Interactions with Other Organisms



The most common mutualistic relationship occurs between the bee and the alfalfa plant. The bees fly from flower to flower taking the nectar from the plant. While the bee is collecting nectar, he is also providing a vital function to the plant; pollination. Without bees to pollinate, alfalfa would cease to exist.

Another important mutualistic relationship is between nitrogen fixing bacteria called Sinorhizobium meliloti and alfalfa. The alfalfa plant cannot break apart the triple bond holding the nitrogen together, however, the bacteria can. The bacteria infect the plant and create nodules where it will convert atmospheric nitrogen into ammonia (which the plant uses to produce proteins). In turn, animals intake protein by eating the plants, or eating an herbivore. We now see how the plant benefits from this relationship, but how does the bacteria benefit? The bacteria receives sugars and other essential nutrients from alfalfa.


healthy alfalfa verse alfalfa infected with a stem nematodeParasitic

Two parasites that invade alfalfa are stem nematodes and root knot nematodes. These roundworms live in the stems and roots of alfalfa. They cause slow growth and in some cases death. 



Many weeds compete with alfalfa for food, water, and sunlight. Roundup Ready alfalfa eliminates the weed problem with their herbicide. It does not kill the alfalfa because the alfalfa has the Roundup Ready gene in it.





Many herbivores eat alfalfa and their primary food source. Cows (Click on "cows" for more information)are one of the main predators. Farmers grow alfalfa to feed their livestock. However, other animals like deer (Click on "deer" for more information), horses, alfalfa weevils, potato leaf hoppers, and aphids also feed on alfalfa. This plant is also important to humans. As a primary producer, alfalfa makes its own food. Herbivores such as cows receive their nutrients from eating the plant. Humans use cows for food sources of meat and dairy. Some people also eat alfalfa directly as alfalfa sprouts. Dehydrated alfalfa is also being used as a dietary supplement for people.

 Taken by Kelsey Brooks


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