<h1>Third, the potential of male bee selection in the breeding of mite-resistant bee species</h1>
1 Feasibility of using male wasp selection
The adverse effects on males caused by bee mites are a selective pressure that can be used to breed mite-resistant wasp species. As can be seen in the following examples, there are still many mite-resistant colonies created by natural selection.
Beginning in 1994; a USDA-ARS research team has studied western bees that are more resistant to mites than North American bees in the Primorsky region of eastern Russia, where bee mites coexist with bees for 45 to 100 years. This relatively long period of coexistence has resulted in years of natural selection for both the colony and the male. Initial observations of bee colonies in the Primorsky area show that after treatment, the number of landlubber mites in the colony was reduced to only a few hundred (and after the same treatment, the number of bee mites in the American colony was reduced to more than 1000), and only 0.5% of the worker bees were parasitic. After being introduced to the United States, the bee continued to maintain its good mite resistance, and the average number of bee mite parasitism was only half the circle of the local bee colony.
A similar example of natural selection has also been found in Kentucky's wild bee colonies. These wild bee colonies have survived untreated mites for many years. Compared with captive bee colonies, wild bee colonies can be found to be more infested by bee mites, and more bee mites reproduce at the same time, but the colonies coexist with bee mites.
Erickson et al. recently reported on a "secret" to breeding resistant bee species using the principle of natural selection, namely the use of surviving colonies that have not been treated with any mite treatment or abandoned, and they have survived in Arizona for several years without the use of mites. Allowing the queen bee to mate with males in partial isolation, these selected colonies have a very low apiary parasitism rate of only 6% to 7% for more than two years, proving that mite-resistant selection is heritable.
Several of the resistances that have been identified so far (e.g., hygienic behavior, duration after larval capping, inhibition of mite reproduction, etc.) all require a minimum heritable level of 25% during breeding. As mentioned earlier, male bees are haploid gametes produced by queen bees, so these traits should be better achieved through male wasps.
The duration after larval capping is the only trait that can be directly observed by male selection. In terms of traits, males of cape bees (A.m.capensis) have greater variability than queen bees. Moreover, in this case, the phenotype of the male bee is more accurate than the phenotype of the queen bee (e.g., the male bee has a short larval capping period, and the offspring produced also have a short larval capping period). This phenomenon provides direct evidence for the feasibility of male bee selection.
In contrast, hygienic behaviour cannot be directly selected in male bee selection; in the colony, male bees do not work and therefore do not exhibit hygienic behaviour. Whether or not the male bee has the alleles necessary for this trait, it does not directly affect its adaptability in any form, nor can the male bee bee selection be used to select this trait. However, through the question-and-answer route, hygienic behaviors can also be selected using male bee selection.
In a well-behaved colony, a large number of male bees that are parasitized by bee mites are removed from the hive, so the male bees that fly for marriage are the healthier males who are not parasitic. If worker bees express hygiene habits at high frequencies, male bees in these colonies are likely to carry the allele of hygiene behavior because their mother (queen bee) should be a homozygous carrying the recessive alleles necessary to manifest this trait. These male bees with hygiene habits will in turn pass on this hygiene habit allele directly to the off-agent workers.
In addition to hygienic behavior, other genetic traits of resistance have been identified, making it difficult to determine which traits are effective for male selection. Indeed, mite resistance is controlled by multiple genes, which makes their selection relatively difficult, and many genes are selected at the same time. The anti-bee mites found from the colonies of Russia, Kentucky and Arizona are also not the result of the action of a single resistance. The anti-mite resistance found in these 3 populations is the result of a combination of many different traits, in which it has been stablely inherited by selecting bee colonies with low apitic rates.
2. Male bee selection and breeding method
If male bee selection is to be successful, breeding methods must be taken seriously. Page and Laidlaw's 1985 invention of the ClosedPopulation Brewing Program (CPBP) is the best way to choose mite resistance. CPBP requires complete control over the mating of the queen and the male by means of isolation or artificial insemination, so the queen can only mate with males who participate in the CFBP swarm. Without these controls, the queen may mate with other male bees with low mite resistance colonies (such as those that are still treated with acaricides), which greatly reduces the selection process.
The selection of swarm anti-mite traits should be based on colonies with low apitic rates. Whenever possible, all bee colonies can be removed from the mite from the embryo, giving the bee mites the opportunity to naturally multiply, which creates selective pressure on the male and worker bees and even the bee colony. Of course, male bees carrying anti-mite genes are not only available from colonies with low apitic rates of bee mites.
In colonies with high apitic rates, individual males will also be parasitized, so they have anti-mite characteristics that other males in the same swarm lack. In CPBP, not all colonies need to be most resistant to mites, especially if they have some other expected order trait (e.g., docile or high honey yield). Therefore, these poorly mite-resistant colonies slow down the selection process.
Through such natural selection, many colonies are lost, but they are either compensated by other bee mite-resistant colonies or colonies that survive are grouped. If needed, especially at the beginning of the breeding year, the colony should receive some short-term treatment that can reduce the number of bee mites in late summer, which can ensure that the colony can safely overwinter. Also maintain a sufficient number of bee mites to maintain selective pressure on the next year's colony. The management of the BEE colony in CPBP needs to be adjusted, such as having enough male bee spleens to ensure that the maximum number of male bees is produced.
<h1>Fourth, the problem of male bee selection and breeding</h1>
Although the use of haploid male gametes to breed mite-resistant wasp species is theoretically feasible, this is not to say that there are no technical problems. Queen bees in CPBP may still mate with some susceptible males, and the expected gene expression rate will be lower than in tightly controlled (e.g., artificial insemination), which can slow down the breeding process. This "slowdown problem" is currently unsolvable. Only controlled techniques such as artificial insemination will produce mite-resistant bee species faster than natural selection.
Another problem that plagues bee breeders is the labor required in the breeding process, and the selection of CPBP by male bees for mite resistance requires a lot of manpower and material resources and a lot of time to repeatedly assess the mite resistance of the colony. Although male bee selection is more costly than single trait selection, cost is still a problem to be addressed. If natural selection is not controlled in time, the death of the bee colony will also produce a large part of the economic loss. These problems can be addressed jointly by establishing a cooperative organization, where breeders and beekeepers share the responsibility for assessing and providing bee colonies.
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