DNA-based Species Identification and Population Genetics of the Eastern Subterranean Termite, Reticulitermes flavipes, in the Southern Appalachian Mountains

Collins, Benjamin

This study investigates the distribution patterns of Reticulitermes flavipes, an important recycler of nutrients and well-known destroyer of man-made structures, in the Southern Appalachian Mountains. As a precursor to this work, it was first necessary to distinguish the target species from other co-occurring termite species. To combat this problem, a modified Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) assay that uses a 384-bp segment of the mitochondrial cytochrome oxidase subunit II (COII) gene was designed. To test the accuracy of this tool, predictions made from using this method were compared to predictions made by genetic sequencing. This modified PCR-RFLP test will make it easier to identify the species of Reiticulitermes found in the Southern Appalachian Mountains of the United States. Next, I used DNA sequences from portions of the COI and COII mitochondrial cytochrome oxidase subunit I (COI) and COII genes from 50 samples of R. flavipes obtained throughout the Southern Appalachian Mountains to examine the genetic diversity and phylogeographic history of this species. Because of the dependence of Reticulitermes on forests for sustenance and habitat, populations of R. flavipes probably retreated into sheltered refuges during the Last Glacial Maximum (~20,000 years ago) when the distribution of the trees they depended on contracted due to the cooler temperatures and limited precipitation. One hypothesis for the distribution of genetic diversity within species that are dependent on timberlines during glacial maxima is that the most southern areas served as a large refuge while northern areas lost their trees and consequently the invertebrates that depended on them. Areas that lost their invertebrates were later recolonized by a subset of invertebrates that survived in the large southern refuge. This idea was tested here by separating R. flavipes termite samples into groups based on geographic location and natural barriers to dispersal and looking at genetic diversity for each group. The results from these analyses were inconsistent with the hypotheses of a single southern refuge because the most northern portion of the Southern Appalachian Mountains was indicated to be more stable the central regions due to its high level of genetic diversity and genetic signatures from mismatch distribution analyses. Overall, this finding suggests alternative hypotheses warrant further investigation.

DNA-based Species Identification and Population Genetics of the Eastern Subterranean Termite, Reticulitermes flavipes, in the Southern Appalachian Mountains

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