Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2004
Publication Date: 5/13/2004
Citation: Carroll, J.F., Kramer, M.H., Weldon, P.J., Robbins, R.G. 2004. Anointing chemicals and ectoparasites: effects of benzoquinones from millipedes on the lone star tick, Ambylomma americanum. Journal of Chemical Ecology. 31:63-75. Interpretive Summary: ' One compound was repellent at the highest concentration tested. Two compounds were toxic at higher concentrations and all compounds impaired tick behavior for months at all concentrations tested. These results not only show that these constituents of millipede secretions may protect against ticks, but they indicate that further investigation of naturally occurring compounds might discover ectoparasites deterrents. Researchers studying chemical ecology, and animal and tick behavior will be interested in these results.
Technical Abstract: Many mammals and birds roll on or rub themselves with millipedes that defensively discharge benzoquinones. Chemicals transferred from millipedes onto the itegument of anointing animals are thought to deter ectoparasites. We tested the lone star tick, Amblyomma americanum (L.) , for responses to three widespread components of millipede defensive secretions, 1,4-benzoquinone; 2-methyl-1,4-benzoquinone (toluquinone); and 2-methoxy-3-methyl-1,4-benzoquinine(MMB). Ticks were confined for oo1 h in filter paper packets treated with serial dilutions of each of the benzoquinones or the commercial insecticide permethrin. All benzoquinones except toluquinone were toxic at a concentration of 6.3 mM compound/cm2. None of the benzoquinones were as toxic as permethrin. Behavioral assays were more sensitive than mortality data for measuring the effects of the benzoquinones. Latencies for ticks to right themselves, and to climb were greater than controls even at the lowest concentration. Ticks exposed to low concentrations of benzoquinones appeared to recover somewhat over time, whereas those exposed to higher concentrations exhibited behavioral abnormalities 1-3 mo later. Our results suggest that benzoquinones appropriated during anointing can reduce the tick loads of anointing animals.