Acarapis woodi
(honeybee mite)

Pictures

Picture	Title	Caption	Copyright
Title Mites in host Caption Honey bee tracheal mite (Acarapis woodi); A. woodi mites, internal parasites of Apis mellifera (common honey bee), visible in bee trachea. Approx. 150 μm in length. Copyright Public Domain - By USDA (USDA), via Wikimedia Common.	Mites in host	Honey bee tracheal mite (Acarapis woodi); A. woodi mites, internal parasites of Apis mellifera (common honey bee), visible in bee trachea. Approx. 150 μm in length.	Public Domain - By USDA (USDA), via Wikimedia Common.

Identity

Preferred Scientific Name

• Acarapis woodi Rennie

Preferred Common Name

• honeybee mite

Other Scientific Names

• Tarsonemus woodi (Rennie, 1921)

International Common Names

• English: acarine mite; honey bee tracheal mite; internal mite; Tarsonemid mite; tracheal mite

Local Common Names

• Germany: Bienenmilbe; Honigbienenmilbe
• UK: acarine disease mite; Isle of Wight disease mite
• USA: honey bee mite

EPPO code

• ACASWO (Acarapis woodi)

Summary of Invasiveness

A. woodi is a tracheal mite affecting the respiratory system of honey bees, causing the disease acarapisosis. These microscopic mites measure 150 μm in length and feed on the haemolymph of their hosts. They enter, live in and reproduce in the large prothoracic tracheae of all bees, but can also be found in the head, thoracic and abdominal air sacs (OIE, 2012).

Honey bee tracheal mites were first reported from dying bee colonies on the Isle of Wight (UK) in 1921 (Woodward and Quinn, 2011). The mites were thought to be responsible for “Isle of Wight disease”, but later evidence suggested that the disease could not be attributed to them (Bailey, 1964 in Denmark et al., 2000). Widespread bee mortality was attributed to the mites in early twentieth-century Europe. They were first discovered in the USA in 1984, and spread rapidly, as a result of swarming, robbing of bee colonies by others, and movement of bees by humans (Woodward and Quinn, 2011). The introduction of A. woodi to the USA caused widespread losses of bee colonies and entire apiaries.

Acarapisosis of honey bees is on the list of diseases notifiable to the World Organisation for Animal Health (OIE).

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Arthropoda
•             Subphylum: Chelicerata
•                 Class: Arachnida
•                     Subclass: Acari
•                         Superorder: Acariformes
•                             Suborder: Prostigmata
•                                 Family: Tarsonemidae
•                                     Genus: Acarapis
•                                         Species: Acarapis woodi

Notes on Taxonomy and Nomenclature

Acarapis is a genus of minute mites that are mainly parasitic on insects. A. woodi invades the tracheae of honey bees and is the cause of acarapisosis (OIE, 2012).

Morse and Eickwort (1990) reported that A. woodi may have evolved from an externally-dwelling species of Acarapis, possibly near the end of the nineteenth century in the UK. They suggest that evidence supporting this hypothesis includes: early severe infestations of acarine disease in the UK, followed by a rapid decline; the apparent absence of tracheal mites in honey bees in several European countries until many years after the initial discovery of the mite; the absence of tracheal mites in European honey bees in Australia, New Zealand, and (until 1984) North America; and great variability among North American honey bees regarding susceptibility to A. woodi.

A. woodi is included in a redescription of the genus Acarapis by Delfinado-Baker and Baker (1982).

Diseases Table

Distribution

The native range of A. woodi is uncertain. The mites were first reported from dying bee colonies in the Isle of Wight, UK, in 1921 (Woodward and Quinn, 2011), although later evidence suggested that the so-called “Isle of Wight” disease could not be attributed to them (Bailey, 1964, in Denmark et al., 2000).

Widespread bee mortality was attributed to the mites in early twentieth-century Europe. They were first discovered in the USA in Hidalgo County, Texas in early July 1984 and had spread to 17 American states by 1985 (Woodward and Quinn, 2011). The species is now present throughout the continental USA, except Alaska, in both managed and feral honey bee colonies (Woodward and Quinn, 2011).

Acarapisosis has been found in North and South America, Europe and the Middle East (OIE, 2012).

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

Honey bee tracheal mites were first reported from dying bee colonies in the Isle of Wight, UK, in 1921 (Woodward and Quinn, 2011), although later evidence suggested that the “Isle of Wight” disease could not be attributed to the mites (Bailey, 1964, in Denmark et al., 2000). Widespread bee mortality was attributed to the mites in early twentieth-century Europe (Woodward and Quinn, 2011) and they were considered as important pests in the UK in the early 1920s (Bailey, 1985).

The mites were unknown in North America before 1980, when they were detected in Mexico, about 200 miles south of the border with the USA. They were first discovered in the USA in Hidalgo County, Texas in early July 1984. By August that year they were reported from Louisiana and by October they had been found in Florida, Nebraska, New York, North Dakota and South Dakota. Seventeen American states reported their presence by August of the following year, and they eventually spread to the rest of the country. Migratory beekeepers and commercial suppliers of bees facilitated their spread (Woodward and Quinn, 2011).

Once in a hive, the mites can move quickly through a colony via bee-to-bee contact. Workers and drones disperse them when moving from hive to hive; the mite is dispersed through entire apiaries or from one apiary to another (Woodward and Quinn, 2011).

Introductions

Risk of Introduction

Bee-to-bee contact within a colony and movement between hives is said to facilitate the rapid spread of mites (Woodward and Quinn, 2011); however, researchers in Finland reported that the risk of natural transmission from one apiary to another seems low, because non-infested apiaries near an infested experimental apiary ‘remained non-infested for years’ (Korpela, 2002).

Swarming can move mites to other areas. Bees may rob honey from other hives, and can come into contact with mites then. Colonies weakened by mite infestation are more vulnerable to robbing (Woodward and Quinn, 2011).

The rapid spread of the mites observed in the USA was facilitated by migratory beekeepers, who moved bee colonies from southern states northwards for crop pollination. Sales of queens and package bees by commercial bee businesses also assisted in dispersing the mites (Woodward and Quinn, 2011).

The federal Honey Bee Act of 1922 was passed in the USA after the initial discovery of A. woodi in the UK in 1921. This Act prohibited the importation of any honey bee into the USA, although in more recent years it has been relaxed somewhat (Woodward and Quinn, 2011).

The movement of bees, equipment and supplies worldwide has assisted in spreading bee diseases to all areas where bees are raised (OIE, 2012).

Pathogen Characteristics

The mites are invisible to the naked eye; the females are 143-147 microns long and 77-81 microns wide, in comparison to the males, which are 125-136 microns long and 60-70 microns wide. They have white oval bodies with a shiny, smooth cuticle. There are several long fine hairs on the body and legs, and the mouthparts are beak-like and elongated. (Woodward and Quinn, 2011).

Denmark et al. (2000) describe the species as follows:

‘Female: Length 140 to 175 microns, width 75 to 84 microns. Idiosoma ovoid or nearly pyriform; dorsal shield and plates faintly sclerotized, with indistinct punctures. Propodosoma lacking pseudostigmatic sensilla; two pairs of long, attenuate setae, verticals V1 and scapulars Sce. V1 setae shorter than Sce, about 1/4 longer than distance between bases of setae Sce. Ventral apodemes I forming Y-shaped structure with anterior median apodeme (a conspicuous transverse band crossing the thorax in front of the scutellum), not joining transverse apodeme. Apodemes III weakly extending lateral to bases of trochanters III. Apodemes IV extending to bases of trochanters IV. Posterior median apodeme rudimentary, sometimes as faintly formed Y- shaped structure. Leg 1 robust with single hooked claw. Legs II and III each with paired claws. Leg IV stubby, widely spaced; femur-genu and tibiotarsus functioning as one segment; tibiotarsus IV two times as long as broad; femur-genu broader than long, with three setae unequal length; tibiotarsus abruptly narrowed, almost straight, about two times as long as broad. For a more complete description see Delfinado-Baker and Baker (1984) [1982].

Male: Length 125 to 136 microns, width 60 to 77 microns. Similar to female except for sexual differences. Apodemes III to IV not developed, barely discernible. Posterior median apodeme indistinct, sometimes forming weak Y-shaped structure. Apodemes V present as weakened transverse apodeme barely discernible. Leg I more robust than others. Leg IV short, about 3/4 as long as leg III, without claw; trochanter large, slightly longer than wide, with seta; femur-genu slightly more than two times as long as wide, without flanges, three setae of unequal length; tibiotarsus nearly straight, slightly shorter than femur-genu; apical with slender pointed solenidion and 1 very long seta. Males and nymphs are difficult to separate from other known species.’

Host Animals

Notes on Natural Enemies

Donovan and Paul (2005) suggested that restoring appropriate species of pseudoscorpions (i.e. Ellingsenius fulleri and E. indicus) to bee colonies could help save bees from problems such as mites, and therefore potentially A. woodi.

Pathway Causes

Pathway Vectors

Economic Impact

Beekeepers and commercial bee suppliers could suffer an economic impact due to A. woodi. Bee mortality caused by infestations of A. woodi varies; if infestations are high, mortality can be high and entire apiaries have reportedly been lost. In particular, when A. woodi was introduced to the USA, widespread losses of bee colonies and entire apiaries were reported. However, most honey bee colonies in the USA have developed some resistance to or tolerance of mite infestations and acarine disease is not as severe as it was in the 1980s and 1990s; the introduction of the varroa mite (Varroa destructor) in 1987 overshadowed the impact of A. woodi (Woodward and Quinn, 2011).

Honey bees are important to the agricultural and horticultural sectors as pollinators, so any disease causing decline in bee populations will have a significant impact on their role in these industries.

Environmental Impact

Impact on Habitats

Jyothi (2004) studied factors affecting pollinators, pollination and seed production of sunflowers in Karnataka, India during 1996-97. The aim of the study was to look at the effects of endosulfan and parasitic mites, including A. woodi, on Apis mellifera, Apis cerana, Apis florea, Apis dorsata and Trigona iridipennis (they also studied fly and butterfly pollinators). As well as reporting a significant decrease in seed yield and pollinator population after insecticide application, they also found a decrease in targets returning with pollen load at mite-infested colonies compared with normal colonies. Obviously factors affecting pollinators will also have an impact on pollination and thus ultimately affect an ecosystem that relies on pollination for development.

Impact on Biodiversity

A. woodi is listed as one of the causes of the decrease of honey bees in the world by Kadowaki (2010).

Social Impact

The effect of acarapisosis outbreaks on honeybee health will also have a significant impact on honey products and thus the livelihood of beekeepers.

Risk and Impact Factors

• Proved invasive outside its native range
• Highly mobile locally

• Host damage
• Negatively impacts animal health
• Negatively impacts livelihoods
• Threat to/ loss of native species
• Negatively impacts trade/international relations

• Parasitism (incl. parasitoid)

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field
• Difficult/costly to control

References

Bailey L, 1985. Acarapis woodi: a modern appraisal. Bee World, 66(3):99-104.

Bitidningen, 1991. The acarine [tracheal] mite is now also in Denmark and Finland. (Även trakékvalstret finns nu i Danmark och Finland.) Bitidningen, 90(11):352.

Danka RG; Villa JD, 1994. Resistance to infestation by tracheal mites in Buckfast honey bees: field test and investigations of mechanisms. In: American Bee Journal, 134(12). 831.

Danka RG; Villa JD, 2005. An association in honey bees between autogrooming and the presence of migrating tracheal mites. Apidologie, 36(3):331-333. http://www.edpsciences.org/journal/index.cfm?edpsname=apido

Delfinado-Baker M; Baker EW, 1982. Notes on honey bee mites of the genus Acarapis Hirst (Acari: Tarsonemidae). International Journal of Acarology, 8(4):211-226.

Denmark HA; Cromroy HL; Sanford MT, 2000. Featured Creatures: honey bee tracheal mite, Acarapis woodi. Florida: University of Florida. http://entnemdept.ufl.edu/creatures/misc/bees/tracheal_mite.htm

Donovan BJ; Paul F, 2005. Pseudoscorpions: the forgotten beneficials inside beehives and their potential for management for control of varroa and other arthropod pests. Bee World, 86(4):83-87.

Eischen FA; Vergara CH, 2004. Natural products smoke and its effect on Acarapis woodi and honey bees. Apidologie, 35(4):341-349. http://www.edpsciences.org/journal/index.cfm?edpsname=apido

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

Evans JD; Pettis JS; Smith IB, 2007. A diagnostic genetic test for the honey bee tracheal mite, Acarapis woodi. Journal of Apicultural Research, 46(3):195-197.

Ewing HE, 1922. Studies on the taxonomy and biology of tarsonemid mites, together with a note on the transformations of Acarapis (Tarsonemus) woodi Rennie (Acarina). Canadian Entomologist, 54:104-113.

FERA (Food and Environment Research Agency), 2010. IPM and Acarine. Sand Hutton, UK: Food and Environment Research Agency, 2 pp. https://secure.fera.defra.gov.uk/beebase/downloadDocument.cfm?id=208

Garrido-Bailón E; Bartolomé C; Prieto L; Botías C; Martínez-Salvador A; Meana A; Martín-Hernández R; Higes M, 2012. The prevalence of Acarapis woodi in Spanish honey bee (Apis mellifera) colonies. Experimental Parasitology, 132(4):530-536. http://www.sciencedirect.com/science/journal/00144894

Jyothi JVA, 2004. Factors affecting the pollinators, pollination and seed production of sunflower. Journal of Entomological Research, 28(3):265-268.

Kadowaki T, 2010. Current situations and causes of the decrease of honey bees in the world. Kagaku to Seibutsu, 48(8):577-582. http://www.jsbba.or.jp/02/kaseiindex.html

Kojima Y; Yoshiyama M; Kimura K; Kadowaki T, 2011. PCR-based detection of a tracheal mite of the honey bee Acarapis woodi. Journal of Invertebrate Pathology, 108(2):135-137. http://www.sciencedirect.com/science/article/pii/S0022201111001601

Korpela S, 1998. Pest status and incidence of the honey bee tracheal mite in Finland. Agricultural and Food Science in Finland, 7(4):469-476.

Korpela S, 2002. Honey bee tracheal mite in Finland: population dynamics, natural transmission between apiaries and impacts of introductions via bee trade. In: Bees without frontiers: Sixth European Bee Conference, Cardiff, UK, 1-5 July 2002 [ed. by Jones, R.]. Cardiff, UK: International Bee Research Association, 66-72.

Leka A, 1986. Some parasitoses of bees. (Disa parazitoza në bletët tona.) Buletini i Shkencave Zooteknike e Veterinare, 4(1):39-44.

McMullan JB; Brown MJF, 2005. Brood pupation temperature affects the susceptibility of honeybees (Apis mellifera) to infestation by tracheal mites (Acarapis woodi). Apidologie, 36(1):97-105. http://www.edpsciences.org

Morse RA; Eickwort GC, 1990. Acarapis woodi, a recently evolved species? In: Proceedings of the International Symposium on Recent Research on Bee Pathology, Ghent, Belgium, September 5-7, 1990. 102-107.

OIE (World Organisation for Animal Health), 2008. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France: World Organisation for Animal Health. http://www.oie.int/fileadmin/Home/eng/Health_standards/tahm/A_index.htm

OIE, 2009. World Animal Health Information Database - Version: 1.4. World Animal Health Information Database. Paris, France: World Organisation for Animal Health. http://www.oie.int

OIE, 2012. World Animal Health Information Database. Version 2. World Animal Health Information Database. Paris, France: World Organisation for Animal Health. http://www.oie.int/wahis_2/public/wahid.php/Wahidhome/Home

Rashad SE; Eweis MA; Nour ME, 1985. Studies on the infestation of honeybees (Apis mellifera) by Acarapis woodi in Egypt. In: Proceedings of the Third International Conference on Apiculture in Tropical Climates, Nairobi, Kenya, 5-9 November 1984. 152-156.

Sammataro D, 2006. An easy dissection technique for finding the tracheal mite, Acarapis woodi (Rennie) (Acari: Tarsonemidae), in honey bees, with video link. International Journal of Acarology, 32(4):339-343.

Theophilidis G; Hatjina F; Gregorc A; Pappas N; Zacharioudakis S; Thrasyvoulou A, 2002. Morphological differences in prothoracic spiracles between three strains of Apis mellifera (L). existence of a resistance mechanism against Acarapis woodi. In: Bees without frontiers: Sixth European Bee Conference, Cardiff, UK, 1-5 July 2002 [ed. by Jones, R.]. Cardiff, UK: International Bee Research Association, 62-65.

Underwood RM; Currie RW, 2009. Indoor winter fumigation with formic acid for control of Acarapis woodi (Acari: Tarsonemidae) and Nosema disease, Nosema sp. Journal of Economic Entomology, 102(5):1729-1736. http://docserver.ingentaconnect.com/deliver/connect/esa/00220493/v102n5/s1.pdf?expires=1264653331&id=0000&titleid=10264&checksum=6C4DFB902969BA9E6A493690CCC09F5C

Woodward SL; Quinn JA, 2011. Encyclopedia of Invasive Species. California, USA: ABC-CLIO, LLC, xlii + 764 pp.

Organizations

World: IBRA, International Bee Research Association, Unit 6, Centre Court, Main Avenue, Treforest, RCT, CF37 5YR, UK, www.ibra.org.uk

World: OIE (World Organisation for Animal Health), 12, rue de Prony, 75017 Paris, France, http://www.oie.int/

UK: British Beekeepers’ Association, National Beekeeping Centre, Stoneleigh Park, Stoneleigh, Warwickshire, CV8 2LG, UK, www.britishbeekeepers.com

Contributors

23/03/2012: Original text by:

Dr. Claire Beverley, CABI, Nosworthy Way, Wallingford, OX10 8BU, UK.

Distribution Maps