Concept/Content mutualism / ant-acacia symbiosis
Information caption Image 1: Ant feeds from acacia's nectary, a source of sugars. At the tips of the leaves are Beltian bodies, a source of fats and protein. Image 2: an ant examines the entrance to a nest, built in a hollowed bullthorn of the acacia.
The ants, in return, help prevent herbivores from eating the plant and they clear the forest floor, suppressing competition from other plants. Both species benefit.
Inquiry caption Here is an example of cooperation, or mutualism, between species: the ant/acacia relationship. The tree has large thorns, which serve as nests; nectaries, which provide sugars for the ants; and Beltian bodies, which provide protein. The ants patrol the tree and the ground underneath it, eating plants that might take light or water from the acacia, removing fungal spores, and stinging any potential herbivore. How might this system have evolved, in steps, from ancestors that had no such cooperative relationship? Why has the cooperation developed, even with increasing "costs" for each organism?
Can you name any other examples of mutualisms or systems of mutual benefit or exchange?
Target Concept: Organisms may cooperate when each benefits.
Photographer Dan Perlman
Credit © Dan L. Perlman/
SIZE in pixels [file size] 348x256 and 512x346

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