The rainforest is teeming with dynamic relationships!

There are many dynamic relationships in the rainforests of the world. Which is expected as they are home to up to 40 percent of known plant and animal species. Within the forest there are a widely variety of symbiotic relationships, which means there are interactions between two species. For some species the relationship is beneficial for both parties, this is call mutualism. For example the Brazil nut trees (Bertholletia excelsa) produces a nut that is an only be cracked by a few species, one of which is various agouti (Dasyprocta sp.) which is a small rat like animal. The tree benefits as it’s seeds are dispersed and the agouti receives a free meal.


English: A Central American Agouti (Dasyprocta punctata) in Panama experimenting with a western diet.
Author Tomfriedel

In some cases one species is unaffected and the other benefits, this is commensalism. A example of this would be a frog sheltering itself from a storm event under the leaves of a plant. The plant is un effected but the frog benefits. Lastly, parasitism is when one species is harmed and the other benefits. Bot flies are a common tropical parasite that lay their eggs on a mammal host. The eggs then hatch and the larva develop in the skin of the host animal.

frog in rain

A frog in the rain in Belize. Image by Lauren Schramm

Competition is a symbiotic relationship in while two species use the same resources. Because it requires an energy investment both species are harmed, but the harm may be unequal. Many rainforest plants are animal pollinated or their seeds are dispersed by animals. Resource partitioning occurs when a resource is divided among species in some way like time or place. One way plants reduce their competition against each other is by targeting different animal groups. For example flowers pollinated by bats are often white making them easier to see at night, while flower pollinated by other animals are red, orange, and yellow. Bat pollinated flowers also contain a musky smells, while flower pollinated by moths, bees, and other insects have a strong fragrance. Plants also reduce competition by flowering and fruiting at different times. This is one reason there are always flowers and fruits available in the rainforest at any given time.

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Impact of Asian Clams (Corbicula fluminea) on on Unionidae, or the family of pearly freshwater mussels

Corbicula fluminea is a species of freshwater clam that is native to eastern Asia and has become an extraordinarily successful invader of freshwater ecosystems and is found on every continent except for Antarctica (Leff et al., 1990; Hornbach, 1992; Karatayev et al., 2007; Lucy & Graczyk, 2008; Sousa et al., 2008a; Crespo et al., 2015). It is widely theorized they were introduced as a food source on the west coast of the United States and were first discovered in the country in 1938 (Sinclair & Isom, 1963; Counts, 1981). Impressivly, C. fluminea have the highest secondary production values ever measured for a species colonizing a freshwater ecosystem and the highest record net productivity for any bivalve (McMahon, 2002; Sousa et al., 2008b). While there are multiple species of Corbicula that are invading aquatic systems, the most common species is C. fluminea (Renard et al., 2000; Siripattrawan et al., 2000). There are several factors that have led to successful invasions of C. fluminea including high fecundity, functional hermaphroditism, self-fertilization, rapid sexual maturity, lack of a parasitic life stage, pedal feeding (that is feeding via the cilia on the foot) and filter feeding, and the ability to disperse across long distances (McMahon, 2002).

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