Susceptibility of Chordodes nobilii (Gordiida, Nematomorpha) to three pesticides: Influence of the water used for dilution on endpoints in an ecotoxicity bioassay.

The increased use of pesticides during recent years necessitates a reevaluation of the effect of those compounds by extending the range of nontarget species commonly used in risk assessment. In the present work, we thus determined the impact of the pesticides glyphosate, carbendazim, and malathion on the parasite Chordodes nobilii in both natural and reconstituted freshwater as the assay medium and tested the sensitivity of three of this species's ecologically relevant parameters-e. g.

Infectivity of Chordodes nobilii larvae (Gordiida: Nematomorpha).

The gordiids are freshwater representatives of the parasite phylum Nematomorpha that function as a link between aquatic and terrestrial ecosystems. In recent years, different ecotoxicologic studies have been made with the South-American gordiid species, Chordodes nobilii, that have demonstrated the capacity of this group to act as a bioindicator of contamination. Despite the Gordiida’s ecologic relevance, further studies are still needed to elucidate different aspects of the biology of the class, and among those, the infective capacity, a parameter that can be evaluated by the infection index mean abundance (IIMA).

Validation test with embryonic and larval stages of Chordodes nobilii (Gordiida, Nematomorpha): sensitivity to three reference toxicants.

Chordodes nobilii is a parasite whose pre- and postparasitic stages are found in different types of freshwater bodies. Due to the peculiarities of its life cycle, it acts as a link between freshwater bodies and terrestrial ecosystems. There is little toxicological information on the group Gordiida.

Sensitivity of preparasitic stages of Chordodes nobilii (Gordiida, Nematomorpha) to malathion.

The largest part of the life cycle of Gordiida, known as horsehair worms, occurs in aquatic environments usually affected by agricultural activities. The free-living adults reproduce in freshwater environments, where preparasitic larvae undergo development. Since malathion is an insecticide used in the distribution area of Chordodes nobilii, the aim of this study is to evaluate the effect of malathion concentrations which might be expected in the environment on preparasitic stages of this species.

Toxicity of the herbicide glyphosate to Chordodes nobilii (Gordiida, Nematomorpha).

Nematomorpha (horsehair worms) is a poorly known group of worm-like animals similar to nematodes. Adults are free-living and reproduction takes place in freshwater environments, where preparasitic larvae undergo development. All species have a parasitic juvenil stage and infection may result in the host's death, insects being the most frequent host.