Bee Mortality

Horowhenua Chronicle, 21 October 1913, Page 4

Bee Mortality

(By F. R, BEUHiYE, Victorian Bee Expert).

Of the cause of the periodical mortality known by the name of disappearing trouble or spring dwindling nothing dolinite is at yet known. It appears to be a result of certain climatic conditions in the autumn preceding a winter or early spring honey-flow from certain eucalypts, and is looked upon rather as a condition of the bees than a disease. A characteristic of this trouble is that there are 110 symptoms. Colonies become gradually, and somelimes rapidly, weaker.day by day without more than the normal number of dead bees being visible in or near the hives, while under the microscopal examination neither dead nor live bees from the dwindling colonics iliJl'er in any way from I lie bees ot normal colonies iu unaffected locality. The dwindling takes place during midwinter the queen and the last, hundred or so of bees perish from the cold; when it occurs in spring, the i|Ueen and bees swarm out and join some oilier colony when a point of number is reached from which the colony could no longer recover. The queens of colonies which dwindled in this way, when introduced to normal colonies in an una Ifected" area, do not reproduce dwindling in succeeding seasons, and the combs from which the bees disappeared in no way all'ected other bees which were put to them.

During the spring of 100!), and again in 1.01 1, heavy losses of bees were experienced in the country near the Grampians, but not in the scrub country on and inside the ranges. In both 1000 and lUI2 there was a dearth of pollen iu the preceding autumn, followed by a honey-flow from ironbark cut alypts, E. Jeueoxlyon and E. sideroxlyon. The former is known by different names in different localities, such as white iron bark, bluegum, white gum, and spotted box. The latter is everywhere called red iron bark. Both arc winter bloomers, and secrete nectar very freely, but produce no pollen for been.

it has been suggested that the abnormal activity of the bees during a period when they should be semi-dormant, which is caused by the flowering of the ironbarks, causes the premature wearing-out of the workers, and there seems to be some force in this contention. The opposition to it, however, the fact that when the tree variously known as as cabbage gum, bastard I.ox, pepermint, etc., (lowers during the winter months, bees work freely on it and come through strong. The tree, however, produces poollcn freely, and while but little brood can ,1)e reared owing to low temperatures, the nitrogen withdrawn from (he body of the bee by the secretion of the enzyme which is necessary for I he changing of the nectar into honey is continuously replaced by the consumption of pollen found on the blossom from which the nectar is gathered, and thus the vigour and vitality of the bee, maintained when gathered from pollenproducing blossoms, but impaired when working on flowers producing nectar only.

Dr Kramer, a well-known Swiss authority, slates that sugar syrup (u hidi contains no nitrogen) fed to bees and extracted contained the same amount of nitrogen as pi;re honey. The nitrogen was added out o|' the bee's own organism. "That," Dr Kramer says.

"explains why alter being fed sugar, bees are so eager for pollen, also why bees rapidly become enfeebled upon being fed with sugar when no pollen or substitute is a vail a bl e."

As bees do not obtain pollen from irouburk blossoms, a winter flow from that source is the equivalent to heavy sugar feeding with a lack of pollen at the same time, which, as Dr Kramer further on in Ihe same article says, "so rapidly decimates the colonics/'