Insects recycle endosymbionts when the benefit is over.

Abstract in brief

• Insects form mutualistic relationships with intracellular bacteria called endosymbionts to supplement their diet, and these symbionts are typically transmitted across generations within specialized host cells.
• In the cereal weevil Sitophilus, endosymbionts multiply in young adults to support rapid exoskeleton formation by providing amino acids like tyrosine and phenylalanine, which are crucial for cuticle synthesis, before being quickly eliminated through cell death processes.
• This study highlights how the weevil-endosymbiont relationship is dynamically regulated, with the host balancing the benefits of bacterial presence against the costs by controlling symbiont proliferation and digestion to enhance survival during a vulnerable developmental stage.]