Managing your meadow for invertebrate life

 

The magic of walking through a flowering meadow in midsummer is enhanced by the myriad of butterflies you may see, as well as the crickets jumping ahead of you as your feet part the grass. A typical meadow can be home to over 500 flowers per square metre in summer; and support over 1400 species of invertebrates. Not only are the flowers attractive to pollinators in search of pollen and nectar; they also provide shelter - as do the leaves, stems and seeds. 

They should not be viewed in isolation, since the complex lifecycles of many invertebrates depend on a mosaic of habitats. 

Ideally meadows should be mown for hay as late as possible, from mid-July to late September. This not only allows flowering plants to set seed, but also allows the majority of adult butterflies, bees and other invertebrates to complete their life cycle. Since cutting a whole meadow at once can deprive a wide variety of invertebrates of vital shelter and nutrition, it is worthwhile leaving small areas uncut each year as a refuge for invertebrates. If a different area is left unmown each year the area is unlikely to become dominated by scrub. 

Reducing soil fertility by removing arisings (cut vegetation) is essential to starve grasses and allow wildflowers to flourish. However if small piles of dead material are left for a season, Common Nettle and umbellifers such as Common Hogweed can flourish. These in turn support a wide variety of caterpillars, including those of the Small Tortoiseshell and Red Admiral butterflies, and Buff Ermine moths. 

 

No inorganic fertiliser or manure should ever be applied to the grassland. Persistent weeds should be controlled by hand-weeding before seed has been set. No avermectin-based antihelminthics (such as Ivermectin) should be used; if the land is to be grazed by livestock which have been treated with Ivermectin this should be done off-site and they should be excluded from the meadow for at least 14-days from treatment.

 

A traditional hay meadow may be just one part of a mosaic of habitats on your land, and it is worthwhile thinking how these work together. For example, while adult oil beetles feed on the leaves and petals of flowering plants and soft grasses, their larvae feed on the stores in solitary bee nests. On leaving the nest, the immature forms may be found in early spring on the flowers of Lesser Celandine growing on the edge of the meadow and at the base of hedgerows. It is therefore a good indicator of a healthy habitat. 

The Western Bee-Fly larvae also feed on solitary mining bee nests. 

The Spotted Longhorn Beetle larvae live in rotting wood for 2-3 years before emerging as adults between May and August to feed on umbellifers such as cow parsley and hogweed.

 

The Scarce Fungus Weevil (Platyrhinus resinosus) lays its eggs in ‘King Alfred’s cakes’ - the fruiting bodies of a fungus which grows on dead and rotting ash wood; the adult is active during June and July only.

Image: Scarce Fungus Weevil (Platyrhinus resinosus) by Liam Olds

 

Field margins and hedgerow bases should be allowed to grow a little wild. Not only will these rougher areas of grass benefit invertebrates, but also small mammals such as voles whose tunnels and runs will in turn will benefit invertebrate species. Verges can be cut on a 2-3-year rotation, to avoid excessive Bracken, Bramble and Blackthorn growth, and should only be cut in the autumn as needed. 

 

Additional measures which will provide shelter and sustenance to invertebrate life: 

Nest boxes may shelter a wide variety  of invertebrate life; if you choose to clear them out then leave the material on site.

Bug boxes can provide additional shelter.

Bare ground is beneficial to mining bees and ground-nesting beetles, such as the Green Tiger beetle. If you don’t already have any e.g. in gateways or alongside a track you can create bare ground by flattening a few molehills or even by laying an area of coir mat in a sunny position for a few weeks. 

Log piles are beneficial to stag beetles, click beetles and longhorn beetles. 

Larger dead wood in hedges and trees can be beneficial to wood-boring insects unable to tolerate ground-level damp such as cavity-nesting bees. 

Image: Green Tiger Beetle (Cicindela campestris) by Liam Olds

If you would like to learn a little more about the invertebrate life you encounter in your meadows, try out Seek, a great beginner and family-friendly app for both flowers and invertebrates. 

Its sister app iRecord Butterflies has a handy ‘Flying now in your area’ feature, and helps you to localise your finds with a 6-figure grid reference provided. 

 

These are both available to download for free from your app store. 

 

Once you are ready to take your studies a little further, iNaturalist is a good place to start.