Varroa sensitive hygiene (VSH) is a behavioral trait of

honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosmop ...

s ''(Apis mellifera)'' in which bees detect and remove bee

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

e that are infested by the

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...

Varroa destructor ''Varroa destructor'', the ''Varroa'' mite is an external parasitic mite that attacks and feeds on the honey bees ''Apis cerana'' and ''Apis mellifera''. The disease caused by the mites is called varroosis. The ''Varroa'' mite can reproduce on ...

. V. destructor'' is considered to be the most dangerous

pest Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant deemed to be detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious disease, an illness resulting from an infection ** ...

problem for honey bees worldwide. VSH activity results in significant resistance to the mites.

Subspecies with Varroa sensitive hygiene

Some subspecies of ''Apis mellifera'' show naturally Varroa sensitive hygiene, for example ''

Apis mellifera lamarckii Lamarck's honey bee or the Egyptian honey bee, ''Apis mellifera lamarckii'', is a subspecies of honey bee occurring in a narrow range along the Egyptian Nile Valley of Egypt and Sudan, named after Jean-Baptiste Lamarck and is considered the fir ...

'' and ''

Apis mellifera carnica The Carniolan honey bee (''Apis mellifera carnica'', Pollmann) is a subspecies of the western honey bee. The Carniolan honey bee is native to Slovenia, southern Austria, and parts of Croatia, Bosnia and Herzegovina, Montenegro, Serbia, Hungary, ...

''.

Development

Bees with the VSH trait were initially bred by the

United States Department of Agriculture The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...

Honey Bee Breeding, Genetics and Physiology Laboratory in

Baton Rouge, Louisiana Baton Rouge ( ; ) is a city in and the capital of the U.S. state of Louisiana. Located the eastern bank of the Mississippi River, it is the parish seat of East Baton Rouge Parish, Louisiana's most populous parish—the equivalent of count ...

from colonies in which mite populations grew only slowly.Harbo, J., and R. Hoopingarner. 1997. Honey Bees (Hymenoptera: Apidae) in the United States that express resistance to ''Varroa jacobsoni'' (Mesostigmata: Varroidae). Journal of Economic Entomology 90: 893-898. The factor causing slow mite

population growth Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...

was found to be

heritable Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic inf ...

. The rate of mite population growth was found to be correlated with the reproductive rates of mites, resulting in naming the factor "suppressed mite reproduction" (SMR).Harbo, J., and J. Harris. 2002. Suppressing Mite Reproduction: SMR an Update. Bee Culture 130: 46-48. It was later discovered that the factor is founded on hygienic activity of adult bees, so SMR was renamed VSH. The behavior involves nest cleaning bees (aged 15-18 days old) recognizing infested brood. Mite-infested bee pupae are either eaten or pulled from their brood cells, which kills any immature varroa mites present. VSH activity results in (1) an abnormally low proportion of mites that produce offspring within the population that remains in capped brood and (2) reducing the brood infestation rate by greater than 70%. The specifics of how hygienic bees detect mite infested

brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American Periodical Cicadas: ** Brood X, the largest br ...

currently are unknown.

Cross-breeding

Bees bred to have high levels of VSH can keep mite populations below thresholds recommended for varroa treatment including

miticides Acaricides are pesticides that kill members of the arachnid subclass ''Acari'', which includes ticks and mites. Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields. Termin ...

Queens Queens is a borough of New York City, coextensive with Queens County, in the U.S. state of New York. Located on Long Island, it is the largest New York City borough by area. It is bordered by the borough of Brooklyn at the western tip of Long ...

from such VSH breeding sources can be allowed to mate freely with non-VSH

drone Drone most commonly refers to: * Drone (bee), a male bee, from an unfertilized egg * Unmanned aerial vehicle * Unmanned surface vehicle, watercraft * Unmanned underwater vehicle or underwater drone Drone, drones or The Drones may also refer to: ...

s, and the resulting

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

colonies from these outcrosses will retain lower and variable but generally still useful resistance to ''V. destructor'' while retaining desirable beekeeping traits such as

honey Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...

production. VSH outcrossed to commercial

Italian bee ''Apis mellifera ligustica'' is the Italian bee which is a subspecies of the western honey bee (''Apis mellifera''). Origin The Italian honey bee is thought to originate from the continental part of Italy, south of the Alps, and north of Sicil ...

s recently have been shown to perform well in migratory

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydropo ...

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...

. VSH thus is a trait that can be used by

breeder A breeder is a person who selectively breeds carefully selected mates, normally of the same breed to sexually reproduce offspring with specific, consistently replicable qualities and characteristics. This might be as a farmer, agriculturalist ...

s to mix with any type of desirable honey bee and is expanding resistance to ''V. destructor'' among diverse bee strains. In 2018 it was announced that VSH ''

Buckfast Buckfast is a small village near Buckfastleigh in Teignbridge district, Devon, England, on the bank of the River Dart. It is the home of Buckfast Abbey, an active Benedictine monastery, which gave its name to Buckfast Tonic Wine, originally ma ...

'' bees would be made available for sale in 2019.{{cite web , last1=Dr. Peter Stöfen , title=REPORTS: NEW: "Hygiene"-Buckfast Queens , url=https://buckfast-zucht.de/index.php?seite=berichte&la=en , website=buckfast-zucht.de , access-date=29 December 2018

References

External links

USDA Honey Bee Breeding, Genetics and Physiology Laboratory

Varroa Sensitive Hygiene and Mite Reproduction

Selecting for Varroa Sensitive Hygiene

VSH Bee Breeders Forum (No longer in service, 05/2016)

Cooperative Research and Development (CRADA) Source of VSH Breeding Material

development of VSH lines in Europe
Western honey bee behavior Agricultural pest mites Behavioural genetics