Gregson, J. D.

English

Journal of the Entomological Society of British Columbia

50 PROC. E NTOMOJ.. Soc. BRIT. COLU MRIA, Vor .. 60 (1963), DEC. I, 1963 THE DECLINE OF THE PACIFIC TICK (Ixotles pocilicus Cooley and Kohls) AT WEST VANCOUVER J. D. GREGSON' The Pacific tick, Ixodes pacificus Cooley and Kohls, is one of three ticks familiar to man in British Columbia (1). The adults are relatively small; the female is about one-eighth of an inch long, with black legs and head and a reddish-brown body. The male, which is usually found with the fe-male, is about half as long and is entirely black. Both sexes "quest" on low vegetation along woodland paths and at rocky exposures along the coast of southern British Colum-bia (2). They are present throughout the year but are most numerous dur-ing the wet winter months and reach a peak of activity during warm spring days. Man and domestic animals are fre-quently hosts for the adults. The males, which do not become distend-ed, feed repeatedly for short periods only and leave multiple bites. The females remain attached ,at one site I Entomology Laboratory, Research Branch, Canada Department of Agriculture, Kamloops, British Columbia. 1. Are ticks a nuisance to you? for a week or more, engorging slowly and turning dull blue-grey. During this period the fiesh of the host may swell around the tick's mouthparts, giving rise to the fallacy that the tiek burrows in. Because of its relatively long, barbed hypostome this tick is very difficult to remove and if it cannot be induced to release by irritating it with such fiuids as kerosene, gasOline, or iodine, it usually has to 'be cut out. The bites may pro-duce sudden and extensive swelling and cause ulcers that persist for many months (3). Where the habitat of 1. pacificus was close to urban areas, such as along the north shore of Burrard Inlet and English Bay, it was con-sidered a pest of man and his pets for many years so that in 1940 this laboratory considered ,it advisable to conduct a survey. Retu.rn - stamped questionnaires were mailed in March to 210 persons residing at or between the communities of West Bay and Horseshoe Bay, their addresses hav-1940 1950 1960 Yes .... ____ .. ____ __ __ . ________________ ._________ 63 31 8 No _ ... ____ ____ _____ ._______ . _____ .____ . ______ ._. 37 2. Are ticks, in your opinion, becoming more numerous? Yes __ __ _____ .. ____ . ____ . ___ _______ .__ __ ______ __ __ 65 No _______ ... .. ________ _ .__ __ .... _______ ___ . __ ._... 8 3. Have you or your family had ticks attach to you? 1-6 times? ____ ._. _____ __ ___ . ____ .. ___ ____ __ . 43 Often ____ ._ .. _____________ ._ .. ______ .. __ .__ ____ 28 Never __ .. _. _______ . ___ . ___ ._. ___ .___ . _____ .__ .. 28 4. Do you possess dogs or cats? Yes _____________ ___ __ .. __ . _______ _______ . _______ . 84 5. Percentage of pets examined for ticks: Daily ____ __ . ____ ._. _____ .. _._ ... _. ___ ... ___ __ .. 60 Occasionally or weekly_ ... ________ 20 Never _____ . ___________ . __________ __ __________ .. 1 69 90 10 4 48 79 30 30 3 1 37+ 37+ 67 57 36 10 38 25 23 40+ PRO(;. E NTOMOr •. Soc. BRIT. COLU MRIA, VOL. 60 (1963), DEC. I , 1963 51 ing been chosen randomly from a telephone directory. This survey was repeated in 1950 and 1960, with 700 and 260 questionnaires sent respec-tively. Many of the addresses in the last year were deliberately chosen from the earlier lists so that the in-formation gained might be more relative. The returns were 38, 34, and 50 per cent of the mailings. The answers are given as percentages of the respective totals. Of the residents replying in 1940, 44 per cent had lived at their address for more than ten years and were thus in a position to compare the relative abundance of ticks over the years. The comparable figures for 1950 'and 1960 were 33 and 69 per cent. Eighteen 4-23 year residents replying in 1950 stated that the ticks had de-clined during the last 2-10 years. The same opinion was echoed in the 1960 returns, although by this time the pest had so declined that remarks on its absence were rather casual. The period of tick activity was generally stated as being in the spring and to a lesser extent in the autumn. Some activity was noted during the summer but not during mid-winter. Descriptions of the effects from the tick bites included: acute swell-ing of the arm; slow healing and painful festering sores with fever; large or hard and painful lumps; severe local inflammation; soreness for six months; fever; slight rash and headache. Many ticks were removed with the aid of kerosene, iodine, turpentine, alcohol, hot needles, fire, and forceps . A surprising number were "unscre,w-ed." One facetious resident removed his with a pick and shovel and an-other added that "a friend of ours had heard about the plague of ticks in West Vancouver, so she examined her dog and was horrified to find several ticks embedded in the ani-mal's belly. She did not think it very odd that these lumps were arranged in two regular columns; it was only after she had inflicted considerable suffering on the dog that she ceased from trying to pry its nipples off!" It would appear that the Pacific tick at West Vancouver reached a peak of activity about 1940 and sub-sequently declined to its present sta-tus as a pest of only minor concern. The reason for its decline is not known, but is probably related to the development of the district from brushland to a well maintained resi-dential area. During the last survey question-naires were also sent to key person-nel in other areas in the province suspected of harbouring I . pacificus . Returns have suggested its presence at Ganges, Nanaimo, Coquit lam, Agassiz, Wilson Creek, Sechelt, Pen-der Harbour, and Squamish, but not at Prince Rupert or Terrace. The most northerly record is from Ocean Falls (4) . References 1. Gregson, J . D. Ticks of Medical Importance in British Columbia. British Columbia Med. Jour. 2: 1-4. 1960. 2. Gregson, J . D. The Coast tick (Ixodes californiclIs Banks) problem in British Colum-bia. Canad. Ent. 74: 3-5. 1942. 3. Gregson, J . D. Host poisoning by Ixodes californicus Banks Proc. Entomol. Soc. Brit. Columbia 38: 5-6. 1942. 4. Gregson, J. D. The Ixodoidea of Canada. Can. Dept. of Agric. Pub. 930, 92pp. 1955. 

The decline of the Pacific tick (Ixodes pacificus Cooley and Kohls) at West Vancouver

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The decline of the Pacific tick (Ixodes pacificus Cooley and Kohls) at West Vancouver

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Journal of the Entomological Society of British Columbia