Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 2, 2003
Publication Date: June 1, 2003
Citation: Danka, R.G., Villa, J.D. 2003. Autogrooming by resistant honey bees which are challenged by individual tracheal mites.. Apidologie 34(4):591-596. Interpretive Summary: Tracheal mites are parasites of honey bees which can damage or kill colonies when infestations rise to involve half or more of the worker bees. Some genetic strains of bees resist infestation by tracheal mites. Indirect evidence has shown resistance is based chiefly on the ability of individual worker bees to effectively groom mites off themselves as mites are moving from bee to bee. This research involved directly measuring grooming responses of individual bees when the bees were challenged by placing tracheal mites directly onto them. Measurements were made by infesting resistant and susceptible bees in observation hives with transparent walls, where bee responses could be measured. Resistant bees were more likely to groom and also made more grooming attempts. Resistant bees and susceptible bees that groomed were equally effective at removing mites. Resistant bees may have a lower response threshold for detecting and acting against mites on their body. Unfortunately, resistant and susceptible bees reacted similarly to a simple stimulus that did not involve a mite (a stroke of the brush used to transfer mites). This suggests that it might be difficult to develop a test to easily screen bees for resistance by giving them a common grooming stimulus (such as applying a dust to them), rather than conducting a more complicated test that involves exposing bees to mites.
Technical Abstract: Autogrooming responses of honey bees of resistant and susceptible strains were measured when bees in observation hives were challenged directly by placing tracheal mites onto them. Resistant and susceptible adult worker bees (<16 h old) were marked and added to a colony of unrelated bees. Adult female mites were dissected out from other bees and a single mite was transferred (through access doors in the hive sides) to the mesoscutum of a marked bee. We monitored the grooming actions of the bee for seven minutes, then caught the bee and examined it for the mite. This procedure was used to test 279 resistant bees and 276 susceptible bees during six 3-day trials. Greater proportions of resistant bees groomed, and resistant bees made more grooming attempts. Bees of the two types had apparently equal grooming success (losing ca. 75% of mites). Control-group bees (those only stroked with the brush used to transfer mites) of the two bee types did not differ in any response parameter. Resistant bees may have a lower threshold for responding by autogrooming when stimulated by mites on their body, enabling more bees to initiate grooming and engage in more extensive grooming.