Fun with Science Club®


			Monito del montes plant mistletoe gardens in the treetops. Carrie Straight 05.18.01 Mistletoe, Tristerix corymbosus is a plant that grows on other plants. It is the plant that people hang over doorways during Christmas to kiss under. Mistletoe does not need to touch the ground to live. It plants its roots into another plant, usually a tree, and sucks up the food it needs from the plant on which it is growing. Mistletoe is called parasitic, because it hurts the plant it is living on. Scientists in South America wanted to figure out what type of animal helped disperse (spread around) the seeds of the mistletoe that was growing in Llao-Llao Reserve, Argentina. For the plant to grow, two things must happen. (1) The outer casing of the seed must be removed, and animals can remove the outer casings by eating the seeds (the digestive tract of an animal removes the casing). (2) The seeds have to be placed on another living branch of the same or a similar tree. Once the outer casing is gone, the seed is ready to grow. And when seeds travel through animals' guts, it begins life with a little fertilizer! Originally, scientists believed that birds dispersed mistletoe seeds. So the scientists watched these plants for 500 hours. If they watched all day that would be more than 20 days straight. They didn’t see any birds eat the mistletoe fruit. Next, they put up nets and caught many birds from the area. Then they made the birds regurgitate (vomit), but none had mistletoe seeds in their stomachs. The scientists recorded the time that seeds disappeared from the plants. They discovered that almost all of the seeds disappeared at night. So the scientists went out into the forest and set up cameras to take pictures of what came to the plants and what ate the seeds. Using motion detectors, the cameras took pictures of animals visiting the plants at night. The most common animal around the plants was a small marsupial mammals called “monito del monte” (Dromiciops australis), but they didn’t see it eating the mistletoe. The next step was to see if the monito del montes had eaten mistletoe seeds. The scientists put up small live-traps (a trap that does not hurt whatever it captures, so that the captives can later be let go). The traps caught some monito del montes. The marsupials defecated (“pooped”) mistletoes seeds while they were in the live trap providing an answer to the question.


			Amico, Guillermo and Marcelo A. Aizen. 2000. Mistletoe seed dispersal by a marsupial. Nature 408: 929-930.