Joint effects of density dependence and toxicant exposure on Drosophila melanogaster populations

Gui, Yue and Grant, Alastair ORCID: (2008) Joint effects of density dependence and toxicant exposure on Drosophila melanogaster populations. Ecotoxicology and Environmental Safety, 70 (2). pp. 236-243. ISSN 1090-2414

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Risk assessment of environmental contaminants is usually based on experiments on well-fed individuals held at low population densities. However, field populations are often subject to resource limitation. Individuals who are already stressed by crowding or food limitation may show greater susceptibility to toxicants. But density dependence could also reduce population-level impacts as toxicant-related mortalities may reduce competition for resources. This study examines the joint effects of toxicants and food availability on populations of Drosophila melanogaster. The interactions between the effects of food limitation and toxicant stress were dose dependent and strongly influenced by toxicity mechanisms. In food-limited conditions, a compensatory effect often occurred, with toxicant exposure having a lower proportional impact than at higher food levels. This provides further evidence that density-dependent population processes can produce an assimilative capacity for the effects of toxicants. But synergistic food–toxicant effects were also common and the interaction often switched between synergistic and compensatory at different toxicant concentrations and food supplies. There is no simple “less-than-additive”, “additive” or “more-than-additive” relationship between density and toxicant effects, even for a single toxicant.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
UEA Research Groups: Faculty of Science > Research Groups > Environmental Biology
Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Faculty of Science > Research Centres > Centre for Ecology, Evolution and Conservation
Depositing User: Rosie Cullington
Date Deposited: 20 May 2011 09:04
Last Modified: 13 Apr 2023 13:35
DOI: 10.1016/j.ecoenv.2007.05.020

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