Community organization of clung beetles (Coleoptera: Scarabaeidae): Differences in body size and functional group structure between habitats

The structure of an Afrotropical, summer rainfall, dung beetle assemblage was analysed in terms of abundance, biomass,body size, dung-exploitation behaviour (functional group=FG) and soil association, This study facilitated design of dung beetle assemblages for dung and fly control in Australia. Overall abundance differed little between sand and clay but biomass was much greater on sand. On sand, biomass was dominated by large ball rollers (FG(I)) and large fast-burying tunnellers (FG(III)) whereas. on clay, dominant groups were large and small ball rollers (FG(I) and FG(II)) plus small-burying tunnellers (FG(IV)). Average body size was much greater on sand in FG(I), FG(III) and FG(VI) (kleptocoprids which use dung buried by other beetles), much larger on clay in FG(II) and similar on both soil types in slow-burying tunnellers (FG(IV), very small FG(V)) and endocoprids which breed within dung pads (FG(VII)). Sand specialists were represented in four logarithmic size classes from large (10(3)-10(4) mg dry weight) to very small (1-10 mg dry weight). Clay specialists were represented in the three smaller size classes and soil generalists primarily in the two smallest size classes. On sand, large body size may be related to lower constraints on dung burial as sand is softer than clay and varies little in hardness with depth. On clay, smaller body size and greater biomass of ball rollers, which disperse dung horizontally, may be related to greater constraints on dung burial since clay is harder than sand and increases in hardness with depth. The design of dung beetle assemblages for east Australia, where clays predominate, must clearly differ from those for sand.