Developmental correspondence of juvenile stages across the locust, harlequin ladybird, and diamondback moth

Insect metamorphosis is a captivating aspect of animal research. To address the controversy regarding the developmental correspondence between hemimetabolous and holometabolous insects, we utilized non-destructive micro-computed tomography (CT) imaging and RNA-seq to examine wing growth and transcriptome profiles across juvenile stages in the <i>Locusta migratoria</i>, <i>Harmonia axyridis</i>, and <i>Plutella xylostella</i>, with distinct metamorphic strategies. Micro-CT revealed that over 88% of wing volume increase in ladybirds and moths occurs during the prepupal-pupal transition, similar to locust nymphs. Developmental transcriptome clustering demonstrated that gene expression patterns more closely resembled those between ladybird/moth prepupae/pupae and locust nymphs, whereas holometabolous larvae exhibited distinct profiles. Notably, gene expression specificity increased across juvenile stages with more recent species divergence. Genes highly expressed around the prepupal/pupal stages accumulated higher evolutionary rates. These integrated findings unveil commonalities in juvenile stage development among the locust, ladybird, and moth, providing insights into the evolution of metamorphosis within neopteran insects.