Title: Collateral damages of pesticides under global warming: Can you still reproduce even if you are not targeted?

Keywords:
Climate change, sublethal effect, pesticides, grapevine pest, Lepidoptera, reproductive physiology, behavioural ecology and evolution

Supervisors:
Philippe Louâpre (UMR CNRS Biogéosciences, Université de Bourgogne Franche-Comté)
Jérôme Moreau (UMR CNRS Biogéosciences, Université de Bourgogne Franche-Comté)
Marlène Goubault (UMR CNRS IRBI – Université de Tours)

Topic:
Pests like insects, bacteria and fungi substantially reduce yields in agriculture and pesticides are largely applied to fight them. Beside direct lethal effects of pesticides, sub-lethal effects are more pernicious as they do not lead to the immediate death of the pest. Indeed, the major physiological functions (nervous, immune, endocrine, and reproductive systems for instance) are impacted through cascading effects and will in turn affect (positively or negatively) the behaviour and the population dynamics of the pests. In the current context of global warming, recent studies showed that the sublethal effects of pesticides on target pests may change drastically due to the increase in local temperature. However, we have no idea about how non-targeted pests may respond to pesticides when experiencing warmer temperatures. This topic is thus of prime importance because it could reveal unexpected consequences (potentially dramatic in agroecology) of current agricultural practices.

The goal of this project is to evaluate the sublethal effects of pesticides used in viticulture (copper-based treatments) on the reproductive success of a non-target insect pest, and to evaluate, in the meantime, to what extent these sublethal effects may change when experiencing global warming. To achieve this objective, we will use the lepidoptera Lobesia botrana, a major grapevine pest, which is not targeted by the considered pesticide. In viticulture, the effects of copper on grapevine and the grape downy and powdery mildew are widely studied and established, but its effects on non-target grapevine moths are mainly unknown.

During this master internship, we will perform experimental manipulations in which larvae of L. botrana will be exposed to different copped-based treatments using a dose-response design. A suite of reproduction-related life history traits (e.g. fertility and fecundity for females, capacity of spermatophores and spermatozoa production for males) and behaviours (calling behaviour, mating latency and duration) will be assessed to evaluate the sublethal effects of these molecules on L. botrana reproductive success. We will perform these experiments at different temperatures using climatic chambers to test the effects of global warming on these sublethal effects.

Techniques involved in the project:
Behavioural tests in controlled conditions, reproductive physiology, dissection, moth rearing.

Desired skills and abilities:
We are seeking a highly motivated student with good organizational skills and strong interests in ecology and evolutionary ecology. Master students in ecology, physiology, behaviour or a related field are welcomed. Previous experience involving laboratory experiments and the use of spreadsheets (e.g. Excel) and statistical analyses (R software) will be appreciated. This study requires rigour and meticulous work.

How to apply:
Please send your CV, motivation letter (1 page max), and names and contact information for two references to Philippe Louâpre ([email protected]). Informal enquiries are welcome – please contact us by email in French or English.

Practical information:
Starting date: preferably from 1st January to 28th February 2022
Duration: ~5-6 months
Salary: stipends provided through the University Bourgogne Franche-Comté will be available.

Relevant literature:
Matzrafi, M. (2019). Pest management science, 75(1), 9-13.
Guedes R.N.C., Smagghe G., Stark J.D. and Desneux N. (2016). Annual Review of Entomology, 61, 1–3.
Müller C. (2018). Basic and Applied Ecology, 30, 1–10.
Iltis C. et al. (2021). Journal of Pest Science, 10.1007/s10340-021-01398-9

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