1984] 
Sorensen, Busch, & Vinson — Solenopsis invicta 
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Members of the three temporal subcastes were tested by 
themselves (i.e., two subcastes excluded) and in paired combina- 
tions to determine if adequate food flow could be maintained. Three 
replications, of the following groups were tested using a different 
colony (A, B, and C) each time. With two of the three subcastes 
excluded, we tested 50 foragers (F), 50 larvae (L), and 1 queen (Q); 
50 reserves (R), 50 L, and 1 Q; and 50 nurses (N), 50 L, and 1 Q. 
With one subcaste excluded we tested combinations of 25 F/25 N, 
50 L, 1 Q; 25 F/25 R, 50 L, 1 Q; and 25 R/25 N, 50 L, 1 Q. Five 
replications using workers from all three subcastes were tested as a 
control using 18 F/18 R/18 N, 50 L, and 1 Q. Different colonies 
from those previously tested were used. 
To determine the biological half-life of the radiolabelled protein 
in the different groups tested (Sorensen et al. 1980) control colonies 
were set up as described previously, allowed to feed for 1 h, and held 
for 7 days without food. All of the ants were measured daily for 
radioactivity as described previously. 
Statistical analyses were done using the Statistical Analysis 
System (SAS) for computer data analysis. We used a SAS REG 
procedure for full rank linear model analysis, regressing the amount 
of food in each ant against the total amount of food in the colony. 
Multiple comparisons among slopes were made using the Newman- 
Keul Multiple Range Test (Zar 1974). Duncan’s Multiple Range 
Test for means (SAS GLM procedure) was used to compare the 
mean amount of food collected by test colonies over time. 
Behavioral observations were made on marked foragers and 
nurses to determine how flexible these subcastes were with regards 
to foraging and brood tending behavior. We isolated 100 nurses 
with larvae, marked them with wires, placed them in stacked 
cylinder nests as previously described, and presented them with food 
twice daily. Nurses that entered the foraging chamber were marked 
with a second wire loop. We then added 100 marked foragers and 
100 reserves and observed them during feeding to see if the doubly 
marked N/F continued to forage or returned to brood tending. 
Three different colonies were tested. Foragers were tested in a 
similar manner except that foragers that stayed in the brood 
chamber were differentially marked and then later observed in the 
reconstituted colonies to see if they remained with the brood or 
returned to the nest periphery or foraging chamber. 
