Attempts to Introduce Stingless Bees for the Pollination of Crops under Greenhouse Conditions in Japan
In Japan, a growing number of greenhouses for crops are now in use, where no wild pollinators are available. Although a large number of colonies of honeybees, Apis mellifera, and bumblebees, Bombus terrestris, are used for pollination, farmers face difficulty because of the absolute shortage of pollinators. Consequently, many of them are obliged to perform artificial pollination or apply hormones to their crops. To respond to these situations, the author has been trying to introduce the use of new efficient pollinators in recent years. Stingless bees, Meliponinae, and honeybees, Apinae, are the only highly social bees living in permanent colonies, and both share many biological characteristics. Many advantages could be expected from the use of stingless bees as pollinators. They are harmless to beekeepers and farmers, are active throughout the year, visit a wide range of crops (polylecty), and do not pose any environmental risks by escaping into natural habits because they cannot tolerate cold weather, especially in the winter. Consequently, among the stingless bees kept in their indigenous habitats, some promising species have been chosen and introduced from tropical and subtropical habitats overseas. These are Meripona beecheii, M. quadrifasciata, Trigona carbonaria, Tetragonula fuscobalteata, Scaptotorigona bipunctata, and Tetragonisca angustula. This paper shows the process of introducing stingless bees and the facilities involved, together with the pollination results obtained by using these bees.