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Published on: July 11, 2025
Species delimitation and global biosecurity
Laura M Boykin1, Karen F Armstrong, Laura Kubatko
1Bio-Protection Research Centre, PO Box 84, Lincoln University, Lincoln 7647, New Zealand.
Evolutionary Bioinformatics Online
|January 24, 2012
Summary
A novel "tip to root" species delimitation approach enhances biosecurity by improving the identification of invasive insect pests like Bemisia tabaci and Lymantria dispar, offering more accurate species assignments for global trade and protection.
Area of Science:
- Ecology and Evolutionary Biology
- Genetics and Genomics
- Biosecurity and Invasive Species Management
Background:
- Accurate species delimitation is crucial for effective global biosecurity, influencing trade regulations and invasive species control measures.
- Invasive insect pests such as Bemisia tabaci (sweetpotato whitefly) and Lymantria dispar (Asian gypsy moth) present complex delimitation challenges due to extreme genetic variability or indistinct subspecies.
Purpose of the Study:
- To introduce and evaluate a novel "tip to root" approach for species delimitation.
- To compare the efficacy of various analytical methods, including DNA barcoding (COI), for rigorous species identification in biosecurity contexts.
- To assess the applicability of different statistical measures for defining species boundaries in genetically complex insect pests.
Main Methods:
- Utilized DNA barcode datasets (COI) from Bemisia tabaci and Lymantria dispar.
- Applied multiple analytical methods: Kimura two-parameter (K2P) distance, Rosenberg's reciprocal monophyly (P(AB)), Rodrigo's P(randomly distinct), genealogical sorting index (gsi), and General mixed Yule-coalescent (GMYC).
- Employed a "tip to root" framework for comparative analysis of species distinctiveness.
Main Results:
- The K2P distance method underestimated species distinctiveness compared to P(AB), P(randomly distinct), and gsi.
- Analysis revealed more distinct groups within B. tabaci than previously identified and less variation within L. dispar subspecies than expected.
- A consensus among P(AB), P(randomly distinct), and gsi provided higher statistical confidence for genetic boundary delineation.
Conclusions:
- The "tip to root" approach, combined with stringent analytical measures, offers more robust species delimitation for biosecurity.
- Further gene sampling is recommended to confirm new species hypotheses for B. tabaci and refine subspecies taxonomy for L. dispar.
- This methodology, facilitated by tools like Geneious plugins, supports defensible biosecurity decisions based on accurate species identification.
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