1979] Christenson, Wenzl & Legum — Nephila clavipes 145 
sion of normal communal webs, and maintaining group integrity 
during the communal phase prior to dispersal. We are currently 
examining the relationship of egg and spiderling numbers to the 
behavior and success of spiderlings after emergence from the egg 
sac. 
It has been suggested that individual egg weight might be reduced 
to produce more eggs, or vice versa (Kessler, 1973; Jackson, 1978). 
Individual female N. clavipes do not adopt such a strategy. Exami¬ 
nation of several clutches produced by our population indicate that 
these two parameters do not vary systematicaly with one another. 
The relationship between egg number and egg weight may be useful, 
however, when applied to differences between well defined popula¬ 
tions or closely related species. 
Nephila is primarily a tropical genus that has expanded into tem¬ 
perate climates, which we suspect results in seasonal variation in egg 
productivity and probably individual reproductive success. In the 
tropics less seasonal variation would be expected, since climate and 
prey availability are more stable, and since adults may mature, 
mate, and oviposit throughout the year. Individual tropical Nephila 
eggs may be relatively light, since after hatching the spiderlings 
probably remain in the egg sac for a shorter period, and require less 
yolk. If this were the case, tropical clutches might also contain more 
eggs than temperate clutches. We calculate from data presented by 
Robinson and Robinson (1976) that topical N. maculata eggs weigh 
about .49 mg, while we have shown that temperate N. clavipes eggs 
weigh about .89 mg. It also appears that tropical N. maculata 
clutches contain about six to eight times the number of eggs as those 
of temperate N. edulis (Austin and Anderson, 1978) and N. clavipes. 
The comparative study of N. clavipes under temperate and tropical 
conditions would contribute to our understanding of reproductive 
strategies as adaptations to ecological conditions. 
Acknowledgements 
The authors wish to thank Allison Shack, Robert Moore, Mike 
Sheltzer, and George Ehringer for their help in the field, and Ken¬ 
neth Goist for his comments on the manuscript. 
