The changing natural world at our doorsteps | Illustration and text by Patterson Clark
June 29, 2010
Wineberry’s glandular hairs
In late June, the tart, seedy fruits of wineberry begin to ripen, capturing a
few small insects in the process.
The exotic, invasive raspberry was imported from Japan to improve cultivated varieties of raspberry. Birds, mammals and even box turtles continue to spread it.
As a fruit develops, it is surrounded by a protective calyx covered in hairs that exude tiny drops of sticky fluid. Some observers have suggested that the plant might derive nutrients from insects caught in the sap.
Not so, according to a 2009 study by Sina Pohl at the University of Vienna. She found that the sticky mucilage contains no digestive enzymes; surrounding tissues are unable to absorb nutrients; and protein-storage tissues are absent. Also, unlike carnivorous plants, which tend to grow in nitrogen-poor soils, wineberry grows in nurient-rich soil, so there's no need for any insect supplements.
Sources: University of Vienna; National Park Service