Establishment and evaluation of a rearing method for Tropilaelaps mercedesae using gelatin capsules

Tropilaelaps mercedesae is a major ectoparasitic mite threatening the western honey bee (Apis mellifera L.), yet the lack of standardized in vitro rearing methods limits mechanistic studies of its biology and control. Here, we extended a gelatin capsule-based rearing method for Varroa destructor to establish an verage, each reproducingin vitro platform for T. mercedesae. Reproductively primed females were co-cultured with freshly capped worker bee larvae (≤ 24 h post-capping) in gelatin capsules until honey bee emergence. To evaluate the efficacy of this method, the fitness of the original foundress mites was monitored throughout the rearing period. Results indicated a foundress mite survival rate of 47.57% (49/103). High fertility (95.92%, 47/49) was achieved among these mites. On a foundress mite produced 2.62 eggs and 1.13 surviving offspring, consistent with the reproductive output observed in natural colony conditions. All developmental stages and mating behaviors were also successfully recapitulated in vitro. These results establish a robust and reproducible rearing method for T. mercedesae, providing a tractable experimental system for investigating mite-host interactions and for developing targeted control strategies.