Pasture diet of cattle contributes to the reproductive success of dung beetles

Abstract

1. Cattle diet plays a crucial role in the quality of dung and the consequent reproductive capacity of dung beetles. We investigated how three pasture types (improved native, forage oat and inter-sown rye/clover) influence the dung quality, the number of broods and reproductive output measured as brood size (dry weight and ellipsoid volume), development time and F1 progeny size (beetle length and pronotum width) of Onthophagus binodis, Euoniticellus africanus and Euoniticellus intermedius. 2. Nitrogen content was highest in rye/clover-derived dung compared with improved native and forage oat. Improved native-derived dung had the highest carbon, energy, organic matter, pH and insoluble non-starch polysaccharide content, whereas forage oat had the lowest contents. Forage oat had the highest moisture content, ash and soluble non-starch polysaccharide content compared with the other pastures. 3. Progeny length was influenced by pasture type, with female E. intermedius, and males and females of O. binodis being 11.4%, 11.2% and 7.3% longer, respectively, in rye/clover-derived dung than forage oat dung. The pronotum width of O. binodis F1 progeny was 9.8% wider when produced from rye/clover dung than forage oat. 4. Rye/clover- and improved native-derived dung provided the best resource for dung beetle reproduction compared with forage oat dung. Based on this study, cattle diet is important for consideration when evaluating reproductive ability and progeny measurements. Cattle diet should be further investigated as only three pasture types were investigated out of a numerous number of species and combinations.