Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2004
Publication Date: 4/1/2005
Citation: Ochoa, R., Pettis, J.S., Erbe, E.F., Wergin, W.P. 2005. Observation on the biology of the honey bee tracheal mite Acarapis woodi (Acari: Tarsonemidae) using low-temperature scanning electron microscopy. Experimental and Applied Acarology. 35:239-249. (#161535: April 1, 2005) Interpretive Summary: White mites include members that feed on fungi, plants, and insects. The family is considered to have originated from tropical and subtropical regions. Several genera in the family are important because of their association with honey bees. The tracheal bee mite is one of the most important parasitic mite species of bees. The honey bee tracheal mite is an internal parasite of adult honey bees. Due to its small size and the destructive sampling methods required to examine mites inside honey bee tracheae, the life history of this mite is poorly known. Tracheal mites are associated with the death of honey bee colonies in the winter when greater than 30% of the bees within a colony are infested. The objective of this study is to describe new findings on honey bee tracheal mite biology and morphology using low-temperature scanning electron microscopy and address their relationship with bees. This paper will be important to bee keepers, extensionists, quarantine officers, entomologists, ecologists, and persons involved with bees or mite systematics.
Technical Abstract: Observations were made of cryo-preserved honey bee tracheal mites Acarapis woodi (Rennie) using scanning electron microscopy. We describe various new morphological characters of A. woodi based on the ability of the cyro-technique to capture live mites in natural positions and observe the Low-Temperature Scanning Electorn Microscopy (LT-SEM) photographs under a 3-D viewer. Most striking was the observation that each leg has the abillity to independently twist its segments with the ambulacrum rotating a minimum of 180° during locomotion; this is a more sophisticated form of locomotion than has been proposed for the Acari. Daughter mites are known to be the dispersal stage moving from the tracheal tube to the thoracic hairs of the bee and then transferring to a new bee. We hypothesize that the tarsal claws and setae on leg IV play a role in attachment to hairs during dispersal but our evidence is that none of the life stages use their tarsal claws within the tracheal tubes. Larval and pharate nymphs were observed to be 'free living' within the tracheal system, their tarsal claws rendered inoperative due to an enlarged swollen empodium. The solenidions of leg I are now known to have striations and the famulus is bifurcated. The bifurcated famulus may have taxonomic implications now that this character has been reported from other genera in the family Tarsonemidae. The dorsal setae of adults appear to be used as a sensory tool to monitor location within the tracheal tubes, most of the setae are oriented vertically up and may help the mite to measure the thickness or radius of the tracheal tubes. The modified caudal region of the male revealed remnants of the h1 and h2 setae and a smooth clean surface supporting the observations that pharate nymphs are not attached in this species.