Development and standardisation of an ecotoxicity test with fungus gnat larvae for the risk assessment of genetically modified plants

According to EU Directive 2001/18/EC, genetically modified organisms (GMO) must be assessed for potential risks to human health, animal and plant life, nature, and the environment prior to experimental release or market authorization. The concepts and methods used for this purpose must correspond to the state of the science and technology and consider the specific issues and characteristics of the testing of GMO. In 2012, the research project ‘Development and standardisation of an ecotoxicity test for the risk assessment of genetically modified plants’ was initiated, in which a new laboratory ecotoxicity test was developed with the fungus gnat species Bradysia impatiens. A preliminary test with the genetically modified (GM) maize line MON810 showed effects on emergence and development time. The project ended in 2016 with the proposal of a draft test guideline (see Jänsch et al. 2018). In the present project (‘Development and standardisation of a laboratory ecotoxicity test with fungus gnat larvae for the risk assessment of genetically modified plants – Part 2’), this test method should be extended to include a second fungus gnat species, Lycoriella castanescens. This species has a higher ecological relevance compared to B. impatiens. However, due to problems encountered with the culturing of the fungus gnats, it was instead decided to test another soil invertebrate organism, for which dietary exposure is feasible. Springtails (Collembola: Folsomia candida and Sinella curviseta) were identified as a relevant group of soil mesofauna, for which there is a standardised test guideline that was adapted for testing of genetically modified material. In the tests performed in the project, no adverse effects of MON810 on B. impatiens were observed. Further trials would be necessary to assess whether the test method with B. impatiens could be made fit for standardisation in other laboratories. F. candida was used to test azadirachtin, GM maize and copper-contaminated plant material. However, the nutritional value of plant material, particularly maize, was found to be insufficient to obtain similar reproduction rates as with standard yeast food. No adverse effect of MON810 on F. candida were recorded. S. curviseta was not suitable for testing due to high reproduction variability, lack of a dose-response with azadirachtin, and low reproduction when fed with maize leaf material.

Last update: August 2024