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===Pathophysiology===
 
===Pathophysiology===
[[File:Family of varroa mites.jpg|thumb|A group of male and immature mites left in a cell after the bee has emerged with the fertilised females<br><small>Copyright Ellmist 2003 Wikimedia Commons]]</small>
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[[File:Family of varroa mites.jpg|thumb|A group of male and immature mites left in a cell after the bee has emerged with the fertilised females<br><small>Copyright USDA 2003 Wikimedia Commons]]</small>
[[File:Adult female varroa mite.jpg|thumb|A mature female mite feeds on a developing worker brood<br><small>Copyright Ellmist 2003 Wikimedia Commons]]</small>
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[[File:Adult female varroa mite.jpg|thumb|A mature female mite feeds on a developing worker brood<br><small>Copyright USDA 2003 Wikimedia Commons]]</small>
 
The fertilised adult female mite enters a random cell<ref>Salvy M, Capowiez Y, Le Conte Y, Clement J. '''Does the spatial distribution of the parasitic mite varroa jacobsoni oud. (Mesostigmata: varroidae) in worker brood of honey bee apis mellifera L. (Hymenoptera: apidae) rely on an aggregative process?''' ''Naturwissenschaften. 1999 Nov;86(11):540-3.''</ref> just before it is sealed and initially feeds on the brood food.  When the bee egg is laid and the cell sealed, the mite bites through the exoskeleton of the larva (usually towards its caudal end) and begins to suck its haemolymph.  These wounds become infected with bacteria but are generally sealed with scar tissue after the first moult<ref>Kanbar G, Engels W. '''Ultrastructure and bacterial infection of wounds in honey bee ( Apis mellifera) pupae punctured by Varroa mites.''' ''Parasitol Res. 2003 Aug;90(5):349-54. Epub 2003 Mar 27.''</ref>.  She lays eggs after around 72 hours and she and her offspring continue to feed on the developing bee.  In heavy infestations, several female mites may enter a single cell.  The next generation of mite offspring are produced in the cell<ref>Akimov IA, Yastrebtsov AV. '''Peculiarities in ontogenesis and reproductive cycle of the mite Varroa jacobsoni (Parasitiformes, Varroidae) and its relation to the host Apis mellifera.''' ''Wiad Parazytol. 1991;37(1):99-102.''</ref> and these individuals continue to inter-breed after 6-7 days of development.  A female mite first produces a male offspring then 5-6 female offspring, giving the mite a high biotic potential.  The sequence of sexes seems to be dependent on a signal from the developing brood as female mites that are moved to a new cell after laying the male egg start an entirely new breeding cycle, apparently caused by the younger age of the new brood<ref>Garrido C, Rosenkranz P. '''The reproductive program of female Varroa destructor mites is triggered by its host, Apis mellifera.''' ''Exp Appl Acarol. 2003;31(3-4):269-73.''</ref>.  When the developed bee breaks out of the cell, it carries adult female mites into the hive but immature stages and male mites are left to die.  The female must therefore be fertilised before she leaves the males behind, one reason why the infestation is sometimes romantically called Amazon disease.  The female mites show a predilection for the cells of drones<ref>Le Conte Y, Arnold G, Trouiller J, Masson C, Chappe B, Ourisson G. '''Attraction of the parasitic mite varroa to the drone larvae of honey bees by simple aliphatic esters.''' ''Science. 1989 Aug 11;245(4918):638-9.''</ref>, probably because these brood take longer to develop and therefore allow a further generation of mites to develop in the cell.  However, unlike ''Varroa'' infestations of the Asian honey bee, it is able to develop in any type of cell.  Developing larvae and pupae that suffer mite infestations often die or appear abnormal at emergence, often being smaller, weaker and having incomplete wings.  Infested drones are unable to fly as far as uninfested bees and they have a lower sperm production<ref>Duay P, De Jong D, Engels W. '''Decreased flight performance and sperm production in drones of the honey bee (Apis mellifera) slightly infested by Varroa destructor mites during pupal development.''' ''Genet Mol Res. 2002 Sep 30;1(3):227-32''</ref>.
 
The fertilised adult female mite enters a random cell<ref>Salvy M, Capowiez Y, Le Conte Y, Clement J. '''Does the spatial distribution of the parasitic mite varroa jacobsoni oud. (Mesostigmata: varroidae) in worker brood of honey bee apis mellifera L. (Hymenoptera: apidae) rely on an aggregative process?''' ''Naturwissenschaften. 1999 Nov;86(11):540-3.''</ref> just before it is sealed and initially feeds on the brood food.  When the bee egg is laid and the cell sealed, the mite bites through the exoskeleton of the larva (usually towards its caudal end) and begins to suck its haemolymph.  These wounds become infected with bacteria but are generally sealed with scar tissue after the first moult<ref>Kanbar G, Engels W. '''Ultrastructure and bacterial infection of wounds in honey bee ( Apis mellifera) pupae punctured by Varroa mites.''' ''Parasitol Res. 2003 Aug;90(5):349-54. Epub 2003 Mar 27.''</ref>.  She lays eggs after around 72 hours and she and her offspring continue to feed on the developing bee.  In heavy infestations, several female mites may enter a single cell.  The next generation of mite offspring are produced in the cell<ref>Akimov IA, Yastrebtsov AV. '''Peculiarities in ontogenesis and reproductive cycle of the mite Varroa jacobsoni (Parasitiformes, Varroidae) and its relation to the host Apis mellifera.''' ''Wiad Parazytol. 1991;37(1):99-102.''</ref> and these individuals continue to inter-breed after 6-7 days of development.  A female mite first produces a male offspring then 5-6 female offspring, giving the mite a high biotic potential.  The sequence of sexes seems to be dependent on a signal from the developing brood as female mites that are moved to a new cell after laying the male egg start an entirely new breeding cycle, apparently caused by the younger age of the new brood<ref>Garrido C, Rosenkranz P. '''The reproductive program of female Varroa destructor mites is triggered by its host, Apis mellifera.''' ''Exp Appl Acarol. 2003;31(3-4):269-73.''</ref>.  When the developed bee breaks out of the cell, it carries adult female mites into the hive but immature stages and male mites are left to die.  The female must therefore be fertilised before she leaves the males behind, one reason why the infestation is sometimes romantically called Amazon disease.  The female mites show a predilection for the cells of drones<ref>Le Conte Y, Arnold G, Trouiller J, Masson C, Chappe B, Ourisson G. '''Attraction of the parasitic mite varroa to the drone larvae of honey bees by simple aliphatic esters.''' ''Science. 1989 Aug 11;245(4918):638-9.''</ref>, probably because these brood take longer to develop and therefore allow a further generation of mites to develop in the cell.  However, unlike ''Varroa'' infestations of the Asian honey bee, it is able to develop in any type of cell.  Developing larvae and pupae that suffer mite infestations often die or appear abnormal at emergence, often being smaller, weaker and having incomplete wings.  Infested drones are unable to fly as far as uninfested bees and they have a lower sperm production<ref>Duay P, De Jong D, Engels W. '''Decreased flight performance and sperm production in drones of the honey bee (Apis mellifera) slightly infested by Varroa destructor mites during pupal development.''' ''Genet Mol Res. 2002 Sep 30;1(3):227-32''</ref>.
  
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