theoretical models do not fully explain the observed negative relationship between within- and across-generation plasticities.
• Refinement of theories on transgenerational plasticity is necessary to account for these findings.