BALSEIRO esteban Gabriel
Fish mediated trait compensation in zooplankton.
HYLANDER, S.; SOUZA, M.S.; BALSEIRO, E.G; MODENUTTI, B.E.; HANSSON, L-A.
WILEY-BLACKWELL PUBLISHING, INC
Año: 2012 vol. 26 p. 608 - 615
1. Environmental factors fluctuate spatially and temporally, and organisms that can alter pheno-type in response to these changes may increase their fitness. Zooplankton are known to be ableto induce body pigmentation in response to ultraviolet radiation (UVR) and to reduce the pig-mentation when exposed to fish predators. Hence, reduced pigmentation because of the presenceof fish could potentially lead to UVR damage, which calls for alternative protective mechanisms.2. We exposed zooplankton to fish cues and UVR stress to assess whether body pigmentationand cellular antioxidants are flexible predation and UVR defences.3. Zooplankton exposed to fish predator cues (no direct predation) reduced their pigmentationby c. 30% in 20 days. However, they were able to rapidly counteract negative UVR effects byincreasing the activity of antioxidant defences such as glutathione S-transferase (GST). Whenexposed to UVR, the GST activity increased by c. 100% in zooplankton that had previouslyreduced their pigmentation because of fish cues. Transparency in the zooplankton did not leadto considerably higher UVR damage, here measured as inhibition of cholinesterase (ChE).4. We conclude that zooplankton pigmentation and antioxidant enzymes are flexible UVRdefence systems, which can be induced when needed. Zooplankton may employ antioxidantdefences when pigmentation is reduced to counteract predation risk and thereby rapidly respondto detrimental effects of UVR exposure, that is, they can compensate one trait with another.