The role of pteropodid bats in pollination of durian (Durio zibethinus) in managed orchards in suburban habitat of Thailand

Pollination specialists are increasingly threatened worldwide, especially in intensively-managed durian orchards where loss of pollinators may lead to reduced fruit production. In tropical plant communities where plant species attract multiple species of pollinators, specialists may have advantages over generalists. The present study examined the pollination ecology of durian (Durio zibethinus) in intensively and non-intensively managed orchards in suburban habitats of Nakhon Nayok and Chanthaburi provinces, respectively, in Thailand. Manual-pollination yielded the greatest fruit set 60 d after pollination, followed by open pollination (mostly by pteropodid bats), and insect pollination, while non-pollinated flowers had no fruit set. Eonycteris spelaea was the major bat pollinator in both provinces. Bats found in suburban habitat of Nakhon Nayok were mostly Eonycteris spelaea (67%). Pollen of at least five plant species was found on Eonycteris spelaea fur, including Musa sp., Oroxylum indicum, Durio zibethinus, Bombax valetonii and an unknown species. Pollen of only two species, Oroxylum indicum and Musa sp., was observed on Cynopterus sphinx fur. The non-intensive orchards in Nakhon Nayok, where mixed-species gardens are maintained under more naturalistic conditions, might offer higher fruit set on average. Such conditions might maintain higher bats capture rate of natural pollinators and reduce the risk of pollination failure in comparison with intensively-managed durian orchards.