大豆為兼具閉花受精及開花受精的作物，自然異交率低於1%，但是由於品種與環境的效應，可能使大豆的異交率高於1%。一般而言，大豆的天然異交可能是由於小型的昆蟲在花朵間移動所造成。本研究的目的即在調查台灣大豆產區昆蟲相的分佈以及可能對大豆授粉的影響，並探討大豆花粉飄散之範圍，以作為未來防範基因轉殖大豆花粉流動的參考。調查結果顯示，不論黏紙取樣或掃網取樣，皆捕獲到薊馬與蜜蜂等昆蟲，這些昆蟲被認為可能是造成大豆異花授粉的媒介。此外，異交率檢測結果顯示，僅發現少數異交，距離貢獻親1.2公尺處的異交率平均為0.07%，而3公尺處的異交率平均為0.13%，超過3公尺後的異交率皆為0%。因此，建議以10公尺作為GM大豆種植與非GM大豆共存的隔離距離。

Soybean is one of cleistogamous and chasmogamous crops with outcrossing rate less than 1%. However, because of the variety and environmental effects, its outcrossing rate could be greater than 1%. Generally, the movement of small insects between flowers could result in the cross-pollination. The objective of this study is to investigate the distribution of insects in the soybean field in Taiwan and their influence on pollination. In addition, the range of pollen dispersal distance was also evaluated. This information provides an useful reference for preventing pollen flow of soybean. The study shows that some pollinator insects, such as honeybee and Thripidae, can be caught in the field regardless of using insect adhesive trap or sweep net sampling methods. Insects mentioned previously were the potential pollinators of the soybean. In addition, the result of outcrossing rate showed that only little outcrossing was detected in our study. The average outcrossing rate was 0.07% at 1.2 m from pollen source, 0.13% at 3 m from pollen source, and 0% beyond 3 m. Therefore, the recommended isolation distance is 10 m for co-existence of GM and non-GM soybeans.