Maladaptive migration behaviour in hybrids links to predator‐mediated ecological selection. Issue 11 (23rd August 2020)

• Record Type: Journal Article
• Authors: Pärssinen, Varpu; Hulthén, Kaj; Brönmark, Christer; Skov, Christian; Brodersen, Jakob; Baktoft, Henrik; Chapman, Ben B.; Hansson, Lars‐Anders; Nilsson, Per Anders
• Editors: Prugh, Laura
• Is Part Of: Journal of animal ecology. Volume 89:Issue 11(2020)
• Page Start: 2596
• Page End: 2604
• Publication Date: 2020-08-23
• Subjects: fish -- hybrid viability -- partial migration -- predator–prey -- species integrity; Animal ecology -- Periodicals; 591.7
• DOI: 10.1111/1365-2656.13308
• Languages: English
• ISSNs: 0021-8790

Abstract

Abstract: Different migratory species have evolved distinct migratory characteristics that improve fitness in their particular ecological niches. However, when such species hybridize, migratory traits from parental species can combine maladaptively and cause hybrids to fall between parental fitness peaks, with potential consequences for hybrid viability and species integrity. Here, we take advantage of a natural cross‐breeding incident to study migratory behaviour in naturally occurring hybrids as well as in their parental species and explore links between migratory traits and predation risk. To achieve this, we used electronic tags and passive telemetry to record detailed individual migration patterns (timing and number of migratory trips) in two common freshwater fish species, roach Rutilus rutilus, common bream Abramis brama as well as their hybrids. Next, we scanned for tags regurgitated by a key avian predator (great cormorant Phalacrocorax carbo ) at nearby roosting sites, allowing us to directly link migratory behaviour to predation risk in the wild. We found that hybrid individuals showed a higher number of short, multi‐trip movements between lake and stream habitats as compared to both parental species. The mean date of first lake departure differed between bream and roach by more than 10 days, while hybrids departed in two distinct peaks that overlapped with the parental species' averages. Moreover, the probability of cormorant predation increased with multi‐trip movement frequency across species and was higher for hybrids. Our data provide novel insights into hybrid viability, with links to predator‐mediated ecological selection. Increased exposure to predators via maladaptive migratory behaviour reduces hybrid survival and can thereby reinforce species integrity. Abstract : The study provides direct empirical support for predator‐mediated ecological selection against hybridization by identifying a mechanism for the higher avian predation risk of hybrids between two cyprinid species, as well as illustrating that hybrids can express novel and intermediate migratory behaviours in relation to their parental species.