Multiplexed lateral flow immunoassay to discriminate Solenopsis invicta from Solenopsis richteri and their hybrids

Authors: Valles, Steven; Strong, Charles; CALLCOTT, ANNE-MARIE - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2018
Publication Date: 6/23/2018
Citation: Valles, S.M., Strong, C.A., Callcott, A.A. 2018. Multiplexed lateral flow immunoassay to discriminate Solenopsis invicta from Solenopsis richteri and their hybrids. Scientific Reports. 65:493-501. https://doi.org/10.1007/s00040-018-0637-4.
DOI: https://doi.org/10.1007/s00040-018-0637-4

Interpretive Summary: The red and black imported fire ants were introduced into the United States in the 1930s and currently infest about 300 million acres. Together, they cause approximately $6 billion in damage annually in livestock and agricultural production and pose a serious threat to human health. USDA-APHIS has imposed a quarantine to help limit the spread of these invasive fire ants in the United States. Unfortunately, there remains an acute need for a rapid, field portable method for the identification of these ants to limit their spread. USDA-ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and USDA-APHIS (Biloxi, MS) have developed novel monoclonal antibodies that specifically bind a protein of the fire ant venom. Using these antibodies, they developed a lateral flow immunoassay that provides a rapid and portable method for the identification and discrimination of red, black, and hybrid imported fire ant species. This device provides a new tool for regulatory agencies in the United States to enforce quarantine protocols and limit the spread of these invasive ants.

Technical Abstract: Solenopsis invicta and S. richteri are aggressive, highly invasive pest ant species from South America that were introduced into North America in the early part of the 20th century. Biosecurity efforts in the United States included the establishment of a quarantine to minimize the human-assisted spread of these ants. A limitation of the quarantine was rapid identification/discrimination of these ants when found entering non-quarantined areas. We describe four novel monoclonal antibodies that specifically bind the Solenopsis venom protein 2 unique to, and produced by, S. invicta and S. richteri. Using these monoclonal antibodies we developed a lateral flow immunoassay that provides a rapid and portable method for the identification and discrimination of S. invicta, S. richteri, and the S. invicta x richteri hybrid. The lateral flow immunoassay was validated against 26 unique ant species and only S. invicta S. richteri, and the S. invicta x richteri hybrid produced a positive result. The LFA did not detect proteins from the congener S. geminata known to produce a Solenopsis invicta venom protein 2 orthologue. The invasive fire ant lateral flow immunoassay provides a new tool for regulatory agencies in the United States to enforce quarantine protocols and limit the spread of these invasive ants.