title: Host shift to an invasive plant triggers rapid animal hybrid speciation.
abstract: Speciation in animals is almost always envisioned as the split of an existing lineage into an ancestral and a derived species. An alternative speciation route is homoploid hybrid speciation in which two ancestral taxa give rise to a third, derived, species by hybridization without a change in chromosome number. Although theoretically possible it has been regarded as rare and hence of little importance in animals. On the basis of molecular and chromosomal evidence, hybridization is the best explanation for the origin of a handful of extant diploid bisexual animal taxa. Here we report the first case in which hybridization between two host-specific animals (tephritid fruitflies) is clearly associated with the shift to a new resource. Such a hybrid host shift presents an ecologically robust scenario for animal hybrid speciation because it offers a potential mechanism for reproductive isolation through differential adaptation to a new ecological niche. The necessary conditions for this mechanism of speciation are common in parasitic animals, which represent much of animal diversity. The frequency of homoploid hybrid speciation in animals may therefore be higher than previously assumed.
authors.affiliation: Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, Pennsylvania 16803, USA. dxs332@psu.edu
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schwarz
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Matta
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Shakir-Botteri
authors.forename: Bruce A
authors.initials: BA
authors.lastname: McPheron
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000483:Alleles; D000818:Animals; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D004175:Diptera / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D005260:Female; D005787:Gene Frequency; D006824:Hybridization, Genetic / Q000235:genetics*; D008297:Male; D010944:Plants / Q000469:parasitology*; D013045:Species Specificity; D013997:Time Factors
chemical_list: D004272:DNA, Mitochondrial