Honeybees, Apis mellifera, are kept for the production of honey, beeswax, pollen, royal jelly, venom, and propolis; for the propagation of queen bees and the preparation of new colonies; and for the purpose of pollination of agricul- tural and horticultural crops. Honeybees are also used in research into, for example, the neural tract and giant neurons.
There is limited information available on the diseases and their treatment in bees. Some diseases have low economic value or have been incompletely researched; for others the causative agent is unknown.
Bees are susceptible to a number of viral, bacterial, proto- zoal, fungal, and acarine infections, which affect either the adult bees or their brood. Diseases affecting adults include nosema caused by the microsporidian Nosema apis. The disease is spread in the faeces of infected bees. During the warmer period of the year the faeces are discharged away from the hive and represent no risk to the colony, but in winter and early spring faecal contamination of the inside of the hive may occur if cleansing flights are limited by adverse weather. The young bees on ‘house’ duties are infected with the organism when cleaning soiled frames. The organism multiplies in the epithelial cells of the midgut producing huge numbers of spores.
‘Amoeba disease’ is caused by the protozoa Mal- pighamoeba mellificae. The organism encysts in the mal- pighian tubules, later moving into the ventriculus where it multiplies, becomes flagellated and then invades the mal- pighian tubules again to form cysts, some of which are discharged through the intestine.
Tracheal mites are acarine mites, Acarapis woodi, which live in the trachea behind the first thoracic spiracle. Eggs are laid in the trachea, which hatch, pass through a nymph stage, and when mature may emerge from the spiracle and transfer to other bees. It is believed that they can only enter the spiracle in young bees where the hairs guarding the entrance are still soft. Feeding on haemolymph through the tracheal wall, they have the potential of passing on infec- tions to their host and their presence is usually associated with chronic bee paralysis virus, characterised by angled wings, fluttering, and bloated abdomen.
The larvae of the greater wax moths Galleria mellonella (honeybee moths) and the lesser wax moths Achroia grisella (Meliphora grisella) feed on larval skins and pupal remains together with some wax in the brood combs. Their tunnels are lined with silken threads and frass, which the bees dislike, causing the bees to abandon areas of comb. There may also be mechanical damage to any brood present resulting in the condition called ‘bald brood’. In an empty hive, there is complete destruction of the combs, leaving a tangled mass of silk threads, frass, and debris, and probably erosions into the woodwork by the pupae.
Braula coeca (‘bee louse’) lives on the adult bees, rarely causing any problem. However its larval stages pass along the cappings of the stored honey, producing lines that dis- figure the appearance of comb honey. (Subjecting the comb