by Deirdre Loughnan, James D. Thomson, Jane E. Ogilvie, and Benjamin Gilbert
Flower-visiting insects tend to visit single species of plants, but in some circumstances they switch flower types within a foraging bout and therefore deposit mixed loads of pollen on stigmas. In a few species, the receipt of foreign pollen has been shown to depress fruit or seed set in the recipient flower. This phenomenon is termed “pollen allelopathy,” and the presumed mode of action is through soluble chemicals leached from the pollen grains.
|Non-native dandelions (Taraxacum officinale, yellow flower heads) invade a subalpine meadow below Mt. Crested Butte, Colorado, USA, where the study was performed.