Individual-based modelling of the recovery of Chaoborus crystallinus in aquatic mesocosm pond studies

The recovery time of chemically stressed populations in aquatic outdoor mesocosms studies is very important for the risk assessment of pesticides. Insects like the phantom midge Chaoborus crystallinus can recover from inside the polluted ponds (autochthonous recovery), and by immigration of adults from uncontaminated ponds (allochthonous recovery). In both mechanisms, the recovery time depends on the strength of toxic effects, population density and spatial vicinity of other non-affected populations. Smaller populations have a higher extinction probability than larger ones, and isolated populations are more sensitive due to the lack of immigration from outside. The dipteran Chaoborus crystallinus, a pelagic invertebrate predator, is well known for its sensitivity to insecticide toxicity, especially the first instars.

Flow Chart Chaoborus

Chaoborus crystallinus larvae

Flow Chart Chaoborus

Modelled life history of Chaoborus

To analyse the recovery time and extinction probability after pesticide application, an individual-based population model for Chaoborus crystallinus has been developed to include the complete life. Density-dependent processes like cannibalism and emigration are important factors for the regulation of population density. The model was validated with experimental data from aquatic outdoor mesocosms, and was used to compare the long and short-term recovery behaviour of isolated and connected populations following exposure to pesticides. In the newest version, the Chaoborus population model was coupled with the General Unified Threshold model for Survival (GUTS, Jager et al. 2011) explicitly simulating toxicokinetics and toxicodynamics (TKTD).


Strauss T, Kulkarni D, Preuss TG, Hammers-Wirtz M (2016): The secret lives of cannibals: Modelling density-dependent processes that regulate population dynamics in Chaoborus crystallinus. Ecological Modelling 321:84-97.

Dohmen, P., Preuss, T.G., Hamer, M., Galic, N., Strauss, T., Van den Brink, P. J., De Laender, F., and Bopp, S. (2016). Population‐level effects and recovery of aquatic invertebrates after multiple applications of an insecticide. Integrated environmental assessment and management 12:67-81.


Strauss T (2013): Incorporating ecological scenarios into population modelling for use in aquatic risk assessment - A simulation study for the emerging insect Chaoborus. Poster presentation, 23th SETAC- Europe Annual Meeting 12-16 May 2013, Glasgow, Scotland.

Strauss T, Bruns E, Goerlitz G, Preuss TG (2011): Modelling toxic effects on Chaoborus populations under field conditions - an individual-based simulation study. Poster presentation, 21th SETAC- Europe Annual Meeting 15-19 May 2011, Milano, Italy.

Strauss T (2010): Density-dependent compensation of toxic effects in Chaoborus crystallinus populations – an individual-based simulation stud. Poster presentation, 20th SETAC- Europe Annual Meeting 23-27 May 2010, Seville, Spain.

Strauss T, Sevim S, Ratte HT (2007): Individual-based modelling of the recovery of Chaoborus crystallinus in aquatic mesocosm pond studies. Poster presentation, 17th SETAC- Europe Annual Meeting 20-24 May 2007, Porto, Portugal.

Strauss T, Ratte HT (2003): Individuenbasierte Modellierung in der Ökotoxikologie am Beispiel von Chaoborus crystallinus. Vortrag SETAC-GLB-Jahrestagung, Heidelberg, 21.- 23. September 2003.

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Dr. Tido Strauss

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