Bee Mite Genome Joins Battle to Save Honey Bees

Amongst the potential causes for the decline in honey bee colonies, pathogens and parasites of the honey bee, particularly mites, are considered major threats to honey bee health and colonies. Now scientists at the University of Liverpool and Xi’an Jiaotong-Liverpool University (XJTLU) have sequenced the genome of the bee mite Tropilaelaps mercedesae to assess the interaction between the parasite and host. The results provide resources for control developing gene-based control strategies, determining the weak points for conventional methods, and identifying new targets for biological control.

T. mercedesae is a honey bee parasite prevalent in most Asian countries, and has a similar impact on bee colonies that the globally-present bee mite Varroa destructor has. More, T. mercedesae and V. destructor typically co-exist in Asian bee colonies and with the global trade of honey bees T. mercedesae is likely to become established world-wide.

Dr Alistair Darby, from the University’s Centre for Genomic Research where said: “The genome sequence data and research findings provide useful resources for understanding mite biology and identifying potential gene-based mite control strategies.”

Of particular interest, the team found that the mite does not rely on sensing stimulatory chemicals to affect their behaviour, meaning that current control methods targeted to gustatory, olfactory and ionotropic receptors are not effective. The researchers also found that T. mercedesae is enriched with detoxifying enzymes and pumps for the toxic xenobiotics, which means the mite can quickly acquire miticide resistance.

Relevant to this, the researchers investigated the bacteria that infect the bee mite, of which little is known. The scientists discovered that the symbiotic Rickettsiella grylli-like bacteria is commonly present in T. mercedesae and suggest that manipulating this bacteria could help in the development of novel control strategiesin the battle to save bee colonies.

The extent of honey bee colony destruction remains a complex problem, but one that has an extensive impact on crop productivity since honey bees are needed for pollination of a variety of plants. The findings, genome, transcriptome, and proteome data from this T. mercedesae study add an important new resource in the battle to save bee colonies.

‘Draft genome of the honey bee ectoparasite mite, Tropilaelaps mercedesae, is shaped by the parasitic life history’ is published in GigaScience.