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Many ixodid species on the South Texas coastal plain can transmit pathogens to their hosts. Substantial areas are dominated by gulf cordgrass, Spartina spartinae (Trin.) Merr. ex Hitch. The S. spartinae habitat was examined in terms of abiotic and biotic factors that likely impinge upon ixodids using the plant for questing. Natural enemies, temperature, humidity, and plant structure were investigated as possible mortality factors and improving ixodid survival. Spartina spartinae (soil and foliage) harbored few natural enemies of ixodids, and soil salinity was nonlethal. Conditions were cooler and more humid inside S. spartinae clumps than in the canopies; hence, questing ixodids can rehydrate inside the clump when threatened by desiccation. Leaves were mostly "V" shaped in cooler months and, during warm months, the tightly folded leaf slot predominated, into which larvae crawled. Immature ixodids were more abundant in the concave side of the "V"-shaped leaves than on the exposed convex side. Larvae sought refuge from potential lethal ambient air conditions by entering tight warm season leaf folds. The leaf "V" and fold offer opportunities for rehydration on the leaf without moving to the clump's base. In addition to five other species collected on the grass, a relatively heavy larval southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini), population was detected, suggesting that abundances in the South Texas cattle fever tick eradication quarantine zone are increasing and might spread further into Texas. [ABSTRACT FROM AUTHOR]

Multiple predatory ant species, including the red imported fire ant, Solenopsis invicta (Buren) (Hymenoptera: Formicidae), have been reported to attack ixodids (Ixodida: Ixodidae), but evidence has largely been circumstantial. When living lone star tick, Amblyomma americanum (L.) (Acarina: Ixodidae), eggs, and unfed and blood-engorged larvae, nymphs, and adults were deployed on bait transects with hot dog slices and dead house flies, Musca domestica L. in West, Central, and South Texas. The various ixodid life stages were not attacked while ants were strongly recruited to the hot dog and M. domestica baits. Similarly, when the same ixodid life stages and other baits were placed adjacent to colonies of two ant species (red harvester ant, Pogonomyrmex barbatus (Smith) and the red imported fire ant, Solenopsis invicta Buren) the ixodids were not preyed upon while hot dog slices and dead M. domestica were immediately attacked. Some ant species dragged blood-engorged adult ixodids and eggs away from the colony entrance, where they were originally placed, and discarded them. Evidence and mechanisms for allomone-based ant deterrence in the genera Amblyomma , Dermacentor , and Rhipicephalus (metastriate ixodids) are discussed. Protection of ixodids from predatory ants helps to explain why metastriate ixodids remain problematic worldwide despite the presence of predaceous ants. [ABSTRACT FROM AUTHOR]

The South Texas coastal plains are mostly dominated by mesquite-thorn scrub from the Mexican border to cattle ranches extending north from Willacy Co. A wildlife corridor on the plains, composed of natural habitat, supportshosts of many ixodid species. Occasional wind tides and infrequent storm surges inundate coastal plain areas with hypersaline water from the Lower Laguna Madre, creating large areas of saline soil. Laboratory and field experiments and observations were used.

The one-host cattle fever tick, Rhipicephalus (Boophilus) annulatus (Say), and southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini), are important ectoparasitic pests of cattle, Bos taurus L., mostly for transmitting the causal agents of bovine babesiosis. Bovine babesiosis inflicted substantial cattle production losses in the United States before the vectors were eliminated by 1943, with the exception of a Permanent Quarantine Zone in South Texas, a buffer along the Mexico border where the invasive ixodids remain. As suitable hosts, infested white-tailed deer and nilgai antelope populations disperse R. annulatus and R. microplus, which increases the risk for emergence of bovine babesiosis in the United States. A R. microplus incursion first detected in 2016 on the South Texas coastal plain wildlife corridor involved infestations on cattle, nilgai antelope, white-tailed deer, and vegetation. Efforts at passive sampling of Rhipicephalus (Boophilus) spp. on hosts are concentrated in the Permanent Quarantine Zone. Hence, a knowledge gap exists on the full extent of the recent incursions. Area-wide, systematic, active sampling and supportive research, involving the Permanent Quarantine Zone, Temporary Quarantine Zone, most of the coastal plain, and other parts of Texas outside of the quarantine zones, are needed to bridge the knowledge gap. Herein, we provide research perspectives and rationale to develop and implement systematic active sampling that will provide an increasingly accurate assessment of Rhipicephalus (Boophilus) spp. distribution in Texas. We suggest that this is essential to advance integrated vector-borne animal disease eradication approaches for keeping cattle free of bovine babesiosis., (Published by Oxford University Press on behalf of Entomological Society of America 2021.)

Background: Some tick species are invasive and of high consequence to public and veterinary health. Socioeconomic development of rural parts of the USA was enabled partly through the eradication by 1943 of cattle fever ticks (CFT, Rhipicephalus (Boophilus) annulatus and R. (B.) microplus). The southern cattle fever ticks (SCFT, R. (B.) microplus) remain a real and present threat to the USA animal agriculture because they are established in Mexico. Livestock-wildlife interactions in the Permanent Quarantine Zone (PQZ) established by the century-old Cattle Fever Tick Eradication Programme (CFTEP) in south Texas endanger its operations. Methods: We describe a spatially-explicit, individual-based model that simulates interactions between cattle, white-tailed deer (WTD, Odocoileus virginianus), and nilgai (Boselaphus tragocamelus) to assess the risk for SCFT infestations across the pathogenic landscape in the PQZ and beyond. We also investigate the potential role of nilgai in sustaining SCFT populations by simulating various hypothetical infestation and eradication scenarios. Results: All infestation scenarios resulted in a phase transition from a relatively small proportion of the ranch infested to almost the entire ranch infested coinciding with the typical period of autumn increases in off-host tick larvae. Results of eradication scenarios suggest that elimination of all on-host ticks on cattle, WTD, or nilgai would have virtually no effect on the proportion of the ranch infested or on the proportions of different tick habitat types infested; the entire ranch would remain infested. If all on-host ticks were eliminated on cattle and WTD, WTD and nilgai, or cattle and nilgai, the proportions of the ranch infested occasionally would drop to 0.6, 0.6 and 0.2, respectively. Differences in proportions of the ranch infested from year to year were due to primarily to differences in winter weather conditions, whereas infestation differences among tick habitat types were due primarily to habitat use preferences of hosts. Conclusions: Infestations in nilgai augment SCFT refugia enabled by WTD and promote pest persistence across the landscape and cattle parasitism. Our study documented the utility of enhanced biosurveillance using simulation tools to mitigate risk and enhance operations of area-wide tick management programmes like the CFTEP through integrated tactics for SCFT suppression. [ABSTRACT FROM AUTHOR]