Q Which cell type makes the better queen?
In the September issue of The Classroom, you had a question about whether a swarm cell or supersedure cell may produce a better queen. The answer may be a swarm cell. See this manuscript for possible insight:
Wei et al. 2019. A maternal effect on queen production in honeybees. Current Biology, 29: 2208–2213. https://doi.org/10.1016/j.cub.2019.05.059.
From the reprint: Wei et al. showed that the in ovo (in the egg) environment in honey bees is a maternal effect on queen development. Honey bee queens selectively lay larger eggs in queen cells to be raised by workers as queens. Egg size influences both gene expression and the adult weight of the queen.
Thanks for these wonderful comments Shelley. I am aware of the manuscript you shared as another reader shared the same manuscript with me in the past. It is very interesting given, as you note, that the authors of the manuscript provide evidence for maternal effects on the fate of the egg. Put simply, they show that queens lay larger eggs (queen eggs?) into queen cells than they do into worker cells. This will, no doubt, inspire additional research on this topic in the future. Their data suggest that queens can do more than just lay fertilized (female) and unfertilized (male) eggs. There may be a distinction, at least in size, between eggs meant to become queens and those meant to become workers. The authors share that egg size can influence the size of the resulting queen and gene expression in that queen. In a second manuscript (https://doi.org/10.3390/insects13050486), nearly the same author team showed that queens reared from eggs laid in queen cells were “better” (measured across multiple parameters) than those reared from eggs laid in worker cells.
This further supports the idea that eggs laid into queen cells are different than those laid in worker cells. This is pretty fascinating stuff and may change the way we think about rearing queens. After all, we all graft 12-hour-old larvae from worker cells into artificial queen cups when wanting to rear queens. Maybe we could improve the quality of our queens by grafting larvae that hatched from eggs laid purposely by queens in queen cells rather than grafting larvae from worker cells.
I do not want to get the cart before the horse here. More work needs to be done. However, it certainly does suggest that queens resulting from swarm cells are “better” than those that result from supersedure cells, simply given that a queen may have laid a “queen egg” in the former and a “worker egg” in the latter. The research is still in its infancy so other work may refute this. In the meantime, I cannot wait to see where all of this goes.
Q Where to find SHBs during winter
Is there any evidence of small hive beetles (SHBs) surviving the mid-Atlantic winters outside of a beehive? I was wondering if they can survive in rotting logs in the forest, or the base of a deep compost pile? I want to go beetle hunting this winter and would appreciate where our searches may turn up SHBs.
I am not aware of any research that has shown that SHBs overwinter in rotting logs, compost piles, etc. Right now, the prevailing thought is that they overwinter as adults in clusters with bees and possibly in the soil as pupae. A former student of mine (Eddie Atkinson) and I found that SHBs move into clusters as the bees begin to cluster (https://link.springer.com/article/10.1007/s10905-012-9326-8).
We found no SHBs outside of bee clusters in the hive by the time the temperature was between 5-10°C (41-50°F). We conducted this study because of previous observations colleagues and I made when we dissected frozen colonies. At that time, we found the vast majority of frozen SHBs directly in the bee cluster. As you know, honey bees will enter empty cells head first when they cluster. This helps them form a more contiguous cluster. I pulled some of these frozen bees out of their cells and I often found SHBs in the very same cells. This suggested that SHBs cluster with adult bees to survive winter (https://www.tandfonline.com/doi/abs/10.1080/00218839.2003.11101089).
I am not really sure what the bee/beetle interactions are in these clusters. It is a bit mind-boggling to me to think that the SHBs would survive bee aggression, if there is any, in the cluster during winter. This has yet to be studied.
Other investigators have looked at the temperatures at which pupae die. For example, pupae have been killed when exposed to 0°C (32°F) for 84 hours. Half of the pupae died when exposed to 5.6°C (42°F) for 7 hours. They had almost no mortality when exposed for 48 hours to 10°C (50°F) (https://www.mdpi.com/2075-4450/12/5/459).
Interestingly, SHBs seem to stop development at and below 13°C (55°F) (https://www.tandfonline.com/doi/full/10.1080/00218839.2020.1740406).
Remember, though, that larvae can tunnel 20 cm (~8 inches) into the soil (https://www.cabdirect.org/cabdirect/abstract/20003025391), possibly to escape the chill of upper soil layers exposed to cold air. Thus, it is conceivable that SHB pupation could be paused during winter, as long at the temperatures remain about 10°C (50°F) in the soil.
Long story short, I think the adults likely survive winter by clustering with the bees while some larvae/pupae may survive in the soil, in a type of suspended animation, until it warms again.
Q Drone mating position
Currently, I am reviewing the following paper:
Slater, Garett P., Nicholas M. A. Smith, Brock A. Harpur. 2021. Prospects in connecting genetic variation to variation in fertility in male bees. Genes 12(8): 1251. https://doi.org/10.3390/genes12081251.
My question is on Figure 2. Do drones mount from dorsal or ventral side of the queen?
Drones mount from the dorsal (top) side and fall over backward during the docking process. Essentially, they grab the queen dorsally and evert their endophallus into her. They lose a lot of their hemolymph to their endophallus during the eversion process. This causes them to fall backward, paralyzed. Queen bees can fly through the air with drones hanging from their bodies. Correspondingly, many of the pictures drawn of the docking process are a little confusing because some show the docking process while others show the drone hanging (or nearly so) from the queen. This can give the appearance that the drone docks from below the queen. It can even give people the impression that drones have to fly upside down and in an opposite direction of the queen to dock. However, this is not the case.
I wrote a document on mating biology of honey bees a few years ago. It was intended to be a summary of a book that Niko Koeniger, Gudrun Koeniger, Larry Connor and I wrote entitled “Mating Biology of Honey Bees” (Wicwas Press, 2014). You can find the summary document here: www.ufhoneybee.com > Extension > Beekeeper Resources > Field Guide to Beekeeping > Mating Biology. Have a look at Figure 8 in that document. It shows the process of the drone docking, everting his …