Influence of food limitation on the effects of fenvalerate pulse exposure on the life history and population growth rate of Daphnia magna

Abstract

Laboratory ecotoxicity tests may not adequately evaluate the effects of pesticides, because they often do not include more environmentally relevant conditions, such as pulsed toxicant exposures and low food conditions. Therefore, we tested the effects of a pulse of the pyrethroid insecticide fenvalerate (FV) on the life history and population growth rate (r) of the cladoceran Daphnia magna. The daphnids were subjected to a 24-h pesticide pulse exposure (0.03, 0.1, 0.3, 0.6, 1.0, and 3.2 microg/L) under high and low food conditions and were monitored for 21 d. Chemical analysis showed that at t = 1 h, the nominal FV concentrations were reduced by 50 to 66%. Fenvalerate decreased survival and growth in the week following pulse exposure. Age at first reproduction increased, with consequent adverse effects on cumulative reproduction per living female and, therefore, on r. Thus, a short-term exposure of FV caused a long-term reduction on r as a result of increased mortality and a delay in development. Low food conditions exacerbated the effects of the FV exposure on juvenile survival and growth during the first week. This caused a much stronger reduction in r under low food conditions. We concluded that a pulsed FV exposure may result in long-term reduction of r that can be predicted only with more environmentally relevant toxicity tests, as described in the present study.

Environmentally sensitive life-cycle traits have low elasticity: implications for theory and practice.

“…3 indicates that the relationship was robust to exclusion of data for D. magna. Some of the data were atypical in that they included variables other than chemical toxicants (Stephenson et al 1991, Martinez-Jeronimo et al 1994, Postma et al 1994, Cotelle and Ferard 1996, Levin et al 1996, LinkeGamenick et al 1999, Ramirez-Perez et al 2004, Pieters et al 2005, Pieters and Liess 2006. Again, the analyses in Figs.…”

“…The former will be referred to as typical studies and the latter as atypical studies. All publications meeting the following criteria were included in the analysis: (1) The experiment started with young juveniles and permitted treatment-dependent estimates of time to first reproduction (t j ) to be made; (2) survival and reproduction were reported as a function of time or age; (3) experimental conditions (e.g., chemical concentration, temperature, and the like) were maintained at constant levels through the entire duration of the experiment (but see Pieters et al 2005, Pieters and Liess 2006; (4) a lowest observed effect concentration (LOEC) was reported for at least one life-cycle trait. In a limited number of cases, it was necessary to estimate values of life-cycle traits from graphs.…”

Modeling responses of Daphnia magna to pesticide pulse exposure under varying food conditions: intrinsic versus apparent sensitivity

“…In spite of its relevance, episodic pollution received relatively little attention Handy 1994;Naddy et al 2000;Reinert et al 2002). Results of our first study (Pieters et al 2005) showed that limiting postnatal food conditions exacerbated the effects of a 24 h FV pulse exposure. In contrast, Pieters and Liess (2006) demonstrated that daphnids originating from low-fed mothers were less sensitive to the pulsed FV exposure compared to daphnids born from high-fed mothers (Pieters and Liess 2006).…”

“…Few studies have actually tested these explanations and the aim of the present study was therefore to analyze whether the contrasting results for the effect of food on sensitivity of daphnids to toxicants were actually the result of a changed intrinsic sensitivity of the test organisms. For this purpose, we examined results of two recently conducted life-cycle studies on Daphnia magna testing the combined effects of food level and a pulsed exposure to the pyrethroid insecticide fenvalerate (FV) (Pieters et al 2005;Pieters and Liess 2006). Episodic exposure to FV was chosen because a single toxicant dose is especially relevant in agriculture, where pesticide application may result in short-term pulse exposures of aquatic biota due to spray drift, drain flow, or field runoff (Liess et al 1999).…”

Evidence of potential long term effects in (aquatic and terrestrial) invertebrates after short term pulsed exposure. Literature reviews on ecotoxicology of chemicals with special focus on plant protection products

“…D. magna neonates were exposed to single short-term (24-hour) pulses of fenvalerate and provided with either low or high food conditions for 21 days post-exposure to determine the conjunctive impacts of food and pyrethroid stress on long-term endpoints (Pieters, et al 2005). Low food availability intensified effects of short term fenvalerate exposure, with reproductive output and growth significantly reduced following fenvalerate exposure as low as 0.3 µg/L (30% fewer broods produced and a 13% reduced body length).…”