Habitat Selection in Dung Beetles (Family Scrabaeidae; Subfamily Scarabaeinae) in the Wasgomuwa National Park

Abstract

A study was carried out to investigate habitat selection of dung beetles in terms of bothhabitat and dung types. The present study was considered necessary as information on theecology of dung beetles in the dry zone of Sri Lanka is lacking. A total of 125 pitfall trapswere set in five habitat types (dry-mixed evergreen forest, riverine forest, stream/river banks,scrubland and grassland) and using five types of mammalian dung (leopard, ungulate,elephant, bear and buffalo) as baits. The pitfall traps were laid in the morning and kept openfor 24 hrs. A two-way ANOVA was conducted to discern significant differences betweenspecies richness and abundance of dung beetles across habitats and dung types.

A total of 455 individuals belonging to 22 species and 7 genera were recorded from the pitfalltraps. This included one endemic species. Significant differences in species richness wasapparent (P<0.05;F=3.34) between the different habitat types with the highest number ofspecies of dung beetles in the riverine habitat (20 species) and the lowest in stream/river bankhabitats (8 species). No significant differences were recorded with respect to abundanceacross the habitat types. However there was a trend that, from among the five habitats, thestream/river banks showed highest abundance whilst the scrubland had the lowest abundance.Considering preferences of dung types, significant differences were apparent for both speciesrichness (P<0.05; F=4.09) and abundance (P<0.05; F= 0.02). The highest species richnesswas supported by leopard dung (19 species) whilst the lowest number of species (11 speciesin each) was observed in both bear and ungulate dung. Highest abundance of dung beetleswas on bear dung whilst the lowest was on ungulate dung. Moreover some species wererestricted only to a few habitats or dung types (Onthophagus cervus only in riverine habitatand Onthophagus quedentatus only in buffalo dung).

This study has for the first time revealed habitat and dung preferences among dung beetles inthe dry zone Sri Lanka. Such information would be essential for the maintenance of a healthypopulation of dung beetles, which in turn would benefit natural ecosystems because of theirinvaluable ecological services.