News News

The costs of mischoosing are not uniform across individuals

250

Matching habitat choice is a particular form of habitat selection based on self?assessment of local performance that offers individuals a means to optimize the match of phenotype to the environment. Despite the advantages of this mechanism in terms of increased local adaptation, examples from natural populations are extremely rare. One possible reason for the apparent rarity of matching habitat choice is that it might be manifest only in those segments of a population for which the cost of a phenotype–environment mismatch is high. To test this hypothesis, we used a breeding population of sockeye salmon (Oncorhynchus nerka) exposed to size-dependent predation risk by bears, and evaluated the costs of mischoosing in discrete groups (e.g. male versus females, and ocean?age 2 versus ocean?age 3) using reproductive life span as a measure of individual performance. Bear preference for larger fish, especially in shallow water, translates into a performance trade-off that sockeye salmon can potentially use to guide their settlement decisions. Consistent with matching habitat choice, we found that salmon of similar ocean?age and size tended to cluster together in sites of similar water depth. However, matching habitat choice was only favoured in 3?ocean females – the segment of the population most vulnerable to bear predation. This study illustrates the unequal relevance of matching habitat choice to different segments of a population, and suggests that ‘partial matching habitat choice' could have resulted in an underestimation of the actual prevalence of this mechanism in nature. informacion[at]ebd.csic.es: Camacho & Hendry (2020) Matching habitat choice: it's not for everyone. Oikos DOI 10.1111/oik.06932


https://onlinelibrary.wiley.com/doi/full/10.1111/oik.06932
Average (0 Votes)

Latest News Latest News

Back

Physiological compartmentalization as a possible cause of phylogenetic signal loss: an example involving melanin-based pigmentation

Physiological compartmentalization as a possible cause of phylogenetic signal loss: an example involving melanin-based pigmentation

Phylogenetic signal is the extent to which phenotypic expression is related to phylogenetic relationships between species, thus reflecting the effect of common ancestry. Signal loss occurs when some species obtain adaptation, regarding a given trait, to certain environmental conditions. Compartmentalization in processes leading to trait expression reduces dependence among them, thus favoring, up to some degree, their independent evolution. Compartmentalization may therefore lead to phylogenetic signal loss, but this effect has been overlooked. Compartmentalization in the expression of melanin-based color traits could exist, which first requires a biochemical process (melanin synthesis in melanocytes) and then a physical process consisting in the deposition of melanins in the integument. To test this hypothesis, the phylogenetic signal was estimated in the concentration of the four structural units of melanins (5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, benzothiazine and benzothiazole) and in the expression of color produced as a consequence of their deposition in feathers in 59 species of birds. While phylogenetic signal was low in all traits, it was not different from zero in melanin concentration but was considerably higher in color expression. This suggests that compartmentalization in the pigmentary system may allow a differential adaptability and phylogenetic signal loss in melanin synthesis. informacion[at]ebd.csic.es: Galván (2018) Physiological compartmentalization as a possible cause of phylogenetic signal loss: an example involving melanin-based pigmentation. Biol J Linn Soc. Doi 10.1093/biolinnean/bly164


https://academic.oup.com/biolinnean/advance-article-abstract/doi/10.1093/biolinnean/bly164/5146750?redirectedFrom=fulltext