DNA barcoding of fire ant species (genus Solenopsis) from Riyadh region, Kingdom of Saudi Arabia

Solenopsis is a largest ant genus under subfamily Myrmicine having almost 200 described species worldwide. They are widely distributed in tropics and warm temperate regions of the world and some are dreadful invasive species. We have already identified, using morphometric approach, and reported a fire ant species Solenopsis saudiensis from Riyadh, Saudi Arabia. In present study we use DNA barcoding to validate this technique to identify Solenopsis ants, and to clarify the population genetic structure of S. saudiensis across its distribution range in Riyadh, the central region of Saudi Arabia. The comparison of DNA barcodes shows no genetic diversity among 6 populations along with that of a queen in S. saudiensis analysed from Riyadh region. This genetic similarity of all populations reflects probably their adaptation to a unique habitat thus forming a single and strong gene pool.  Our extensive field survey provided no evidence of any fire ants species in Riyadh region except S. saudiensis that was only restricted in city area (Riyadh) suggesting strongly that this species is associated with irrigated date palm orchards in the central desert region of the country. Our findings of a single gene pool underline probably the significance of natural barriers/factors in impeding the dispersal and gene flow of S. saudiensis populations. Moreover, S. saudiensis has revealed 83-86% identity to other Solenopsis spp from other part of the world. Interestingly, the highest identity (86%) was shown with that of Solenopsis molesta, the thief ant, from USA. This study resulted in an appropriate lab protocol and a reference library beneficial to identify ants of the genus Solenopsis in Saudi Arabia.