Female Preference and Adverse Developmental Effects of Glyphosate-Based Herbicides on Ecologically Relevant Traits in Japanese Quails

Controversial glyphosate-based herbicides (GBHs) are the most frequently
used herbicides globally. An increasing number of studies have identified
GBH residues in soil, water, and even human food that may expose nontarget
organisms including wildlife, livestock, and humans to health risks.
After a heated debate, the European Union allowed the use of GBHs
to continue until 2022, after which their risks will be re-evaluated.
Thus, decision makers urgently need scientific evidence on GBH residues
and their possible effects on ecosystems. An important, yet neglected,
aspect is to assess whether animals show preference or avoidance for
GBH-contaminated food, as it can influence the likelihood of adverse
health effects in wildlife. Here, using Japanese quails (Coturnix japonica) as our model, we show that females
preferred GBH-contaminated food compared to control food. In females,
exposure to GBHs caused delayed plumage development, and GBH residues
were present in eggs, muscles, and liver. These results indicate that
female preference is not adaptive, potentially exposing nontarget
animals to greater risk of adverse effects of GBHs in natural and
agricultural environments. Our results on tissue residues suggest
that further studies are needed to understand the risks of such residues
in the food chain.