Population Genetics Of Phanaeus vindex And P. difformis And Congruence With Morphology Across A Geographic Zone Of Species Overlap

Abstract

Amplified Fragment Length Polymorphisms (AFLPs) reveal that the rainbow scarabs Phanaeus vindex (MacLeay) and Phanaeus difformis (LeConte) are distinct evolutionary units which occur in sympatry at the Fort Worth Nature Center. The genetic structure at this location is distinctly bimodal with strong segregation of taxa based on soil type. In addition, certain allele frequencies within P. vindex locations exhibited a significant correlation with a precipitation gradient and other allele frequencies within P. vindex locations were significantly different on loam soil than on both sand and clay soils. Phanaeus vindex and P. difformis exhibit continuous morphological character states between two extremes, with character states of one species periodically occurring in the other species, particularly within the zone of geographic overlap. A very high degree of congruence between principal component 1 of morphological variance and principal component 2 of molecular variance was obtained using a taxonomic congruence approach. Presence/absence of mid-longitudinal costae on elytral interstriae was 99% accurate in predicting an individual's genotype within my data set.