Wednesday, April 29, 2015

maroon pawpaw bells

maroon pawpaw bells 
sway in the spring breeze, exuding
a fetid odor

Lovely to look at, but don't sniff the pawpaw blossoms. The color and odor of rotting meat, the flowers attract carrion flies and beetles for pollination. 
          This is the first year our young tree has produced flowers, so if it does get pollinated, and I can get to the delicious fruit before the raccoons, squirrels or opossums, we'll be in for a treat. The large fruits have a creamy texture and taste a bit like a ripe banana, not surprising since they hail from the same family as the custard-apple and cherimoya. This our largest native fruit and, as an added bonus, it contains more protein than most fruits.
          Actually, the entire tree has a disagreeable smell, due to the presence of acetogenins, a natural insecticide, which can be used to make an organic pesticide. Other pests, in the form of rabbits and deer, avoid nibbling the leaves and twigs. Where deer are dense, pawpaw patches prosper.
          There is one insect that is not deterred by the pawpaw's insecticide. The larvae of the zebra swallowtail butterfly feed exclusively on the young leaves, though not enough to harm the plant. Trace amounts of those nasty chemicals protect the butterfly from predators throughout all stages of its life, since birds avoid eating the bad-tasting insect.

Another fascinating story of survival. The pawpaw protects itself chemically from getting eaten by mammals and most insects. Then it gets its flowers pollinated, not in the usual way of alluring colors and sweet fragrance that attract bees and butterflies, but through imitating carrion to lure carrion insects. Finally, its sweet fruit gets consumed by mammals, which disperse the seeds to a new location. Meanwhile, the larvae of the zebra swallowtail eat the pawpaw leaves and somehow manage to avoid getting killed by the insecticide. Then the butterfly turns that chemical into its own defense against predators.

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