Date of Degree

12-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Program

Biology

Advisor

David Starkey

Advisor

Ridhard Peigler

Abstract

Pill bugs (Armadillidium vulgare) were examined at 4 time points during 2015- 2016. The time points corresponded to summer, fall, winter, and spring. At each time point, 2 to 10 pill bugs were collected from each of three sites. All sites were located in San Antonio, Texas. The first site was in central San Antonio, but due to difficulties in collecting specimens the first site was only utilized at the first time point. The remaining localities, Bonilla Science Hall on the campus of the University of the Incarnate Word and a private residence in northwest San Antonio, were utilized for the remaining three time points. After collection, pill bugs were washed. The recovered supernatant was serially diluted and plated on nutrient agar plates and incubated overnight at 37o C. After incubation, colonies were scored for morphological characteristics and subjected to a variety of biochemical tests. The results of these analyses revealed 65 unique isolates, four of which could not be sequenced. The 16s rRNA gene was sequenced for each of these isolates in order to classify each to genus and species. Based upon DNA analysis, 61 isolates generated DNA data that were found to represent 15 described genera of bacteria. These 61 isolates were further identified to 30 unique species of which 16 were described species. The most common bacterial genus identified was Bacillus. At least one species of Bacillus was identified at time points and in all localities. Overall, the most common species identified was B. cereus. This species was found at all localities and at all time points. There was no other genera or species identified at more than two localities or time points—although several were found at two time points or sites. In general, other than B. cereus, there was no genus or species consistently found at a single site. These data suggest that there is a unique bacterial fauna at each site and each time point—which could be correlated to climatological conditions, such as temperature, humidity and/or rainfall. These data reveal that there are pathogens associated with pill bugs at each site and during each season. The highest incidence of pathogenic bacteria occurs during time points associated with summer and spring. These are times of the year when mammals, particularly humans, could be in contact with pill bugs and suggest that there is the potential for pathogens to be transferred from pill bugs to humans. Overall, this study suggests that there is a diverse bacterial fauna associated with pill bugs.

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