1973] 
Raiwousse — A rcineus diadematus 
45 
building period the males were distinctly different from the females 
only during the last stage. The males lived shorter and grew less 
than the females. The last intermolt was distinct from the other 
stages: the males built more webs, ate more food, grew faster than 
during the other stages. 
Two different rates of development appeared among the males 
of each set, determining a fast and slow growing group. The fre- 
quency, the amount of food eaten, the rate of weight increase and 
the rate of maturation were higher for the fast growers than for the 
slow growers. As a consequence of the rapid growth, the life-span 
of the fast growing males was shorter and the maximum weight was 
lower (but not significantly) than for the slow growing males. 
Hunger and amount of food eaten determined the different growth 
rates and related maturation rates; a lower threshold is supposed 
for the fast growing males than for the slow growing males, and 
may be the consequence of a genetic difference. Maturation would 
be controlled by different patterns of behavior determined on a 
genetic level. 
The differential maturation, which occurs within animals of a set 
and between sets, results in a distribution of mature animals over 
various times of year. The relative quick maturation prevents the 
fast growing males from mating with a female of the same set, but 
limited inbreeding is possible between the slow growing males and 
the females of the same set. A potential high survival of the species 
is assured by the dispersion of the individuals of one set and the dis- 
persion of the sets over different seasons. 
ACKNOWLEDGEMENTS 
This work was carried out in the laboratories of the Division of 
Research, North Carolina Department of Mental Health and was 
supported by Grant Number GB-25274 from the National Science 
Foundation to Dr. Peter N. Witt. The author gratefully ack- 
nowledges the assistance of Dr. Witt during all stages, the assistance 
of Mrs. Mabel Scarboro for all technical and laboratory work, Mrs. 
Rubenia Daniels for her administrative assistance, and of Dr. John 
O. Rawlings with whom the statistical tests used were discussed. 
References cited 
Benforado, J. and Kistler, K. H. 
1973. Growth of the orb weaver, Araneus diadematus, and correlation 
with web measurements. Psyche, 80: 90-100. 
