AC-DC electropenetrography unmasks fine temporal details of feeding behaviors for two tick species on unsedated hosts

Authors: REIF, KATHRYN - Kansas State University; Backus, Elaine

Submitted to: Nature Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2020
Publication Date: 1/21/2021
Citation: Reif, K.E., Backus, E.A. 2021. AC-DC electropenetrography unmasks fine temporal details of feeding behaviors for two tick species on unsedated hosts. Nature Scientific Reports. 11:2040. https://doi.org/10.1038/s41598-020-80257-6.
DOI: https://doi.org/10.1038/s41598-020-80257-6

Interpretive Summary: Ticks are important nuisance pests and disease carriers for humans, companion animals, and livestock. In the U.S., tick-borne diseases are the most common vector-carried diseases of people, with 59,349 cases of tick-carried diseases reported to the Centers for Disease Control and Prevention in 2017, a 200% increase in the last two decades. The true annual incidence of Lyme disease in the U.S. is thought to be over 300,000 cases per year, with annual healthcare costs of $712 million to $1.3 billion. Despite this importance, relatively little is known about tick feeding behaviors. This knowledge gap slows the development and testing of methods to control ticks and tick-borne diseases. To address this problem, the present study examined the value of using AC-DC electropenetrography (EPG) to study feeding behaviors of the American dog tick and Lone star tick in real-time. EPG recording was performed during early-stage tick feeding using an awake, unsedated calf. Both tick species performed identifiable waveforms of low-, medium-, and high-frequencies. Similar waveforms were observed for both tick species; however, some differences were also observed. This study successfully demonstrated that AC-DC EPG can be used to study tick feeding. It provides a foundation for future studies aimed at associating specific feeding behaviors with waveforms, and ultimately will help develop new chemical measures to control tick feeding and transmisson of diseases.

Technical Abstract: Ticks are significant nuisance pests and vectors of pathogens for humans, companion animals, and livestock. Limited information on tick feeding behaviors hampers development and rigorous evaluation of tick and tick-borne pathogen control measures. To address this obstacle, the present study examined the utility of AC-DC electropenetrography (EPG) to monitor feeding behaviors of adult Dermacentor variabilis and Amblyomma americanum in real-time. EPG recording was performed during early stages of slow-phase tick feeding using an awake calf host. Both tick species exhibited discernable and stereotypical waveforms of low-, medium-, and high-frequencies. Similar waveform families and types were observed for both tick species; however, species-specific waveform structural differences were also observed. Tick waveforms were hierarchically categorized into three families containing seven types. Some waveform types were conserved by both species (e.g. Types 1b, 1c, 2b, 2c) while others were variably performed among species and individually recorded ticks (e.g. Types 1a, 2a, 2d). This study provides a proof-of-principle benchmark for tick EPG research, serving as a foundation for future studies aimed at correlating specific feeding behaviors with waveforms, and ultimately the influence of control measures and pathogens on tick feeding.