Optimization of detection of Ixodiphagus spp. infection in Rhipicephalus sanguineus S.L.

Authors: ABALOS, ABBEY - University Of Texas Rio Grande Valley; Maestas, Lauren; MAESTAS, SARAH - University Of Texas Rio Grande Valley

Submitted to: Entomological Society of America Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Tick specific parasitoid wasps are known to parasitize several closely related tick species. The development of non-toxic and environmentally safe biological control options is critical for tick management, particularly for species such as cattle fever ticks, a pest of livestock that causes billions of dollars in loss to the livestock industry worldwide. The brown dog tick species complex is closely related and found in many of the same locations as CFT, and parasitism of Brown dog ticks by tick parasitoids has been observed. It is unknown if CFT can be parasitized by tick parasitoids, but accurate and specific identification of parasitoids is needed to determine potential usefulness of these species in CFT control. The goal of this research is to optimize and implement a qPCR-screening protocol to detect Ixodiphagus spp. infestation, ultimately with the goal of identifying potential agents for cattle fever tick control. Methods of sample preparation for DNA isolation such as various grinding methods to break up exoskeleton and DNA extraction protocols are being tested to optimize DNA concentration and purity. Additionally, a qPCR protocol is being optimized to develop a taxa-specific qPCR that results in amplification of parasitoid DNA while minimizing non-target invertebrate DNA amplification. This protocol will be used to screen for parasitoids in CFT and BDT collected from part of the native range of CFT in four provinces of Vietnam.

Technical Abstract: Ixodiphagus spp. parasitoid wasps are known to parasitize several closely related tick species. The development of non-toxic and environmentally safe biological control options is critical for tick management, particularly for species such as Rhipicephalus microplus, a pest of livestock that causes billions of dollars in loss to the livestock industry worldwide. Rhipicephalus sanguineus S.L. is a sympatric species with R. microplus, and parasitism of R. sanguineus by Ixodiphagus sp. in areas of co-occurrence has been observed. It is unknown if R. microplus can be parasitized by Ixodiphagus spp., but accurate and specific identification of parasitoids is needed to determine potential usefulness of these species in CFT control. The goal of this research is to optimize and implement a qPCR-screening protocol to detect Ixodiphagus spp. infestation, ultimately with the goal of identifying potential agents for cattle fever tick control. Methods of sample preparation for DNA extraction such as various homogenization methods and extraction protocols are being tested to optimize DNA concentration and purity, and a qPCR protocol is being optimized to develop a taxa-specific qPCR that results in amplification of parasitoid DNA while minimizing non-target arthropod DNA amplification. This protocol will be used to screen for parasitoids in R. microplus and R. sanguineus S.L. collected from part of the native range of R. microplus in four provinces of Vietnam.