Date of Graduation

8-2018

Document Type

Thesis

Degree Name

Master of Science in Entomology (MS)

Degree Level

Graduate

Department

Entomology

Advisor/Mentor

Szalanski, Allen L.

Committee Member

Lee, Jacquelyn A.

Second Committee Member

Joshi, Neelendra K.

Keywords

Bee; Entomology; Genetics; Honey; Molecular; Parasite

Abstract

Honey bee populations have been fluctuating within recent years. No one cause has been attributed to colony fluctuations due to the theory that multiple stressors interact with one another to impact colony health. Consequently, microorganisms such as internal parasites of honey bees have been understudied as a contributor to colony health decline.

Molecular diagnostics were utilized to detect the presence of two honey bee trypanosome parasites, Crithidia mellificae and Lotmaria passim, in managed and feral honey bee populations from eight states in the United States (USA). Because studies on trypanosome infections are lacking in the USA, it is important to know how frequently honey bee colonies are infected and if management techniques are impacting colony susceptibility to trypanosome infections.

This is the first national survey for honey bee trypanosomes in the USA. This study confirmed that L. passim is present in the USA, but C. mellificae was not observed from the sampled colonies. From the 1,360 honey bee colonies that were screened, 11% were infected with L. passim. New York samples had the highest infection rate and Utah samples had the lowest. One state from the survey (Mississippi) did not have any samples positive for L. passim. The proportion of samples positive for L. passim was significantly different between managed and feral honey bee colonies. Results from this study revealed that L. passim has a widespread distribution in the USA and should be monitored as a contributor to honey bee health decline.

Subsequent analyses were performed on the data set to understand trypanosome infections between two honey bee subspecies, co-infection with a fungal pathogen, seasonality in the USA, and if queen breeding facilities are distributing trypanosomes in the USA.

This research demonstrates the importance of learning more about internal parasites because it is unknown to what extent internal parasites impact honey bee health. Therefore, it is imperative to understand how internal parasites impact honey bees. Further research should be conducted to observe how trypanosomes are spread in the environment and what type of preventative measures should be taken to ensure colonies remain healthy.

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