Gut microbiota variation drives differential performance in leaf beetles across host plants

Area of Science:

• Ecology
• Microbiology
• Insect Science

Background:

• Host plant selection significantly impacts herbivore fitness.
• Plant-mediated gut microbiota are crucial for insect performance, but their exact role in differential performance across plants is unclear.

Purpose of the Study:

• To investigate the influence of gut microbiota on the preference-performance relationship of the leaf beetle Plagiodera versicolora on different host plants.
• To identify specific microbial players and molecular mechanisms mediating plant-insect interactions.

Main Methods:

• Comparative performance assays of P. versicolora on various host plants.
• Germ-free (GF) insect rearing and microbial reintroduction experiments.
• 16S rRNA gene sequencing for gut microbiota analysis.
• Transcriptomic and metabolomic analyses to identify molecular pathways.

Main Results:

• P. versicolora preferred and performed better on Salix babylonica, but this relationship vanished in microbiota-depleted larvae.
• Rosenbergiella nectarea was enriched in S. babylonica-fed larvae and essential for restoring superior performance in GF larvae.
• R. nectarea promoted larval growth by enhancing nutritional metabolism and developmental signaling, potentially via a PvABCG5-mediated cholesterol-to-20E synthesis pathway.

Conclusions:

• Host plant-induced performance differences in herbivorous insects are largely mediated by their gut microbiota.
• The gut microbiome plays a critical role in establishing herbivore host preference and the preference-performance relationship.