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Effects of Clearing in a Tropical Rain Forest on the Composition of the Coprophagous Scarab Beetle Fauna (Coleoptera)

1975; Wiley; Volume: 7; Issue: 2 Linguagem: Inglês

10.2307/2989750

1744-7429

HF Howden, Vincent G. Nealis,

Dermatological diseases and infestations

Sixty species of beetles in the family Scarabaeidae were attracted to dung and carrion traps set near Leticia, Amazonas, Colombia, in 1972 and 1974. Diversity remained fairly constant in forested areas of firma, with 11 species comprising the great majority of individuals. Bait preference was low, being most pronounced between dung and carrion with little difference between human and monkey dung. However, human dung was most attractive in terms of both numbers of individuals and species. In a five-day period dung traps lost much of their attractiveness. There was no evidence of a trapping-out effect. Forested areas of had a scarab fauna approximately five times as diverse as areas flooded annually. Forest clearing drastically reduced both numbers of species and individuals, only six species being taken in traps set in clearings. However, four of these six species were not taken in any of the forest areas. This reduction of the coprophagous fauna in clearings drastically slows the removal of dung from the surface of the ground, increasing the number of potential breeding sites for flies and greatly increasing the possibility of helminth infections in man and other animals. IN RECENT YEARS there has been considerable interest in the habits of some of the coprophagous scarab beetles. Their ability to dispose rapidly of dung and carrion has been considered, not only from the aspect of pasture improvement (Bornemissza 1960, Woodruff 1972), but from the medical implications of removing helminth eggs from the soil surface (Miller 1954). A recent compendium of the biological information concerning these beetles, published by Halffter and Matthews (1966), is a major source of information concerning the habits of various species. However, a review of the literature quickly indicates that there is relatively little information on tropical South American species and even less on the variety of species one might expect to find in a single locality in the Amazonian rain forest. A recent paper by Fittkau and Klinge (1973) discusses the surface fauna of a tropical forest near Manaus and gives the distinct impression that the coprophagous beetle fauna is very depauperate in the central Amazon region, an impression that our data do not support. The present paper is essentially a pilot study to determine what species of coprophagous Scarabaeidae coexist in a relatively restricted area of terra firma (land not flooded annually) rain forest, what changes in the fauna occur over short periods as the bait ages, and what changes may occur in the species composition when the study is repeated two years later. Also, in the second study, a comparison is made between the forest and cleared areas to determine if there are any differences in the two faunas. Some speculation is included concerning the effects that the faunal changes caused by forest clearing have on the disposal of dung and carrion and the inherent medical implications of these changes in the fauna. An area 11 km northwest of Leticia, Amazonas, Colombia, was selected for the study (referred to herein as the pepper farm). The area (fig. 3) consisted of relatively dense, level rain forest with adjacent cleared areas. Some selective cutting had occurred, but this was true for most of the accessible areas near Leticia, and the disturbance was not con-