THE BROOD-REARING CYCLE OF THE HONEYBEE 7 
conducive factors, brood-rearing activity is prevalent, and that in 
the remaining portion of the year brood-rearing activity is suspended. 
The annual brood-rearing cycle may therefore be divided into two 
parts: (1) a period of seasonal activity and (2) a period of seasonal 
suspension. The period of seasonal brood-rearing activity, or the 
" active season," takes place, roughly speaking, during the summer; 
the period of seasonal suspension of brood rearing, here called the 
" inactive season," occurs in winter. 
SEASONAL ACTIVITY 
At the end of the inactive season, marked normally by the first 
incoming nectar or pollen, brood rearing is resumed and may proceed 
to a certain maximum in the fore part of the active season at a rate 
which is often strikingly noticeable. Brood-rearing activity during 
the remainder of the active season, up to the period of final decline, 
varies widely with geographical location or climatic conditions. In 
some regions it is maintained at a uniformly high rate throughout; 
in other regions it is broken in continuity by an interval of partial 
suspension. In still other regions there is a gradation between these 
two extreme types of seasonal brood-rearing activity. The final 
decline is either abrupt or gradual, depending also on geographical 
location. Regardless of geographical location or climatic conditions, 
the period of seasonal activity may be divided into the three following 
phases: (1) A period of initial expansion, (2) a major period, (3) a 
period of final contraction. It is not always possible to draw a sharp 
line of demarcation between these three seasonal phases of brood- 
rearing activity, because external environment, such as weather or 
incoming nectar and pollen, often causes the end of one seasonal 
phase to become so merged with the beginning of the next that the 
initial influence of the succeeding phase can not easily be detected. 
PERIOD OP INITIAL EXPANSION 
The initial expansion covers that period of the active season 
immediately following the inactive season, in which brood-rearing 
activity is normally resumed and is continued in spite of conditions 
which if occurring later in the season would tend to check brood 
rearing. It should be pointed out that the beginning of brood rearing 
here discussed is that caused by the incoming of the first nectar or 
pollen and does not apply to abnormal brood rearing during the 
inactive season, which will be discussed later. At no other time in 
the year does the tendency to rear brood seem so persistent as during 
this initial phase, except possibly when a colony has just swarmed 
or when a queen is beginning to lay for the first time. Although the 
rate of increase in brood-rearing activity may be greatly accelerated 
during the period of initial seasonal expansion by incoming nectar or 
pollen, the fact that such an expansion continues after resumption 
of brood rearing, even with no incoming nectar or pollen, indicates 
that this phase is purely seasonal and needs only the approach of 
spring to cause its appearance. 
Since this expansion in the spring is a seasonal phenomenon, and 
is bound to occur, the colony which will gain the most rapidly in 
population in the spring is the one possessing the largest number of 
factors favorable for brood rearing. It becomes readily apparent, 
