a1 ODA Insect Pest Management Initiative, c/o Tsetse and Trypanosomiasis Control Branch, Harare, Zimbabwe
In Zimbabwe, living and stuffed warthogs (Phacochoerus aethiopicus Pallas) were placed within an incomplete ring of electric nets and observations were made of the numbers of Glossina pallidipes Austen and G. morsitans morsitans Westwood attracted to the hogs, the alighting position and feeding responses of tsetse, and the grooming behaviour of the warthogs. Between 26 and 31% of tsetse landed on the head region of an adult live warthog compared to 8% for a juvenile and 4% for a stuffed warthog. The number of tsetse alighting adjacent to the eye of a stuffed warthog increased 20 times if dark patches were fixed there. The percentage of tsetse alighting on the head region of the adult warthog increased from 25% to 50% as the number of tsetse caught on the ring of nets increased from <100 to > 800. There was a concurrent increase in the rate of skin twitches and ear flicks by the warthog. For an adult warthog, 26% of tsetse leaving the vicinity had fed compared to only 1% for a juvenile. It is suggested that the concentration of tsetse on the head of adult warthogs is a visual response to the dark patch produced by the pre-orbital glands of a mature warthog and to density-dependent changes in the grooming responses of warthogs.
(Accepted January 12 1994)
c1 Dr S. Torr, NRI, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK.