I've still got the headache.Originally Posted by Jon
I've still got the headache.
Which may prove to be an advantage for a society such as yours. You already have people loosley united by one common interest.
I'm pretty sure that Varroa exhibit very little genetic diversity as a result of male haploidy and full-sib mating behaviour. See this article. The final section of results is relevant.
This would suggest that adaptation by Varroa is perhaps less likely ... like DR I still remain sceptical it can be done (resistance that is).
A. cerana has resistance due to dramatically shortened development cycles. We're not going to select that any time soon.
I beg to differ. Nearly had a rant about a UK scientist who has apparently given the line for years that Apis mellifera can't adapt but I've never heard it directly from him so I'll not name him. What did disappoint was being at a bee conference some years ago and meeting the same attitude from some leading European scientists. I asked them what they thought of John Harbo and Jeff Harris' work (the main trait they described was later termed VSH) and they hadn't seemed to have heard of it despite it being in the refereed literature for a few years. John Kefuss was in the audience (and actively propagating Varroa-tolerant lines at the time in two continents) and when I asked him what he thought of the opinions on display he just shrugged. Oh dear, did have a rant after all ..... right, Apis cerana ....
Shortened life cycles are one of many mechanisms displayed by Apis cerana which impact on Varroa and probably not an important one. A. cerana seems particularly good at hygienic behaviour, grooming, and even entombing infested drone pupae (a trick I've never heard that mellifera has in its arsenal). I thought I read somewhere that drone brood uncapping happens too but I can't find it. Apis cerana has Varroa so well under control that only the spring drone raising season allows it to multiply effectively.
Boecking and Spivak
Behavioral defenses of honey bees against Varroa jacobsoni Oud.
Abstract - Two behaviors of honey bees, hygienic behavior and grooming, are mechanisms of defense against brood diseases and parasitic mites. Studies have shown that Apis mellifera colonies remove worker brood infested with Varroa jacobsoni mites from the nest (hygienic behavior), and groom the mites off other adult bees, but to a limited extent compared to the original host of V. jacobsoni, A. cerana. Research is reviewed on hygienic and grooming behaviors with respect to their potential as mechanisms of resistance to V. jacobsoni. Studies related to hygienic behavior include the removal of experimentally infested and naturally infested brood, measurements of heritability, the uncapping and recapping of cells containing infested pupae, and the detection of infested brood. Studies on grooming include the process by which a groomer detects and damages a mite found on itself or on another adult bee, how the behavior is quantified, and problems with these methods of quantification. Finally, unresolved questions concerning grooming and the effects of hygienic and non-hygienic behaviors on limiting the population growth of V. jacobsoni are discussed.
Rath
Co-adaptation of Apis cerana Fabr. and Varroa jacobsoni Oud
Abstract - The research on bee and mite biology over the past 20 years has uncovered numerous details of the A. cerana-V. jacobsoni co-adaptation which are systematically summarized here. A. cerana acquired a high degree of hygienic efficiency with a differentiated set of behavioural traits that we describe in this review in a broad sense to include grooming of mites by adult bees, uncapping and removal of infested brood and entombing of infested brood. Approximately 20 % of the reproducing mite population can be eliminated by entombing of lethally parasitized drone pupae. In their equally effective infesting behaviour the parasites explore the most suitable adult and larval host individuals for safe phoretic positions, the favourable caste and suitable age. A. cerana compel V. jacobsoni to reproduce exclusively on drone brood hosts. This limited reproduction, in combination with characteristics of the population dynamics of the host, are key factors which limit mite populations to tolerable levels.
Gavin I don't think Cerana learned to cope with varroa
Varroa are adapted to co-exist with the shorter development time of cerana larva
Mink are not a problem in frozen climates they are adapted
Mink in UK are a wildlife disaster
I hadn’t realised that.
This recent paper by Harris and others backs that up as well.
Varying congruence of hygienic responses to Varroa destructor and freeze-killed brood among different types of honey bees
Authors
Danka, Robert
Harris, Jeffrey
Villa, Joseph
Dodds, Garrett
Honey bees use a hygienic behavior to remove dead and diseased brood from sealed cells. Bees selected for fast hygienic response to freeze-killed brood (FKB hygienic bees, such as Minnesota hygienic stock) have good resistance to some diseases and moderate resistance to varroa mites. Bees with varroa sensitive hygiene (VSH bees) have been selected for response against varroa mites and have good resistance against this dangerous parasite. A simple, standard test can be used to measure the FKB hygienic response but measuring VSH behavior is much more technically difficult. It has been suggested that the ability of a colony to remove FKB and remove varroa mites may be highly related, so that FKB removal might be used as a simple way to select for enhanced VSH. We measured responses to both FKB and varroa mites in four types of bees that have had different selection histories. All four types removed large amounts of FKB but the removal of mites was much more variable. VSH bees effectively removed FKB and varroa mites, but FKB hygienic bees removed FKB at much greater frequencies than they removed mites. Control bees (with little selection for FKB hygiene) removed the least amount of FKB and almost no varroa mites. Outcrossed VSH bees (i.e., colonies from VSH queens mated to unselected drones) removed intermediate amounts of FKB and varroa mites. Overall, the results suggest that there is not necessarily a strong relationship between hygiene against FKB and hygiene against varroa. VSH bees appear to respond to varroa-related stimuli that are probably are in addition to stimuli that regulate a more generalized response of honey bees to dead brood.
I understand that otters can bully mink when they come back into the landscape in a big way. The wildlife adapts and the checks and balances come into play.
I corrected myself earlier with the wrong Wallner name. Read about what he was up to here. This bit suggests that Alois Wallner may have been the first to spot the possibility that bees might simply carry mites away as well as take bites out of them and disrupt their reproduction cycle and, in the case of Apis cerana, seal them in with their hosts. Who knows, if they really do carry mites out of the colony, they may decide to go and drop them off bridges!
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AN IMPORTANT OBSERVATION (p.26)
In the first week of May 1989 I made a very interesting observation while working with my colonies. On controlling (inspecting) one colony I had removed the honey super and put aside. Between the two frames I found some drone brood comb. This is not unusual. By moving the frames this construction became torn and several pupae of drones were exposed. There was one Varroa mite on one pupa. The mite moved forth and back on the pupa. While I observed this mite, something special happened. I almost could not believe what I saw. There was a bee a few centimeters away from the pupa. Suddenly this bee ran wildly toward the pupa. I thought that the bee wanted to remove the uncovered pupa, but the bee grasped the mite with her mouth organ. I noticed that the bee caught the mite with her mandible in a horizontal way from the front. One third of the hind part of the mite was still visible in front of the mandible. Then, with the mite in her mouth, the bee took off. This was an unique observationthat I have not made again.
Illustr. p.26: Varroa mite with bitten off legs.
That is a very interesting observation. If a bee can remove a mite by (a) flying away with it after grabbing it or (b) removing it via altruistic suicide, this has implications for estimating the mite levels in a colony via counting those which fall through the mesh floor.
I hope anyone following this thread and planning to breed for resistance is ready to adapt to having no bees
Sorting that out is the point of the thread.
people will not participate if they are expected to lose colonies for the good of science.
The aim of a project would be to make step by step progress, treating when necessary.
That may well be the normal annual level of treatment, but meanwhile the search is on for the colonies which can keep mite numbers lower through some behaviour or other.
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