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Dartmoor Tick Watch
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The only way to identify a tick is to follow keys in books by recognised authorities. These are principally:
Ticks of North West Europe by Paul Hillyard, published for The Linnean Society of London, by the Field Studies Council, Shrewsbury, 1996, ISBN 1 85153 257 9. £19.50 plus postage.
British Ticks by Don. R Arthur, published by Butterworths, London, 1963. Out of print.
This page cannot duplicate the keys. What it intends to do is to present a list of pictorial characters that confirms the identity of a tick, starting with Ixodes ricinus. Other ticks will be added if found.
Some identifying features can only be distinguished using a microscope with suitable lighting and by frequent reference to the keys or a checklist while comparing with actual specimens.
Checklists to identify ticks on/around Dartmoor
(based on features in Hillyard, 1996)
Section 1 - Identification of life cycle stages, sexes and family
Characteristic |
Photo |
1. Mouthparts (capitulum, arrowed) project
anteriorly (i.e. not hidden underneath) = Family Ixodidae |
Photo 1 |
2. Four pairs of legs =
adult or nymph otherwise, 3 pairs legs = larva |
4 pairs legs - see Photo 1 above
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3. Dorsal shield (scutum) covers
back of tick = male otherwise covers anterior part of body only = female or nymph |
Photo 2 Male scutum covers the entire tick
Female scutum - see Photo 1 above
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4. Genital opening and porose
areas
present = female absent = nymph |
Photo 3 Genital opening (top, female) and anus (below)
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5. Anal groove circles anus anteriorly = Ixodes | See Photo 3 above |
Section 2 -
Identification of Ixodes females
- featuring I. ricinus (Sheep tick) & I. hexagonus
(Hedgehog tick|)
- continuing from Section 1 - Identification of life cycle
stages, sexes and family
1. Legs not long and slender | |
2. Two porose areas (not undivided) | See Photo 4 above |
3. Basal
segment of palp (segment one) without lateral spur on article 1 - I. ricinus & I. hexagonus |
Photo 5 |
4. Palps
relatively long with articles 2 and 3 as long or longer than base of capitulum is wide - I. ricinus
Palps
shorter than base of capitulum - I. hexagonus |
See Photo 8 below (I. ricinus)
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5. Coxa 1 has a
long internal spur and a short external spur. The ventral base of the capitulum has no auriculae
Coxa 1 has only an internal spur with no external spurs. The other coxae have no spurs.
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Photo 6 The external spurs are difficult to see, especially in dead specimens that have distorted or shrivelled
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Section 3 -
Identification of Ixodes males
- continuing from Section 1 - Identification of life cycle
stages, sexes and family
1. Legs not long and slender | |
2. No brushes of setae on posterior body margin |
Photo 7 A few single setae only |
3. Coxa 1 has 1 or 2 spurs | See Photo 6 above |
4. Palp
articles free, with visible divisions (arrows indicating the division between articles 2 and 3) |
Photo 8 |
5. Median plate 1½ times long as wide | Photo 9 Detail slightly hidden because of the shrivelled leg 4 on the right side |
6. Tarsus 1 tapers and lacks hump near tip |
Photo 10 |
7. Coxa 1 with internal and external spurs | See Photo 6 above |
8. Coxa 1 internal spur is 3 times longer than external spur | See Photo 6 above |
Section 4 -
Identification of Ixodes nymphs
- continuing from Section 1 - Identification of life cycle
stages, sexes and family
1. Legs not long and slender | |
2. Palp article 1 has no lateral spur | See Photo 6 above |
3. Articles 2 & 3 of palp as long or longer than base of capitulum is wide | See Photo 5 above |
4. Coxa 1
internal spur longer than external spur, auriculae are dark divergent triangles |
Photo needed - not possible to see in the engorged nymphs collected |
Section 5 -
Identification of Ixodes larvae
- continuing from Section 1 - Identification of life cycle
stages, sexes and family
(based on features in Butterworth, 1963)
1. Internal spur
on coxa 1 plus other variable spur arrangement - and NOT only on 1 and NOT lacking spurs completely |
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2. External spurs on all coxae | |
3. Scutum ovate, NOT wider nearer the front | |
4. Auricular lobes (if present) NOT well defined and NOT rounded apically | |
5. Postero-lateral
angles of dorsal ridge drawn out to form cornua-like extensions (fig. 24) |
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