142 
Beth B. Norden and Aubrey G. Scarbrough 
Fig. 1. Study site, March 1977. 
benches as well as in open walkways. As pointed out by Osgood (1972), 
sites with well drained soil, good surface flow, and sparse plant cover are 
most often selected for nest construction by solitary bees. The sandy soil 
of the amphitheater provided these characteristics, while the hammock 
floor was densely matted with plant debris. The loose leaf litter covering 
the amphitheater floor presented no obstacle for bees to crawl beneath. 
Davis and LaBerge (1975) suggested that loose debris protects nests 
against beating rain and parasites, and may aid Andrena in nest recogni- 
tion. 
The amphitheater soil is classified as Sunniland-Bradenton which con- 
sists of fine sand down to marl hardpan. It is moderately wet and has a 
pH of 5. 0-6. 5. The sand is dark gray and contains fine carbon particles 
from fires of previous years. The soil is permeated by a complex network 
of roots at a depth of 2 to 5 cm below the surface. These roots, originating 
from hammock trees, hindered excavation. 
Nest Construction . — The density of nests was determined by counting the 
number of nest openings within a 15 cm wire frame, placed at 1 m inter- 
vals along a line transect diagonally crossing the amphitheater. An 
average of 11 nests per 15 cm area (N = 30) was found, and the nests 
