Evolutionary dynamics of frequency-dependent growth strategy in cannibalistic amphibians
Authored by JY Wakano, Y Kohmatsu, N Yamamura
Date Published: 2002
Sponsors:
Japanese Ministries
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
Cannibalistic amphibian larval morphs, which have greater head widths
than typical morphs and therefore have larger mouths, provide the basis
for the construction of a simple model of cannibalism that describes the
growth dynamics of body shape. As the relative head sizes of interacting
individuals determine the occurrence of cannibalism, the situation is
frequency-dependent. Because natural enemies prey more often upon
individuals with a more unbalanced body shape, an optimal growth
schedule should exist. The necessary conditions for an evolutionarily
stable strategy (ESS) are derived analytically; these conditions are
checked by evolutionary simulation. When the probability of cannibalism
is low, an ESS exists. In such cases, the body shape is more balanced
(less adaptive to cannibalism) when predation pressure is higher and
population density is lower. When the probability of cannibalism is
high, there is no ESS. For such cases, a computer simulation of the
evolutionary dynamics revealed that the dominant growth strategy changes
cyclically. The development of a more detailed model of individual-based
population dynamics showed that the qualitative results of the simple
model held for the individual-based model. Accompanied by cyclic
evolution, the number of surviving individuals at metamorphosis
oscillated. The frequency-dependent models suggested that the
evolutionary dynamics of cannibalism change dramatically depending upon
environmental conditions.
Tags
Competition
Predation
Model
Density
Larvae
Size-structured populations
Salamanders hynobius-retardatus
Tiger
salamanders
Metamorphosis