Moths and gardens need each other

Cinnabar moth caterpillar on ragwort_Rowena Millar

Rowena Millar, Cornwall Wildlife Trust's (currently Non-Roving) Wildlife Reporter, continues to show us how to make the best of our gardens for wildlife. This week Rowena marvels at the beauty of moths and how helpful they can be in our gardens.

Until now, the role of moths in gardens has been largely overlooked, while public support for bees has been encouraged by many wildlife organisations. Yet it turns out that moths are vital pollinators, visiting a wide range of plants, their furry bodies transporting pollen widely and efficiently. As pollinators and prey species, moths are essential to our living world.

The beauty of moths

It astounds me that many people think of moths in terms of those little silvery-dusty clothes moths, perhaps because the others are ‘out of sight, out of mind’ – just a blur of wings on a window pane. In fact, the variety is astonishing, and the different shapes and sizes, patterns and colours are incredible, from the intricately cryptic to the in-your-face gaudy or sizzlingly metallic. Not noticing moths means missing out on fabulous wonders in our own back gardens.

Marvelling at moths

Naturalists belonging to organisations including The Wildlife Trusts have been discovering moths together for years, holding moth nights where different species are attracted to light, trapped safely, then identified (often in the morning) with gasps of wonder and awe from newcomers –and from experienced moth watchers too. Look for moth nights among Cornwall Wildlife Trust’s events once they are up and running again

In the meantime, you can

see some iconic species

Learn how to attract moths to your own garden

Send your records to ERCCIS

I strongly recommend reading Mary Atkinson’s concise, reader-friendly monthly moth reports on the LAPWG website (Launceston Area Parish Wildlife Group is one of Cornwall Wildlife Trust’s Local Groups.) Mary’s June 2020 report includes a picture of the White Plume. This feathery, fairy-like white moth is one of the most graceful and distinctive creatures in our garden. We have plenty of Calystegia sepium (hedge bindweed), which is a nuisance due to its habit of pulling down bush fruit stems as it winds and climbs around them, not to mention draping itself over everything else. But now that I know it is a foodplant for the White Plume moth caterpillar, I will be happier to see its large, white trumpet flowers.

Gardening for moths

The obvious way to help and attract moths is to grow plants that release their scents at night. Evening primrose, night-scented stock and tobacco plants fill the dusk air with scent, and sweet rocket, honeysuckle and jasmine are other classics.

• Day-flying moths benefit from the same flowers as butterflies. Hummingbird hawkmoths go for buddleia and honeysuckle in our garden.  Extend the flowering season by growing native primroses for early spring, foxgloves for mid-spring, lady’s bedstraw for summer and sedum (ice plant) for autumn flowering. Ivy flowers supply vital nectar for moths late in the year. (Elephant hawkmoth caterpillars feed on fuchsia, bogbean and willowherbs.)

• Leave some long grass with wild flowers (‘weeds’) amongst the stems. This is where many caterpillars and moths find food and shelter. You may find pupae too, attached to long stems. Tall thistles and even hawkweeds can look stunningly architectural, and attract bumblebees too.

• Most British moth caterpillars rely upon native plants, including trees such as oak, willow and birch. Trees (hawthorn, blackthorn, beech, and spindle for example) can be packed into a hedge…  and don’t forget to leave some bramble! Only a few caterpillars, such as that of the Angle Shades moth, are less fussy about what they eat.

• Hedges and trees are a natural place for moths to seek shelter, and some are camouflaged to look like parts of a tree.

Last month I was amazed by the antennae and dancing group flight of Longhorn moths in the garden. Last night, amongst the fruit bushes, I came across a lovely Buff Arches moth, which sat on my finger. Go out on a warm summer evening, see what moths are visiting your garden, then encourage more. They will bring in other wildlife, and you are likely to find something amazing.

Losing our moths

Studies show that in southern Britain, moth numbers are down 40% since 1968. Sixty-two moth species are known to have become extinct since the 1960s (note, we only have 56 species of resident butterfly in the UK).

Now, only the occasional moth comes into a lighted room through our windows. Bats used to swoop around our house every evening, but now we have to walk down the valley to be sure to find them.

Burnout

I guess this could be the result of an increase in bright lighting on houses and businesses in our village. The introduction of floodlights to nearby sports grounds and tennis courts, built on fields near woodland and hedges, brought out an amazing host of moths, only for them to crash and burn. The ground below the floodlights was covered in little battered bodies, some in superb colours like dazzling scarlet. At first, the local bats had a great time catching stunned moths and beetles, but now the wildlife is gone.

Garden lighting

In a country that’s lost almost all of its wildflower meadows, moths must rely on flowery hedges, uncultivated field edges, grass verges and importantly, our gardens. Our plants benefit in return.

It is tempting to install trendy outdoor lighting to line paths or beautify our gardens after dusk. There is a trend to install bright LED lighting on houses too – and new street lighting is installed on new housing estates and roads. Whilst congratulating ourselves on efficient bulbs that increase brightness yet combat climate change, we must take insects and their predators into account.

Lighting solutions

One answer is not to be afraid of the dark (and enjoy star gazing), use reflectors to find entrances at night, or develop ways of triggering bright lights only when we genuinely need them, e.g. to navigate a path or scare off a thief).

There are other answers. Insects usually see ultraviolet, blue and green light. If we can make bulbs unattractive to insects, we benefit outdoor diners, too. The advice is to use warm yellow/orange colours rather than icy blue lights. In experiments carried out in the USA, yellow LED lights were much better than the old incandescent bulbs and the so-called ‘bug lights’ too. LEDs use less power, so it’s win-win.

Further information/sources used for this article

https://www.rhs.org.uk/advice/profile?PID=513

https://www.bbc.co.uk/news/science-environment-52630991#:~:text=New%20research%20suggests%20they%20play,stem%20declines%20in%20moth%20numbers.

https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0877

http://www.mothscount.org/text/19/moths_in_decline.html#:~:text=Moths%20are%20declining%20in%20the,extinct%20in%20the%2020th%20century.

https://www.independent.co.uk/environment/light-pollution-spring-week-early-trees-street-lights-study-insects-birds-a7107936.html