Details

Autor(en) / Beteiligte

• Wright, Jonathan
• Solbu, Erik Blystad
• Engen, Steinar

Titel

Contrasting patterns of density‐dependent selection at different life stages can create more than one fast–slow axis of life‐history variation

Ist Teil von

• Ecology and evolution, 2020-03, Vol.10 (6), p.3068-3078

Ort / Verlag

England: John Wiley & Sons, Inc

Erscheinungsjahr

2020

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• There has been much recent research interest in the existence of a major axis of life‐history variation along a fast–slow continuum within almost all major taxonomic groups. Eco‐evolutionary models of density‐dependent selection provide a general explanation for such observations of interspecific variation in the "pace of life." One issue, however, is that some large‐bodied long‐lived “slow” species (e.g., trees and large fish) often show an explosive “fast” type of reproduction with many small offspring, and species with “fast” adult life stages can have comparatively “slow” offspring life stages (e.g., mayflies). We attempt to explain such life‐history evolution using the same eco‐evolutionary modeling approach but with two life stages, separating adult reproductive strategies from offspring survival strategies. When the population dynamics in the two life stages are closely linked and affect each other, density‐dependent selection occurs in parallel on both reproduction and survival, producing the usual one‐dimensional fast–slow continuum (e.g., houseflies to blue whales). However, strong density dependence at either the adult reproduction or offspring survival life stage creates quasi‐independent population dynamics, allowing fast‐type reproduction alongside slow‐type survival (e.g., trees and large fish), or the perhaps rarer slow‐type reproduction alongside fast‐type survival (e.g., mayflies—short‐lived adults producing few long‐lived offspring). Therefore, most types of species life histories in nature can potentially be explained via the eco‐evolutionary consequences of density‐dependent selection given the possible separation of demographic effects at different life stages. Our model demonstrates how density dependence can uncouple the eco‐evolutionary dynamics of adult reproduction versus offspring survival to allow independent life‐history (fast vs. slow) evolution at different life stages. The normal simple fast–slow life‐history continuum can thus be modified into more complex life histories, such as those seen in most trees and large fish with large‐bodied long‐lived “slow” adults but explosive “fast” reproduction with many small offspring. We therefore show that fast–slow density‐dependent selection theory has the potential to explain even the most complex types of life‐history strategies seen in nature.