Temperature And Queen Colour

It’s a non-beekeeping day today, and we have had some much-needed rain overnight. This should not be unusual here in Manchester, but it’s actually been untypically dry. My bees have generally got off to a quick start this year. Many forage plants are available simultaneously, especially dandelion, apple, oilseed rape and trees such as horse chestnut. After the winter break, such a resource surge has got the bees in a frenzy. Hawthorne seems to be coming on too. I fear that everything will be over in May and that the June gap is on the cards; sometimes we get one, sometimes not. 

Cat Pee?

My bees certainly love dandelions. This is all well and good except for the unpleasant odour imparted to the hives. I have heard it described as like old socks or cat pee. I just sold a couple of nucs at an auction, and I wonder what beginners might make of the stench when they open up the box and place the frames into their new home.

Navigating the June Gap

Presumably, in a June gap, the thing to do is remove supers and possibly feed a little syrup/pollen sub to keep the bees strong for the summer nectar flow, if it comes. I’ve never done any of that clever stuff. I think in a June gap, my bees eat half of the honey, and the queen slows down her laying rate. I haven’t produced the vast honey yields that some bee farmers get. Managing tricky periods when forage is unavailable makes a big difference by the end of the season. Of course, it’s not important if you aren’t bothered by how much honey you make. 

First Graft of 2022

There are loads of drones about, and hives are booming, so I thought I’d crack on with raising queens even though it’s a bit early by the calendar. A couple of days ago, I grafted my first larvae of the season; 24 tiny little babies all lined up in their JZ-BZ cell cups. My cell builder is the same set-up as last year, which worked well, but I’m anxious until I see queen cells full of jelly. The grafts go into the top box of a Demaree; the queen is down in the bottom – I have not made them queenless. She is below a couple of supers and queen excluders.

Jelly Babies

It makes me nervous because many people use a queenless starter followed by a queen-right finisher. Still, Jolanta up in Blairgowrie keeps them queen-right throughout. Mike Palmer moves the bottom box with the queen away for a few days, then recombines it later to make a finisher. There are many ways to make queens. The amount of effort required means that it’s worth making great queens. Mike says, “It’s all about the jelly”, so if I see that the cell cups are full of the milky substance right up to emergence, I know I did my part.

Having an excess of royal jelly to consume from a very young age (day 4 after the egg was laid) is a significant factor in raising good queens. The other two big variables are the mother’s genetics and the temperature/humidity in which the cell is kept as the new queen develops. I’ve been delving into some old research to see what effect temperature has. I mean the temperature at which the bees (or incubator) keep the sealed cell as the pupa grows into a queen.

Timing is Critical

The typical timings for queen development are shown on the chart below. I’ve been caught out before by queens emerging earlier than I expected, with unfortunate results. Could this be that sometimes I graft a larva that is 1.5 or 2 days old (4.5-5 days after laying) and/or could temperature be a factor? I can’t do much about the temperature that bees maintain in the hive, but the incubator is another matter. 

Incubator Temperature Matters

Some old research by Marla Spivak et al. called Influence of Temperature on Rate of Development and Color Patterns of Queen Honey Bees makes fascinating reading. Once cells were capped, researchers put them into an incubator and kept them at a constant temperature until emergence. The total time from egg to a virgin queen is typically 16 days. The research shows that lower temperatures extend the development time:

31.5 Celsius (89 deg F) = 18.1 – 18.4 days

33.5 Celsius (92 deg F) = 16.4 – 16.9 days

35.5 Celsius (96 deg F) = 15.1 – 15.7 days

These temperatures were for the period after the cells were sealed (they went into incubators). It also turned out that the line of queens with darker genetics was quicker to develop than lighter queens. What I did not expect was this:

Incubation Temperature Effects Colour

Colour patterns of honey bees are heritable, although this study demonstrates that pigmentation is significantly influenced by temperature during the post capping period. Queen bees that develop at the low end of the range of brood nest temperatures will exhibit darker colouration than if they developed at the high end of the temperature range. If brood nest temperatures are maintained at only 3-4°C lower during cooler months of the year, darker queens will emerge, whereas, in the warmer months, queens of the same genetic composition will be lighter in colour. 

which leads to:

Many apiculturists select queens on the basis of colour as an indicator of subspecies, lineage, and behavioural characteristics (such as docility or honey production). Taxonomists have traditionally used colour patterns on the abdominal tergites as a character to distinguish subspecies of A. mellifera (Alpatov 1929, Ruttner 1988). If queens are reared at the extreme ranges of brood nest temperature or at times of the year when ambient temperatures are low or exceptionally high, colour patterns may not be reliable indicators of subspecies, lineage, or behaviour unless queen rearing conditions are taken into account. 

What About Quality?

I know what you’re thinking – that unscrupulous queen sellers could manipulate the colours of their queens by varying the incubation temperature. Then all those people who believe that local queens are black will be satisfied. What about queen quality, though – will it suffer if the temperature is low? From what I can tell, it seems that 32-35 deg C is a safe range. The thermometer on incubators is not always the most accurate, so there’s that issue too.

I found some research done in Poland in 2015 called The Quality of Honey Bee Queens from Queen Cells Incubated at Different Temperatures which addresses this point. I am no expert at discerning the quality of research, so bear that in mind. They compared incubation at 32 deg C to 34.5 deg C and found, as expected, that the cooler batch took longer to emerge (27 hours longer). There was no significant difference in body weight, spermathecal volume, ovariole number in both ovaries, or onset of oviposition. So, the answer seems to be that if you stay within a safe temperature range, queen quality is the same throughout. 

I don’t care about the queen’s colour, but I do care about being on hand to deal with virgins as they emerge rather than letting them die in their roller cages because I did not account for temperature.