Evolving together: the biology of symbiosis, part 1
Symbiotic relationships exist everywhere we look; they are beginning to .. of the aquatic fern Azolla, which floats on the water in our cypress swamps (Figure 9). Commensalism is a relationship between two organisms where one receives a benefit or benefits from the other and the other is not affected by it. In other words . Mutualism and protection rackets in the Florida Everglades. Actually, perhaps friendly isn't the best word for the relationship. In many ways.
As mentioned above, the zooxanthellae "trade" sugars for nutrients; it's convenient that the wastes of the coral CO2, ammonia, etc. Interestingly, both the corals and the zooxanthellae can survive without the other at least for a while ; under conditions of stress the corals are known to expel the endosymbionts in a phenomenon known as coral bleaching. Under happier times, the corals direct their growth to maximize sun exposure for their algal guests; you can see this clearly in the photo of the Elkhorn Coral above.
This jellyfish spends its time upside down in the shallows of mangrove swamps exposing its algal endosymbionts to the sun. Two other mutualistic symbioses found on the coral reef are pictured to the right, although they are not as tight as the endosymbioses of coral and zooxanthellae.
In the photo to the right, a barracuda takes an unusual heads-up posture.
Evolving together: the biology of symbiosis, part 1
He has arrived at the large brain coral, which makes a conspicuous landmark seamark? When the barracuda takes this pose, the Cleaning Fish know it is safe for them to approach - the 'cuda is looking for a cleaning, not a meal. The tiny fish will scour the skin, mouth and gills of the Barracuda, removing any ectoparasites they find and getting a good meal out of it. There was a line of about 6 barracuda waiting to get cleaned here; the others were behind me in the line.
Finally, everyone who has seen "Finding Nemo" knows about the association between Clownfish and Anemones. By working its way carefully into the anemone, the clownfish gradually accustoms the anemone to the chemical makeup of the fish's skin; this gradual acclimatization prevents the anemone from stinging the clownfish while fish with a different "taste" will be stung and eaten.
The fish gets a safe house and some tidbits; the anemone gets cleaned and has the clownfish working as lures to bring in potential prey, or chasing away fish that would harm the anemone.
Symbiotic Relationships - Everglades National Park
Some scientists do not see any benefit for the anemone and classify this as a commensalism. The Sea Lamprey, above left, is a sort of temporary parasite.
It latches onto a fish and uses the teeth to hold on and rasp away the skin, leaving an open wound for the lamprey to feed on. It drops off, usually without killing the "host". Sea Lampreys are not specific on any species of fish; they will latch onto any living thing and try to feed.
The wasp above has stung and paralyzed a spider. It will take the spider to a nest and lay an egg on it. The larvae will consume the still-living spider; often from the inside. This is usually considered to be a parasitoid relationship.
Swamp by Dallas Williams on Prezi
Two more mutualistic relationships from the Costa Rican forests. These algae help to camouflage the sloth against the lichen-covered tree note the brown fur of the baby, not yet covered with algae.
There is even a moth that lives only in the sloth's fur and consumes the algae; this is a commensal relationship between the moth and the sloth.
Below, a mutualistic relationship. The Acacia Tree is partially protected by large thorns, but it gets extra protection from Acacia Ants.
The plant does 3 things to lure in the ants.
First, the large thorns are hollow and provide a place for the ants to live. Second, the plants have swollen glands, nectaries, which produce a sugary solution the ants drink. The nectaries are obvious in the photo below. In return for the room and board the ants chase off herbivores, kill and eat herbivorous insects, and destroy and plants that try to compete with the acacia. The horsehair worm starts life as an egg laid in a puddle.
The puddle dries out and a grasshopper or similar insect comes along and eats the egg, which promptly hatches and burrows through the gut of the insect into its body cavity or hemolymph. Here, surrounded by the nutritious blood of the insect it grows until it reaches adulthood. At that point it starts producing chemicals which take over the brain of the insect and cause the insect to seek out water, which it jumps into.
The worm then exits the hopper and lives in the puddle, mating and laying more eggs.
The grasshopper, if it doesn't drown, may survive the ordeal. Below, a social parasite. This cricket lives in an ant nest. It disguises itself with a chemical signature that fools the ants into thinking it is just another ant. It is free to roam the nest and it even gets the ants to feed it. The Brown-Headed Cowbirds above are nest parasites.
They originally followed the bison on the Great Plains, feeding on insects kicked up by the large herds.
Since the bison themselves migrated, following the melting snows and eating the fresh spring grass, the cowbirds had to move as well. This presented a problem, as it's hard to incubate eggs on the move. Lay the eggs in other birds' nests, and trick the other birds into raising your young.
The cowbirds hatch out first, push the other eggs out of the nest, and the nest-builders often much smaller than the rapidly growing cowbird end up feeding it instead of their own young. Even though the other birds may pattern their eggs the cowbirds are up to the challenge.
Cowbirds hesitate entering forests, but roads, farms, powerlines and other human intrusions give them a pathway deep into the woods where they are free to parasitize the nests of birds which until the arrival of humans didn't have to worry about the cowbirds. Some of these bird species are on the verge of extinction as a result. Bromeliads left, above left avoid the hassle of crating a trunk to lift their leaves above the forest floor and closer to the sun.
They simply grow on the branches of trees. Since the bromeliads don't take any nutrients from the trees this is usually classified as a commensalism, but if there are a lot of bromeliads left the tree will need to add extra wood to support the weight a bromeliad can trap up to 10 gallons 80 pounds of water in its leaves.
So, if there are a lot of bromeliads the relationship overall turns into a negative for the tree. The bromeliads also host a number of organisms in the water they trap; the wastes from the animals living there undoubtedly fertilizes the bromeliad in a mutualistic relationship. The tree at lower left is absolutely covered with epiphytes. This project will test that general hypothesis using both field and laboratory experiments to study the crayfish-worm model system.
The project will examine the importance of species behaviors and other traits in maintaining the interaction at mutually beneficial levels, and explore how the mutualism is shaped by environmental context.
The project will also explore the broader consequences of a shift from mutualism to parasitism to the rest of the food web and stream ecosystem. This project has substantial broader impacts; it is a collaboration among faculty at three universities, one of which is a predominantly undergraduate institution.
Many undergraduate students will be training in aquatic ecology, and will participate in team-structured, multi-year research projects. A number of graduate students will also be supported by this project, and will lead outreach efforts through partnerships with local watershed associations and university extension programs. Project Report Most people are aware of, and fascinated by, mutualistic relationships — symbioses between species that benefit all involved. Well known mutualisms include cleaner shrimp removing parasites from fish and pollination of flowers by bees.
A lesser-known mutualism involves crayfish and branchiobdellidan worms. These worms, which are closely related to earthworms and leeches, feed on material found on the surface of their crayfish hosts. Worms gain food, transportation, and a site for reproduction.
Crayfish benefit by being cleaned of fouling organisms. Just as in our own relationships, the outcomes of this symbiosis can change over time. The relationship can change from benefiting both partners, to helping only one but not the other commensalismto harming one partner parasitism. Understanding the factors that lead to shifts in symbiotic outcomes help scientists understand how changing environmental conditions can facilitate mutualisms or cause shifts to commensal or parasitic relationships in natural and aquaculture systems.
We used red swamp crayfish Proambarus clarkii and their associated worms Cambarincola barbarae to investigate shifts between mutualistic, commensal, and parasitic relationships. Similar to previous studies, we found that crayfish in surface waters with a lot of organic material leaves, sticks, etc.
As the pods ripen, they fall into the mud and roots form that eventually become a new tree. Across the globe the location of mangroves usually runs parallel to coral reefs. The relationship between the two is clear: Mangroves act to purify the water from human wastes and pollutants, and in doing so, coral reefs are less effected.
An essential component of the island ecosystem, mangroves provide structure to the island, while preventing erosion.
The coastline is protected because the roots of mangroves act to trap sediments that would otherwise be washed back out by the waves. Moreover, mangroves provide a habitat for many different species of animals, including bats, lobsters, manatees, and birds.