Assessing the Toxicity of Neonicotinoid Insecticides Towards Soil Invertebrates

Background

Soil invertebrates perform an important role in ecosystems, for example by recycling the organic matter. However, the services provided by these organisms are at risk because of the widespread use of insecticides, like the neonicotinoids. This family of insecticides already at low doses may cause high mortality rates among target and non-target organisms. Some of the consequences are the reduction of local biodiversity and the loss of ecosystem services. So far, however, there is very limited data on the toxicity of these chemicals to soil invertebrates. Earlier research of our group has shown that the widely used parthenogenetic springtail species Folsomia candida is quite sensitive to neonicotinoids, and also that other springtail species show similar sensitivity. Several questions remain however, to be answered, like for instance: 1. How do effects at the individual level translate to the performance of springtails in a community, 2. How can differences in the toxicity of closely related compounds be explained from interactions at the level of gene expression of these animals, and how may gene expression analysis help explaining for differences in the sensitivity of different species.

Approach

1.     The effects of selected neonicotinoids will be studied in soil mesocosms, containing a community of different springtail species representing different ecological groups (traits). The goal of this project is to measure the toxicity of these neonicotinoids on structural and functional  endpoints, like reproduction and survival of the springtails but also on their role in decomposition and other soil processes (ecosystem services). Final aim is to determine to what extent soil communities may be affected by these insecticides.

2.     The springtail F. candida will be exposed to different neonicotinoids in order to assess the expression of relevant genes (up and down regulation). The goal is to identify which genes are affected, whether this happens in a dose-related manner, how this links to the mode of action of the compounds and to effects at the individual and population level. In this way, the gene expression analysis may be used to develop an Adverse Outcome Pathway for neonicotinoid effects on springtails.

What you can learn?

You will be taught how to identify useful literature, and you will gain experience with methods for culturing, toxicity testing of soil organisms, extraction of neonicotinoids from soil, the design of (complex) experiments, biomolecular techniques, modelling and statistical analysis of ecotoxicity data, etc. You will write a scientific report at the end of this internship, with the possibility of contributing to a publication in a peer-reviewed scientific journal.

Supervision and information

Claudia de Lima e Silva (MSc)
Room H127, W&N building, VU Amsterdam
Email: c.l.s.delimaesilva@vu.nl
Phone: +31 (0)20 – 59 87073

Dr. Ir. C.A.M. (Kees) van Gestel
Room H150, W&N building, VU Amsterdam
Email: kees.van.gestel@vu.nl
Phone: +31 (0)20 – 59 87079

Dr.Ir. D. (Dick) Roelofs
Room H147, W&N building, VU Amsterdam
e-mail: dick.roelofs@vu.nl
Phone: +31 (0)20 – 59 87078