The dead can talk: museum specimens show the origins of a cryptic species used in biological control.

摘要

The parasitoid wasp species Cales noacki Howard (Aphelinidae) is an important biological control agent against woolly whitefly, Aleurothrixus floccosus (Aleyrodidae), in citrus-growing regions worldwide. We recently discovered two cryptic species of Cales on citrus in California: C. noacki and Cales rosei Mottern. Examination of historical biological control records is combined with a geometric morphometric analysis of fore wing shape to reconstruct aspects of the biological control history of Cales. Our analyses indicate that C. rosei is most likely descended from populations introduced from Argentina in the mid 1970s, with newly collected specimens from California clustering with Argentinian slide-mounted specimens from the original importation. Our analyses support a Chilean origin of C. noacki. Morphometrics confirms the earlier synonymy of Diaspidophilus pallidus Brethes with C. noacki. A potential third species was imported from Brazil and Tucuman, Argentina, although it does not appear to have established in the field. The implications of these results for future studies on the bionomics of Cales and also the utility of geometric morphometric analyses for species identification and description are discussed.