Autogrooming and bee age influence migration of tracheal mites to Russian and susceptible worker honey bees (Apis mellifera L)
José D. Villa
The role of autogrooming in controlling tracheal mites in Russian and susceptible colonies was evaluated by gluing together the midlegs of workers and exposing them to mite infestation. In one experiment, young workers (less than 10 h old) from both strains having midlegs glued together at the tarsi (G) or left unglued as controls (C) were introduced into colonies with 50 to 75% of workers infested and retrieved after five or six days. G Russian and susceptible workers had very high mite abundances (8.2 and 7.9 female mites/worker). However, C workers had significantly lower infestations, and strains differed significantly (Russian = 1.5, Susceptible = 3.0 female mites/worker). In a second experiment, C and G workers of both strains and from age classes produced every 24 h (1, 2, 3, or 4 d-old), were simultaneously introduced into an infested colony. Infestation of bees declined significantly in older bees. Differences due to gluing of midlegs and strain became less marked with increasing age of bees. The majority of mites infested the tracheae of workers less than 48 hours old. The autogrooming efficacy of Russian workers during this critical period of 48 hours of high potential for mite migration appears to explain the resistance of their colonies to tracheal mites.