Another observation from my garden, only now the insights are more fascinating. This involves three different species and their symbiotic relationships. Read on to learn more!
- Amruthaballi vine – Tinospora cordifolia
This is a medicinal plant (local common names – giloy, gurjo, amruthaballi) indigenous to tropical regions of India. It is a climbing shrub with several elongated twining branches. These have heart shaped leaves and bright red fruits that attract birds. It is a fast-growing shrub. The ones in my balcony garden have climbed two floors clinging on to the rain water drain and can be seen on the terrace!
- White-footed Ant – Technomyrmex albipes
These are small ants 2 to 4 mm long with legs that have white lower parts, which gives it the name. Foraging for food is done by worker ants, which also build and care for the nest and care for the brood (larvae and pupae). It is considered a pest because it is found foraging in kitchens, bathrooms, and building exteriors. Their feeding behavior leads to the main part of the story. Wait for it!
- Cotton Mealybug – Phenacoccus solenopsis
These are common pests of many plants and considered a serious agricultural pest. These are soft-bodied insects covered with white, waxy and cottony material. The white fluff around their body helps prevent loss of moisture and protect from excessive heat.
Symbiosis – Parasitism
Now comes the symbiotic relationship between two species – Tinospora plant and the mealybug. In this case the mealybug is a parasite on the Tinospora plant. Parasitism is the type of symbiosis in which the parasite will benefit from the relationship while the host is affected adversely. I noticed that in our garden the cotton mealybug seems to be prevalent over nodules where fresh leaves are sprouting. I guess it is because these are places with a high concentration of nutrients to support the newly growing leaves. In this relationship the mealybug benefits from the nutrients with no apparent benefit to the plant.
Symbiosis – Mutualism
Now we come to the most interesting part, the symbiotic relationship between the cotton mealybug and the white-footed ant. It is Mutualism in which both the species stand to benefit. The mealybug provides food to white-footed ant in exchange for protection from predators and transport to different parts of the host plant!
How does this work? The mealybug takes nutrients from the plant. It provides excess nutrient in the form of a “Honey dew” to the ants after some “tending” by the ant. The ants stand over the mealybugs and start caressing them (called tending). After some time, the mealybugs slowly exude a bubble of honeydew that the ants pick up and feed on!
You can see the process of tending in the video from my garden below. Around 19 secs into the video, a mealybug has started exuding the honeydew. The ants picks up the honeydew at 32 secs. You can see the second smaller ant quickly pick up another honeydew at 42 secs.
Ecosystem and symbiotic relationships
Here’s some food for thought. The world that we live in is a complex ecosystem, a web of interconnections between different species in the form of symbiotic relationships. Everything is connected to everything else! There are many different types of symbiosis – mutualism, commensalism, parasitism, predation and competition. Our understanding of how the genetic material carries hereditary information across generations led to an interpretation of the “Survival of the fittest”. This provides a view of a “dog-eat-dog” world where everything is competing with each other to survive. But this worldview addresses only a small part of the symbiotic relationships. The large ecosystem (which humans are part of) has a rhythm for all different species to survive without having to compete with each other all the time. Till the humans started playing with it!