3.1.1. Manual collection
Phoretic mites can be picked up by hand from their host with a fine bristle brush or a small mouth aspirator.
1. Collect honey bees from a colony.
This task is easier when the colony is highly infested (see section 4.6. ‘Breeding mites in colonies’ for a method to obtain regular supply of highly infested colonies), but to collect ‘healthy’ mites it is recommended that the host colony does not reveal visible damages of Varroosis like crippled bees.
2. Catch honey bees one by one and examine them for the presence of mites.
Mites may run freely over the bee's body or be hidden between two sternites. Finding and collecting them sometimes necessitates grasping the bee by the thorax and sting apparatus with forceps to stretch the abdomen, thus making the mites visible and reachable.
3. Honey bees can be treated with CO2 to facilitate the physical collection.
CO2 affects the bees' physiology (Czekońska, 2009), but recent results indicate that a short treatment with CO2 does not affect fertility and fecundity of varroa female artificially introduced into brood cells (Rosenkranz et al., unpublished data). The effect of cooling on mites is not known and might affect mite survival. An alternative to CO2 and cooling treatment is (i) to let the bees crawl out of their container one by one so they can be caught easily or (ii) to cut off the head of the bees; mites tend to leave dead bees within a short time period.
4. Place the mites collected in a mite-tight container with a source of humidity (a wet cotton plug or ball of paper) to prevent the mites desiccating.
Pros: allows for the collection of mites that have not been stressed by a treatment with water or powdered sugar (see sections 3.1.2. ‘Icing sugar’ and 3.1.3. ‘Washing with water’). This is an advantage if mites are used in long lasting experiments.
Cons: tedious, few mites can be sampled in a short time.