First great project to look at the bumblebees. In France where I live they are replacing the honeybee. And there seems to be lots species of large solitary bees of various colors as well. They certainly have taken up the workload in my backyard.
Why flowers? Recently in England, honeybees go out of their way for lavender, bourrache, and marjolaine. So these flowers all are used in traditional European medicines and have the reputation of being anti-fungal, anti-inflammatory, antimicrobial. Have you noticed any "pharmaceutical " use by Bumblebees?
Dear Christopher,
Although bumblebees are social bees, their foraging strategy is totally different then the honeybees' behavior. Honeybees forage in working groups, which are organized according to information that is collected and presented in the hive by the scout bees. Usually each working group forages on one food source in one location at a time only (species and location constancy). The bumblebees, on the other hand, don't have a communication system among the workers, and each worker bee forages alone. Throughout the foraging flight the bumblebee worker collect both food and information about an available more food options. Therefore, bumblebee worker don't present constancy, neither for flower species, nor for location. Usually it forages through a personal routine rout, visiting some different flower species for food collection, and sometimes also for checking more options. The personal foraging rout may change from flight to the next. As an agricultural pollinator the bumblebee has some important advantages over the honeybee. The bumblebee is much more mobile during the foraging flight, and therefore more effective in performing cross pollination. It is more hairy, usually bigger, and also more effective in pollen transfer. Also the bumblebee works faster, and is active under low temperatures that don't fit the honeybee character.
Yes, interesting but has anyone looked at their individual choices over time. I had read long ago that honeybees preferred flowers like the honeysuckle which gave more nectar per flower. Today they seem to choose medicinal herbs
see:
https://www.theguardian.com/environment/2013/oct/17/bees-most-attracted-lavender-marjoram
and this article does mention bumblebees in passing. I would like to verify a change in eating habits. It seems logical if bees (bumblebees too) are under some sort of immune stress they might opt to search for plants known for antimicrobial and anti inflammatory properties. thanks for responding.
Honeybees prefer flowers not according to the amount of nectar per flower, but mainly according to the amount of sugar they collect per minute. Dilute nectar (like the butterfly flowers' nectar) is not preferred. Easy entrance to a dense small flowers may be preferred over a big flower with large amount of a hard to get large amount of nectar. Interestingly honeybees also consider the nectar quality. They prefer the citrus flowers over the avocado's, although they can collect more sugar in the avocado, because the avocado's nectar contains too much Potassium. It should be checked whether honeybees visit the Labiatea flowers because their sugar amounts, or for their antimicrobial properties. I assume that these behavior types may be similar with the bumblebees.
See in this paper:
📷SourceLow attractiveness of avocado (Persea americana Mill.) flowers to honeybees (Apis mellifera L.) limits fruit set in Israel ArticleFull-text available
- Mar 1998
- Journal of Horticultural Science and Biotechnology
- 📷Gad Ish-Am
- 📷Dan Eisikowitch
And also this paper:
📷SourceThe effect of avocado (Persea americana) nectar composition on its attractiveness to honey bees (Apis mellifera) ArticleFull-text available
- May 2006
- Apidologie
- 📷Ohad Afik
- 📷Arnon Dag
- 📷Sharoni Shafir
Interesting comments about avocado. Honey bees actively forage on the avocado (palachichi in Swahili) trees in Tanzania. The species may be different. The fruit is large and delicious: the best avocados I've eaten (but maybe that's because they were ripened on the tree).
Kerry,
Thanks
gee, different species or genetics is too often the easy answer and yet we live in a dominated by diverse conditions, microbiota and microclimates. So by such a narrow answer we may miss the big picture. What I suspect in Tanzania is that there are factors that encourage Bumblebees to forage on palachichi :-) Wish I knew which ones!
Are industrial chemical fertilizers common where you are? For example Spain is big on hydroponics and industrial optimization of agriculture and they have very few honeybees, yet Bumblebees are holding their own while seeming to avoid commercial crops. Or Israel, the area where the cited article mentioned, plants lots of attractive trees with differing pollination periods (especially lots of eucalyptus) every year to fight against CCD. This environmental change could conceivably change Bumblebee forging patterns. That is the whole premise of this question. Personally, I feel that current success of bumblebees in stressful areas is because of pharmaceutical foraging analogous to pregnant women craving dirt when they are eating a diet low on iron. I know this may sound kind of new age but perhaps honeybees are too domesticated and don't listen to their inner voice or simply are placed where they can not choose which flower to pollinate or feed on.
I might have confused with my answer. I'm in northern Canada, was just visiting in Tanzania (there, honey bees are the dominant (and native) pollinator, doing well and with no obvious effect from Varroa). Here in my part of Canada bumblebees seem to be doing very well. I was trying to find for you a reference to a paper that TRACKED bumblebees (GPS) in Britain (I think) and showed a map of individual foraging that would interest you. Sorry I didn't find it.
The honeybees in Tanzania are different subspecies than those in Israel and in North America. They may have different preferences. Also in Israel, when and where they don't have a better option, the honeybees intensively visit the avocado bloom. Interestingly, in honeybee hives that were located on the same place and time I found different preferences. I got the impression that they do it for minimizing competition. However, since bumblebees don't have working groups and each worker choose her own collection rout and her preferred flower species, the picture should be different.
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