1974 ] 
Wilson — Camponotus fraxinicola 
185 
large size. A few minor workers with distended abdomens taken 
from within the nest had similar abdominal contents, but the ma- 
jority from both within and outside the nest had proportionately 
much smaller fat bodies and reduced ovaries. Thus the soldiers store 
substantially more food in the form of fat than do the minors. The 
nature of their eggs has not been ascertained. Should they prove to 
be trophic eggs, this form of storage would be primarily the province 
of the soldier caste. 
The following data reveal that the soldiers also store dispropor- 
tionately large quantities otf liquid food in their crops. When colonies 
are fed ad libitum with saturated sucrose solution or honey, most of 
the workers in both subcastes become repletes. Repletism has been 
defined for purposes of this analysis as distention of the abdomen to 
the extent that the intersegmented membranes are exposed, permitting 
the interior of the crop to be seen when light is transmitted from 
below. It has been repeatedly observed in our laboratory colonies 
that a higher proportion of the major workers — sometimes all of 
them — become repletes when the colony is offered a superabundance 
of liquid food. But when the colony is starved, the proportion of 
repletes among the majors drops below that off the minors. Two 
examples are presented in Figure 2. 
The amount of liquid stored by each major is substantially greater 
than that stored by each minor, on both an absolute and per-unit- 
weight basis. This difference, which was first guessed by simple in- 
spection, was proved by the following series of measurements. Twenty 
minors and 11 majors were selected at random and weighed from a 
colony anesthetized after two weeks of starvation. Then the colony 
was fed to satiety over a 24-hour period and anesthetized again; 20 
minors and 16 majors were next selected at random from among the 
replete individuals and weighed. The mean weight of the starved 
minors was 1.62 mg (range 1.29-2.42 mg) ; after feeding, their mean 
weight was 2.44 mg (range 1.75-3.33 mg), a gain of 0.82 mg or 
50.6 percent. The mean weight of the starved majors was 3.44 mg 
(range 2.38-4.65 mg); after feeding, their mean weight was 5.62 
mg (3.14-7.34 mg), a gain of 2.18 mg or 63.4 percent. 
The disparity in storage capacity can be seen even more clearly by 
examining the colony as a whole. The colony labelled No. 1 in 
Figure 2 can be taken as typical; it contained 139 minors, 26 majors, 
and a single queen. Using the data on weight gain and percentage of 
repletism during a single experimental run, the following storage 
capacities were estimated: the entire minor population stored 88.52 
