Dōtaku (銅鐸?) are Japanese bells smelted from relatively thin bronze and richly decorated. For a topic outline on this subject see List of basic Japan topics. A bell is a simple Sound -making device The bell is a Percussion instrument and an Idiophone. Bronze is any of a broad range of Copper alloys, usually with Tin as the main additive but sometimes with other elements such as Phosphorus The oldest dōtaku found date from the 2nd or 3rd century (corresponding to the end of the Yayoi era), and were nearly only used as decorations for rituals. The 2nd century is the period from 101 to 200 in accordance with the Julian calendar in the Christian / Common Era. The 3rd century is the period from 201 to 300 in accordance with the Julian calendar in the Christian / Common Era. The is an era in the history of Japan from about 500 BC to 300 AD. A ritual is a set of actions often thought to have Symbolic value the performance of which is usually prescribed by a Religion or by the Traditions Richly decorated with patterns representing nature and animals (among which the dragonfly, praying mantis and spider are featured), historians believe that dōtaku were used to pray for good harvests. Nature, in the broadest sense is equivalent to the natural world, physical universe, material world or material universe. Anisoptera redirects here For the genus of trees see Anisoptera (tree. The Insect order Mantodea or mantises consists of approximately 2000 species worldwide in Temperate and Tropical habitats of Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings In Agriculture, the harvest is the process of Gathering mature crops from the fields Reaping is the cutting of Grain The animals featured are indeed natural enemies of insect pests that attack paddy fields. A paddy field is a flooded parcel of Arable land used for growing Rice and other semiaquatic crops.