AGGREGATIONS OF MALLOS AND DICTYNA 
(ARANEAE, DICTYNIDAE): 
POPULATION CHARACTERISTICS 
By Robert R. Jackson 1 and Sandra E. Smith 
North Carolina Division of Mental Health Services 
Research Section 
P.O. Box 7532 
Raleigh, North Carolina 27611 
Introduction 
Generally web spiders are solitary animals. Usually only a single 
spider occupies a single web, with the relatively common exception 
of webs jointly occupied by a male-female pair or females with their 
young. In most species, occupied webs are usually not connected to 
other occupied webs by silk lines. However, aggregations of various 
types and degrees occur in some species (reviewed by Buskirk, 1975; 
Krafft, 1970; and Shear, 1970). These include cases in which 
occupied webs are in close proximity (sometimes touching), but 
occupied by single spiders, as well as cases in which single webs are 
occupied by groups of spiders of all sex/age classes. The species 
involved are sometimes referred to as “social spiders” (e.g., Burgess, 
1978; Kullmann, 1972). At present relatively little is known about 
the social adaptations of these spiders. Some of the first things we 
would like to know about animals that occur in aggregations are the 
size, composition and spacing characteristics of naturally occurring 
groups. Data concerning these basic social characteristics will be 
presented in this paper for several species of dictynid spiders. 
The Dictynidae are a group of web-building cribellate spiders, 
most of which have body lengths less than 5 mm. In the closely 
related genera Mallos and Dictyna, there are species with different 
types of social organization. Most are solitary; at least three are 
communal, territorial; and at least one is communal, non-territorial. 
Each individual web of a solitary species consists of a mesh in which 
prey is captured and a nest within the mesh. Communal, territorial 
Present address: 
Department of Zoology, University of Canterbury, Christchurch 1, New Zealand. 
Manuscript received by the editor June 10, 1978. 
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