Observations on the bionomics of Linognathus pedalis

Abstract

Studies on the life cycle and on populations of Linognathus pedalis are described. The incubation period of the egg is 17 days, followed by three nymphal instars, each of approximately 7 days, and a preoviposition period of 5 days. The period from egg to egg is, therefore, approximately 43 days. The female deposits approximately one egg per day. There is a pronounced seasonal fluctuation in populations, which reach a maximum from July to October and a minimum from December to March. Lambs are most susceptible to L. pedalis and may become infested within a few hours after birth. Infestations may be acquired either by direct contact with infested sheep or from an infested environment. Under suitable conditions of temperature and humidity, L. pedalis can survive far up to 18 days away from the sheep, and it has been shown experimentally that lambs can become infested from pastures at least three clays after removal of infested sheep.