We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
Comparisons of successful and failed attempts to eradicate livestock ticks reveal that the social context of farming and management of the campaigns have greater influence than techniques of treatment. The biology of ticks is considered principally where it has contributed to control of ticks as practiced on farms. The timing of treatments by life cycle and season can be exploited to reduce numbers of treatments per year. Pastures can be managed to starve and desiccate vulnerable larvae questing on vegetation. Immunity to ticks acquired by hosts can be enhanced by livestock breeding. The aggregated distribution of ticks on hosts with poor immunity can be used to select animals for removal from the herd. Models of tick population dynamics required for predicting outcomes of control methods need better understanding of drivers of distribution, aggregation, stability, and density-dependent mortality. Changing social circumstances, especially of land-use, has an influence on exposure to tick-borne pathogens that can be exploited for disease control.
Data are presented from five series of 240 adults of Rhipicephalus appendiculatus Neumann kept in the laboratory, in which a steady decline in the numbers of granules in e cells of type 3 acini of the salivary glands occurred. This was readily detected in whole gland preparations of the salivary glands stained with methyl green and pyronin, and the same specimens could be used for detecting Theileria parasites in the salivary glands. Characteristics for grading these ticks into three physiological age grades are given, and a formula is provided for incorporating the age grade with infection rate. This gives a value for comparative estimates of the challenge posed by field populations of ticks for the transmission of Theileria to cattle.
Light-traps were used to collect adult Culicoides from 61 sites throughout Kenya and to sample long-term population fluctuations at six sites. Activity patterns were recorded with a suction trap and larval habitats were sampled with laboratory emergence traps. Culicoides cornutus De Medllon, C. milnei Aust., C. pallidipennis C, I. & M., C. schultzei (End.) gp. and C. zuluensis De Meillon were found widespread and also concentrated at livestock pens. Their seasonal population fluctuations did not correlate clearly with rainfall but all these species persist throughout the year. The activity of C. pallidipennis and C. schultzei gp. extends over the whole night and is inhibited by winds in excess of 3 m/s and stimulated by high temperatures and relative humidity. Larval habitats were mainly in mud mixed with detritus or dung; larvae of C. pallidipennis and C. schultzei gp. were both found in swamp mud but not in dung pats. The significance of these findings is discussed in relation to the epidemiology of bluetongue virus disease of sheep and ephemeral fever virus disease of cattle.
Light-traps were used to sample populations of C. comutus De Meillon, C. pallidipennis G, I. & M. and C. schultzei (End.) gp. at sites at Embakasi, Kiboko and Makindu between 1971 and 1975. The samples were graded into age-groups by the degree of abdominal pigmentation, estimates of calendar ageing were made, and the seasonal variation in age-structure of the populations was recorded. Survival rates were calculated on the basis of a graphical model of the continually overlapping generations, and the survival rate of 0·8 was found typical. This rate is considered sufficiently high for C. cornutus, C. pallidipennis and C. schultzei gp. to act as vectors of bluetongue virus disease of sheep and/or ephemeral fever virus disease of cattle.
An assessment of carnivore species richness and food habits was carried out in a 100 km2 area of dry tropical forest in Huai Kha Khaeng Wildlife Sanctuary, Thailand. Twenty-one carnivore species of five families were found to be feeding on at least 34 mammal species, as well as birds, lizards, snakes, crabs, fish, insects, and fruits. Forty-four percent of the prey identified in faeces of larger carnivores, primarily leopards, consisted of barking deer, Muntiacus muntjak. Sambar deer, macaques, wild boar, porcupine, and hog badger were important secondary prey items. In faeces from small carnivores (< 10kg), murid rodents accounted for 33% of identified food items. The two most frequently encountered mammalian prey species were the yellow rajah rat, Maxomys surifer, and the bay bamboo rat, Cannomys badius. Non-mammal prey accounted for 21.3%, and fruit seeds for 12.4%, of all food items found in small carnivore faeces.
Email your librarian or administrator to recommend adding this to your organisation's collection.