5 examples of animals helping each other that you might not have heard of

Posted on Tue September 1, 2020.

For me, one of the most interesting things in nature is symbiosis - two separate organisms that have adapted to each other and are now benefiting each other. They're working together and this is known as mutualism, it's a win-win situation.

The first example that comes to mind is often the oxpecker and the rhino, but have you heard about the warthog and the mongoose? Or perhaps the ant and the Acacia tree?

There are many other mutualistic relationships occuring in nature that you may not have heard of before. This week, Elly unearths some of the fascinating ways animals and plants are joining forces.

The termite and the protozoa:

Let's start with one of the smallest and most prehistoric examples of mutualism that, despite dating back almost 100 million years, is not well-known among modern-day safari-goers.

Termites, as we know, are one of the key players in the African bush. They serve a very important ecological role in helping to shape new habitat, increase soil fertility, recycle nutrients and serve as food for predators like aardvarks, birds and other insects.

Termites live on cellulose which is present in the dead wood they chew. However, this plant material is notoriously difficult to digest and termites lack the enzyme in their gut to break it down. Instead, many species recruit the services of tiny micro-organisms known as protozoa, which live happily in their gut and provide the missing enzymes required to digest the termite's fibrous diet. 

Although primitive termites may have had a diet that was more varied and digestible, they eventually acquired these protozoa which made it far easier to digest cellulose and soon came to rely on them.

Perhaps more interestingly, termites pass on these beneficial micro-organisms to their offspring by excreting a liquid that contains the protozoa. The young termites consume this faeces which delivers the special protozoa to their own digestive systems.

Unable to survive outside of the termite, these protozoa benefit from having a unique environment in which to live and a constant supply of food. Without these micro-organisms in their gut, the termite would starve, and it is in this way that the two depend on each other for survival.

The sunbird and the wild dagga:

Wild dagga (Leonotis leonurus), also known as lion’s tail, is fast-growing shrub with ball-like inflorescences on the stem. Harboured within its striking, red-orange flowers is a nectar that is simply irresistible to sunbirds. Like bees, they fly from one flower bloom to the next searching for this calorific reward.

Over evolutionary history, flowers have utilised many devices to solve the problem of pollination, that is, needing to get pollen from one flower to the next to produce seeds. As time went on, some plants developed such close partnerships that they even adapted their anatomy to suit their chosen pollinator.

Looking at a sunbird, you can tell immediately that it must be nectivorous. Its long, slender and curved beak fits like a jigsaw piece into the similarly long and curved flowers of the wild dagga. When sunbirds dip their bills into the flowers, they sip the sweet nectar and pick up grains of pollen from the flower. They then carry this pollen with them to the next flower, allowing the plant to reproduce.

The colour of the wild dagga flower is not a mistake either, with most bird-pollinated flowers being red or orange. Sunbirds, like hummingbirds, have a highly developed ability to perceive the colour red, but bees do not. A bee’s visible spectrum starts somewhere in the yellower shades of orange and peaks in the bright blues. This is why insect-pollinated plants usually have yellow or blue flowers, whereas bird-pollinated plants are often red.

Over time, the wild dagga is adapting to its pollinator, the sunbird, which are in turn adapting to the plant. This specialized plant-sunbird partnership has taken years to evolve, with each deriving a benefit from their incredible, close relationship.

The warthog and the mongoose:

Mutually beneficial relationships between two mammal species are uncommon in nature, yet an unlikely pairing has emerged in Queen Elizabeth National Park, Uganda.

Warthogs are not immune to the irritable effects of ticks; whose itchy bites have their mammalian hosts searching frantically for a possible remedy or relief. Buffalo often scratch against stumps or rubbing posts, giraffes walk back and forth over the tops of small trees, but warthogs have found another answer...

Lying down in the presence of banded mongooses, warthogs have learnt that their herpestid cleaning crew will come and inspect them for parasites, sometimes climbing on top of their customers for better access to ticks. Banded mongoose eat mostly insects, so this protein-rich tick supplement is an opportunity not to be missed.

This rare example of mammal-mammal mutualism is beneficial for both parties: the warthogs are cleaned of their irritating ticks and the mongooses score a free lunch. This is very similar to the more common relationship between oxpecker birds and their hosts, which include rhinos, giraffe and buffalo.

You can watch a video of this amazing interaction here.

The ant and the Acacia:

Some of the earliest accounts of mutualism in nature came from Central America, where scientists noticed plants and insects working together for the common good. More recently, a closer look at Acacia trees unearthed some serious plant-insect teamwork going on in Africa too.

Acacia trees (since renamed Senegalia orVachellia) are common across sub-Saharan Africa and have developed many mechanisms of defence against the large, browsing herbivores that feed on them. Alongside their physical defence (nasty, sharp thorns) and chemical defence (the release of distasteful tannins into the leaves), these cunning trees are also employing the support of ants as bodyguards. 

Three species of biting ants use these swollen thorns as nests and collect nectar from the bases of Acacia leaves. So closely cohabiting are these two partners that healthy trees, which have hundreds of thorns, can contain more than 100,000 ants per tree!

In return for the thorny accommodation and plentiful food, the tree benefits by gaining a third line of defence against herbivorous predators. The ants will swarm against anything that molests the tree and inflict nasty bites in an attempt to ward it off.

Interestingly, scientists in Kenya found that this insect-tree partnership is not as effective without the ever-present threat of browsing mammals. Trees that were protected from browsers had fewer nesting ants, and these ant colonies were less able to defend themselves against a nasty rival.

This fourth species of ant does not enjoy a friendly relationship with the Acacia tree. On the contrary, it actually encourages a destructive, wood-boring beetle to make cavities in the tree which then serve as the ant's home. This beetle infestation causes the trees to become poorly.

So, if it werent for the giraffes munching away at their favourite Acacias and giving the 'good ants' a defensive job to do, they would be replaced by 'bad ants' and everybody loses. In this way, both insect and tree derive benefits from each other, but even more so if hungry browsers are searching for lunch!

The honeyguide and the hunter:

Honey provides traditional hunter-gatherers with an important source of energy, and the Hadza people of northern Tanzania go in search of bees’ nests on a daily basis. with honey providing about 15 percent of the calories in their diet.

Another animal with a love of this golden treat is the Greater honeyguide, so named for its unique talent of ushering humans to beehives. This amazing showcase of bird-human cooperation has also resulted in the species’ fantastic scientific name, Indicator indicator.

It is believed that honeyguides and humans have been co-evolving on the plains of Africa for millions of years, solidifying a very close relationship between the two. Traditional Hadza honey hunters have learned to rely on this brown, robin-sized bird, following it through the savanna as it hops from branch to branch with an excited chatter.

In following honeyguides, the Hadza people were able to increase the rate at which they found bees’ nests by 560 percent! Not only that, the birds led them to nests that were significantly bigger and more productive than those they would have found by themselves.

Once the beehive has been located by the honey hunters and their spoils collected, the honeyguide benefits from the sweet leftovers afforded to them for their efforts. In fact, this unique diet has resulted in these birds developing the unusual ability of digesting beeswax, thanks to a collection of special enzymes in their digestive tract.

Although these birds are wild and certainly have not been trained to behave in this way, recent research in Mozambique found that honeyguides will even respond to specific calls made by humans. By using these special calls to communicate with each other, people and honeyguides have evolved a unique and special partnership that is rarely seen in the wild.

 

Article written by Elly Gearing with photos courtesy of Meggyn Pomerleau, Nerise Bekker, Sanjay Shivakumar and Elly Gearing.