Identification of sex chromosomes and primary sex ratio in the small hive beetle, a worldwide parasite of honey bees

Authors: HUANG, QIANG - Jiangxi Agricultural University; Sim, Sheina; Geib, Scott; Childers, Anna; LIU, JUNFENG - Jiangxi Agricultural University; WEI, XIUXIU - Jiangxi Agricultural University; HAN, WENSU - Chinese Academy Of Tropical Agricultural Sciences; Posada-Florez, Francisco; XUE, ALLEN - University Of Texas At Austin; LI, ZHENG - University Of Texas At Austin; Evans, Jay

Submitted to: Gigascience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2023
Publication Date: 7/25/2023
Citation: Huang, Q., Sim, S.B., Geib, S.M., Childers, A.K., Liu, J., Wei, X., Han, W., Posada-Florez, F.J., Xue, A., Li, Z., Evans, J.D. 2023. Identification of sex chromosomes and primary sex ratio in the small hive beetle, a worldwide parasite of honey bees. Gigascience. 12:1-9. https://doi.org/10.1093/gigascience/giad056.
DOI: https://doi.org/10.1093/gigascience/giad056

Interpretive Summary: Honey bees face numerous pests and pathogens. The small hive beetle (SHB) impacts honey bee colonies and beekeeping in the United States and on five other continents. SHB take food from colonies and feed on developing honey bee larvae. Thanks to a symbiotic fungus, heavy infestation by SHB can lead to a resinous covering within honey bee colonies, spoiling hive resources and killing bees. Here we describe a nearly complete genome sequence for SHB and use that genome to identify key genes for beetle biology, address a perceived over-representation of female beetles, and set a path for gene-based beetle controls. These resources can be used to help reduce the effects of a key parasite of the most important managed pollinator.

Technical Abstract: The small hive beetle, Aethina tumida (SHB), has emerged as a worldwide threat to honey bees in the past two decades. These beetles harvest nest resources, feed on larval bees, and ultimately can spoil nest resources with a gelatinous slime. Genetic resources have enabled the tracking of invasion paths as this beetle has expanded from Africa to six continents. Here we present the first chromosome-level genome assembly for the SHB. With 99.1% representation of conserved (BUSCO) arthropod genes, this resource enables the study of chemosensory, digestive, and detoxification traits critical for SHB success and possible control. We use this annotated assembly to characterize features of SHB sex chromosomes and tackle a pressing question related to birth and adult sex ratio biases. We also provide insights into chromosome fusion, recombination, tandem repeat structure, and other genome-level traits. SHB is a successful emerging pest that endangers multiple pollinator species, including the primary agricultural pollinator, the honey bee. It also falls within the most successful insect order, the Coleoptera, and provides a pivotal contrast to other beetle genomes. Genome-enabled insights will clarify the adaptive traits that allowed this beetle to spread rapidly and will be critical for determining the causes of observed sex ratio asymmetries.