Normal and atypical nesting behaviour of Copris lunaris (L.): Comparison with a related species (Coleoptera, Scarabaeidae)

1. The life cycle, mating and larval behaviour of C. lunaris are described. Adults appeared in the autumn and nested in the following spring. The female beetle remained in the nest with the brood and could nest again the following year. 2. Nesting was initiated when virgin females were mated in the spring. Brood balls were formed by techniques sirnilar to those used by Scarabaeini. The female beetle left the nest soon after the first imagos broke out of the brood balls. 3. Nesting behaviour was readily modified by external conditions. Many parts of the sequence could be repeated or omitted. The female beetle left the nest if the brood was removed, but she remained for longer than usual if younger brood was substituted near the end of the normal nesting period. 4. Certain experimental conditions released behaviour patterns typical of other species. These were formation of superficial nests or of two-chambered nests, oviposition before completing the brood ball, and coating of the brood balls with soil (all found in other Coprini), as well as ball rolling and ball burial (found in Scarabaeini). The results are discussed in relation to the evolution of Copris nesting behaviour.