Module 6 - foraging

[Mellifera Crofter]

I'm reading through the Mid Bucks Module 6 notes (http://blog.mbbka.org.uk/category/education/bbka-module-6/).

According to the notes bees can move from pollen-collection to collecting nectar, but not the other way round.

They also say that worker bees have cells with iron-containing granules around the abdominal section which, it is thought, help with magnetic navigation.

I can't find any reference in any of my books to either of these statements. Do you think they are accurate?

Kitta

[Neils]

We got to here this evening. If its the point I think it is it came off the 2010 paper and there are a couple of other questions on that which our group questioned as "gotcha" questions. The other I think was "can laying workers fly?".

With regards to the first point about foraging, personally I call bull's excrement (but I'm willing to be corrected). Foraging, I don't believe that there is any difference to the capability of the bee as such, but a forager can revert to a Nurse bee by ingesting pollen to "reactivate" or revert the function of the.. spelling alert.. hypopharangyl gland.

[Mellifera Crofter]

Thanks Nellie. I did not know that eating pollen helped older bees in becoming nurse bees again - but it seems this rejuvenation is also a great help for the older brain (http://io9.com/5923749/giving-an-old-bee-a-youngsters-job-causes-brain-rejuvenation). I think I found the link on Bee-L but if the link was posted here, then sorry for repeating it.

[Jimbo]

A number of years ago a paper was published that scientists had found the gene responsible for foraging. The gene was called the FOR gene This gene was also the same gene found in fruit flies. In their experiments they could switch on the gene in house bees to make them foragers at an earlier age by using a chemical stimulant but I am uncertain if they could resverse the effect

[Easy beesy]

Re laying workers - our groups consensus was yes they can - but if you shake them out far enough away they've never flown to do orientation flights so that's how they don't make it back to hive/home

Cx

[thada1]

I think it's safe to say that the answer to this question can be made as complex as you like! If you read ch10 of Winston (1987), then only 17% foragers collect P&N, workers do tend to specialise, staying constant on one foodstuff (as well as flower type) for many consecutive trips. Mostly foragers collect nectar (60%)

If you read ch 8 of Seeley's Wisdom of the Hive (1995), then he talks in terms of 3 types of forager - p, n and unemployed. He speculates (reasonably, being Prof Seeley!) about the mechanism by which individual bees "decide" whether to collect P or N, which revolves around each bee sensing her own hunger for protein. So a P forager can convert to N, if the colony doesn't need so much P, or vice versa.

The most up-to-date research (Seeley review, ch 2.3 in "Honeybee Neurobiology and Behaviour", 2012), talks in terms of novice,experienced, reactivated and employed foragers. Re-activated foragers tend to work from scent cues, rather than reading a waggle dance - blow scent into a hive and lots of foragers will go out to the feeding station they associate with that scent. 80% of foraging is done via reactivation. This is a more detailed explanation of constancy.

And if you're not confused yet, then the last strand of research that might be relevant is that of the genetics of pollen foragers. People have bred for pollen hoarding (high or low). They've found that high strain pollen foragers are more responsive to water and dilute sugar solutions, than low-strain. So sucrose responsiveness could be an indicator of fundamental neurological differences that affect foraging decisions. Remember that a hive typically has multiple patrilines, so bees with different fathers will likely have different threshold responses to "hunger".

The research community is finding ever more comprehensive explanations for how a superorganism of 20-40K bees manages to maintain food balance, using the properties that emerge from relatively simple "rules" of stimulus-response interactions between the individual forager bees. (Page review, ch 1.1 in "Honeybee Neurobiology and Behaviour", 2012)

[thada1]

They also say that worker bees have cells with iron-containing granules around the abdominal section which, it is thought, help with magnetic navigation.

I can't find any reference in any of my books to either of these statements. Do you think they are accurate?

Kitta

This is a direct quote from Winston's "The Biology of the Honeybee".pp165-166. p205 references a paper that demonstrates these granules are found in drones too. There's more up-to-date work in primary science literature. I recommend you read only the introduction sections: Magnetoreception System in Honeybees (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000395) and Definitive identification of magnetite nanoparticles in the abdomen of the honeybee (http://iopscience.iop.org/1742-6596/17/1/007/pdf/jpconf5_17_007.pdf)

[Mellifera Crofter]

Thanks Thada. I had a quick look and noticed that the second paper refers to the effect of magnetic fields on the waggle dance - but that's not the same as 'an electrical phonomenon' (as in my question in the other thread (http://www.sbai.org.uk/sbai_forum/showthread.php?1117-Module-6-a-few-one-point-questions)), is it?


The honeybee Apis mellifera (figure 1) is known to be sensitive to magnetic fields. Its “waggle dance” is modified when the Earth’s magnetic field is cancelled, which is a strong indication of a highly sensitive magnetic detection system.

Kitta

[thada1]

No - I don't think so. I'd go with the group consensus that electrical phenomenon is weather-related (although there is some research on effects of electro-magnetic fields generated by mobile phones, it's too early to tell whether that is widely supported). I'd assume that the examiners are referencing one of the standard texts - but not one that is on my bookshelf!