The Economics of Egg Trading: Mating Rate, Sperm Competition and Positive Frequency-Dependence
In: Dynamic games and applications: DGA, Band 4, Heft 4, S. 379-390
ISSN: 2153-0793
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In: Dynamic games and applications: DGA, Band 4, Heft 4, S. 379-390
ISSN: 2153-0793
Background The optimal allocation of resources to sexual signals and other life history traits is usually dependent on an individual's condition, while variation in the expression of sexual traits across environments depends on the combined effects of local adaptation, mean condition, and phenotypic responses to environment-specific cues that affect resource allocation. A clear contrast can often be drawn between natural habitats and novel habitats, such as forest plantations and urban areas. In some species, males seem to change their sexual signals in these novel environments, but why this occurs and how it affects signal reliability is still poorly understood. ; Results The relative size of sexual traits and level of immune responses were significantly lower for male palmate newts Lissotriton helveticus caught in pine and eucalyptus plantations compared to those caught in native forests, but there was no habitat-dependent difference in body condition (n = 18 sites, 382 males). The reliability with which sexual traits signalled body condition and immune responses was the same in all three habitats. Finally, we conducted a mesocosm experiment in which males were maintained in pine, eucalypt or oak infused water for 21 days. Males in plantation-like water (pine or eucalypt) showed significantly lower immune responses but no change in body condition. This matches the pattern seen for field-caught males. Unlike field-caught males, however, there was no relationship between water type and relative sexual trait size. ; Conclusions Pine and eucalyptus plantations are likely to be detrimental to male palmate newt because they are associated with reduced immune function and smaller sexual traits. This could be because ecological aspects of these novel habitats, such as high water turbidity or changes in male-male competition, drive selection for reduced investment into sexual traits. However, it is more probable that there are differences in the ease of acquisition, hence optimal allocation, of resources among habitats. Our mesocosm experiment also provides some evidence that water toxicity is a causal factor. Our findings offer insights into how plantations affect amphibian life histories, and how novel habitats might generate long-term selection for new resource allocation strategies in native species. ; This work was supported by the Basque Government, Aquitaine-Euskadi Euroregion and the Spanish Ministry of Education and Culture with a pre-doctoral grant to M. I-C (grant number FPU12/04148). ; Peer reviewed
BASE
In: Encyclopedias of the Natural World 4
This major reference is an overview of the current state of theoretical ecology through a series of topical entries centered on both ecological and statistical themes. Coverage ranges across scales—from the physiological, to populations, landscapes, and ecosystems. Entries provide an introduction to broad fields such as Applied Ecology, Behavioral Ecology, Computational Ecology, Ecosystem Ecology, Epidemiology and Epidemic Modeling, Population Ecology, Spatial Ecology and Statistics in Ecology. Others provide greater specificity and depth, including discussions on the Allee effect, ordinary differential equations, and ecosystem services. Descriptions of modern statistical and modeling approaches and how they contributed to advances in theoretical ecology are also included. Succinct, uncompromising, and authoritative—a "must have" for those interested in the use of theory in the ecological sciences