Pitcher plant leaves are primarily green in the summer, tinged with red, but as summer turns into fall, many become deep red. Although this red color was thought to attract insects, it appears that this is not the case. The color change, according to research cited in the Journal of Ecology, is due to the level of phosphorus this carnivorous plant has received from its insect meals. There is a limited amount of phosphorus in a bog and plants living there acquire it in different ways. The pitcher plant acquires phosphorus from insects that it traps. It then utilizes the phosphorus to revitalize the (green) chlorophyll in its leaves for photosynthesis. The deep red color that the leaves turn in the fall indicates that the plant has not had a good meal in quite some time.
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