Special structures of hoopoe eggshells enhance the adhesion of symbiont-carrying uropygial secretion that increase hatching success.

Abstract in brief

• The study investigates the special microscopic structures called crypts in hoopoe eggshells that help retain antimicrobial uropygial secretions, which contain mutualistic bacteria that can protect embryos from infections.
• Experiments blocking female access to the uropygial gland showed that without the secretion, eggshells had higher bacterial permeability and fewer favorable bacteria, leading to reduced hatching success, highlighting the importance of these secretions.
• Overall, the research suggests that the unique eggshell structures and the bacteria-rich secretions play a crucial role in improving hatching success by providing antimicrobial protection through a mutualistic relationship between the hoophoe bird and beneficial bacteria.]