Feeding honey bee colonies to prevent starvation

                            Feeding honey bee colonies to prevent starvation

This note provides information for beekeepers about feeding bee colonies with sugar to prevent starvation when they have little or no food and supplies of nectar are poor or unavailable.

Introduction

Honey bees store honey in the hive to provide food for winter and for other times when there are few or no nectar secreting flowers available.

When nectar is in short supply or unavailable, bees draw on their honey stores in the hive. During these times, it is important to frequently monitor the amount of honey in the hive because when it has all gone, the colony will starve.

Starvation can be prevented by moving bees to an area where plants are yielding nectar or by feeding them white table sugar, or syrup made with white sugar. Never use raw, brown and dark brown sugar, and molasses as these may cause dysentery in bees. Bee colonies can be kept alive for long periods by feeding white sugar.

Honey as feed for bees

It is extremely important not to feed honey to bees unless it is from your own disease free hives. Spores of American foulbrood disease can be present in honey. Feeding honey from an unknown source, for example, a supermarket or even another beekeeper, may cause infection in your hives. If you feed suitable honey to your bees, it must be placed inside the hive. Never place honey in the open outside the hive as this is illegal under the Livestock Disease Control Act 1994.

How and when to feed bees

If sugar syrup or dry sugar is fed in the open, bees from nearby managed and feral colonies will be attracted. You will end up feeding other bees as well as your own. Besides being a waste of money, feeding in the open may cause robber bee activity in the apiary and possible interchange of bee disease pathogens.

Placement of sugar syrup or dry sugar in hives is best done towards evening to minimise any tendency for bees to rob the hives that are fed.

Making and feeding sugar syrup

There are differing views about the correct amount of sugar in syrup. Some beekeepers prefer a ratio of one part of sugar to one part of water, measured by weight (known as 1:1). Others prefer a dense syrup of two parts of sugar to one part of water (known as 2:1). Generally, 1:1 syrup is used to supplement honey stores, stimulate colonies to rear brood and encourage drawing of comb foundation particularly in spring. The stronger syrup is used to provide food when honey stores in the hive are low. Measuring the sugar and water by weight or volume is alright because there is no need to be 100% exact about the sugar concentration.

Heat the water in a container large enough to hold both the water and sugar. As soon as the water has begun to boil gently, remove the container from the heat source. Pour in the sugar and stir the mixture until the sugar crystals are dissolved. Never boil the mixture as the sugars may caramelise and may be partially indigestible and toxic to bees.

Always let the syrup cool to room temperature before feeding it to bees. The cooled syrup can be given to hives using one of the following four methods.

Container with sealable lid

Fill a clean jar, tin with a push-down lid, or similar container with sugar syrup. Drill or punch the lid with 6-8 very small holes. Cut two 12 mm high risers from a piece of wood and place them across the top bars of the frames that are in the top box of the hive. Invert the filled container and place it on the risers. Next, place an empty super on the hive to enclose the feeder and then replace the hive lid. The risers provide a bee space between the top bars and the holes in the container lid. It is a good idea to remove the cardboard insert commonly found in jar lids.

Plastic bag

Partially fill a plastic freezer bag with sugar syrup, about half full. Gently squeeze the bag to expel all the air. Tie the neck of the bag using an elastic band. Place the bag on the top bars of the frames in the top box of the hive, under the hive cover. Use a brad or very small diameter nail to punch about 6-8 small holes into the upper surface of the bag. The bees will suck the syrup through the holes. Never put the holes on the under surface of the bag as the syrup may leak out faster than the bees can gather it. This may lead to loss of syrup outside the hive and cause robbing by nearby bees. It is important to have a bee space between the upper surface of the bag and the under surface of the hive lid so the bees can gain access to the syrup. If required, a wooden riser of the dimensions of the hive may be used to raise the lid.

Shallow tray

Place sugar syrup in a shallow tray, such as aluminium foil tray, under the hive lid. Bees need to be able to reach the syrup without falling into the liquid and drowning. Some grass straw or wood straw of the type used in cooling devices may be placed in the syrup for this purpose. It is important not use any straw or floating that has been treated, or been in contact, with chemicals as this may be hazardous to bees. The hives should be on level ground to prevent loss of syrup and a riser may need to be used if the tray is not shallow.

Frame feeder

Place sugar syrup in a 'frame or division board feeder'. This is a container, the size of a full-depth Langstroth frame, that has an open top and which sits in the super as a normal frame does. The feeder requires a flotation material or other means to allow bees to access the syrup without drowning.

How often to feed

It is normal for bees to remove syrup from a feeder, reduce the water content and store it in the combs as if it were honey. Whatever feeder is used, a medium to strong colony will usually empty it in a matter of days.

For colonies with virtually no stored honey and no incoming nectar, the initial feed will be largely determined by the amount of brood, the size of the colony and to some degree, the size of the container used to hold the syrup. It is safer to over-feed a colony than to skimp and possibly cause the death of the colony. Some beginners have tried tablespoons of syrup, but this amount is much too small. An initial feed of around 1-3 litres could be tried. It is then important to frequently check the combs to see how much syrup has been stored. This will give a guide as to how often and how much syrup should be given. Feeding can be stopped when nectar becomes available.

Properly ripened syrup should have a moisture content of around 18%. Syrup that is not ripened adequately will ferment and adversely affect bees. Colonies with insufficient stores for winter should be given enough syrup to boost their stores before the cold weather of autumn sets in. This will enable the bees to fully process the syrup.

Feeding dry sugar

Medium to strong colonies can also be fed dry white table sugar placed on hive mats or in trays under the hive lid. Bees require water for liquefying the sugar crystals. They will obtain supplies from sources outside the hive and sometimes use condensation that may occur inside the hive. Some beekeepers prefer to wet the sugar with water to prevent it from solidifying. In effect, this creates a partial syrup. Weak colonies may be incapable of gathering sufficient water and feeding of dry sugar to them is not recommended. Regardless of colony size, feeding dry sugar works best during autumn and spring when humidity is relatively high. The hot, dry conditions of summer make it hard for bees to dissolve sugar crystals into a liquid.

It may be preferable for a colony at starvation level to be first fed syrup before dry sugar is given. This will give the bees immediate food without the need to liquefy crystals. Bees will generally not use dry sugar when they are able to collect sufficient nectar for the colony's needs. The sugar will remain in the hive and in some cases will be deposited by the bees outside the hive entrance. A small amount of dry sugar may be converted to liquid and stored in the cells.

Important note

Sugar remaining in combs must not be extracted with the next honey crop. The sugar will contaminate the honey and the extracted product will not conform to the legal standards set out in the Australia New Zealand Food Standards Code - Standard 2.8.2 – Honey. Ideally, the amount of sugar that was given to the hive will be fully eaten by the bees at the time hives are placed on a honey flow. This is not always possible to achieve. Also, during expansion of the brood nest, sugar stored in brood nest combs may be moved by the bees to the honey super.

Acknowledgements

This Agnote was developed by Russell Goodman, Biosecurity Victoria, Knoxfield. It was reviewed by apiary officers, Joe Riordan and Daniel Martin, and commercial beekeeper, Bob McDonald.