Interspecific Variation in Nematode Responses to Metals

Abstract

Performing toxicity testing on multiple species with differing degrees of evolutionary relatedness can provide important information on how chemical sensitivity varies among species and can help pinpoint the biological drivers of species sensitivity. Such knowledge could ultimately be used to design better multispecies predictive ecological risk assessment models and identify particularly sensitive species. However, laboratory toxicity tests involving multiple species can also be resource intensive, especially when each species has unique husbandry conditions. We performed lethality tests with 2 metals, copper chloride and zinc chloride, on 5 different nematode species, which are nested in their degree of evolutionary relatedness: Caenorhabditis briggsae, Caenorhabditis elegans, Oscheius myriophila, Oscheius tipulae, and Pristionchus pacificus. All species were successfully cultured and tested concurrently with limited resources, demonstrating that inexpensive, multispecies nematode toxicity testing systems are achievable. The results indicate that P. pacificus is the most sensitive to both metals. Conversely, C. elegans is the least sensitive species to copper, but the second most sensitive to zinc, indicating that species relationships do not necessarily predict species sensitivity. Toxicity testing with additional nematode species and types of chemicals is feasible and will help form more generalizable conclusions about relative species sensitivity. Environ Toxicol Chem 2020;39:1006–1016. © 2020 SETAC

Intra- and interspecific toxicity testing methods and data for nematodes exposed to metals

“…These data were originally published separately by Heaton et al. [1 , 2] . Both raw and analyzed toxicity data are reported here to catalog all data collected from both studies into a single consistent information source for use by the scientific community.…”

“…A subset of nominal test concentrations were analytically verified using a commercial laboratory testing service (Pace Analytical Services, St. Rose, Louisiana) as reported in Heaton et al. [2] . Samples were analyzed according to EPA Method 6010 using Inductively Coupled Plasma (ICP) – Atomic Emission Spectroscopy.…”

“…For zinc concentrations that were not tested, we used the regression formula in Heaton et al. [2] to correct nominal concentrations for the expected verified concentrations.…”

“…These raw data represent the entire datasets produced by Heaton et al. [1 , 2] in a single spreadsheet. The rationale for presenting all the raw data here is so other researchers can easily perform a reanalysis or compare directly with other toxicity datasets.…”

Extrapolating Acute Contact Bee Sensitivity to Insecticides Based on Body Weight Using a Phylogenetically Informed Interspecies Scaling Framework

“…It can be hypothesized that intrinsic factors are likely linked to organisms' evolutionary history (phylogeny) because more closely related species are often more similar in their traits compared to more distantly related ones (Hansen and Martins 1996). This important and potentially confounding factor for such interspecies analyses has long been recognized (Felsenstein 1985), but only recently have authors started to directly address this issue in their ecotoxicological studies (Raimondo et al 2007;Brady et al 2017aBrady et al , 2017bHylton et al 2018;Heaton et al 2020).…”