Studies of the sheep tick, Ixodes ricinus, in S.W. Scotland

Campbell, Jane (1988) Studies of the sheep tick, Ixodes ricinus, in S.W. Scotland. MSc(R) thesis, University of Glasgow.

Abstract

The seasonal activity of the tick, Ixodes ricinus, in S.W. Scotland was studied by sampling by blanket dragging in two adjacent habitats, an area of rough grazing pasture and a coniferous woodland. Most ticks, particularly nymphs, were found in the wood which shows the importance of vegetational cover in the distribution of Xi. ricinus. Adult ticks were found in low numbers at both sites. A spring peak of activity from May to July was observed for nymphs and larvae. Weather conditions were found to influence tick activity. Small mammals were trapped and examined for ticks from March to December in a coniferous plantation. Wood mice and bank voles were infested with ricinus and I. trianquliceps larvae which comprised 82% and 13% respectively of the ticks found. Nymphs of both species were also found. I. ricinus larvae were found from April to November the peak of infestation being in late June and early July with a smaller peak in September. Most ticks were found on the head, especially the ears. An outdoor insectary was used to study the life cycle of I. ricinus by observing the times taken for the pre- oviposition, egg development, larval and nymphal development periods. The insectary allowed maximum accessibility to observe tick development with little disturbance to the ticks. Larvae and nymphs feeding by June developed into the next stage by autumn of the same year while those feeding from July onwards entered developmental diapause and completed development the following year. Female ticks feeding between April and June produced eggs which developed into larvae in autumn of the same year. The observed development times were compared with predicted times from a computer prediction model, the most accurate predictions were for pre- oviposition and egg development times. Dry and wet heat extractions were used with similar success to recover ticks ricinus ) from turves artificially infested with ticks. Adult male ticks were most efficiently extracted (61% success). Nymphs and adult females were extracted with less success (32% and 21% recovery respectively). Neither method is thought to be practical for assessment of tick populations. Tick control trials were carried out to assess and compare the efficacies of various insecticidal preparations containing synthetic pyrethroids to control - ricinus on sheep. Dip and pour-on formulations, containing cypermethrin, gave good control of ticks for at least 8 weeks post-treatment. A deltamethrin pour-on was the least effective of the treatments used. The literature review covered aspects of the biology of I. ricinus including; environmental factors influencing tick distribution, hosts, tick behaviour and physiology, and disease aspects of tick infestation especially of livestock.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Parasitology.
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Titchener, Dr. R.N. and Newbold, Mr. J.W.
• Date of Award: 1988
• Depositing User: Enlighten Team
• Unique ID: glathesis:1988-73093
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 15 Jun 2021 13:52
• URI: https://theses.gla.ac.uk/id/eprint/73093