Foraging strategy mediates ectotherm predator-prey responses to climate warming

Area of Science:

• Ecology
• Climate Change Biology
• Predator-Prey Dynamics

Background:

• Climate warming impacts predator performance, affecting feeding and growth rates.
• The role of predator foraging strategy in mediating these effects is not well understood.

Purpose of the Study:

• To investigate how predator foraging strategy (active vs. sit-and-wait) interacts with temperature to influence predator performance.
• To quantify changes in feeding rates, growth, and underlying mechanisms across a temperature gradient.

Main Methods:

• Experimental manipulation of temperature across a gradient.
• Measurement of predator feeding rates, growth rates, swimming speeds (predator and prey), prey encounter rates, capture success, attack rates, and handling times.
• Utilized two ectotherm predators (backswimmer Notonecta undulata and damselfly Enallagma annexum) and active prey (zooplankton Daphnia pulex).

Main Results:

• Warming increased feeding rates for both predator types by altering components of their functional response.
• Prey swimming speed increased significantly with temperature.
• Active predators experienced higher prey encounter rates at warmer temperatures, but decreased capture success.
• Sit-and-wait predators experienced a fourfold increase in prey encounter rates with rising temperatures and slightly increased capture success.

Conclusions:

• Predator foraging strategy mediates the indirect effects of climate warming on predator performance.
• Understanding trait-mediated responses to warming is crucial for predicting climate change impacts on ecological communities and functional groups.