Does long-term fungicide exposure affect the reproductive performance of leaf-shredders? A partial life-cycle study using Hyalella azteca. (March 2017)

• Record Type: Journal Article
• Authors: Baudy, Patrick; Zubrod, Jochen P.; Konschak, Marco; Weil, Mirco; Schulz, Ralf; Bundschuh, Mirco
• Is Part Of: Environmental pollution. Volume 222(2017)
• Page Start: 458
• Page End: 464
• Publication Date: 2017-03
• Subjects: Shredder -- Fungicide -- Mixture -- Energy allocation -- Reproduction; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2016.11.079
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Leaf-shredding amphipods play a critical role in the ecosystem function of leaf litter breakdown, a key process in many low order streams. Fungicides, however, may adversely influence shredders' behavior and the functions they provide, while there is only limited knowledge concerning effects on their reproductive performance. To assess the latter, a semi-static 56-day partial life-cycle bioassay using the model shredder Hyalella azteca ( n = 30) was performed applying two environmentally relevant concentrations of a model fungicide mixture (i.e., 5 and 25 μg/L) composed of five fungicides with different modes of toxic action. Variables related to the food processing (leaf consumption and feces production), growth (body length and dry weight), energy reserves (lipid content), and reproduction (amplexus pairs, number and length of offspring) were determined to understand potential implications in the organisms' energy budget. While the fungicides did not affect leaf consumption, both fungicide treatments significantly reduced amphipods' feces production (∼20%) compared to the control. This observation suggests an increased food utilization to counteract the elevated and stress-related energy demand: although growth as well as energy reserves were unaffected, amplexus pairs were less frequently observed in both fungicide treatments (∼50–100%) suggesting a tradeoff regarding energy allocation favoring the maintenance of fundamental functions at the organism level over reproduction. As a result, the time to release of first offspring was delayed in both fungicide treatments (7 and 14 days) and the median number of offspring was significantly lower in the 25-μg/L treatment (100%), whereas offspring length remained unaffected. The results of this study thus indicate that chronic fungicide exposures can negatively impact shredders' reproductive performance. This may translate into lower abundances and thus a reduced contribution to leaf litter breakdown in fungicide-impacted streams with potentially far-reaching consequences for detritus-based food webs. Graphical abstract: Highlights: Hyalella azteca is affected by field-relevant concentrations of fungicide mixtures. Reduced feces production (=higher assimilation) is insufficient for compensation. Reduced reproductive performance in fungicide-exposed Hyalella . Potential for far-reaching consequences in heterotrophic ecosystems. Abstract : Chronic exposure to environmentally relevant fungicide concentrations can negatively impact leaf-shredders' reproductive performance.