Effects of Atrazine and Metolachlor on Snails, Tadpoles, and Their Trematode Parasites

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dc.contributor.authorGriggs, Jennifer Lynnen
dc.contributor.committeechairBelden, Lisa K.en
dc.contributor.committeememberMcNabb, F. M. Anneen
dc.contributor.committeememberCherry, Donald S.en
dc.contributor.departmentBiological Sciencesen
dc.date.accessioned2014-03-14T20:49:30Zen
dc.date.adate2007-01-26en
dc.date.available2014-03-14T20:49:30Zen
dc.date.issued2006-11-30en
dc.date.rdate2007-01-26en
dc.date.sdate2006-12-14en
dc.description.abstractThe widespread use and subsequent release of pesticides into aquatic environments have sparked concerns about how organisms within these aquatic systems are affected by pesticide pollution. While many studies have examined the effects of pesticides on individual organisms, in a series of experiments, I investigated the effects of a pesticide mixture on members of a complex host-parasite system and on host susceptibility to infection. In my first experiment in the laboratory, I examined changes in survivorship when trematode parasites (Echinostoma trivolvis) and their first intermediate host, Planorbella trivolvis snails, were exposed to a low concentration (10 ppb: 15 ppb) and high concentration (85 ppb: 100 ppb) mixture of atrazine and metolachlor, respectively. There was a significant decline in parasite survivorship in the high concentration treatment at 14 hours, while snail survivorship was unaffected across all treatments. In my second experiment, prior to infection, I exposed the parasites and/or second intermediate hosts, Rana clamitans and Rana sylvatica tadpoles, to the pesticide mixtures and examined subsequent infection levels in the tadpoles. The atrazine and metolachlor mixtures had no significant effects on parasite load in the laboratory. Newly shed parasites were more likely than 10 hours old parasites to infect tadpoles, regardless of pesticide exposure. In my final experiment, I utilized outdoor mesocosms to expose parasites, snail hosts, and Rana sylvatica tadpoles to the pesticide mixture, and I examined differences in parasite load within the tadpoles after two weeks. The pesticides had no significant effect on parasite loads in the field. Overall, my findings suggest the atrazine and metolachlor mixtures used in this study had no significant effects on disease dynamics in a system involving Echinostome parasites, snails, and tadpoles.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-12142006-142824en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12142006-142824/en
dc.identifier.urihttp://hdl.handle.net/10919/36122en
dc.publisherVirginia Techen
dc.relation.haspartJennifer.L.Griggs.Final.Thesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectparasitesen
dc.subjecttrematodesen
dc.subjecttadpolesen
dc.subjectmetolachloren
dc.subjectsnailsen
dc.subjectatrazineen
dc.titleEffects of Atrazine and Metolachlor on Snails, Tadpoles, and Their Trematode Parasitesen
dc.typeThesisen
thesis.degree.disciplineBiological Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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