4.3. Collecting live mites

  1. Anesthetize a bee with CO2 (or place bees in refrigerator until immobile).
  2. Grab the paranotal lobe that covers the metathoracic spiracle with fine forceps and pull the lobe posteriorly at a modest angle to the bee’s surface (Smith et al. (1987).
  3. The lobe, spiracle, and most of the main tracheal trunk will be removed together. This technique was subsequently used by Phelan et al. (1991), Bruce et al. (1991), and Sammataro and Needham (1996) to obtain living mites.
  4. Other researchers have removed the bee’s head and pronotum to expose the large thoracic tracheal trunks. These are either grasped at the spiracle with fine forceps (Pettis, pers. comm.; vanEngelsdorp and Otis, 2001b) or a cut is made around the spiracle before removing the tracheal trunk (McMullan et al., 2010).
  5. Allow the section of the trachea to dry onto a glass slide for ~ 2 min.
  6. Tear open trachea with a minute pin and pick up the mites with an eyelash attached to a wooden dowel (Phelan et al., 1991; vanEngelsdorp and Otis, 2001b; McMullan et al., 2010
  7. Young, lightly bronzed female mites can be selected; males, darker (older) females and those obviously gravid with an egg can be avoided because they have reduced mobility (McMullan et al., 2010; J Pettis, pers. comm.).
  8. A female mite placed externally near the paranotal flap of a bee will crawl towards and enter the spiracle, (D Sammataro, pers. obs.). When drones are present, they are preferred because mite intensity is generally higher in drones than in workers (Dawicke et al., 1992).
  9. Exposed mites are sensitive to desiccation, so they should be kept at high humidity.
  10. vanEngelsdorp and Otis (2001b) could perform bioassays with living mites only at night, perhaps because of a circadian rhythm in mite activity that influences their nocturnal dispersal to new hosts (Pettis et al., 1992).