by Dewey M. Caron, Communications and Content Specialist for the Oregon Master Beekeeper Program
Asian bees slap away invading ants
Scientists in Japan have demonstrated that guards of Asian honey bees (Apis cerana) can use their wings to knock ants away from their colony entrance. Smaller bodied ants are more easily knocked away than the larger bodied wood ants. This same honey bee might use animal feces around their colony entrance to defend against larger-bodied hornets. So far as we know our European bees don’t possess either defense. See wing flicking bees in the video https://www.nytimes.com/2024/07/17/science/honeybees-ants-wings-slap.html?campaign_id=34&emc=edit_sc_20240723&instance_id=129512&nl=science-times®i_id=102266668&segment_id=172906&te=1&user_id=43fab400bfec968cc4da6a919d67c02e
Size of Bee Eggs
A bee egg is 1/1000th the size of the eventual adult bee. It may not surprise you that all eggs a queen lays in beeswax cells are NOT the same size. Younger queens, not surprisingly, lay more robust eggs than older-aged queens. Two-year old queens lay eggs that weigh 1/3rd less. A further difference is the mortality rate of eggs increases as queens age – from 3.5% to 10% by the time the queen is 3-years of age. Studies by Oleg Ruppell, Dave Tarpy et al have shown that different queen stocks consistently lay eggs of different sizes in response to both genetic and environmental factors.
An additional interesting difference these ongoing studies have revealed is that queens heading smaller colonies tended to lay larger eggs – 15% larger in fact – than queens in larger, more populus colonies. The larger eggs seemed to have more metabolites, the chemicals used in energy production and growth. Queens apparently have the ability to determine their colony size as they reduce egg size as their colony grows in population size. Despite being larger in size initially, the good news is that emerged adult workers are essentially the same size regardless of egg size. The nurse -age bees are capable of making up the differences for egg size.
On the topic of egg size, an earlier study on egg size has caught the attention of others. Hao Wei and colleagues in China (Jiangxi Agricultural University, Nanchang) found that confined queens laid larger eggs in larger cells set up for queen rearing, suggesting queens can adjust egg size when beekeepers modify egg-laying conditions. It will be interesting to see if this finding holds with further research. I direct listeners to the Regular monthly column by Jay Evans, lead scientist of the USDA Bee Lab in Beltsville MD, recently recognized as AAAS (American Association for the Advancement of Science) Fellow in recognition of his scientific contributions and leadership, a guest in early August on Beekeeping Today Podcast. Jay summarizes the topic egg sizing in his Found in Translation of Bee Culture Magazine and has the references to Hao Wei and Ruppell/Tarpy publications.
Orientation flights
We know bees need to orient to the location of their hive. Orientation flights of naïve, new foragers, is a pattern that involves short flights that eventually widen out to encompass a greater area. Bees are memorizing landmarks. Many new-aged forager bees will join in these orientation flights often in the afternoon. There is safety in numbers. But what happens when the colony is moved, say to a better overwintering location or in the case of our commercial beekeepers, to a new pollination or honey production site? Do the bees need to go through the whole process of re-orientation to the new site. It turns out no they do not.
Using harmonic radar technology, the patterns and flight parameters of initial flights when colonies were moved to a new location were compared with the initial exploratory orientation flights of young honey bees and the foraging flights of experienced foragers. The flight patterns of orienting bees clearly differs from those of foraging flights. Just as with initial orientation, re-orientation flights can be classified into short- and long-range flights. And similarly the short-range re-orientation flights were performed under unfavorable weather conditions, meaning the bees adapt their flight patterns under changing weather conditions in a similar way.
However, re-orienting bees explored a larger terrain than bees performing their first exploratory orientation flight. A single re-orientation flight was found to be sufficient to learn the new location of the hive. How can we alert the bees to a move? Change the orientation of the hive entrance from its previous orientation by at least 15 degrees. Our bees then know to fly their shorter re-orientation flights to help them reset their landscape image so they can become more efficient foragers.
Degen J, Hovestadt T, Storms M, Menzel R. 2028. Exploratory behavior of re-orienting foragers differs from other flight patterns of honeybees. PLoS One;13(8):e0202171. doi: 10.1371/journal.pone.0202171. eCollection 2018.PMID: 30157186