In vitro assessment of Tropilaelaps mercedesae survival across different substrates

Maggie C. Gill; Bajaree Chuttong; Paul Davies; Avril Earl; George  Tonge; Dan Etheridge

doi:10.62949/02634299.0581119

Maggie C. Gill PHIRA-Science, Llandybie, Ammanford, UK. and Department for Environment Food and Rural Affairs, Horizon House, Bristol, UK.
Bajaree Chuttong Meliponini and Apini Research Laboratory, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand.
Paul Davies PHIRA-Science, Llandybie, Ammanford, UK.
Avril Earl PHIRA-Science, Llandybie, Ammanford, UK.
George Tonge PHIRA-Science, Llandybie, Ammanford, UK.
Dan Etheridge PHIRA-Science, Llandybie, Ammanford, UK.

DOI: https://doi.org/10.62949/02634299.0581119

Keywords: Apis mellifera, Tropilaelaps, survival transmission, honey bee mites, broodless survival, parasitic mites, matrix-dependent viability

Abstract

Tropilaelaps spp. are parasitic mites that feed and reproduce within honey bee brood (Apis spp.), causing significant damage to Apis mellifera colonies. While traditionally believed to be incapable of surviving without brood, recent findings suggest T. mercedesae may persist during broodless periods. This study aimed to investigate the survival potential of T. mercedesae on various matrices in the absence of brood, with a focus on understanding possible mechanisms supporting its persistence and spread.

An in vitro survival experiment was conducted using T. mercedesae mites placed on three matrix types: live adult bees (A. dorsata / A. mellifera), decomposing pupae, and decomposing adults. Mite survival was monitored over time under controlled conditions. Survival duration was recorded and analysed using Log Rank tests and visualized with Kaplan Meier survival curves to identify differences in survival across matrices.

Mites survived for over 96 hours on live adult A. mellifera, over 144 hours on decomposing pupae, and up to 168 hours on decomposing adults. These findings demonstrate the mite’s ability to survive for extended periods without access to live brood, challenging existing assumptions about its biology and survival limits.

This study highlights a potential survival mechanism of T. mercedesae outside brood environments, which may contribute to its spread through previously considered low-risk pathways, such as queen/package bee trade and used beekeeping equipment. These findings underscore the need for updated biosecurity protocols and further research into transmission dynamics and control strategies.