Insects and Apocynum cannabinum.

Abstract

The objective of this study was to collect and study the flower visitors of Apocynum cannabinum, dogbane, to try to isolate the pollinators. In addition, observations were made on other insects associated with the plant. The reasons for studying this plant are that the pollination system is unknown, it has extremely low fruit set, and the family Apocynaceae is closely related to the Asclepiadaceae, whose pollination system is well understood and very interesting. Although the pollination of Apocynum cannabinum has not been completely verified, it appears that a wide assortment of insects could be responsible. Pollination seems to be primarily an accidental event occurring when an insect gets some body part trapped under the edge of the anther and in that way dislodges pollen onto the stigma. Many of the visiting insects have body parts long enough to accomplish this type of pollination. There are several other insects and spiders associated with the plant. They are either eating the plant or the insects the plants' flowers attract.