Publication Date

Spring 4-10-2023

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Department

Biology

Committee Chair

Dr. C Neal McReynolds

Committee Member

Dr. Cord Eversole

Committee Member

Dr. Monica Mendez

Committee Member

Dr. Kenneth J Tobin

Abstract

Co-existence between Centruroides vittatus and Vaejovis waueri is influenced by environmental factors that shape their habitats. Differences in surface activity frequency between the two species suggest differential microhabitat use. The observed frequency of scorpions using microhabitats in the Martinez Ranch and La Union Ranch were not significantly different from the expected frequencies. Frequency of scorpions observed using microhabitats in La Union South was significantly different from the expected frequency (P<0.001). Microhabitat use of catclaw was lower than expected and higher than expected for other vegetation. Conditional comparisons of microhabitats were significantly different among habitats (P<0.001), size classes were significantly different among microhabitats (P<0.001), and size classes were significantly different among habitats (P<0.01). Microhabitat use by scorpions on the ground was higher among all habitats. Scorpion use of ground and grass were different among size classes. Size class I-II scorpions had a higher frequency than size class III. Scorpion density for C. vittatus was significantly different among habitats (P<0.0001) and scorpion density for V. waueri was significantly different among habitats (P<0.0001). Centruroides vittatus was significantly higher in the Martinez Ranch and in La Union South. Vaejovis waueri was significantly higher in La iv Union South. Associations between plant densities and scorpion size classes were tested. Plant densities had a significant association with C. vittatus size classes I and II in the Martinez Ranch. Association between plants had a significant correlation with C. vittatus size classes I and IV in La Union Ranch. Association between plants had a significant correlation with V. waueri’s total density. These associations may suggest plant densities may have a synergistic effect on scorpion densities. Soil type composition for the different habitats was hypothesized to influence scorpion densities. Maps for each site were created to show soil type compositions. Soil type findings suggest that La Union South had the soil types with the lowest soil strength. Vaejovis waueri was shown to have a higher density in La Union South where soils are sandier. Results indicate that co-existence between C. vittatus and V. waueri is possible because competition is low through minimal overlap in microhabitat use and intraguild predation avoidance.

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