Bursting Berries

Much of the world's crop production, about 35 percent, relies on pollinators such as bees, birds and bats, according to a study published in October in the Proceedings of the Royal Society B: Biological Sciences.

The study comes on the heels of a National Research Council (NRC) report that detailed the decline in populations of key North American pollinators, which help spread the pollen needed for fertilization of crops.

The NRC report notes that honey bees in North America have been decimated by infestations of parasitic mites that were inadvertently introduced to the United States. Other factors pushing out the bees include antibiotic-resistant pathogens, competition from Africanized honey bees and habitat loss.

With dwindling natural pollinators, plants must find alternatives in order to survive and reproduce. Some crops, such as passion fruits in Brazil, are being hand-pollinated by day laborers. Another alternative is self-pollination, in which the sperm comes from pollen produced by the same flower or by another flower on the same plant.

This method can lead to reduced crop output due to "inbreeding." The image (above) shows raspberries (Rubus ideaus L) after passive self-pollination (left and middle) and open insect pollination (right).

-- LiveScience Staff

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Credit: Jim Cane/Bee Research Institute, Longan, USA