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Eukaryotic initiation factor 6 (eIF6) is necessary for ribosome biogenesis and translation, but eIF6 has been poorly elucidated in insects. Phylogenetic analysis demonstrated that eIF6 originated from one ancestral gene among animals and exhibited specific duplication in Tribolium, yielding three homologues in Tribolium castaneum, eIF6, eIF6‐like 1 (eIF6l1), and eIF6‐like 2 (eIF6l2). It was found that eIF6 was highly expressed in the embryonic and early adult stages, eIF6l1 had peak expression at the adult stage, and eIF6l2 showed peak expression in late adults of T. castaneum. Tissue‐specific analyses in late‐stage larvae demonstrated that eIF6 was abundantly expressed in all tissues, while eIF6l1 and eIF6l2 had the highest expression in the gut and the lowest expression in the head of T. castaneum. Knockdown of eIF6 caused precocious pupation and eclosion, impaired ovary and testis development and completely repressed egg production. The expression levels of vitellogenin 1 (Vg1), Vg2 and Vg receptor (VgR) significantly decreased in ds‐eIF6 females 5 days post‐adult emergence. Silencing eIF6 activated ecdysteroid biosynthesis and juvenile hormone degradation but reduced the activity of insulin signalling in T. castaneum, which might mediate its roles in metamorphosis, reproduction and gene expression regulation. However, silence of eIF6l1 or eIF6l2 had no effects on metamorphosis and reproduction in T. castaneum. This study provides comprehensive information for eIF6 evolution and function in the insect. [ABSTRACT FROM AUTHOR]

The zona pellucida domain protein Dusky (Dy) plays a vital role in wing morphogenesis in insects, but little information on its function has been reported. In this study, we found that dy regulated wing cell size, larval and pupal duration, and the metabolism of amino acid and 20‐hydroxyecdysone in Tribolium castaneum. Using RNA‐seq, 413 differentially expressed genes were identified between physiological buffer‐injected and dy‐double‐stranded RNA‐treated larvae, including 88 downregulated genes and 325 upregulated genes. Among these genes, dy knockdown increased CYP18A1 expression to elevate the 26‐hydroxylation of 20‐hydroxyecdysone, which ultimately led to growth defects in wing cells. Silencing of dy upregulated the transcription of genes encoding tyrosine aminotransferase, 4‐hydroxyphenylpyruvate dioxygenase, homogentisate 1, 2‐dioxygenase, and Pale to promote the catabolism of tyrosine and phenylalanine, which eventually reduced amino acid content. Furthermore, dy knockdown upregulated 4E‐BP expression, and 4E‐BP silencing partially phenocopied dy RNA interference‐mediated wing morphogenesis. These results suggest that Dy controls 20‐hydroxyecdysone and amino acid metabolism to regulate wing morphogenesis in the insect. [ABSTRACT FROM AUTHOR]