TY - JOUR
T1 - Neurophysiological and behavioral responses of blacklegged ticks to host odors
AU - Josek, Tanya
AU - Sperrazza, Jared
AU - Alleyne, Marianne
AU - Syed, Zainulabeuddin
N1 - Publisher Copyright:
© 2020 The Author(s)
PY - 2021/1
Y1 - 2021/1
N2 - The blacklegged tick, Ixodes scapularis (Ixodida, Ixodidae), is one of the major disease vectors in the United States, and due to multiple human impact factors, such as decreasing forest size for land development and climate change, it has expanded its range and established across the United States. Throughout the life cycle, ticks locate hosts for their blood-meal, and although the ecologies of this tick and their hosts have been studied in depth, the sensory physiology behind host location largely remains unexplored. Here, we report establishing a robust paradigm to isolate and identify odors from the natural milieu for I. scapularis. We performed single sensillum recordings (SSR) from the olfactory sensilla on the tick tarsi, and used the SSR system as a biological detector to isolate natural compounds that elicited biological activity. The SSR setup was further tested in tandem with gas chromatography (GC) wherein the ticks’ olfactory sensillum activity served as a biological detector. The GC-SSR recordings from the wall pore sensilla in the Haller's organ, and further identification of the biologically active deer gland constituents by GC-mass spectrometry (GC–MS) revealed methyl substituted phenols as strong chemostimuli, as compared to ethyl or propyl substitutions. The strongest electrophysiological activity was elicited by m- cresol followed by p- cresol. Ethyl- and propylphenols with any of the three substitutions (ortho, meta or para), did not induce any neurophysiological activity. Finally, a behavioral analysis in a dual-choice olfactometer of all these phenols at three different doses revealed no significant behavioral response, except for p- cresol at −3 dilution. Overall, this study contributes to our understanding of I. scapularis tick's neurophysiology and provides a robust platform to isolate and identify natural attractants and repellents.
AB - The blacklegged tick, Ixodes scapularis (Ixodida, Ixodidae), is one of the major disease vectors in the United States, and due to multiple human impact factors, such as decreasing forest size for land development and climate change, it has expanded its range and established across the United States. Throughout the life cycle, ticks locate hosts for their blood-meal, and although the ecologies of this tick and their hosts have been studied in depth, the sensory physiology behind host location largely remains unexplored. Here, we report establishing a robust paradigm to isolate and identify odors from the natural milieu for I. scapularis. We performed single sensillum recordings (SSR) from the olfactory sensilla on the tick tarsi, and used the SSR system as a biological detector to isolate natural compounds that elicited biological activity. The SSR setup was further tested in tandem with gas chromatography (GC) wherein the ticks’ olfactory sensillum activity served as a biological detector. The GC-SSR recordings from the wall pore sensilla in the Haller's organ, and further identification of the biologically active deer gland constituents by GC-mass spectrometry (GC–MS) revealed methyl substituted phenols as strong chemostimuli, as compared to ethyl or propyl substitutions. The strongest electrophysiological activity was elicited by m- cresol followed by p- cresol. Ethyl- and propylphenols with any of the three substitutions (ortho, meta or para), did not induce any neurophysiological activity. Finally, a behavioral analysis in a dual-choice olfactometer of all these phenols at three different doses revealed no significant behavioral response, except for p- cresol at −3 dilution. Overall, this study contributes to our understanding of I. scapularis tick's neurophysiology and provides a robust platform to isolate and identify natural attractants and repellents.
KW - Dual-choice assay
KW - GC-Mass spectrometry
KW - GC-linked single sensillum recordings
KW - Ixodes scapularis
KW - Single sensillum recordings
UR - http://www.scopus.com/inward/record.url?scp=85097397224&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85097397224&partnerID=8YFLogxK
U2 - 10.1016/j.jinsphys.2020.104175
DO - 10.1016/j.jinsphys.2020.104175
M3 - Article
C2 - 33253713
AN - SCOPUS:85097397224
SN - 0022-1910
VL - 128
JO - Journal of Insect Physiology
JF - Journal of Insect Physiology
M1 - 104175
ER -