Sectors of activity, topography, and parasitism in home areas of New Guinea coarse-haired rats, and Trombiculidae (Acarina)

Summary

Home areas of hosts are, in effect the gardens in which parasite populations grow. The parasites flourish in response to the kind and amount of host activity modified, of course, by the habitat, and become microcommunities supported by their host and its artifacts. When scatter diagrams of points at which hosts have been observed are divided by median major and minor axes, and when the resulting four quarters, designated A, B, C, D, corresponding to concentration of points in the quarters, the relative concentration usually is: A>B>C>D. The concentration of observed points also is generally greatest nearest the major axis and frequently, but not always, near the median center. Nests of hosts, hence nest-parasites, appear generally to be near the center. For the host examined in detail here, the New Guinea coarse-haired rat, mostLeptotrombidium deliensis appear to have been acquired in the AB sector of the host's home areas but a greater diversity of chiggers is acquired in the CD sector. It is postulated that, ifL. akamushi had been present, it would have occurred in the CD sector where, though the observed concentration of host activity was least, the mixed grassforb and shrub habitat would have been more suitable than in the AB sector.Gahrliepia pingue, C. ewingi, Schoengastia blestowei andS. schueffneri, appear also to be more abundant in the CD sector than in the AB sector. The chiggers themselves have home clusters, or lairs, and adjacent areas of activity (home areas) somewhat resembling those of the hosts.