Date of Award:

5-1978

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Committee Chair(s)

James A. MacMahon

Committee

James A. MacMahon

Committee

Loyd W. Bennett

Committee

B. K. Gilbert

Committee

Ronald V. Canfield

Committee

Ivan G. Palmbald

Abstract

Spider community acceptance of, and segregation by, architectural configuration was investigated for the spiders of Green Canyon in northern Utah. Modular habitat units consisting of 30.48 centimeter (1 foot) cubes of chicken wire supporting internal strands of macrame jute tied in different orthogonal configurations were used. Configurations including all three axes were tested at two strand densities.

The primary null hypothesis tested, that spider species use structures independent of architecture, was rejected in favor of the alternate hypothesis that spider species differentially use structures dependent upon architecture. Of the eight most abundant species, two showed preferences for horizontal substrata and one chose vertical substrata. All spiders strongly responded to the amount of jute available in each module. The two most abundant jumping spiders were biased toward modules with widely spaced jute, while the two most abundant web-builders preferred closely spaced jute.

Of the eight most abundant species, two species fell within each of the following four hunting guilds: jumpers, ambushers, pursuers, and web-builders. Within each pair of species, juveniles of the larger species emerged earlier in each of the two field seasons studied. In three of the species pairs, the body lengths were sufficiently different to fulfill theoretical requirements for their coexistence based upon differential prey size use. The remaining species pair, ambushers, had sufficiently different cryptic coloration and abundance patterns to suggest that their coexistence was determined by a combination of microhabitat and seasonal separation.

Checksum

6ca07341f159d5beac6b06b352584dfa

Included in

Biology Commons

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