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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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Scrapes as a communication tool in the largest Neotropical felids

Scrapes as a communication tool in the largest Neotropical felids

Details of how, why and in what conditions large felids make scrapes is unknown. Here, the general hypothesis about the use of scrapes for marking proposals, as well as to communicate with other individuals to signalize particular points or areas of interest were examined by studying scrape-marking behaviour of jaguars and pumas. Scrapes were surveyed during dry season in five study areas from Mexico (El Edén and San Ignacio), Belize (Cockscomb) and Brazil (Angatuba and Serra das Almas), which differed in presence and/or abundance of jaguars and pumas. A total of 269 felid scrapes were found along 467 km of paths surveyed, obtaining a finding rate of 0.576 scrapes per km. In trails, scrapes were found in a similar frequency in the centre and edge, whereas in car tracks they were mainly found in the edge. Scrapes were located mainly in the centre in areas only with pumas, in the centre and in the edge in areas with a similar number of jaguars and pumas, and in the edge in area mainly dominated by jaguars. Felids chose sites mainly covered by leaves and located in paths less wide, clean and rarely used. Scrapes seem to be signalizing some specific areas within territories and data suggest that they are made with the proposal of communication between individuals. informacion[at] Palomares et al (2018) Scraping marking behaviour of the largest Neotropical felids. PeerJ 6:e498; DOI 10.7717/peerj.4983