Inducible defenses in prey intensify predator cannibalism

Trophic cascades are often a potent force in ecological communities, but abiotic and biotic heterogeneity can diffuse their influence. For example, inducible defenses in many species create variation in prey edibility, and size-structured interactions, such as cannibalism, can shift predator diets a...

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Bibliographic Details
Published in:Ecology (Durham) 2009-11, Vol.90 (11), p.3150-3158
Main Authors: Kishida, Osamu, Trussell, Geoffrey C, Nishimura, Kinya, Ohgushi, Takayuki
Format: Article
Language:English
Subjects:
Animal cannibalism
Animals
behavior
Body length
body size
Cannibalism
Caudata
defensive behavior
diet
Ecological genetics
Ecology
Effects
evolution
Food Chain
food webs
Fresh Water
frogs
Hynobius retardatus
Hynobius retardatus (Dunn)
inducible defense
Larva
Larvae
Mortality
Predation
predation risk
predator-prey relationships
Predators
Predatory Behavior - physiology
Rana
Rana pirica
Rana pirica (Matsui)
Ranidae - physiology
salamander
Salamanders
salamanders and newts
Synecology
Tadpoles
Toads
trait-mediated indirect effects
traits
trophic cascade
Trophic relationships
Urodela - physiology
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Summary:Trophic cascades are often a potent force in ecological communities, but abiotic and biotic heterogeneity can diffuse their influence. For example, inducible defenses in many species create variation in prey edibility, and size-structured interactions, such as cannibalism, can shift predator diets away from heterospecific prey. Although both factors diffuse cascade strength by adding heterogeneity to trophic interactions, the consequences of their interaction remain poorly understood. We show that inducible defenses in tadpole prey greatly intensify cannibalism in predatory larval salamanders. The likelihood of cannibalism was also strongly influenced by asymmetries in salamander size that appear to be most important in the presence of defended prey. Hence, variation in prey edibility and the size structure of the predator may synergistically affect predator-prey population dynamics by reducing prey mortality and increasing predator mortality via cannibalism. We also suggest that the indirect effects of prey defenses may shape the evolution of predator traits that determine diet breadth and how trophic dynamics unfold in natural systems.
ISSN:0012-9658
1939-9170
DOI:10.1890/08-2158.1