Establishment and spread of a single parthenogenic genotype of the Mediterranean arundo wasp, Tetramesa romana in the variable climate of Texas

Authors: Goolsby, John; Gaskin, John; TARIN, DANIEL - Texas A&M University; PEPPER, ALAN - Texas A&M University; HENNE, DON - Texas A&M Agrilife; AUCLAIR, ALLAN - Animal And Plant Health Inspection Service (APHIS); RACELIS, ALEX - The University Of Texas-Pan American; SUMMY, KENNETH - The University Of Texas-Pan American; Moran, Patrick; Thomas, Donald; Yang, Chenghai; JIMENEZ, MARICELA - Instituto Mexicano De Tecnologia Del Aguas; CIOMPWELIK, MATTHEW - Animal And Plant Health Inspection Service (APHIS); Perez De Leon, Adalberto - Beto; KIRK, ALAN - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2014
Publication Date: 12/1/2014
Publication URL: https://handle.nal.usda.gov/10113/62154
Citation: Goolsby, J., Gaskin, J.F., Tarin, D.V., Pepper, A., Henne, D.C., Auclair, A., Racelis, A.E., Summy, K.R., Moran, P.J., Thomas, D.B., Yang, C., Jimenez, M., Ciompwelik, M.J., Perez De Leon, A.A., Kirk, A.A. 2014. Establishment and spread of a single parthenogenic genotype of the Mediterranean arundo wasp, Tetramesa romana in the variable climate of Texas. Southwestern Entomologist. 39(4):675-690.

Interpretive Summary: In Texas, especially along the Rio Grande, large infestations of giant reed are causing serious ecological impacts by displacing native vegetation, facilitating the invasion of cattle fever ticks from Mexico, interfering with law enforcement activities along the international border, and competing for scarce water resources in an arid region already experiencing an extended drought and potential changes in rainfall patterns due to climate change. Currently, A. donax is managed in limited areas by costly mechanical and chemical means. Classical biological control may be the most cost-effective and sustainable option for management of this weed over large areas such as the Rio Grande and Nueces River Basins in Texas. A biological control program is in progress for giant reed. Several unique populations of the plant feeding wasp, Tetramesa romana from Spain and France were released along the Rio Grande from Brownsville to Del Rio, TX. A population of the wasp of unknown origin with limited distribution in TX was also discovered, evaluated, and released as part of the program. More than 1.2 million wasps representing the mix of genotypes were aerially released from 2009 to 2011. Wasp populations migrated from their original release locations and now have a continuous distribution along the Rio Grande from Brownsville to Del Rio; and have dispersed throughout most of Central Texas. Individuals of most successful population comes from the Mediterranean coast of Spain. Population levels of T. romana on the Rio Grande from Laredo to Del Rio averaged 190% higher in 2013-14 compared to a similar study conducted in 2008-09 before release of the European populations. A favorability index was developed which showed that conditions from 1969 to 1977 would have been adverse to the wasp; with conditions after 2009 more favorable. Climate matching predicts the wasp will disperse throughout the southern U.S. and Mexico.

Technical Abstract: As part of a biological control program for the invasive weed, Arundo donax, several genotypically unique populations of the parthenogenetic stem-galling wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae), from Spain and France were released in the infested riparian zone along the Rio Grande from Brownsville to Del Rio, TX. An adventive population of the wasp of unknown origin with limited distribution in TX was also discovered, evaluated, and released as part of the program. More than 1.2 million wasps representing the mix of genotypes were aerially released from 2009 to 2011. Wasp populations dispersed from their original release locations and now have a continuous distribution along the Rio Grande from Brownsville to Del Rio; and have dispersed throughout most of Central Texas with satellite populations as far west as San Angelo (Tom Green Co.), north as far as Kaufman (Kaufman Co.) and east to Navasota (Brazos Co.). Individuals of most successful genotype represented 390 of the 409 wasps recovered and match both an imported population from the Mediterranean coast of Spain and an adventive population. Several genotypes released in the program apparently failed to establish. This result demonstrates the benefits of evaluating and releasing the maximum genetic diversity of the biological control agent in the introduced range. Population levels of T. romana on the Rio Grande from Laredo to Del Rio averaged 190% higher in 2013-14 compared to a similar study conducted in 2008-09 before release of the European populations. A favorability index was developed which showed that conditions from 1969 to 1977 would have been adverse to the wasp; with conditions after 2009 more favorable. Climate matching predicts the wasp will disperse throughout the southern U.S. and Mexico.