THE BROOD-REARING CYCLE OF THE HONEYBEE 9 



depending on weather conditions; in the one case the force of the 

 resulting explosion is definitely predetermined by the quantity of 

 the charge; in the other case the amount of brood reared is definitely 

 predetermined by the provisions made in the preceding season to 

 give the colony the conditions most favorable for this purpose. 



THE MAJOR PERIOD 



The major period of brood-rearing activity extends throughout the 

 active season from the time when normally the initial seasonal 

 tendency would cease to make itself felt until the beginning of the 

 period of final contraction. It is the longest of the three phases of 

 seasonal activity. The character and sequence of honey flows under 

 different climatic conditions cause brood-rearing activity during this 

 phase to vary widely in different regions. Throughout the world, on 

 the whole, brood-rearing activity during the major period falls either 

 into one of two extreme types or into a gradation between the two. 

 During this period one of the extreme types is marked by a con- 

 tinuous high rate of brood-rearing activity, while the other extreme 

 type is marked by a pronounced slackening or series of slackenings in 

 such activity. In the third or intermediate type there is neither a con- 

 tinuous high rate of brood-rearing activity during the major period, 

 nor under normal conditions is there at any time a complete suspen- 

 sion. This intermediate type, however, does show a seasonal slack- 

 ening at some time within the major period. 



A continuous high rate of brood-rearing activity during the major 

 period occurs in regions with a long inactive season in winter, fol- 

 lowed by a short active season, usually characterized by overlapping 

 honey flows. Following the prolonged period of winter suspension 

 in such a region, brood-rearing activity during the period of initial 

 expansion attains with striking rapidity a high rate, which, unless 

 checked by conditions within the hive, is maintained throughout 

 the major period extending over practically the whole of a relatively 

 short active season and then, owing to the proximity of the period 

 of winter suspension, undergoes an abrupt contraction. Such a type 

 of seasonal brood-rearing activity during the major period is typical 

 of subarctic conditions. 



A more or less complete suspension of brood rearing, or series of 

 such suspensions, is found in regions with a short, almost nonexistent, 

 inactive season, followed by a long season of activity, usually charac- 

 terized by one or more periods of drought during the hottest weather. 

 In such a region the initial expansion in brood rearing does not prog- 

 ress so rapidly as in regions with a long, inactive winter season, nor is 

 the final contraction so abrupt. The major period, instead of being 

 characterized by a uniformly continued high rate of brood-rearing 

 activity, is characterized by a pronounced midsummer slackening, or 

 scries of slackenings, in brood-rearing activity, probably caused by 

 an absence of incoming nectar and pollen during the periods of 

 drought. This type of brood-rearing activity during the major period 

 i typical of Ironical conditions. 



Intermediate between the two types just described is that type of 

 oiiid brood-rearing activity which exhibits a more or less marked 

 slackening at some time during the major period, but never a com- 

 plete suspension under normal conditions. This type may bo found 



46969°— 251— Bull. 1349 2 



