# Complete Mitochondrial Genome Characterization and Phylogenomics of the Stingless Bee, Heterotrigona itama (Apidae: Meliponini)

## TL;DR

This paper analyzes the complete mitochondrial genome of Heterotrigona itama, a vulnerable stingless bee species, to understand its genetic makeup and evolutionary relationships for conservation and research purposes.

## Contribution

The study provides the first complete mitochondrial genome characterization of Heterotrigona itama, revealing its gene structure and phylogenetic placement.

## Key findings

- The mitogenome is 15,318 bp with 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes.
- The genome has a strong A+T bias (75.41%) and conserved gene arrangement similar to Tetragonula species.
- Phylogenetic analysis shows H. itama is more closely related to bumblebees than honeybees.

## Abstract

Stingless bees serve an important part in tropical ecosystems by pollinating and producing medicinal honey. Heterotrigona itama is a commercially significant stingless bee species in Southeast Asia. However, overexploitation has raised questions about its conservation status in some areas, notably Thailand. We examined H. itama’s entire mitochondrial genome to gain a better understanding of its genetic traits and evolutionary ties. Our findings shed light on gene organization, nucleotide composition, codon usage, and evolutionary relationships among other corbiculate bees. This knowledge will help to further taxonomy, population genetics, and stingless bee conservation efforts.

With increasing demand for stingless bee honey, meliponiculture has gained widespread attention. Heterotrigona itama is one of the most economically important species. However, excessive exploitation for commercial purposes has led to population declines, and the species is now considered vulnerable in Thailand. Despite its ecological and economic significance, genomic and taxonomic information on H. itama remains limited. In this study, we sequenced and characterized the complete mitochondrial genome (mitogenome) of H. itama to explore its genome structure and phylogenetic position. The circular mitogenome is 15,318 bp in length and consists of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and 2 ribosomal RNA (rRNA) genes. The genome exhibits a strong A+T bias (75.41%), which affects codon usage and amino acid composition. Isoleucine, methionine, and phenylalanine were the most commonly encoded amino acids. Gene arrangement was highly conserved and closely resembled that of Tetragonula species. Phylogenetic analyses confirmed that H. itama clusters with other stingless bees and is more closely related to bumblebees than to honeybees. Several gene rearrangements suggest a high degree of mitogenomic plasticity. This study provides essential genomic resources for future studies in systematics, phylogenetics, population genetics, and conservation of stingless bees in the Meliponini tribe.