F. L. Landacre.
While working on the Honey Bee in the laboratory at the University
it was observed that the number of hooks connecting the
posterior wing with the anterior was not constant.
The query at once arose as to the amount of variation there
might be between different bees in the same hive and also between
different hives. Out of this grew a somewhat practical problem as
to whether the increase in number of hooks was associated with a
decrease in the size of the wing, or whether the increase in number
of hooks also implied an increase in size of wing.
The wings of the bee are undoubtedly more efficient for being
closely attached to each other. The life of the workers is so
short, being only about three weeks, and their activity so great that
any increase in efficiency, especially in the organs of flight, must
have a very direct influence on the welfare of the whole swarm.
So far as the well being of the swarm depends upon nutritive processes
the efficiency of the hive is equal to the average efficiency of
the workers. Now, if the increase in number of hooks and the consequent,
firmer attachment of the wings is compensated for by a
smaller wing, there is much less opportunity for the operation of
natural selection on the individual bees than if the greater number
of hooks is always associated with a broader or longer wing.
This selective process might occur either in the hive or between
hives. If it occurs in the hive it would increase the efficiency of the
hive somewhat; but if it occurs between hives it finally means the
elimination of the weaker hive and the consequent increased efficiency
of the species.
In order to find out the real conditions, one of the students, Mr.
J. N. Frank, took twenty-five workers from each of four hives and
counted the number of hooks on each wing, right and left, and also
measured the width of the anterior and posterior wings on each side,
The width only was taken on account of the difficulty in finding a
good point at the base of the wing from which to measure the length.
The results are so uniform that the width probably gives sufficient
data from which to draw conclusions.
Of the four hives studied, numbers one and two were very weak.
Number three was a strong hive which made forty (40) pounds of
extra honey in the summer of 1900. Number four was weaker than
number three and made only ten (10) pounds of extra honey.
The complete measurements are too long to give in detail, and
the averages only will be offered here.
AVERAGES OF TWENTY-FIVE MEASUREMENTS FOR EACH HIVE TAKEN
WITH AN EYE-PIECE MICROMETER, EXPRESSED IN MM.
HIVE NUMBER ONE.
| Average Number of Hooks. |
Average Width of Wing. |
| Right wing. |
Left wing. |
Right wing. |
Left wing. |
|
|
Ant. |
Pos. |
Ant. |
Pos. |
| 21.3 |
20.9 |
4.21 |
3.61 |
4.28 |
3.55 |
HIVE NUMBER TWO.
| Average Number of Hooks. |
Average Width of Wing. |
| Right wing. |
Left wing. |
Right wing. |
Left wing. |
|
|
Ant. |
Pos. |
Ant. |
Pos. |
| 19.2 |
18.8 |
4.14 |
3.48 |
4.16 |
3.48 |
HIVE NUMBER THREE.
| Average Number of Hooks. |
Average Width of Wing. |
| Right wing. |
Left wing. |
Right wing. |
Left wing. |
|
|
Ant. |
Pos. |
Ant. |
Pos. |
| 21.0 |
21.0 |
4.06 |
3.48 |
4.07 |
3.50 |
HIVE NUMBER FOUR.
| Average Number of Hooks. |
Average Width of Wing. |
| Right wing. |
Left wing. |
Right wing. |
Left wing. |
|
|
Ant. |
Pos. |
Ant. |
Pos. |
| 19.6 |
19.6 |
4.09 |
3.47 |
4.03 |
3.41 |
As to the first query concerning the individual variations in a
single hive the complete table shows that No. 1 varies from 18-21
hooks, No. 2 from 17-21, No. 3 from 18-23 and No. 4 from 17-21. The
right wing is taken as the standard, and the most active hive, No. 3.
shows the greatest individual variation. One bee in this hive had
only sixteen hooks, the remaining three being straight spines, showing
how the hooks have been modified from ordinary hairs. This
reversion occurred on three separate wings, in No. 2 one hook on
each wing being straight.
As to the relation between the number of hooks and the width
of the wing the averages are very definite. Taking hives number
one and two from the same apiary, it will be seen that the increase
in number of hooks goes with the increase in width of wing. The
same relation is shown by hives numbers three and four from another
apiary in the case of the posterior portion of the right wing
and in both anterior and posterior portions of left wing.
The results are not conclusive as to the relative efficiency of different
hives because there are so many conditions entering into the
production of large quantities of honey. The number of bees, the
care during the winter, the age of the queen, the number of swarms
produced, and several other factors would have to be taken into
consideration.
The differences in the right and left wings in the bees of the
same hive is marked. The right wing has the larger number
of hooks, but the left wing is the broader. In hive number one the
average number of hooks in the right wing is 21.3, left 20.9; but the
anterior wing on the right side is 4.21 mm., while the left anterior
wing is 4.28; that is, there is a compensation for the reduced number
of hooks in the increased width of the wing. This is true of the first
three hives. In the fourth hive there is a slight advantage in favor
of the right wing.
The following general conclusions may be drawn from these
measurements:
(a) There is a variation in the number of hooks in a given hive
ranging between 17 and 23.
(b) The difference in the number of hooks in the right and left
wing is compensated for in a given hive by the increased size of the
wing. The right and left wings are in physiological equilibrium.
(c) In different hives the increase in the number of hooks is
accompanied by an increase in width of wing; that is, the variation
is emphasized so that selection would work much more effectively;
while in the individual, where—if selection operated on account of
this variation—it would have to be between different wings of the
same bee, the variation is eliminated.