Variations in lethal and sublethal effects of cypermethrin among aquatic stages and species of anuran amphibians

Abstract

Despite the use of model species to predict the effects of chemicals in the environment, unpredicted variation in levels of risk to organisms from xenobiotics can be observed. Physiological and morphological differences between species and life stages may lead to differences in sensitivity, while seasonal and spatial variation in pesticide concentrations may affect the level of risk faced by organisms in the environment. Because anurans breed in aquatic habitats subject to contamination by runoff and spraying, they are particularly vulnerable to pesticides. In the present study, embryos, newly hatched larvae, and larvae with limb buds of 3 anuran amphibian species--Pseudacris regilla, Rana cascadae, and Rana aurora--were exposed for 48 h to either 0.5 µg/L or 5.0 µg/L cypermethrin under laboratory conditions. The authors monitored hatching success, larval survival, and measured growth. Additionally, they assayed avoidance behavior 2 wk after exposure or 2 wk after hatching for individuals exposed as embryos. Hatching and survival were not affected in animals of any species exposed as embryos. After exposure as embryos and as newly hatched larvae, however, P. regilla displayed behavioral abnormalities in response to prodding. Cypermethrin increased mortality in P. regilla exposed in both larval stages. Cypermethrin also increased mortality in larval R. cascadae when exposed at the early stage. These results indicate variation in sensitivity to environmentally relevant concentrations of cypermethrin among anuran species and life stages.

Effects of an environmentally relevant temporal application scheme of low herbicide concentrations on larvae of two anuran species

“…Likewise, metamorphs of the European moor frog (Rana arvalis), which were chronically exposed to another insecticide (a-cypermethrin) (Greulich and Pflugmacher, 2003) and metamorphs of four North American anurans (Lithobates [Rana] clamitans, Lithobates [Rana] pipiens, Lithobates sylvaticus [R. sylvatica], Anaxyrus [Bufo] americanus), which were chronically exposed to glyphosate-based herbicides (Howe et al, 2004) showed decreased SVL. Comparable to our results, also Biga and Blaustein (2013) did not observe effects on body length when larvae of North American Pseudacris regilla, Rana cascadae and Rana aurora were exposed to a sublethal insecticide (cypermethrin) concentration at early and late developmental stages. Exposure of eggs and newly hatched individuals of R. arvalis to sublethal carbaryl concentrations shortened time to metamorphosis, whereas chronic exposure prolonged it (Greulich and Pflugmacher, 2003).…”

“…Significantly elevated mortality at metamorphosis after exposure of different developmental stages to sublethal insecticide (carbaryl) concentrations was also observed in Southern leopard frogs (Lithobates sphenocephalus [Rana sphenocephala]) (Bridges, 2000). Biga and Blaustein (2013) observed species-specific effects on survival when different aquatic life stages of three North American anurans (P. regilla, R. cascadae and R. aurora) were exposed to sublethal concentrations of another insecticide (cypermethrin). These authors did not observe increased mortality in animals of any species exposed during embryonic development, but in R. cascadae when exposed at early and in P. regilla when exposed at early and late larval stages.…”

“…They were found to be formulationspecific and species-specific (Mann and Bidwell, 1999;Wagner et al, , 2014b. Additionally effects were reported whose nature was understood as developmental-specific (Greulich and Pflugmacher, 2003;Biga and Blaustein, 2013). After steps of embryonic development organogenesis starts and continues in the early larvae (early premetamorphosis).…”

“…Furthermore, we suggested that, (iii) early larvae would be more sensitive concerning acute toxic effects (i.e. clinical signs after 1 and 2 d and mortality after 1 week) than later stages (Jones et al, 2010;Biga and Blaustein, 2013).…”

How Does Changing Pesticide Usage Over Time Affect Migrating Amphibians: A Case Study on the Use of Glyphosate-Based Herbicides in German Agriculture Over 20 Years

“…In addition to the loss of habitats in agricultural areas, agrochemical pollution, which often interacts with other factors like climate change, UV-B radiation, emerging infectious diseases and alien species (Collins and Storfer, 2003;Stuart et al, 2008), is detrimental to amphibians (Mann et al, 2009). The impacts of agrochemicals on amphibians in water bodies (Xu and Oldham, 1997;Relyea, 2009;Biga and Blaustein, 2013) and on land Mann and Bidwell, 1999;Marco et al, 2001;Howe et al, 2004;Cauble and Wagner, 2005;Relyea, 2005;Bernal et al, 2009;Dinehart et al, 2009;Belden et al, 2010;Brühl et al, 2013) have been thoroughly studied and documented (Govindarajulu, 2008;Mann et al, 2009;Relyea, 2011;.…”