Artwork by

Iris Notecard



Larger Blue Flag (Iris versicolor) and Bumblebee (Bombus sp.)

This native iris occurs throughout the northeastern meadows and wetlands from late spring to early summer. The name “blue flag” probably derives from the delicate texture of the flowers and the graceful manner in which they sway in the breeze. A variety of insects are attracted to this showy flower, but the bumblebee is probably its most effective pollinator. Bumblebees have an acute sense of smell and are often attracted by floral odors. As the bee approaches, the pattern of lines (nectar guides) on the flower helps direct the bee to the nectaries. The bee’s landing pad, tinged with yellow, underlies the overarching sexual parts of the flower. On its visit to the nectaries, the bee first brushes against the upturned stigma (receptive female structure) and then the upturned anther (pollen-producing male structure). The bumblebee’s hairy coat is ideally suited for transferring pollen from anthers to stigma to effect cross pollination as the bee travels to other flowers.

Bumblebees are social insects living predominantly in cool temperate regions. Their colonies, which may grow to a few hundred individuals, do not survive the winter. Mated queens leave the hive before cool weather sets in to seek hibernating quarters. In spring, the queens emerge from hibernation to search for a nest site, typically a small cavity such as an old mouse nest. As female workers are produced they assume foraging responsibilities while the queen concentrates on rearing males and new queens. Bumblebees forage for nectar and pollen from dawn to dusk and can fly at temperatures below freezing (most bees are grounded at temperatures below 60° F). They have evolved mechanisms to regulate their body temperature which allows them to fly under harsh weather conditions; their hairy coats serves well as an insulator. The pollination services of these bees are appreciated by fruit growers during the spring when the weather may be unfavorable for other bees.

artwork by Lynn Usack © 1994

text by Steve Sierigk