Royal Society Open Science (Jul 2019)

Low-latitude zooplankton pigmentation plasticity in response to multiple threats

  • Marcus Lee,
  • Huan Zhang,
  • Yongcui Sha,
  • Alexander Hegg,
  • Gustaf Ekelund Ugge,
  • Jerker Vinterstare,
  • Martin Škerlep,
  • Varpu Pärssinen,
  • Simon David Herzog,
  • Caroline Björnerås,
  • Raphael Gollnisch,
  • Emma Johansson,
  • Nan Hu,
  • P. Anders Nilsson,
  • Kaj Hulthén,
  • Karin Rengefors,
  • R. Brian Langerhans,
  • Christer Brönmark,
  • Lars-Anders Hansson

DOI
https://doi.org/10.1098/rsos.190321
Journal volume & issue
Vol. 6, no. 7

Abstract

Read online

Crustacean copepods in high-latitude lakes frequently alter their pigmentation facultatively to defend themselves against prevailing threats, such as solar ultraviolet radiation (UVR) and visually oriented predators. Strong seasonality in those environments promotes phenotypic plasticity. To date, no one has investigated whether low-latitude copepods, experiencing continuous stress from UVR and predation threats, exhibit similar inducible defences. We here investigated the pigmentation levels of Bahamian ‘blue hole’ copepods, addressing this deficit. Examining several populations varying in predation risk, we found the lowest levels of pigmentation in the population experiencing the highest predation pressure. In a laboratory experiment, we found that, in contrast with our predictions, copepods from these relatively constant environments did show some changes in pigmentation subsequent to the removal of UVR; however, exposure to water from different predation regimes induced minor and idiosyncratic pigmentation change. Our findings suggest that low-latitude zooplankton in inland environments may exhibit reduced, but non-zero, levels of phenotypic plasticity compared with their high-latitude counterparts.

Keywords