Thursday, 3 October 2013

Hive Check 2/10

Rachel Tara and I did the check today probably one of the last this season. The bees are still numerous and we saw the queen in the original hive but both hives have plenty of brood. They both have plenty of stores too so all looking well on that front.

As theres not too much to report heres some info on a couple of the jobs bees undertake in the hive

Hive Roles (1) - Multi-tasking and ‘Heater Bees’
We know honeybees have age dependent jobs in the hive. However, younger bees sometimes fill the ‘older bee jobs’ earlier than normal when not enough bees are doing the work needed by the colony. For example, if there are not enough foragers, younger bees can become foragers at an earlier age. This allows for greater hive flexibility. We also know bees somehow bees know who goes in the swarm and who stays with the mother hive. Bees do not have to ‘pick a number’, to decide - like we do! Do they read each other’s minds? Instead of thinking of a single bee job one after another based on a bee’s age, we can expand the concept to a colony need based model’ with some job rotation. One good example of this are ‘heater bees’ . These bees are a more recent discovery .

Bees of almost all ages can become ‘heater bees’. They do this by detaching their flight wings and the vibrating their bodies while their wings are motionless. By doing this they can heat their bodies
up to 30°C in the brood area. Good queens may leave empty brood cells to be used by ‘heater bees’ to crawl in and keep the surrounding seventy cells at the right temperature. This makes it very important to give the queen enough room in the brood nest so she does not have to lay eggs in the cells she wants to leave empty. This is not the occurrence of ‘spotty brood’ which is a problem of queen/hive weakness. The normal brood temperature is kept by the nurse and house bees at 20°C. The bees emerging from this temperature have a normal hive job progression. When ‘heater bees’ raise the brood temperature to 27°C, the brood that hatches prefers to forage more than to do
other hive jobs. Consequently for this reason not chilling the brood is critical throughout the year.
‘Heater bees’ are given food by supplier bees who feed the ‘heater bees’ so they can keep a consistent temperature where they place themselves in the brood nest. Two-thirds of the nectar or honey used by bees in a colony is to generate heat! Then other bees rotate in and become ‘heater bees’ when needed. Every bee cooperates by doing their part of the work needing to be done for the good of the hive! The more we look into the life of bees in our hives, the more we can see bee ‘multi-job tasking’ and job rotation involves complex decision making honey beehaviour!

Hive Roles (2) - ‘Undertaker Bees’
It's a dirty job and only about1% do it at any one time. But middle-aged honeybees that serve as undertakers, removing dead bees from the hive, appear to be a distinct cadre of workers that are developmentally ahead of their peers. In this social world known for its division of labour, there also were unexpected discoveries by researchers. ‘Undertakers’ don't get better with experience, and they don't do well working together. The findings are detailed in papers by Gene Robinson, University of Illinois entomologist, and Stephen Trumbo, a professor at the University of Connecticut. The study on development, also written by entomologist Zhi-Yong Huang, appears in ‘Behavioural Ecology and Sociobiology’. The work - which involved identifying the ‘undertakers’, marking them with tiny, coloured and numbered plastic tags, and following them closely through middle age - provides the first close look at ‘undertakers’.  Since bees' nests are built in cavities, such a specialty is important for keeping the nests clean. ‘Undertakers’ had very similar activity levels as other bees, they just do a little bit less of the other middle-aged tasks, like building the comb and storing food brought in by older foragers. They also remove debris, which fits in nicely with undertaking. ‘Undertakers’ also develop slightly faster than other middle-aged bees, moving on to foraging before the food storers and hive builders. Middle age lasts about 10 days. ‘Undertakers’ usually removed dead bees for a day or two, but "one extraordinary bee remained at the task for thirteen days," comments Trumbo. ‘Undertakers’ respond to the odour of the dead, locating the bodies and carrying them out of the hive for 50-100 metres before dropping them. The researchers also monitored how swiftly ‘undertakers’ worked. “We didn't find any evidence for learning for this particular task," Trumbo said. "This rules out one of the major hypotheses that has been put forward for middle-aged specialisation: That social insects will get better and better at what they do." Previous research had shown that learning is important for the older foragers, who get more efficient as they le

arn what flowers are producing nectar at what time. Not only did undertakers not improve in efficiency they also got in each other's way and slowed their efficiency. Robinson had shown previously that some bees are genetically inclined to be ‘undertakers’. He says "We're beginning to get a clearer picture
of the behavioural profiles of interesting types of specialist bees, such as ‘undertakers’, Understanding the career choices of bees is a useful model for understanding behaviour in general. This new information should enable us to develop new hypotheses about how neurons and genes in the brain function to produce the marvellously complex behaviour seen in honeybee society.”
Honeybees acquire different job descriptions as they age. Normally, it takes about three weeks
for a baby bee to mature into a forager. Undertaker bees are usually around fourteen days old, in the transition from nursing to foraging.

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