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The costs of mischoosing are not uniform across individuals


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] Camacho & Hendry (2020) Matching habitat choice: it's not for everyone. Oikos DOI 10.1111/oik.06932
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Adaptation to high-altitude habitats in the Eastern honey

Adaptation to high-altitude habitats in the Eastern honey

The Eastern honey bee Apis cerana is of central importance for agriculture in Asia. It has adapted to a wide variety of environmental conditions across its native range in southern and eastern Asia, which includes high?altitude regions. Eastern honey bees inhabiting mountains differ morphologically from neighboring lowland populations, and may also exhibit differences in physiology and behavior. The genomes of 60 Eastern honey bees collected from high and low altitudes in Yunnan and Gansu provinces, China, were compared to infer their evolutionary history and to identify candidate genes that may underlie adaptation to high altitude. Using a combination of F_ST?based statistics, long?range haplotype tests, and population branch statistics, several regions of the genome were identified that appear to have been under positive selection. These candidate regions were strongly enriched for coding sequences and had high haplotype homozygosity and increased divergence specifically in highland bee populations, suggesting they have been subjected to recent selection in high altitude habitats. Candidate loci in these genomic regions included genes related to reproduction and feeding behavior in honey bees. Functional investigation of these candidate loci is necessary to fully understand the mechanisms of adaptation to high?altitude habitats in the Eastern honey bee. The results of this research will be very useful to monitor the populations of Asian bees and establish conservation priorities. Pollination services provided by bees are essential for food production throughout the world, but Asian bee populations in China have been declining since the early 20th century due to changes in agricultural practices and the introduction of non-native bees. Therefore, it is important to understand how populations of this species adapt to different environmental conditions such as altitude, as this can help improve conservation efforts and management. informacion[at] Montero-Mendieta et al (2018) The genomic basis of adaptation to high-altitude habitats in the Eastern honey bee (Apis cerana). Mol Ecol DOI 10.1111/mec.14986.