DNA Barcoding studies on Thrips in India: Cryptic species and Species complexes

Area of Science:

• Entomology
• Molecular Biology
• Agricultural Science

Background:

• Thrips are significant agricultural pests and plant virus vectors, causing substantial economic losses.
• Accurate thrips identification is vital for effective pest management, but morphology-based methods have limitations.
• Molecular data integration, specifically DNA barcoding, is essential for robust thrips identification.

Purpose of the Study:

• To conduct the largest DNA barcoding initiative on thrips, aiming to improve species identification and uncover cryptic diversity.
• To compare multiple species delimitation methods for their consistency with morphological identification.
• To establish a molecular operational taxonomic unit (MOTU) framework for thrips identification.

Main Methods:

• DNA barcoding of 370 sequences from 89 thrips morphospecies, including 104 novel sequences.
• Application of multiple species delimitation algorithms: BIN, ABGD, GMYC, and bPTP.
• Superimposition of results from multiple methods and application of a three-level nomenclature system.

Main Results:

• Consistent species delimitation between molecular methods and morphology for 82% of species.
• Recovery of 107 molecular operational taxonomic units (MOTUs) for 89 morphospecies.
• Detection of cryptic diversity in 14 morphospecies, including key virus vectors like *Frankliniella schultzei* and *Thrips palmi*.
• Identification of four morphospecies with low genetic divergence requiring further investigation.

Conclusions:

• DNA barcoding, combined with multiple delimitation methods, effectively identifies thrips species and reveals cryptic diversity.
• This molecular approach provides a robust framework for taxonomic judgment and pest management strategies.
• Further research with broader sampling and multiple markers is recommended for species with ambiguous genetic divergence.