Canadian Journal of Arthropod Identification
 
 

Identification of Delia pest species (Diptera: Anthomyiidae) in cultivated crucifers and other vegetable crops in Canada

CJAI 29 -- June 29, 2016
doi:10.3752/cjai.2016.29

Jade Savage, Anne-Marie Fortier, François Fournier, Véronique Bellavance


| Abstract | Introduction | DNA Barcoding | Larval Host Associations | Checklist | Keys to Delia pests | Acknowledgments | References | PDF | Cite |
 
 

 

DNA Barcoding

DNA barcodes (Folmer region of COI gene) were sequenced for multiple adult specimens of all species except D. planipalpis (lack of recently collected material) as well as for the eggs and larvae (1st and 3rd instars) of most other species included in this work. A neighbor joining tree including a subset of high quality sequences from various life stages is presented in Fig. 1. Images, collection details and individual COI sequences for a subset of barcoded specimens can be retrieved from the Barcode of Life Data System (BOLD) (www.barcodinglife.org) in the public dataset: Delia pests of Canada (dx.doi.org/10.5883/DS-DPOC). All vouchers were deposited in the BUIC.

The DNA barcodes for D. radicum, D. floralis, D. antiqua and D. florilega all clustered in single, well-defined Barcode Index Numbers (BIN, Ratnasingham and Hebert 2013) (Fig. 1). Delia platura sequences, however, formed two distinct BINs (AAA3453 and AAG2511) separated by a minimum distance of 4.45% (Fig. 1). More than 100 adults (both sexes) and 50 third instar larvae from each of these two D. platura BINs were examined but no morphological differences was found. There is, however, a distinctive pattern in the geographical distributions of these BINs based on thousands of records found in the Barcode of Life Data System (BOLD, Ratnasingham and Hebert 2007): AAA3453 is almost entirely restricted to the New World (transcontinental distribution in Canada and the United States, Costa Rica) with a single record from South Africa whereas AAG2511 is found throughout Europe, Asia, Greenland, eastern Canada (NB, NS, NL, ON, PEI, QC), with a single record from Alaska. Delia platura is found on all continents except Antarctica (Griffiths 1993) and little is known of the origins of the North American fauna. The global distribution pattern reported here for the two BINs suggests, however, that the New World fauna includes at least two distinct populations, one possibly native (AAA3453) and one introduced (AAG2511). The phylogeography of these two groups of D. platura will be further investigated in a separate project as it will require additional data beyond the scope of the present work.

 

Fig. 1. Neighbor-joining tree based on Kimura 2-parameter distances (K2P, Kimura 1980) for representative sequences from each species. Each line includes species name, BOLD sample ID, read length, number of ambiguities and Barcode Index Number.