Sympatric Sibling Species from Three Phenotypically Distinct Asteromyia (Diptera: Cecidomyiidae) Galls on the Same Host Plant Species

Morphological data show three phenotypically distinct gall morphs produced by what was previously thought to be a single gallmaker, Asteromyia carbonifera (Osten Sacken). Protein gel electrophoresis was used to determine if the variants were produced by a single polymorphic species or by distinct races or species of gallmakers. Electrophoretic data support the hypothesis that the three gall morphs are produced by three different species of gallmakers. Near-fixation of alternate alleles in larvae from different gall morphs suggests very limited gene flow among the three sympatric populations. Models of sympatric and allopatric speciation are considered.