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THE AMPHIBIAN SHORT TERM ASSAY (ASTA): DEVELOPMENT & EVALUATION OF AN INNOVATIVE & COST-EFFECTIVE SOLUTION FOR TESTING IMPACT OF ORGANOPHOSPHATE PESTICIDES ON AMPHIBIANS BEHAVIORAL TRAITS.

Presentation of the full solution process.

Neurotoxic pesticides are used worldwide to protect crops from insects. Developed at the beginning of the 20th century, they now represent a threat to non-target organisms that live in areas surrounded by treated crops. Many biochemical and cell-based solutions have been developed for testing insecticide neurotoxicity. Nevertheless, such solutions provide a partial assessment of the impact of neurotoxicity and there is a call for the development of solution including behavioral endpoints.

During my PhD, I enjoyed developping a 8-day method for assessing the impacts of organophosphate insecticides (OPI) on early stage of X. laevis, a model species for amphibians. This promising method implies the measurement of biochemical (AChE activity)[1], morphometrical (lengths and shape)[1] and locomotor traits[publication coming very soon]. For measuring the latter, I conceived a home-made device for recording larvae swimming behavior. I also developed a Python application for tracking larvae trajectories and computing different locomotor speed- and direction-related components.

The home-made device for recording the larvae swimming behavior.

For evaluating the efficiency of the method, I used two OPIs, the diazinon and the chlorpyrifos insecticide.

The application process and its successive steps for tracking larvae swimming from video files.
The Python application tracking a larvae trajectory.

The results of this work are numerous:

  • I was able to prove the efficiency of the method for highlighting the impact of these OPIs on AChE activity, body length and shape, growth rate and locomotor components,
  • 6-day larvae were demonstrated to be the most relevant stage for testing OPIs,
  • the impact of exposure on locomotor performance was time-dependent with day 6 as the most critical time.

I am confident that this method would be a good candidate for standardization after implementing improvement and leading few investigation about its repeatability and reproducibility. I am also confident that it would be tested with pharmaceuticals such as antidepressants.

2023

Boualit, L., Cayuela, H., Ballu, A. , Cattin, L., Reis, C. & Chèvre, N. The Amphibian Short Term  Assay (ASTA): Evaluation of a New Ecotoxicological Method for Amphibians Using Two Organophosphate Pesticides Commonly Found in Nature. Assessment of of behavioral traits. Environmental Toxicology and Chemistry (accepted)

2022

Boualit, L., Cayuela, H., Cattin, L., & Chèvre, N. (2022). The Amphibian Short‐Term Assay: Evaluation of a New Ecotoxicological Method for Amphibians Using Two Organophosphate Pesticides Commonly Found in Nature—Assessment of Biochemical, Morphological, and Life‐History Traits. Environmental Toxicology and Chemistry, 41(11), 2688-2699.

2021

Cayuela, H., Prunier, J. G., Laporte, M., Gippet, J. M., Boualit, L., Guérold, F., … & Jacob, G. (2021). Demography, genetics, and decline of a spatially structured population of lekking bird. Oecologia, 195(1), 117-129.

2019

Cayuela, H., Boualit, L., Laporte, M., Prunier, J. G., Preiss, F., Laurent, A., ... & Jacob, G. (2019). Kin-dependent dispersal influences relatedness and genetic structuring in a lek system. Oecologia, 191(1), 97-112.

Boualit, L., Pichenot, J., Besnard, A., Helder, R., Joly, P., Cayuela, H., 2019. Environmentally mediated reproductive success predicts breeding dispersal decisions in an early successional amphibian. Animal Behaviour 149, 107–120. https://doi.org/10.1016/j.anbehav.2019.01.008

2016

Cayuela, H., Boualit, L., Arsovski, D., Bonnaire, E., Pichenot, J., Bellec, A., … & Besnard, A. (2016). Does habitat unpredictability promote the evolution of a colonizer syndrome in amphibian metapopulations?. Ecology, 97(10), 2658-2670.

2015

Cayuela, H., Arsovski, D., Boitaud, S., Bonnaire, E., Boualit, L., Miaud, C., … & Besnard, A. (2015). Slow life history and rapid extreme flood: demographic mechanisms and their consequences on population viability in a threatened amphibian. Freshwater biology, 60(11), 2349-2361.