Evolutionary Dynamics of Host Organs for Microbial Symbiosis in Tortoise Leaf Beetles (Coleoptera: Chrysomelidae: Cassidinae)

Abstract

Insects represent the biodiversity of the terrestrial ecosystem, and their prosperity is attributable to their association with symbiotic microorganisms. By sequestering microbial functionality into their bodies, organs, tissues, or cells, diverse insects have successfully exploited otherwise inaccessible ecological niches and resources, including herbivory enabled by utilization of indigestible plant cell wall components. In leaf beetles of the subfamily Cassininae, an ancient symbiont lineage, Stammera , whose genome is extremely reduced and specialized for encoding pectin-degrading enzymes, is hosted in gut-associated symbiotic organs and contributes to the host’s food plant digestion.