Predators drive selection for adaptive plasticity in prey defense behavior

Area of Science:

• Ecology
• Evolutionary Biology
• Animal Behavior

Background:

• Prey animals often reduce activity to evade predators, a strategy known as plasticity.
• This reduced activity can lead to lower growth rates due to decreased foraging opportunities.
• Selection may favor not only reduced activity but also the ability to resume activity when predation risk diminishes.

Purpose of the Study:

• To investigate how fish predation influences the activity plasticity of damselflies.
• To determine if damselflies exhibit adaptive plasticity in activity in response to predation threats.
• To examine the relationship between predator density and the extent of prey activity plasticity.

Main Methods:

• A mesocosm experiment was conducted using a damselfly-prey/fish-predator system.
• An observational study was performed in natural lakes with varying fish densities.
• Damselfly activity rates were monitored in relation to predation pressure.

Main Results:

• Fish predation was found to select for greater plasticity in damselfly activity rates.
• Damselflies decreased activity when fish were present and resumed activity when the threat subsided.
• The degree of activity plasticity increased slightly with increasing fish densities in natural lakes.

Conclusions:

• Selection drives adaptive plasticity in predator avoidance strategies.
• Damselflies demonstrate plasticity in activity to mitigate predation risk and potential growth penalties.
• Environmental factors, such as predator density, shape the magnitude of adaptive plasticity.