ORIGINAL ABSTRACT

Pesticides and climate change are significant drivers of biodiversity loss, with their interaction likely increasing their detrimental consequences. Ectotherms, such as lizards, are among the most vulnerable non-target organisms given their occurrence in agricultural habitats. Combined exposure to pesticides, and increased temperature can alter the energetic cost for maintenance as most physiological processes, including detoxification, are temperature-depended. However, their combined effects on the rate of metabolic processes of lizards are currently unknown. We conducted a biologically relevant ecotoxicological experiment to assess the combined effects of glyphosate, the most widely used herbicide worldwide, and temperature on the level of expression of standard metabolic rates (SMR) of male wall lizards Podarcis bocagei. Exposure to glyphosate occurred every second day, for 21 days, through contaminated mealworms previously injected with 5 μl of glyphosate sub-lethal dosage (0.5 mg/kg bw). We measured post-exposure SMRs through open-flow respirometry at three different temperatures relevant for the species (18, 25, 29 °C). Across the tested temperature range, SMR increased with temperature, glyphosate-exposed animals displayed elevated SMRs and heavier animals showed greater increase of energy expenditure. The combined mass and exposure effects may pose a threat for populations occurring in agricultural environments, as the largest animals have the highest reproductive output. This evidence is valuable for future risk assessment and conservation prioritization of species which bioenergetic processes may be particularly sensitive to glyphosate exposure.