Comparative Body Size and Shape Analyses of F1 HybridRhagoletis pomonellaandRhagoletis zephyria(Diptera: Tephritidae)

Abstract

AbstractHybridization between apple maggot, Rhagoletis pomonella (Walsh), and Rhagoletis zephyria Snow (Diptera: Tephritidae) occurs in Washington State, complicating fly identifications. Here, experimentally generated F1 hybrids of R. pomonella and R. zephyria were classified using morphometric methods. Five of nine mean body size measurements of hybrids from crossing female R. pomonella × male R. zephyria were intermediate between those of nonhybrids. Aculeus lengths of hybrid females were intermediate or were more similar to those of R. pomonella than R. zephyria. Based on six or seven body size measures, 25.0% of female and 44.4% of male hybrids were correctly classified. Misclassified female and male hybrids resembled R. pomonella and one or the other parental species, respectively. Mean wing shapes of hybrid females based on landmark measurements were novel, whereas those of males were intermediate between those of nonhybrids. Based on wing shapes + natural log (In) centroid size, 90.9% of female and 66.7% of male hybrids were correctly classified. Hybrid females were misclassified as R. pomonella and more hybrid males as R. zephyria. Based on surstylus shape, 27.7% of male hybrids were correctly classified, with more being misclassified as R. pomonella. Results show wing shape + In centroid size is the most useful measure for identifying female and male hybrids and that R. pomonella traits for aculeus length and/or wing shape appear dominant to those of R. zephyria in hybrid females.