What do dung beetles eat

• Published in: Ecological entomology 2007-12, Vol.32 (6), p.690-697
• Main Authors: HOLTER, PETER, SCHOLTZ, CLARKE.H
• Format: Article
• Language: English
• Subjects: Assimilable carbon; C/N ratio; carbon nitrogen ratio; coprophagous; Elephantidae; food exploitation; nitrogen; selective feeding
• ISSN: 0307-6946; 1365-2311
• DOI: 10.1111/j.1365-2311.2007.00915.x

1. Most adult coprophagous beetles feed on fresh dung of mammalian herbivores, confining ingestion to small particles with measured maximum diameters from 2-5 to 130 μm, according to body size and kind of beetle. This study explores benefits and costs of selective feeding in a 'typical' dung beetle with a maximum diameter of ingested particles (MDIP) of 20 μm. 2. Examined dung types (from Danish domestic sheep, cattle and horse, and African wild buffalo, white rhino and elephant) contained 76-89% water. Costs of a 20 μm MDIP were often low, since 69-87% of the total nitrogen in bulk dung other than that of elephant and rhino (40-58%) was available to selective feeders. 3. Nitrogen concentrations were high - and C/N ratios low - in most types of bulk dung compared with the average food of terrestrial detritivores or herbivores. Exceptions were elephant and rhino dung with low nitrogen concentrations and high C/N ratios. 4. Estimated C/N ratios of 13-39 in bulk dung (sheep-elephant) were decreased by selective feeding to 7.3-12.6 in the ingested material. In assimilated food, ratios are probably only 5-7, as most assimilable nitrogen and carbon may be of microbial origin. If so, the assimilable food contains a surplus of nitrogen relative to carbon. 5. The primary advantage of selective feeding, particularly in dung with a high C/N ratio, may be to concentrate assimilable carbon in the ingested food. Effects of changing the MDIP within 20-106 μm are modest, especially in dung with a low C/N ratio.