Molecular comparison of cattle fever ticks from native and introduced ranges with insights into optimal search areas for classical biological control agents

Authors: Goolsby, John; Guerrero, Felicito; Gaskin, John; Bendele, Kylie; AZHAHIANAMBI, P - Former ARS Employee; AMALIN, D - De La Salle University; FLORES-CRUZ, M - De La Salle University; KASHEFI, J - European Biological Control Laboratory (EBCL); SMITH, L - European Biological Control Laboratory (EBCL); SAINI, R - African Insect Science For Food And Health (ICIPE); RACELIS, A - University Of Texas Rio Grande Valley; Perez De Leon, Adalberto - Beto

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2016
Publication Date: 9/1/2016
Citation: Goolsby, J., Guerrero, F., Gaskin, J.F., Bendele, K.G., Azhahianambi, P., Amalin, D., Flores-Cruz, M., Kashefi, J., Smith, L., Saini, R.K., Racelis, A., Perez De Leon, A.A. 2016. Molecular comparison of cattle fever ticks from native and introduced ranges with insights into optimal search areas for classical biological control agents. Southwestern Entomologist. 41(3):595-604.

Interpretive Summary: Cattle fever ticks (CFT), Rhipicephalus (=Boophilus) microplus and Rhipicephalus annulatus, are invasive livestock pests that are endemic to Mexico and cause outbreaks in the U.S. along the south Texas – Mexico border. Acaricide resistance, alternate wildlife hosts, and pathogenic landscape forming weeds present challenges for sustainable eradication of this pest in the U.S. Classical biological control of CFT is being explored as a strategy to control this pest, especially with regards to infestations in alternate hosts such as nilgai antelope and white-tailed deer. Molecular genetic tools were used to compare populations of CFT from the native and introduced ranges to provide insights into optimal search areas for potential biological control agents. Accessions representative of invasive populations of R. microplus from subtropical Zapata, Texas, USA and other parts of the invaded range, including Brazil and Kenya, matched most closely with populations in The Philippines and Cambodia. Similarly, accessions of R. annulatus from invaded range in Del Rio, TX matched closely with accessions from the native range in Bulgaria and Romania. These regions should be prioritized for field exploration for biological control agents.

Technical Abstract: Classical biological control using specialist parasitoids, predators and/or nematodes from the native ranges of cattle fever ticks could complement existing control strategies for this livestock pest in the transboundary region between Mexico and Texas. DNA fingerprinting tools were used to compare populations of these ticks from Texas to the tick's native ranges in Europe and Asia. These tools will give us insight into what part of the native range the Texas outbreak populations come from. We will then focus on these areas to look for biological control agents. The results of the DNA fingerprinting indicate the southern cattle fever tick, R. microplus, outbreak populations match with data for populations in the Philippines and Cambodia. Data for cattle fever tick, R. annulatus, outbreak populations matched well with results for conspecifics from Romania and Bulgaria. These parts of the native range will be prioritized in the search for biological control agents to control cattle fever tick outbreaks in south Texas along the border with Mexico.