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Honey Bee Medicine for the Veterinary Practitioner. Группа авторов
Читать онлайн.Название Honey Bee Medicine for the Veterinary Practitioner
Год выпуска 0
isbn 9781119583424
Автор произведения Группа авторов
Жанр Биология
Издательство John Wiley & Sons Limited
2 How well she was mated – the number of viable spermatozoa in her spermatheca, and
3 Environmental factors, such as chilling and heating during shipment, or pathogen or pesticide exposure in the colony.
A queen's potential performance is largely fixed by how lavishly she is fed jelly during the approximately four days between the emergence of her larva from its egg until her cell is sealed (she continues to feed and grow after sealing). And then she must get properly mated.
Queen Performance vs. Colony Performance
The queen's contributions to colony “colony performance” are:
1 The number of eggs that she produces,
2 Her genetics, which then supply half the genetics to each of her daughters – the workers,
3 The genetics of the guys she mated with – the other half of the genetic equation, and
4 Some passing on of transgenerational epigenetic immunity.
After that, it's up to her offspring. Colony‐level performance is mostly the result of how well the genetically‐diverse patrilines of workers work as a “team.”
Practical application: In general, a well‐reared, well‐mated queen of average genetics will outperform a poorly reared, poorly mated queen of the best genetics. After that, it's largely a matter of chance of how the patrilines of daughters happen to function together as a “team” (Figure 5.8), “performance” being more the result of the workers than the queen.
Practical application: Unlike other livestock, honey bee queens are polyandrous, resulting in a colony of bees consisting of a mix of patrilines of half‐sisters, each fathered by one of the many drones with which their mother mated. Thus, there will always be genetic differences and diversity, even with colonies headed by sister queens. The performance of each colony as a whole is thus a matter of chance, similar to putting together a sports team of players (each patriline of worker bees) without knowing how well they will perform as a group (the colony). Bottom line: you might advise beekeepers to start in spring with twice as many colonies as they hope to take through the winter, and not waste their time on those that don't perform well. Some commercial beekeepers (the author included) simply cull any poor performers.
Figure 5.8 A histogram of colony performance (weight gain) of 35 colonies, started with sister queens mated and managed identically in one of the author's yards. Note the normal distribution of performance.
Practical application: On the other hand, many a poorly‐performing colony can completely turn around once it clears itself of disease, or enjoys better nutrition. If honey production is not the beekeeper's main goal, they may find joy in helping a struggling colony to get back on its feet.
Queen Longevity
Beekeepers often refer to a queen's “age” in years. But biologically, chronology has little to do with it – a queen's “age” is a function of the number of viable spermatozoa remaining in her spermatheca, or more specifically, her ability to fertilize each egg laid in a worker cell (Baer et al. 2016).
Practical application: Thus, in a colony in a commercial operation in California or Florida, supplementally fed for near year‐round broodrearing, a queen may begin to run out of spermatozoa in the late summer of her second year. On the other hand, a queen in a cold‐winter area, in which she rests for five months of the year, may be productive for several seasons.
Queen Succession
A colony of bees is theoretically immortal, but not so its queen. In the natural state, with colonies living in tree cavities, the queen is replaced at least once a year (due to swarming). And prior to varroa it was not uncommon for a relatively unmanaged hive to live for many years, also replacing its queen without help from the beekeeper.
Practical application: There are three ways in which a colony can replace its queen, each due to different circumstances:
Supersedure – when the workers build a supersedure cell to smoothly replace a failing queen.
Swarming – in which a colony in a crowded cavity builds swarm cells, and then divides by fission, with roughly half the workers flying off with their mother, leaving behind daughters in those cells to take her place.
Emergency – when workers respond to the sudden loss of a queen by converting a young larva in a worker cell into an emergency queen.
There is much overlap involved in the three methods above; the vet needs to be familiar with each.
Supersedure
A colony normally replaces an aging or failing queen by a process called “supersedure.” The main factors that determine when a queen gets superseded are when she starts to run out of viable sperm with which to fertilize worker eggs, or by colony stress.
Practical application: Bees appear to “blame” their queen if the colony becomes seriously stressed by disease or parasites, which then triggers supersedure.
Worker bees often build “cell cups” on the face of a brood comb (Figure 5.9), but this does not necessarily mean that they are preparing to supersede or swarm. An “aging” queen will “willingly” lay an egg in a prepared cup, at which point the workers may turn it into a queen cell.
Practical application: The presence of cell cups does not indicate that a colony is about to supersede their queen. Even if supersedure larvae initially get fed, that doesn't mean that supersedure is inevitable, since the colony will often tear the cells down before emergence. Russian bees are noted for their continual starting of supersedure cells.
A mature supersedure cells looks similar to a peanut stuck to the side of the comb (Figure 5.10).
Practical application: beekeepers often ask whether they should destroy supersedure cells. I tell them that the bees likely have a better idea of the quality of their queen than they do. I see no reason to remove supersedure cells. 4
Figure 5.9 Preconstructed natural “queen cups.” It is not unusual to see these in a colony. Their presence does not necessarily mean that the queen is about to be replaced. Even when there is an egg or a larva with jelly in a queen cell, they are often destroyed by the bees during that new queen's development.