1986] Berbers & Tucker — Leptothorax longispinosus 221 
Table 1. Occupants of nests positioned on forest floors in early May 
Marker 
Queens 
Workers 
Eggs 
Larvae 
Floor 1A 
BD 
22 
91 
10 
178 
YC 
4 
30 
2 
73 
WH 
2 
24 
0 
28 
YD 
7 
80 
0 
99 
Floor IB 
YD 
1 
20 
14 
11 
BD 
5 
13 
0 
28 
RC 
2 
28 
5 
19 
Floor 2A 
BH 
0 
13 
0 
18 
WD 
0 
9 
0 
8 
RD 
3 
9 
0 
47 
GC 
4 
63 
0 
64 
YS 
2 
39 
0 
67 
Floor 2B 
GD 
1 
12 
5 
29 
OS 
3 
1 1 
0 
15 
YC 
0 
101 
0 
66 
BS 
3 
29 
13 
15 
RC 
0 
21 
0 
39 
week. Moreover, the five observations of tandem running behavior 
were restricted to the first 2 weeks. Workers and/or brood moved 
between existing nests primarily within the first four weeks. By 
mid-June there was little activity on the floors other than routine 
foraging. 
The first month of census data for nests on floor 2B are given in 
Table 2. From these data we can infer the following: a group of 
workers moved from RC to GD on May 9. On the 10th, a queen and 
some workers moved from GD to RC, and the fusion of GD and 
RC continued over the following three days. On May 28 the YC nest 
split, with 47 workers moving to GD and 35 remaining behind. At 
about this time members of the RC site started to explore OH; this 
tentative exploration continued for about two weeks more. Thus a 
great deal of information about population fluidity can be gleaned 
from census data alone. 
The census data also showed striking differences in activity 
between the first few weeks and the rest of the summer. Wholescale 
migration, fission into subunits, and fusion of nests occurred most 
often early in the experiments (Figure 3). Of three migration events, 
two occurred in the first two weeks. Of four fission events, two 
