Life inside a bag: multiomics insights into the bagworm species Eumeta crameri

Bagworms are commonly known for the well-organized case or bag surrounding them constructed using their silk and plant materials. To understand the genetic basis of these unique characteristics in bagworms, we performed multiomics analyses of a bagworm species, Eumeta crameri. The genome and transcriptome sequencing of E. crameri were used to construct the nuclear genome with a size of 668.2 Mb, N50 value of 6.6 Mb, and 13,554 coding genes, which was further assembled into 31 pseudochromosomes. The mitochondrial genome had a size of 15.6 Kb. We established the phylogenetic position of E. crameri with respect to 54 other insect species. The comparative analyses of E. crameri with other Lepidopterans revealed the adaptive evolution of genes related to primary metabolic pathways, defense, molting, and metamorphosis, and silk formation in the bagworm species. We also showed the ultrafine nature of the E. crameri silk fibres. Further, we performed the gut microbiome sequencing for E. crameri and constructed a gut microbial gene catalogue, which revealed the unique composition of the gut microbiome and its significance for host metabolism and defense. Together, the results provide multifaceted insights into the biological processes that support the well-organized holometabolous metamorphosis inside the bags of E. crameri.