Development and testing of artificial membranes for rearing of Rhipicephalus microplus, the southern cattle fever tick

Authors: VACEK, ANN - University Of Texas Rio Grande Valley; Goolsby, John; KARIYAT, RUPESH - University Of Texas Rio Grande Valley

Submitted to: Subtropical Agriculture and Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2020
Publication Date: 10/23/2020
Citation: Vacek, A.T., Goolsby, J., Kariyat, R.R. 2020. Development and testing of artificial membranes for rearing of Rhipicephalus microplus, the southern cattle fever tick. Subtropical Agriculture and Environments. 71:59-66.

Interpretive Summary: Cattle fever ticks (CFT) are invasive livestock pests that are prevalent in Mexico and pose a constant threat along the Texas – Mexico border. Resistance to acarcides, wildlife hosts, and the south Texas landscape present challenges for eradication of this pest in the U.S. CFT are the vector for babesiosis, a lethal disease that can cause high mortality in cattle and could severely impact the U.S. beef cattle industry. Efforts to eradicate CFT from the U.S. have been successful; however, a permanent quarantine zone (PQZ) is maintained between Texas and Mexico to prevent movement of CFT by wildlife such as nilgai and white-tailed deer and stray cattle from Mexico. In recent years, there has been an increase in CFT infestations outside of the PQZ in Texas. Biological control using specialized parasitic insects from the native ranges of CFT could reduce invasion pressure from Mexico and on wildlife hosts that cannot be treated with acaricides. Methods for rearing insects parasitic on CFT are needed, including artificial feeding membranes for rearing CFT. In this paper, methods to artificially rear CFT are investigated. We successfully fed CFT larvae and nymphs on an artificial membrane and cow blood. Further research is needed to refine these methods and are discussed in the paper.

Technical Abstract: The southern cattle fever tick, Rhipicephalus microplus, is a livestock pest worldwide in tropical and subtropical climates, including South Texas, and can vector Babesia spp., the causal agents of bovine babesiosis. Artificial rearing methods for R. microplus are needed, especially for rearing of specialist tick parasitoids that are under evaluation for classical biological control. In this study, we tested the efficiency of artificial feeding of R. microplus larvae, nymphs, and adults on a siliconized substrate (goldbeater’s membrane, lens paper, or Hemotek), or on non-siliconized goldbeater’s membrane or Hemotek. Other variables used were a warm water bath, incubator, positioning blood above or below ticks, using various attractants to stimulate attachment to membrane, incubating with or without 5% CO2, changing static blood once a day versus peristaltic pumping of blood, and using heparinized versus defibrinated blood. We found that up to 25% percent of these life stages would attach to the siliconized goldbeater’s membrane and feed, although none completed their entire life cycle.A red color observable in the “fed” ticks’ legs seemed to indicate that bovine hemoglobin had penetrated the gut and entered the hemolymph of the ticks. We were successful rearing unfed nymphs to the engorged stage, which is the pre-requisite for rearing Ixoidiphagus tick parasitoids. Suggestions for future experimentation for rearing R. microplus on artificial membranes are discussed.