Insects are often associated with pests, but only a small proportion of insects are pest species. Others fulfil important roles in the garden, such as pollinating flowers, decomposing leaf litter and… controlling pest insects (e.g. ladybird beetles feed on aphids).
Insects form by far the most diverse group of animals, which means that making your garden “insect friendly” is in itself the most efficient way to enhance biodiversity in your backyard. In addition, insects are food for other animals such as spiders, frogs and toads, lizards, skinks and geckos, insect-eating birds and small mammals such as shrews and hedgehogs.
Lastly, apart from the roles they fulfil, many insects are simply breathtakingly beautiful and fascinating and can add a splash of colour to your garden. Butterflies are the obvious example, but there are other insects that warrant a closer look, such as dragon- and damselflies, lacewings, fruit beetles, dung beetles, parasitic wasps, grasshoppers and praying mantises, to mention a few.
Butterflies in particular are very choosy about where they lay their eggs. Most species will only use a few, or only one, ‘host plant’ species. This makes butterflies very vulnerable to extinction. By gardening with locally indigenous plants we can help protect them.
Given the riches that butterflies and other insects can bring to your garden, it pays to tolerate some insect damage to your plants rather than to use insecticides to prevent insect damage. Indigenous plants have evolved their own defence mechanisms against local species of insects and they do not need us to assist them with chemicals that kill everything that crawls.
Compost and mulch
Biodiversity does not only occur in places where we can see it. There is a whole world of diversity of which few people are aware – the community of organisms that live in the soil. Healthy soils are brimming with life. There are earthworms, millipedes, centipedes, woodlice, crickets, scorpions and pseudo-scorpions, slugs and snails, beetle larvae and spiders.
Many of these organisms fulfil important functions in the soil. Earthworms, millipedes and woodlice, for instance stimulate decomposition by fragmenting organic matter into small particles, making it more accessible to micro-organisms. Furthermore, earthworms improve the structure of your soil by digging tunnels and mixing the organic matter with sand and clay particles, giving it a granular aspect. This enhances both drainage and aeration of the soil, which in turn stimulates root growth.