The energy of a hive, and with that its ability to complete all of the important tasks – from foraging to raising new bees and producing honey – ultimately comes from just two vital substances: pollen and nectar. Pollen is the powdery substance that contains the fertilizing male component of the next generation of plants. Worker bees collect this and feed it to larvae back at the hive. Nectar, on the other hand, is produced by plants in order to draw the bees (and other pollinators) in. It is a rich, sweet liquid – full of energy – that worker bees both consume on the spot and bring back to the hive for feeding purposes. It is from nectar that honey is produced – but it is also the substance which, more so than pollen, really keeps a hive going. Unfortunately, it is not always in abundant supply.
Bees cannot survive on pollen alone and, when nectar is in short supply, there comes times when it has to be replaced by beekeepers themselves. This is not only to prevent imminent starvation (as is occasionally a serious risk) but also to ensure sufficient stores of food for bees over the winter months when there is simply no means of retrieving any from plants.
Nectar, with its unique composition and honey-producing elements, of course cannot be recreated by beekeepers. However, the energy levels normally supplied by nectar can at least be matched by the sugar syrup, which is the stock-in-trade feeding substance used by beekeepers to keep the energy of a hive up when supplies of nectar are not readily forthcoming.
It might well come as pretty surprising then – especially when a colony is in risk of collapse or some other disaster – that bees will sometimes flatly reject the sugar syrup provided for them within the hive. This can be alarming for beekeepers, especially when the energy of a hive is critical. So why does this happen? In most cases, it comes down to atmospheric temperature above all else.
It is Just Too Cold
In the vast majority of cases, the reason why bees will not accept the sugar syrup provided from a feeder is simply that it is too cold. What matters here though is the temperature of the syrup itself (although this is of course influenced by how cold it is). When its temperature drops to around 10°C, bees will simply reject the syrup.
Depending on where you live, these temperature usually become common from the early fall onwards, so this can become a real problem for some beekeepers.
Nevertheless, even though the bees refusing to feed can be attributed in most cases to temperature, this does not mean that the situation is a simple case of “no feeding when it is too cold.” As mentioned, what matters is the temperature of the syrup itself. Bees do not refuse to feed because the cold makes them unable to; they refuse to feed because to consume the chilly syrup would cool them even further at a time when conservation of heat is essential for survival.
Keeping in mind therefore that it is the temperature of the syrup that matters, the situation can become more complicated. Why exactly is the syrup too cold? If you use an internal feeder (as is most commonly the case), the temperature of syrup is influenced not only by the outside atmospheric temperature, but also by the heat produced within the hive. This is a factor entirely controlled by the bees, with more active and larger colonies producing more heat.
Your syrup temperature problem could therefore be down to the size of your colony. There is an easy way to check this. If you find that one of your colonies isn’t feeding while the rest are, you can fairly reliably conclude that it is not only the outside temperature that is causing this. In such cases, it is highly likely that the colony refusing to feed is simply too small.
There does, of course, come a point when it is too cold for any colony to feed on artificially supplied sugar syrup. As we approach the winter months, the temperature is simply too low for even the largest colonies to keep sugar syrup warm enough for consumption. The trick then is to notice which of the hives ceases feeding first. If you can catch this, then you can start taking action to ensure the bees can build up food stores before it become too cold to add to them at all.
What to Do About It?
If some of your hives are feeding while others are not, the size of the non-feeding hives is most likely the primary problem. The solution might then be to combine them. Combining hives is a common beekeeping solution that is applied in all manner of cases. It could be because of a poor nectar flow, a weak and irregularly laying queen, queen absence or, indeed, bees refusing to drink their sugar syrup.
Combining two hives is a matter of prioritizing the strong hive, retaining its location, and placing it underneath the weak hive that will be moved. If you have more than one hive that is refusing to feed, you should combine these with each other to avoid destabilizing any strong hives. By combining the two, you should increase the internal temperature through more activity and simply more bee bodies contributing heat. This should raise the temperature of your syrup to a palatable level.
Before you go to the trouble of combining any hives (and this is a task that can be a fair bit of trouble), it is worth making sure that your sugar syrup is both properly positioned and provided in the correct amount. Sometimes, temperature may not be the sole cause of your woes. If a sugar syrup feeder is positioned too far from the cluster, bees will often refuse to feed. It may also be the case that you have simply provided too much sugar syrup, and the very volume of the syrup is too great to keep warm. As a rule of thumb, remember to check your feeder position and syrup volume before doing anything more drastic.
Ultimately, if your bees are refusing to feed there is normally something you can do it about. So long as you notice the signs early enough, the problem need not be a death sentence for your hive.