Environmental Certainty, Trophic Level, and Resource Availability in Life History Evolution

1974 ◽  
Vol 108 (964) ◽  
pp. 805-817 ◽  
Author(s):  
Henry M. Wilbur ◽  
Donald W. Tinkle ◽  
James P. Collins
2021 ◽  
Vol 9 ◽  
Author(s):  
Kaj Hulthén ◽  
Jacob S. Hill ◽  
Matthew R. Jenkins ◽  
Randall Brian Langerhans

Predation risk and resource availability are two primary factors predicted by theory to drive the evolution of life histories. Yet, disentangling their roles in life-history evolution in the wild is challenging because (1) the two factors often co-vary across environments, and (2) environmental effects on phenotypes can mask patterns of genotypic evolution. Here, we use the model system of the post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes to provide a strong test of the roles of predation and resources in life-history evolution, as the two factors do not co-vary in this system and we attempted to minimize environmental effects by raising eight populations under common laboratory conditions. We tested a priori predictions of predation- and resource-driven evolution in five life-history traits. We found that life-history evolution in Bahamas mosquitofish largely reflected complex interactions in the effects of predation and resource availability. High predation risk has driven the evolution of higher fecundity, smaller offspring size, more frequent reproduction, and slower growth rate—but this predation-driven divergence primarily occurred in environments with relatively high resource availability, and the effects of resources on life-history evolution was generally greater within environments having high predation risk. This implies that resource-driven selection on life histories overrides selection from predators when resources are particularly scarce. While several results matched a priori predictions, with the added nuance of interdependence among selective agents, some did not. For instance, only resource levels, not predation risk, explained evolutionary change in male age at maturity, with more rapid sexual maturation in higher-resource environments. We also found faster (not slower) juvenile growth rates within low-resource and low-predation environments, probably caused by selection in these high-competition scenarios favoring greater growth efficiency. Our approach, using common-garden experiments with a natural system of low- and high-predation populations that span a continuum of resource availability, provides a powerful way to deepen our understanding of life-history evolution. Overall, it appears that life-history evolution in this adaptive radiation has resulted from a complex interplay between predation and resources, underscoring the need for increased attention on more sophisticated interactions among selective agents in driving phenotypic diversification.


Ecology ◽  
2001 ◽  
Vol 82 (6) ◽  
pp. 1546-1559 ◽  
Author(s):  
Gregory F. Grether ◽  
David F. Millie ◽  
Michael J. Bryant ◽  
David N. Reznick ◽  
Wendy Mayea

2010 ◽  
Vol 59 (5) ◽  
pp. 504-517 ◽  
Author(s):  
Jonathan M. Waters ◽  
Diane L. Rowe ◽  
Christopher P. Burridge ◽  
Graham P. Wallis

2015 ◽  
Vol 8 (7) ◽  
pp. 635-649 ◽  
Author(s):  
Emilie Snell‐Rood ◽  
Rickey Cothran ◽  
Anne Espeset ◽  
Punidan Jeyasingh ◽  
Sarah Hobbie ◽  
...  

2006 ◽  
Vol 84 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Stephen P. Bonser ◽  
Lonnie W. Aarssen

Generalisations of life histories in plants are often framed in terms of allocation to reproduction. For example, relative allocation to reproduction is commonly found to be higher in semelparous than in iteroparous plant species. However, the association between vegetative traits and life history has been largely unexplored. In higher plants, reproductive and vegetative function can be measured in terms of meristem allocation. Under this approach, two vegetative traits (apical dominance (the suppression of axillary meristem development) and branching intensity (the commitment of axillary meristems to branches)) can be measured as well as one reproductive trait (reproductive effort). We used phylogenetically independent contrasts to compare reproductive and vegetative function in annual semelparous and perennial iteroparous species. Twenty congeneric species pairs (each species pair represented by one semelparous and one iteroparous species) across nine families were selected based on availability of herbarium specimens. Semelparous life-history evolution was associated with higher reproductive effort. Conversely, iteroparous life-history evolution was associated with higher apical dominance. Branching intensity was not associated with life history. An evolutionary association between life history and apical dominance but not branching intensity suggests a complex relationship between allocation to vegetative traits and the evolution of plant strategies across environments.


Oikos ◽  
1982 ◽  
Vol 38 (1) ◽  
pp. 118 ◽  
Author(s):  
William J. Etges

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