Dynastinae or rhinoceros beetles are a subfamily of the scarab beetle family (Scarabaeidae). Other common names – some for particular groups of rhinoceros beetles – are for example Hercules beetles, unicorn beetles or horn beetles. Over 300 species of rhinoceros beetles are known. They are important due to their role in recycling plant material and promoting nutrient turnover. However, some species are phytophagous and can attack crop plants, thus becoming pests.