Glyphosate threatens lizard adaptation to warming: disruption to maternal effects

Ectothermic reptiles, vulnerable to future warming, may adapt through maternal effects. However, the effects of glyphosate-based herbicides (GBHs) on this adaptive mechanism remain unclear. To explore, we conducted a cross-design experiment on lizards (Eremias argus) under normal and elevated temperatures, with or without GBH exposure. We assessed maternal reproductive output, egg composition, embryo hatching performance, and the morphological and performance traits of offspring which were uniformly reared under warming regime. Under warming conditions, female enhanced reproductive output by reducing relative clutch mass and increasing egg-laying frequency. They also helped offspring adapt to warmer environments via maternal resource transfer, likely by the observed increases in unsaturated fatty acids and amino acids in eggs. Hatchlings from the warming treatment groups exhibited higher survival rates, underscoring the potential of maternal effect in thermal adaptation. GBH exposure in a warming environment led to reduced reproductive frequency, lower hatching rates, smaller hatchlings and decreased offspring thermal tolerance, diminishing the benefits of maternal effect. These effects may be linked to reduced levels of nucleotide metabolism-related substances, triglycerides, proline, and citrulline in eggs. Our study revealed the adverse effects of GBH on lizards and provided new insights into the impact of chemical pollutants on biological adaptability in the context of climate change.