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Systematic Studies of the Parasitoid Wasp Genus Cales (Chalcidoidea: Aphelinidae): Combined Molecular and Morphological Approaches to Classification and Evolution


Calesinae is a small group of chalcidoid wasps that, for species with known host associations, are parasitoids of whiteflies (Hemiptera: Aleyrodidae). Prior to this study, Cales diversity included one species in the Neotropical region (Cales noacki, introduced from South America into citrus growing regions of North America, the Mediterranean and tropical Africa for biological control of woolly whitefly), and two species from Australia (Cales spenceri and Cales orchamoplati). The morphological study emphasizes the likely plesiomorphic Australian species, and includes a description of a new species from New Zealand reared from the whitefly Asterochiton pittospori. Cales shares many characteristics with Aphelinidae, though additional studies of character systems across Chalcidoidea are needed to determine the likely sister taxon.

Studies of the Neotropical Cales fauna reveal far greater diversity than previously thought. Twenty-one new species are described, and a neotype is designated for C. noacki, which is redescribed based on specimens molecularly determined to be conspecific with the neotype. The Neotropical Cales fauna is very morphologically conserved, so species cannot always be determined based on morphology alone. Therefore, species boundaries are established using combined evidence from morphology, biogeography, 28S-D2-5 rDNA and a 390bp fragment of the cytochrome oxidase c subunit I (COI) gene. A molecular phylogeny and separate identification keys to male and female species are provided.

The molecular phylogenetic studies of Cales revealed that two molecularly distinct but morphologically cryptic species were introduced into California for control of woolly whitefly in citrus. The most common of the two was determined to be C. noacki, which molecularly matched specimens from Chile, and the second was newly described as Cales rosei, which did not molecularly match any of the specimens collected from Central or South American. We employ multivariate analyses of fore wing shape combined with biological control importation and release records to infer the likely source locality for C. rosei. The analyses support a Chilean origin of C. noacki. In addition, the wing shapes of molecularly-determined C. rosei specimens most closely matched biological control specimens collected near Buenos Aires, Argentina, indicating that this is the likely source locality for this species.

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