MACROHABITAT SELECTION BY THE 
ORB WEAVING SPIDER, MICRATHENA GRACILIS. 
By Margaret A. Hodge* 
Department of Entomology, University of Georgia, 
Athens, Georgia 30602 
Introduction 
Animals often do not occupy all potential habitats even when 
they are capable of dispersing into unoccupied areas. This may 
reflect a “choice” by individuals not to live in certain habitats. In 
theory, habitat selection behaviors may evolve when large differ- 
ences between habitats result in differential survival and reproduc- 
tion rates. If an animal cannot survive and reproduce everywhere, 
natural selection will favor recognition of suitable habitats (Levins 
1968; Krebs 1985). 
The mobility and activity patterns of many animals make them 
difficult subjects for studies of habitat selection. Web building spi- 
ders, however, are an exception. Web conspicuousness and the rela- 
tive ease of marking and following individuals makes them ideal 
subjects for studying the behavioral mechanisms involved in habitat 
choice. Micrathena gracilis (Walckenaer) (Araneae: Araneidae), an 
orb weaving spider, characteristically builds webs which span wide 
spaces in shady deciduous forests, and rarely occur in adjacent suc- 
cessional areas (Elliot 1930; Uetz et al., 1978; Biere & Uetz 1981; 
Hartsock 1983; Hodge 1985). In this study, release experiments were 
conducted to determine whether M. gracilis actively selects decidu- 
ous forests, and if so, what environmental variables influence this 
choice. 
Methods and Materials 
Study organism 
Members of the Neotropical genus Micrathena are mostly diur- 
nal, forest dwelling, orb weaving spiders. Although most species are 
♦Present address: Department of Biological Sciences, University of Cincinnati, Cin- 
cinnati, Ohio 45221 
Manuscript received by the editor July 24, 1987. Publication delayed on request of 
author. 
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