1 1 6 
Psyche 
[March-June 
Table 2. — The effect of diet on the reproductive maturation of lab-reared 
females of Chrysopa carnea. 
Diet* 
Mean Ovariole 
Diameter 
Mean Number of 
Yolky Oocytes 
per Female 
Mean Number of 
Mature Eggs 
per Female 
Pollen Only 
0.21 ± 0.03mm" 
4.6 ± 1.08 
0.2 ± 0.20 
Sucrose Only 
0.14 ± 0.01mm 
0.7 ± 0.47 
0.0 ± 0.00 
Sucrose + Pollen 
0.41 ± 0.00 mm 
28.0 ± 2.42 
12.2 ± 1.67 
Wheast® 
0.41 ± 0.00 mm 
26.5 ± 2.14 
12.4 ± 1.5 
* N =: 10 females per dietary group 
b The ovariole diameter in a teneral or diapausing female is approximately 
0.07 mm; in a field-collected, reproductively active female it is about 
0.41 mm. The standard error of the mean is given for each group. 
achieved when pollen (of an unstated species) was supplemented 
with honey. We found a similar marked increase in the reproduc- 
tive potential of females in the present study when our experimental 
diet of corn pollen was supplemented with sucrose (Table 2). In 
this case, however, the carbohydrate inadequacy of corn pollen was 
unexpected since hand-collected samples of this pollen have been 
shown to have the exceptionally high value of 36.59% carbohydrate 
(Todd and Bretherick, 1942). This large proportion of carbo- 
hydrate is due primarily to a high content of starch, 22.4% (as 
opposed to 2-3% found in other hand-collected pollens), and the 
proportions of reducing and non-reducing sugars, 7.31% and 6.88% 
respectively, are much lower and closer to the means of other hand- 
collected pollens. The results of a separate study on the utilization 
of dietary starch by adult chrysopids, which we initiated after the 
surprising results from the corn pollen experiments were obtained 
and which will be published elsewhere, show that in C. carnea a 
large proportion of the starch incorporated into experimental diets 
remains in an unaltered form in the feces. These findings suggest 
that the large quantity of starch present in corn pollen is nutritionally 
unavailable to C. carnea and that the lower concentrations of sugars 
which are present provide an insufficient carbohydrate source for 
maximal egg production. 
The importance of pollen in the natural diet of C. carnea can be 
