Controlling Invasive Ant Species in Okinawa

Invasive ant species are a serious concern in Okinawa, with potential negative impacts for both the environment and the economy. The Environmental Science Section (ESS) and the Biodiversity and Biocomplexity Unit at OIST have developed several partnership projects to raise awareness of the problem and implement practical solutions.  

The ESS itself was established in 2019 as an independent function of the OKEON Churamori Project. The section aims to maintain and promote OIST's Okinawa terrestrial field research and community network in a more sustainable and stable manner by leveraging local relationships, environmental monitoring networks, and experienced support teams to achieve united goals. 

Invasive Species Surveys 

ESS performs regular surveys to monitor invasive species in Okinawa. For example, they are conducting an alien ant monitoring survey in major port areas across the prefecture. Using a method called modified time-united sampling, they are also studying the dynamics of regional ant species. In addition, they are using camera traps to assess the status and function of fauna on the main island of Okinawa, including rare and alien species. These activities are part of the OKEON Churamori Project. 

Fire Ant Identification Training  

ESS has developed a fire ant identification training course for government officials and port/logistics operators who are involved in fire ant control in Okinawa Prefecture. The objective is for participants to acquire identification skills so they can take part in primary screening in case of a suspected fire ant invasion. ESS also runs fire ant identification workshops for the general public, including talks and ant identification demonstrations to raise awareness about invasive species control. 

Masashi Yoshimura from ESS gave a fire ant identification seminar hosted by the Ministry of the Environment in Miyakojima. He has also presented at workshops hosted by the Naha Port Authority.

Okinawa Prefectural Government Invasive Species Countermeasure Committee  

OIST is a participating member of Okinawa Prefecture’s cross-organizational Invasive Species Countermeasure Committee. The group meets several times a year to select designated target species and to create countermeasure guidelines. 

Okinawa Prefectural Government Invasive Species Countermeasure Committee (March 2020).

Invasive Ant Countermeasure Project 

ESS is leading a cross-organizational project to control invasive ant species, in collaboration with Ryukyu University, Naha City, and the Ministry of the Environment. The project is targeting a specific invasive ant called Lepisiota frauenfeldi. 

Joint Research Agreement with National Taiwan University 

ESS is working together with National Taiwan University and the Taiwan National RIFA Control Center to develop fire ant countermeasure technologies as part of a joint research agreement. The project aims to strengthen invasive ant control strategies and to foster research cooperation between Taiwan and Okinawa.  

Project Publications 

• Yoshimura, M., Suwabe, M., Ikeda, T., Ogasawara, M., Economo, E.P.. (2020) Development and Implementation of a workshop on alien species and Red Imported Fire Ants (RIFA) for elementary school students. Japanese Journal of Science Communication 26: 39-56. 
• Aoyama Y., Yoshimura M., Ogasawara M., Suwabe M., Economo E. P. (2020) Potential Economic Impact on Invasion of the Red Imported Fire Ant in Okinawa, Japan. Japanese Journal of Ecology, 70: 3-14. 
• Yoshimura M. (2020) Taxonomy of Alien Ants. Pp. 34-50. In: Hashimoto Y. (Ed) Alien Ants. Asakura-shobo, Tokyo.  
• Hashimoto Y., Yoshimura M. & Huang Rn. (2019) Wasabi Versus Red Imported Fire Ants: Preliminary Test of Repellency of Microencapsulated Allyl Isothiocyanate Against Solenopsis invicta (Hymenoptera: Formicidae) Using Bait Traps in Taiwan. Applied Entomology and Zoology, 54: 193-196. 
• Yoshimura M., Yoshida T., Ogasawara M. & Economo E. P. (2016) Ant Research Program for High School Students Using the Time-unit Sampling Method. Research bulletin of Environmental Education Center, Miyagi University of Education, 18: 43-47.  
• Yoshimura M., Ogasawara K., Suwabe M., Taga A., Naka M., Ogasawara M., Takahara Y. & Tamashiro Y. (in press) The First Record of the Argentine Ant Linepithema humile in Okinawa (Hymenoptera: Formicidae: Dolichoderinae). The Biological Magazine Okinawa.