GROWTH OF THE ORB WEAVER, 
ARANEUS DIADEM A TVS, AND 
CORRELATION WITH WEB MEASUREMENTS* 
By Jay Benforado and Kent H. Kistler 
Division of Research, North Carolina Department of Mental Health 
Raleigh, North Carolina 27611 
Introduction 
It is a well-known fact that within any population of spiders of 
similar age there is considerable variation in the size of individual 
spiders of the same species. In literature as early as 1890, McCook 
has observed this variation and repeated observations (Comstock, 
1940; Savory, 1928) have verified this phenomenon. Although ob- 
servations are frequent, explanations are few. Bristowe (1958) 
cites differences in feeding as a reason for differential size, but the 
reference is made merely in passing and to the authors’ knowledge 
is not elaborated upon elsewhere. This paucity of explanation lends 
itself to further analysis of the factors contributing to the phenom- 
enon of differential size. 
Our purpose in this paper is to isolate some of the factors which 
contribute to differential size in Araneus diadematus Clerck (for 
identification of species, see Levi, 1971), and to elaborate upon cer- 
tain of these factors as we are able. 
Corresponding with differential size, in an orb-weaver such as 
Araneus diadematus , differential growth is also manifested in chang- 
ing dimensions of the web. That large differences in dimensions 
exist betwen the individual webs of spiders is also a well-known 
fact. An attempt to clarify some of the factors influencing web 
changes is also made. 
Method 
environment: The spiders used were from two cocoons of Ara- 
neus diadematus , obtained from Canastota, New York, which hatched 
on April 26, 1972. From the time of hatching and throughout the 
experiment, the spiders were kept in a room which was lighted 16 
hours per day aand kept cool during the eight dark hours by an air 
conditioner. (See Witt, 1971). 
early rearing: At the time of hatching, the offspring from each 
* Manuscript received by the editor March 1 , 1973 
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