1. Beyond the ecology of fear: non-lethal effects of predators are strong whereas those of parasites are diverse
- Author
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Daversa, D.R., Hechinger, R.F., Madin, E., Fenton, A., Dell, A.I., Ritchie, E., Rohr, J., and Rudolf, V.H.W.
- Abstract
Individuals can alter their behaviour and other traits to reduce threats from predators and parasites. However, predators and parasites likely elicit different responses, which subsequently lead to different non-lethal effects. We created a sequentially structured framework to examine trait responses to distinct predatory and parasitic consumers. We predicted that parasites with strong negative effects on host fitness should act like predators and elicit strong responses before attack. We also predicted that less damaging parasites and micropredators should elicit diverse responses across multiple interaction stages, because their hosts and prey remain alive while being eaten. A meta-analysis indicated that predators do tend to elicit stronger responses than parasites before attack, whereas parasites generally elicit responses after attack, albeit weaker than pre-attack responses to predators. Organisms exposed simultaneously to predator and parasite cues responded similarly when exposed to predator cues alone, suggesting that individuals prioritize anti-predator responses over responses to less harmful parasites. Extending these findings requires addressing knowledge gaps concerning responses to different consumer types, costs of immune responses, and cumulative effects of repeated responses. Expanding research beyond the predator vs. parasite dichotomy toward a broader consumer-resource perspective will facilitate understanding of non-lethal effects in complex, multi-trophic food webs.
- Published
- 2019
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