COMPARATIVE STUDIES OF DICTYNA AND MALLOS 
(ARANEAE, DICTYNIDAE): 
III. PREY AND PREDATORY BEHAVIOR 
By Robert R. Jackson* 
North Carolina Division of Mental Health Services 
Research Section, P. O. Box 7532 
Raleigh, N. C. 27611 
Introduction 
Although spiders are a major group of predaceous arthropods 
(see Turnbull, 1973), the types of prey consumed in their natural 
habitats are known for relatively few species. Some of the more 
noteworthy studies have employed daily monitoring of webs of 
araneids (Robinson and Robinson, 1970) and immunological tech- 
niques with lycosids (Greenstone, 1978); however, very little infor- 
mation is available for the dictynids. There is particular interest in 
the diet of dictynids because different species in this family live 
under a variety of types of social organization (Jackson, 1978). 
Discussions of the prime movers in the evolution of social phenom- 
ena frequently emphasize the type of prey taken by social predators 
(Wilson, 1975). An important factor for some species (e.g., army 
ants, canids, and killer whales) seems to be the ability of groups of 
individuals acting together to handle relatively large and dangerous 
prey. In order to evaluate the importance of this factor in the 
evolution of social phenomena in spiders, we need information 
concerning the diet and predatory behavior of species with differ- 
ing types of social organization. 
The species in this study belong to the closely related genera, 
M alios and Dictyna. These are small cribellate spiders (body length 
usually 5 mm or less). Observations of actual feeding and other 
behavior related to predation were made in the western United 
States of America in June and July, and in south-central Mexico 
in September. Additional observations were made in the labora- 
*Present address: Department of Zoology, University of Canterbury, Christchurch 
1, New Zealand. 
Manuscript received by the editor January 15, 1978. 
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