i5K: Bull-headed dung beetle
Bull-headed Dung Beetle (Onthophagus taurus)
Bull-headed dung beetle
Image source: Armin Moczek
Contact: Armin Moczek
Researchers involved: ~200
Size (or size of nearest relative): 310mb
Keywords (and why important): morphological innovation, extreme species and morphological diversity, sexual selection, developmental plasticity, alternative reproductive tactics
The dung beetle genus Onthophagus comprises with over 2,400 extant species the most speciose genus within the animal kingdom. O. taurus itself is the most studied dung beetle and a focal taxon for studies in evolutionary ecology, evolutionary genetics, behavioral ecology, evo-devo and developmental genetics.
Like many species within the genus it features extreme secondary sexual traits (horns) and extreme sexual dimorphism (cued by sex-specific development). At the same time this species possesses an equally remarkable (and representative) male dimorphism (cued entirely by larval nutrition) in which large males express huge horns which they use as weapons in male combat, whereas small males remain hornless, non-aggressive, and instead invest into enlarged testes and ejaculates.
Onthophagus beetle are emerging as a model system in evodevo and ecodevo, in particular with respect to the evolutionary developmental genetics of plasticity, pattern formation, trait integration, and growth regulation. Extensive transcriptomic data already exist for this as well as other species, alongside a growing number of functional studies using larval RNAi-mediated transcript depletion, which works easily and routinely across diverse species within the genus.