the laboratory for weighing. The weight of each swarm
was determined to the nearest 4 oz (7.1 g). The number of bees in each swarm was calculated using Mitchell's
(1970) figure of 3500 bees/lb. All swarms were taken
from within 10 miles of Ithaca, NY, 42°27' north latitude.
The Time of Natural Swarming
in Honey Be&'2
D. MICHAEL BURGTT AND ROGER A. MORSE
in those instances where the exact time of swarm
Department of Entomology, Cornell University,
Ithaca, NY
emergence was known, the queens were weighed during
the first 2 days following emergence of the swarm. There
is a rapid increase in queen weight which starts about
2 days after a swarm emerges (R. D. Fell, unpublished
data). Multiple queens, taken from secondary swarms,
were dissected to determine if they were mated.
Of the 95 swarms collected during the study, 77
Colony division (swarming) is a natural method of reproduction in honey bees, Apis niellif era L. It also represents a potential economic loss for beekeepers, and management practices have been devised to reduce its incidence. Simpson (1957) estimated that in an average year
(81.0%) emerged between May 16 and July 11, the tradi-
10-40% of the colonies in a commercial apiary will
tional swarming season in the Ithaca area. Seventeen of
the swarnss (17.9%) emerged during the period Aug. 14
to Sept. 12. A well-defined, non-swarming period existed
between mid-July and mid-August (Fig. la) ; a swarm
which emerged on July 21 was the only exception. It is
significant that those swarms issuing in the late summer
have little chance of survival in northern latitudes.
Swarms varied in size. The smallest swarm contained
swarm if left unattended.
All swarms reported to us in phone calls, and from our
own intentionally crowded colonies, were collected in
5:fme nucleus boxes over a 3-yr period and returned to
Hymenoptera: Apidae. Received for publication Nov. 28,
1
1973.
This research was supported by National Science Foundation
grant, GB-13840, Reproduction in Honey Bees.
:..:J
15
25
20
a.J
I
0
3
15
20
25
20
10
50
25
10
5
5
20
5
25
SWARM IMERGENCE DATES
971,
5000
7000
'
9000
11,000
13,000
'
5000
'
7,000
20
25
072, 1973
.
5000
IS
l
5072 EM 00
A 00 0 5
JUNE
MAY
9000
21,000
25,000
23,000
'
27,000
29,000
51,000
33,000
33,000
SWARM SIZE . NUMBER OF BEES 1972 & 973
z
0
.
.1. a.
ISO
ISO
170
180
MATSD QUEEN
90
200
210
220
030
240
060
250
270
WT.("g. OF QUEENS TAKEN FROM HONEY BEE SWARMS
* VIRGIN QUEEN
FIG. 1A.Swarm emergence dates: 1B, Swarm size; 1C, Queen weight.
just over 3000 bees while the largest had slightly under
33,000 bees (Fig. ib). The mean swarm population was
14,000 individuals. The mean weight was 4.0 lb (1.8 Kg).
The mean weight of 29 swarm queens was 191.2 mg
(Fig. ic). Mated queens averaged 195.9 mg and virgin
queens averaged 176.4 mg.
REFERENCES CITED
1970. \Veights of workers and drones.
Mitchell, C.
.Am. Bee T. 110: 468-9.
Simpson, J. 1957. The incidence of swarming among
colonies of honey-bees in England. J. Agric, Scj.
49: 387-93.
Reprinted front the
ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA
Volume 67, Number 4, pp.719-720, July 1974