Complete mitochondrial genome of yellow meal worm (Tenebrio molitor)

The complete mitochondrial genomes of four lagriine species (Coleoptera, Tenebrionidae) and phylogenetic relationships within Tenebrionidae

It is common to use whole mitochondrial genomes to analyze phylogenetic relationships among insects. In this study, seven mitogenomes of Tenebrionidae are newly sequenced and annotated. Among them, four species (Cerogira janthinipennis (Fairmaire, 1886), Luprops yunnanus (Fairmaire, 1887), Anaedus unidentasus Wang & Ren, 2007, and Spinolyprops cribricollis Schawaller, 2012) represent the subfamily Lagriinae. In this subfamily, the mitogenomes of the tribes Goniaderini (A. unidentasus) and Lupropini (L. yunnanus and S. cribricollis) were first reported; they were found to be 15,328-16,437 bp in length and encode 37 typical mitochondrial genes (13 PCGs, 2 rRNAs, 22 tRNAs, and a single noncoding control region). Most protein-coding genes in these mitogenomes have typical ATN start codons and TAR or an incomplete stop codon T-. In these four lagriine species, F, L2, I, and N are the most frequently used amino acids. In the 13 PCGs, the gene atp8 (Pi = 0.978) was the most diverse nucleotide, while cox1 was the most conserved gene with the lowest value (Pi = 0.211). The phylogenetic results suggest that Pimelinae, Lagriinae, Blaptinae, Stenochiinae, and Alleculinae are monophyletic, Diaperinae is paraphyletic, and Tenebrioninae appears polyphyletic. In Lagriinae, the tribe Lupropini appears paraphyletic because Spinolyprops is clustered with Anaedus in Goniaderini. These mitogenomic data provide important molecular data for the phylogeny of Tenebrionidae.

Whole genome assemblies of Zophobas morio and Tenebrio molitor

Zophobas morio (=Zophobas atratus) and Tenebrio molitor are darkling beetles with industrial importance due to their use as feeder insects and their apparent ability to biodegrade plastics. High quality genome assemblies were recently reported for both species. Here, we report additional independent Z. morio and T. molitor genome assemblies generated from Nanopore and Illumina data. Following scaffolding against the published genomes, haploid assemblies of 462 Mb (scaffold N90 of 16.8 Mb) and 258 Mb (scaffold N90 of 5.9 Mb) were produced for Z. morio and T. molitor, respectively. Gene prediction led to the prediction of 28,544 and 19,830 genes for Z. morio and T. molitor, respectively. Benchmarking Universal Single Copy Orthologs (BUSCO) analyses suggested that both assemblies have a high level of completeness; 91.5 and 89.0% of the BUSCO endopterygota marker genes were complete in the Z. morio assembly and proteome, respectively, while 99.1 and 92.8% were complete in the T. molitor assembly and proteome, respectively. Phylogenomic analyses of four genera from the family Tenebrionidae yielded phylogenies consistent with those previously constructed based on mitochondrial genomes. Synteny analyses revealed large stretches of macrosynteny across the family Tenebrionidae, as well as numerous within-chromosome rearrangements. Finally, orthogroup analysis identified ∼28,000 gene families across the family Tenebrionidae, of which 8,185 were identified in all five of the analyzed species, and 10,837 were conserved between Z. morio and T. molitor. We expect that the availability of multiple whole genome sequences for Z. morio and T. molitor will facilitate population genetics studies to identify genetic variation associated with industrially relevant phenotypes.

The complete mitochondrial genome of Alphitobius diaperinus Panzer, 1797 (Coleoptera: Tenebrionidae)

Alphitobius diaperinus Panzer, 1797 is a major pest in poultry production and easily observed in poultry litter. We have determined mitochondrial genome of A. diaperinus collected in Chungcheongbuk-do, Republic of Korea. The circular mitogenome of A. diaperinus is 15,511 bp long which is longer than that of Z. atratus but shorter than that of T. obscurus. It includes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNAs. The base composition was AT-biased (72.4%). Phylogenetic tree displays that tribe Alphitobiini is clustered with tribes Helopini and Diaperini with enough supportive values of three phylogenetic trees.

The complete mitochondrial genome of dark mealworm Tenebrio obscurus (Coleoptera: Tenebrionidae)

Mealworms are the most common edible insect and feed additives in poultry, livestock, and aquaculture production. In the present study, the complete mitochondrial genome of dark mealworm Tenebrio obscurus (Zunyi population) was sequenced and annotated. The 15,509 bp circular mitogenome contains a conserved set of 37 mitochondrial genes including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and an A + T-rich region. The gene order is identical to the typical insect gene arrangement. Great differences were found in A + T-rich regions between Zunyi population and Guiyang population including large deletion and substitution. Phylogenetic analysis showed that T. obscurus clustered within Tenebrionoidea and was closely related to Tenebrio molitor.

Complete mitochondrial genome of the dark mealworm Tenebrio obscurus Fabricius (Insecta: Coleoptera: Tenebrionidae)

The dark meal worm Tenehrio obscurus (Fabricius) is frequently found as a pest of stored grain, but it is an important resource insect like the yellow meal worm (Tenebrio molitor), larvae of which has high-protein content. The mitochondrial genome of T. obscurus is a circular molecule of 15,771 bp (GenBank accession number MG739327), with A + T bias of 72.69%. It comprises 13 protein-coding, 22 tRNA and two rDNA genes. The protein-coding genes had typical ATN (Met) as the initiation codon and were terminated by the typical stop codon TAN, except for COX2, COX3, nadh5 and nadh4. The phylogenetic tree based on maximum-likelihood method showed that the phylogenetic position of T. obscurus is closely related to T. molitor.