Predation risk estimated on live and artificial insect prey follows different patterns

Area of Science:

• Ecology
• Evolutionary Biology
• Predator-Prey Dynamics

Background:

• Artificial prey models are increasingly used in ecological research to test theories.
• Current understanding suggests artificial models may not perfectly mirror predation pressure on live prey.
• Previous studies indicate that while quantitative accuracy may differ, artificial models can still be valuable for comparative analyses.

Purpose of the Study:

• To investigate if live and artificial prey reveal similar patterns of predation risk variation.
• To compare predation rates and seasonal dynamics between live prey (blowfly larvae/puparia) and artificial models.
• To assess the influence of predator type (avian vs. invertebrate) and seasonal changes on predation estimates.

Main Methods:

• Live blowfly larvae and puparia, alongside plasticine models of puparia, were exposed in boreal forest sites.
• Open exposure and exclusion treatments (ant- and bird-) were employed to differentiate predator impacts.
• Avian and invertebrate predator attacks were quantified, with observations on wood ant interactions.

Main Results:

• Bird attack rates were higher on live puparia than models, with this difference decreasing seasonally.
• Invertebrate predation on live maggots decreased seasonally, while model attacks showed no seasonal change.
• Invertebrate predation on live prey was substantially higher (67-fold) than on models, and wood ants did not attack models.

Conclusions:

• Estimates of predator importance (birds vs. invertebrates) can differ significantly based on whether live or artificial prey is used.
• Artificial prey may overestimate bird predation and underestimate invertebrate predation.
• Seasonal changes in predation risk and potential spatial patterns may be inaccurately represented when using artificial prey models.