Melanin and antipredatory defenses in Daphnia dadayana under UVR exposure

WOLINSKI, LAURA; MODENUTTI, BEATRIZ; BALSEIRO, ESTEBAN

INTERNATIONAL REVIEW OF HYDROBIOLOGY

WILEY-V C H VERLAG GMBH

Año: 2020 vol. 105 p. 106 - 114

1434-2944

AbstractUltraviolet radiation (UVR) exposure has potentially hazardous effects on aquaticlife, even more in the southern hemisphere, which is close to ozone layer depletion.Aquatic animals living in shallow water cannot escape from UVR effects swimmingdown, so they have to generate other traits to confront it (i.e., enzymes or pigments).Daphnia is a worldwide freshwater genus that inhabits ponds and lakes. Daphniadadayana inhabits shallow lakes in Patagonia presenting a yellowish carapace and ahorn‐like structure in juveniles assumed for avoiding invertebrate predator attacks.We aimed to determine the effect of UVR exposure on the accumulation of melaninand if the development of the antipredatory defense affects the antioxidant response(glutathione S‐transferase [GST] activity) to UVR. We carried out laboratoryexperiments with treatments with and without UVR exposure measuring melaninaccumulation by photographic analyses. Also, we performed an experiment togenerate the antipredatory structure exposing D. dadayana indirectly to the predaceouscopepod Parabroteas sarsi. Our results showed that UVR increased melaninaccumulation in D. dadayana and that the morphological structure against predatorsdid not decrease the antioxidant enzymatic defenses (GST). Our concluding remarksare that D. dadayana is a successful organism that can use its phenotypic plasticity tocope with environmental stressors such as invertebrate predators and UVR exposurewith no trade‐off between these two stressors.