Maladaptive migration behaviour in hybrids links to predator-mediated ecological selection

Research output: Contribution to journalArticle

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.

Details

Authors
Organisations
External organisations
  • National Institute of Aquatic Resources
  • Technical University of Denmark
  • Eawag: Swiss Federal Institute of Aquatic Science and Technology
  • University of Bern
  • University of Manchester
  • Karlstad University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology

Keywords

  • fish, hybrid viability, partial migration, predator–prey, species integrity
Original languageEnglish
Pages (from-to)2596-2604
Number of pages9
JournalJournal of Animal Ecology
Volume89
Issue number11
Publication statusPublished - 2020 Nov 1
Publication categoryResearch
Peer-reviewedYes