title: Interplay between fungicides and parasites: Tebuconazole, but not copper, suppresses infection in a Daphnia-Metschnikowia experimental model.
abstract: Natural populations are commonly exposed to complex stress scenarios, including anthropogenic contamination and their biological enemies (e.g., parasites). The study of the pollutant-parasite interplay is especially important, given the need for adequate regulations to promote improved ecosystem protection. In this study, a host-parasite model system (Daphnia spp. and the microparasitic yeast Metschnikowia bicuspidata) was used to explore the reciprocal effects of contamination by common agrochemical fungicides (copper sulphate and tebuconazole) and parasite challenge. We conducted 21-day life history experiments with two host clones exposed to copper (0.00, 25.0, 28.8 and 33.1 μg L-1) or tebuconazole (0.00, 154, 192 and 240 μg L-1), in the absence or presence of the parasite. For each contaminant, the experimental design consisted of 2 Daphnia clones × 4 contaminant concentrations × 2 parasite treatments × 20 replicates = 320 experimental units. Copper and tebuconazole decreased Daphnia survival or reproduction, respectively, whilst the parasite strongly reduced host survival. Most importantly, while copper and parasite effects were mostly independent, tebuconazole suppressed infection. In a follow-up experiment, we tested the effect of a lower range of tebuconazole concentrations (0.00, 6.25, 12.5, 25.0, 50.0 and 100 μg L-1) crossed with increasing parasite challenge (2 Daphnia clones × 6 contaminant concentrations × 2 parasite levels × 20 replicates = 480 experimental units). Suppression of infection was confirmed at environmentally relevant concentrations (> 6.25 μg L-1), irrespective of the numbers of parasite challenge. The ecological consequences of such a suppression of infection include interferences in host population dynamics and diversity, as well as community structure and energy flow across the food web, which could upscale to ecosystem level given the important role of parasites.
authors.affiliation: Department of Biology, University of Aveiro, Aveiro, Portugal.|Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Cuco
authors.affiliation: Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal.|Department of Environment and Planning, University of Aveiro, Aveiro, Portugal.
authors.forename: Nelson
authors.initials: N
authors.lastname: Abrantes
authors.affiliation: Department of Biology, University of Aveiro, Aveiro, Portugal.|Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Gonçalves
authors.affiliation: Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.|Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany.
authors.forename: Justyna
authors.initials: J
authors.lastname: Wolinska
authors.affiliation: Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal.|Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Bruno B
authors.identifier: http://orcid.org/0000-0002-7130-6061
authors.initials: BB
authors.lastname: Castro
mesh_terms: D000818:Animals; D003300:Copper / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects* / Q000382:microbiology* / Q000502:physiology; D005260:Female; D005659:Fungicides, Industrial / Q000633:toxicity*; D054884:Host-Pathogen Interactions; D055163:Metschnikowia / Q000187:drug effects* / Q000502:physiology; D012098:Reproduction / Q000187:drug effects; D014230:Triazoles / Q000633:toxicity*
chemical_list: D005659:Fungicides, Industrial; D014230:Triazoles; C087114:tebuconazole; D003300:Copper