1. Symbioses make the world go round
Clockwise from top left: Clownfish with sea anemone (+/+), ox with ox pecker (+/+), caterpiller infected by parasitoid wasp (+/-), Leaf cutter ants farm a fungus to feed themselves (+/+), human stomach bateria (+/+), root nodules with nitrogen fixing bacteria (+/+)
Joanna Weremijewicz
University of Miami

2. A close relationship between two different species
A symbiosis is a close relationship between two different species. Organisms have needs such as food or shelter for survival and sometimes another organism can provide those in exchange for food/shelter to the other organism.

3. Parasitism is a symbiosis where one organism benefits (+) and another is harmed (-) by the relationship.
Tomato horn worm infected by braconid wasp. Wasp lays its eggs inside the caterpillar where they hatch into larvae that feed on the hornworm’s muscle tissues. When larvae are mature, they exit through a hole they make in the skin and build a cocoon on the outside where they transform into adults.
Parasitism (+/-)

4. Mutualism (+/+)
A mutualism is a symbiosis where both orgnaisms benefit. Here, a butterfly pollinates a flower and get pollen on its body while obtaining nectar for food (+). The flower benefits when the butterfly spreads the pollen to another flower and helps it reproduce (+).

5. Commensalism (+/0)
Commensalism is when one organism benefits without affecting the other
A titan triggerfish (Balistoides viridescens) creates feeding opportunities for smaller fish (+) by moving large rocks too big for them to shift themselves, but it does not benefit nor is it harmed by the relationship.

6. Plants need symbioses for growth
Plants need water, sunlight and soil to grow. Soil contains many nutrients similar to when people eat food or take vitamins everyday. Plants have mutualisms that help them obtain that food and vitamins from the soil.

7. Plant root Fungus hyphae (cells)
Left: Some plants have these nodules (ball-like structures) that provide a home for bacteria (+). These bacteria make nutrients for the plant (called nitrogen) to help the plant grow (+).
Right: 90% of plants in the world have an association with mycorrhizal fungi that help take up nutrients.
Plant root

8. Mycorrhizal fungi
These fungi live on or in the plant root because they need a home. The plant feeds the fungus some of the sugar it made through photosynthesis (+). The fungus spreads out in the soil with it’s hyphae, or cells, and takes up nutrients the plant roots can not reach and feeds the plant (+)

9. Without mycorrhizal fungi With mycorrhizal fungi
Plants grow very poorly without these fungi.
With
mycorrhizal fungi

10. Mycorrhizal networks can connect plants belowground
The circle shows where the fungus hyphae connect belowground, therefore connecting plants growing near one another. Joanna Weremijewicz, a scientist at the University of Miami, researches how plant competition for nutrients is affected when plants are connected.

11. Competition is INCREASED when plants are connected by mycorrhizal networks
Several large plants
Many small plants
Frequency (%)
Plant weight (g)
The result is competition is INCREASED when plants are connected through mycorrhizal networks, which results in many small plants and several large plants.