In any Ecosystem, plants and animals are dependent on each other for food and can be linked together in Food Chains.

Here is an example of a Food Chain involving Butterflies and Moths in a woodland ecosystem:

The larvae of the Green Oak Tortrix feed on oak leaves.

Blue Tits feed on the moth larvae and Sparrowhawks eat the Blue Tits. This is a simple Food Chain.

The Oak Tree is the Producer in this food chain.

The Oak leaves capture the energy of the sun and use it to convert carbon dioxide in the atmosphere and water from the soil into plant materials. So the Oak Tree produces the organic material that passes up the Food Chain.

The Green Oak Tortrix Moth larvae are the Herbivores in this

Food Chain

The larvae of the Green Oak Tortrix Moth feed on fresh oak leaves in the spring. The female moths lay their eggs the previous summer, the eggs survive over the winter to hatch in the following spring. The moth is also called the 'Oak leaf-roller' because of the way the larvae roll up the leaves they are feeding on.

The life of the Green Oak Tortrix moth is one that is ruled by split second timing. The caterpillars need to hatch from their eggs in spring, at just the same time as the oak tree forms its first leaves. When the oak leaves are young they are the ideal food for the hungry young caterpillars.

Large numbers of larvae of this moth can completely defoliate the oak trees in an area. The picture to the right shows an oak tree and a beech tree side by side with the oak almost completely defoliated.

The oaks will then produce a second flush of leaves in the summer called the Lammas growth – these leaves are redder as they have more tannins in them to protect them against caterpillar attacks.

If the caterpillars hatch too early there are no leaves on the tree at all, and they starve to death. If they hatch too late, the leaves will have produced more tannins and will be indigestible to them.

The Green Oak Tortrix Moth is one of the moths that appears in early summer from the continent. Click here to read about Butterfly and Moth migration.

The Green Oak Tortrix caterpillars are the Herbivores in this food chain.

The Winter Moth is another species which has to time its lifecycle exactly to fit in with the new growth of the leaves on the trees - Go to Learn More about it - click here.

The Blue Tit is called a Carnivore in this Food Chain

Blue Tits, Great Tits, and other woodland birds will take MILLIONS of caterpillars to feed to their young.The Pied Flycatcher on the right has a beak full of moth larvae to take to its nesthole.

Animals that eat insects are also called Insectivores.

The Sparrowhawk is the Top Carnivore in this Food Chain

Birds of Prey like the Sparrowhawk hunt and catch smaller birds to feed themselves and their young.  

Blue Tits may lay up to 14 eggs and in a good caterpillar year may rear that many young, so there should be plenty to spare for the predators like the Sparrowhawk, which only has four or five young in a good year. The Sparrowhawk is the Top Carnivore in this Food Chain as it feeds on other animals and has no predators itself.

Here's a question for you: What happens to the material which passed up the Food Chain from the Oak Tree to the caterpillars to the Blue tits to the Sparrowhawk when the Sparrowhawk dies?

Food Webs

In Nature, each organism in an ecosystem has a variety of species preying on it, and the animals will have a variety of food items. So many food chains will be joined to form a complicated Food Web. More about Food Webs soon!