Relationships Among Insect Pollinators, Micro-environmental Factors and Fruit Settings of Teak (Tectona grandis L.F.) in Seed Orchards in Thailand
The ecological effects of insectsin the tropics have been studied generally in terms of their impact on species diversity and abundance. However, information is very limited regarding the inter-relationship of insects and ecological processes, such as, insect pollinators, environmental variables and fruit settings of teak. Five main teak seed orchards in Thailand were studied. Observations were carried out by walking on line transects and using air-flight malaise trapsfrom tree canopies in each site during the peak flowering season of teak. A total of 63 species in 17 families and three orders (Hymenoptera, Lepidoptera and Diptera) of flower visitors were found. The relationships between insect pollinator composition and environmental factors among the teak seed plantations were significantly different in species composition and some environmental variables. The results of this study showed that micro-environmental factors (temperature and photosynthetic active radiation) significantly affected species diversity and abundance of insect pollinators, especially in their foraging behavior responses to the photosynthetic active radiation variable. We, thus, concluded that some pollinators have different responses to environmental variables that affect their visiting behavior on flowers and also fruit set, and this was associated with visiting periods and habitats.