Ectosymbionts alter spontaneous responses to the Earth’s magnetic field in a crustacean

Research output: Contribution to journalArticle

Abstract

Magnetic sensing is used to structure every-day, non-migratory behaviours in many animals. We show that crayfish exhibit robust spontaneous magnetic alignment responses. These magnetic behaviours are altered by interactions with Branchiobdellidan worms, which are obligate ectosymbionts. Branchiobdellidan worms have previously been shown to have positive effects on host growth when present at moderate densities, and negative effects at relatively high densities. Here we show that crayfish with moderate densities of symbionts aligned bimodally along the magnetic northeast-southwest axis, similar to passive magnetic alignment responses observed across a range of stationary vertebrates. In contrast, crayfish with high symbiont densities failed to exhibit consistent alignment relative to the magnetic field. Crayfish without symbionts shifted exhibited quadramodal magnetic alignment and were more active. These behavioural changes suggest a change in the organization of spatial behaviour with increasing ectosymbiont densities. We propose that the increased activity and a switch to quadramodal magnetic alignment may be associated with the use of systematic search strategies. Such a strategy could increase contact-rates with conspecifics in order to replenish the beneficial ectosymbionts that only disperse between hosts during direct contact. Our results demonstrate that crayfish perceive and respond to magnetic fields, and that symbionts influence magnetically structured spatial behaviour of their hosts.

Details

Authors
  • Lukas Landler
  • James Skelton
  • Michael S. Painter
  • Paul W. Youmans
  • Rachel Muheim
  • Robert P. Creed
  • Bryan L. Brown
  • John B. Phillips
Organisations
External organisations
  • Virginia Polytechnic Institute and State University
  • Czech University of Life Sciences Prague
  • University of Florida
  • Appalachian State University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Zoology
  • Behavioral Sciences Biology
Original languageEnglish
Article number3105
JournalScientific Reports
Volume9
Issue number1
Publication statusPublished - 2019 Feb 28
Publication categoryResearch
Peer-reviewedYes