Hairs that grow on plant organs have been shown to play a variety of roles. Paederia foetida (Rubiaceae) is a perennial vine with many glandular hairs in the floral tube. The hairs of P. foetida are thought to play a role in preventing ants from entering the floral tube, but this has not been tested. We aimed to test this hypothesis by trimming the glandular hairs in the floral tube in the field. The results showed that trimming the glandular hairs increased the success rate of ants entering the floral tube. Thus, our findings indicate that the presence or absence of glandular hairs in the floral tube of P. foetida has an effect on an ant's ability to enter a flower and suggest that the glandular hairs in the floral tube of P. foetida might have played a role in preventing ants from entering.
