Symbiosis – exploring the unseen ties that bind us

All of life is an unravelling, a shedding of perception into deeper understanding, which in turn paints a richer, more vibrant world. For most of us, symbiosis is “a close, prolonged association between two or more different biological species”. But this, along with many other definitions, oversimplifies the idea, and removes some of the warmth behind the word’s earliest meaning: the living together of unlike organisms.

The behaviours and relationships in nature have been developed not only for forms of life to survive, but, at times, to help others survive as well. These unseen ties bind us all together, enriching our lives in countless, often unseen ways. By looking to symbiosis in nature, we begin to glimpse just how deep these ties are.

Beneath mud, moss, and leaf-lined forest floors live vast fungal sprawls known as mycorrhizal networks, or more colloquially, the Wood Wide Web. This web, mycelium, which underlies the fungi we see protruding from the ground, connects plants and trees. The tiny threads that comprise it burrow into root systems, enabling an exchange of nutrients and information.

Through photosynthesis, trees and plants produce sugars and fats and store carbon that fungi need to survive, which they share. In return, fungi absorb water and nutrients from the soil and pass them along to trees in a microscopic act of reciprocity. Mycelium also suppresses pathogens that might harm trees and allows them to detect if their brethren are ailing and direct nutrients to them to help their survival. This is a form of mutualism, in which both species in an ongoing interaction benefit from their relationship.

Egrets following elephants, who kick up appetising insects as they trudge along, dung beetles gathering droppings up to 50 times their weight, weaver birds crafting intricate nests in thorny acacias to stave off predators. These are just some of many examples of commensalism – a form of symbiosis in which an organism doesn’t harm their host or collaborator, but benefits from the relationship – in the wild. Some are more readily apparent or observable, even well-known, and some are less obvious to the eye, like the relationship between mites and millipedes.

In an act called phoresy, mites latch onto millipedes’ bodies, purely for transport, without feeding on or harming their hosts. Sometimes, they might consume dirt or debris stuck in the gaps between their plates, but mostly, this form of hitchhiking is simply a way for the mites to move between habitats quickly.

Honeyguides are fascinating birds. The Greater honeyguide, for example, has a reciprocal relationship with humans. Through shared whistles and calls, they lead people to beehives to harvest honey in return for nourishing honeycomb, wax, and larvae. This is a beautiful example of mutualism. However, species can engage in more than one symbiotic relationship at a time, and more than one type.

Honeyguides are also obligate brood parasites, meaning they lay their eggs in the nests of other birds. When chicks hatch, they use their sharp, hooked beaks to get rid of the original species’ young, effectively gaining a monopoly on maternal care. These host birds then raise the honeyguide’s young instead of their own.

For well over a century, Darwin’s idea of ‘survival of the fittest’ has shaped our understanding of evolution as a story driven solely by competition and domination. Yet the theory of symbiogenesis gestures toward another possibility: that early life evolved through the merging, cooperation, and co-dependence of different organisms – through symbiosis itself. Both narratives may be true, unfolding at different scales or in different moments. And perhaps there are more perspectives, or ones yet undiscovered.

But either way, when we observe the depth, diversity, complexity and intricacy of the natural world, we begin to see that life isn’t sustained by isolated mechanisms, or by strength, skill, and luck alone, but by the relationships that weave them together, forming the living fabric of the world. Even in human culture and community, we see this. And in observing how closely symbiosis is bound to survival, perhaps we can learn or relearn ways of living together with the rest of nature, for its sake and each other’s.

Explore symbiosis further in the latest volume of the Singita Magazine.