title: Linking sub-individual and population level toxicity effects in Daphnia schoedleri (Cladocera: Anomopoda) exposed to sublethal concentrations of the pesticide α-cypermethrin.
abstract: Synthetic pyrethroids are classified as moderately toxic to mammals and birds; nevertheless, they are highly toxic to non-target aquatic organisms such as fish and zooplankters. Chemical pollutants produce different effects in exposed organisms, ranging from biochemical to population responses. Cladocerans can modify the energy content of their offspring according to the surrounding medium as a way to improve their odds in case they have to cope with stressful conditions at birth. In this study, the effect of a synthetic pesticide on two levels of response in a Daphnia species different from those traditionally used as test organisms was evaluated. With this aim, Daphnia schoedleri neonates (<24 h) were exposed for 21 days to three sublethal concentrations of α-cypermethrin, 0.54, 5.4, and 54 ng L(-1), which correspond to 48-h EC1/100, EC1/10, and EC1, respectively. Effects were measured through a life table analysis for fecundity and survivorship. For effects on progeny, protein, carbohydrates, and lipids were determined and then transformed to caloric content. Biomarkers (BM) were expected to be the most sensitive evaluated response; nevertheless, population parameters such as survivorship and net reproductive rate (R0) were more sensitive since they presented significant differences with respect to controls at the lowest tested concentration. Neonates' caloric content varied during the reproductive period assessed and was negatively correlated to fecundity: as more neonates were born, less energy was provided by the adult females. Macromolecules concentration and caloric content values in cypermethrin-exposed adults were not different from those recorded in the control at the end of exposure time. The results herein presented suggest that stressed daphnids allocate more energy reserves to their offspring, although this strategy can vary depending on the number of reproductive events during the lifecycle, and on the toxicant's concentration. Sub-individual approaches to assess toxicant effects should be accompanied by demographic studies, which support population effect predictions inferred from BMs assessment.
authors: Laboratorio de Hidrobiología Experimental, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N, Col. Santo Tomás, 11340, Mexico, DF, Mexico. fjeroni@ipn.mx
authors: Fernando
authors: F
authors: Martínez-Jerónimo
authors: Mario
authors: M
authors: Arzate-Cárdenas
authors: Rocío
authors: R
authors: Ortiz-Butrón
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects; D015415:Biomarkers / Q000032:analysis; D003621:Daphnia / Q000187:drug effects*; D054750:Ecotoxicology; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D015993:Life Tables; D010575:Pesticides / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D010575:Pesticides; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; C017160:cypermethrin
references: Riv Biol. 2005 May-Aug;98(2):349-57
references: 16180201
references: Aquat Toxicol. 2005 Jun 15;73(2):210-20
references: 15917095
references: Chemosphere. 2012 Apr;87(4):326-32
references: 22209250
references: Bull Environ Contam Toxicol. 2005 Oct;75(4):820-6
references: 16400566
references: Environ Pollut. 2004 May;129(1):99-112
references: 14749074
references: Neurotoxicology. 2009 Nov;30 Suppl 1:S17-31
references: 19766671
references: J Environ Sci (China). 2004;16(5):770-1
references: 15559809
references: Chemosphere. 2009 Mar;74(9):1171-8
references: 19135699
references: Environ Pollut. 2001;112(1):1-10
references: 11202648
references: J Exp Biol. 2012 Mar 15;215(Pt 6):892-902
references: 22357583
references: Aquat Toxicol. 2001 Mar;52(1):1-12
references: 11163426
references: Philos Trans R Soc Lond B Biol Sci. 2001 Mar 29;356(1407):331-49
references: 11316483
references: Insect Biochem Mol Biol. 2011 Jan;41(1):9-13
references: 20869441
references: Mar Environ Res. 2002 Aug;54(2):169-77
references: 12206409
references: J Am Mosq Control Assoc. 2010 Dec;26(4):387-97
references: 21290934
references: Arch Environ Contam Toxicol. 2004 Apr;46(3):324-35
references: 15195804
references: Anal Biochem. 1976 May 7;72:248-54
references: 942051
references: Ecotoxicol Environ Saf. 2007 Jul;67(3):411-6
references: 17055052
references: Oecologia. 1992 Jul;90(4):540-549
references: 28313574
references: Environ Pollut. 2009 Jan;157(1):287-94
references: 18676072
references: Arch Environ Contam Toxicol. 2002 Jan;42(1):17-22
references: 11706363
references: Toxicol Mech Methods. 2009 Jan;19(1):29-39
references: 19778230
references: J Environ Sci Health B. 1996 Jan;31(1):87-98
references: 8847448
references: Oecologia. 1991 May;86(3):414-418
references: 28312930
references: J Environ Sci Health B. 2008 Jan;43(1):56-64
references: 18161574
references: Environ Toxicol Chem. 2005 Jan;24(1):78-86
references: 15683170
references: Sci Total Environ. 2009 Oct 15;407(21):5537-42
references: 19651429
references: Environ Toxicol Chem. 2010 Oct;29(10):2371-8
references: 20872702
references: Aquat Toxicol. 2003 May 29;63(4):357-71
references: 12758002
references: Ecotoxicology. 2010 Oct;19(7):1201-8
references: 20526673
references: Rev Environ Contam Toxicol. 1989;108:133-77
references: 2646661
references: Ecotoxicol Environ Saf. 2012 Apr;78:9-13
references: 22189213
references: Environ Toxicol Chem. 2006 May;25(5):1326-31
references: 16704065