Invertebrates play an essential role in the sustainability of our planet’s ecosystems. They are an incredibly diverse group of organisms that are present in huge numbers in both natural and managed habitats. 

They are key to maintaining healthy environments and support many important ecosystem services, such as nutrient cycling, pollination and pest control. They have an effect on other organisms (the organisms they eat, those they are eaten by and others they compete with for resources), as well as on the environment as a whole (e.g. by cycling carbon, water and nutrients). 

At SCRI, we are interested in how invertebrates help the functioning of farmland habitats.

Plant Feeders
Many arthropods feed on plants. Some feed on crop plants, such as wheat and barley, and can become pests if they reach very high numbers. However, most of them are beneficial, feeding on very common plants such as thistles and nettles. This can reduce competition between plants and may increase the chances that the rarer ones survive.

Pollinators
Many insects are attracted to flowers by colour and scent. As they feed on the nectar, they pick up grains of pollen which they move around from flower to flower. In this way, they pollinate and generate the seeds of vast numbers of wild flowers. Pollinators thus help plants to reproduce and survive. Many of our food crops are pollinated by arthropods such as butterflies, bumblebees, hoverflies and pollen beetles.

Predators
Many insects survive by killing and eating other arthropods. These predators are themselves an important food source for many other animals, such as birds and mammals. They also help to reduce the number of pests, such as greenfly. They are especially valuable in controlling the numbers of plant feeders that live on different kinds of crop plants and wild flowers.

Parasites
Parasites such as parasitic wasps lay their eggs in other insects. These hosts continue to live while parasitic larvae hatch and grow inside them. The host dies when the parasite is fully-grown and ready to emerge as an adult. Adult parasitoids usually feed on nectar, so parasitoids perform two important functions: the larvae control insect pests and the adults pollinate flowers.

Recyclers
The breakdown of waste products is a very important activity carried out by invertebrates. They help in the breakdown of waste products and release nutrients into the soil, keeping it fertile. They feed on a wide variety of material such as, fallen leaves, rotten wood and dung. It is thought that insects, millipedes, mites and other invertebrates feed on and break down 90% of decaying materials.

Wildflower field margins provide many beneficial aspects to conservation as well as being pleasant to look at. Ecological benefits include:

• Source of nectar for hoverflies and butterflies
• Leaf litter provides cover for predatory beetles
• Insects encouraged by the diverse flora provide food for both birds and game-bird chicks
• Food for songbirds
• Nest sites for ground nesting birds such as skylarks