Bucking the national moth trend at Allerton

Nationally moths are declining, but these important species are flourishing at our Allerton Project

A report last year by Butterfly Conservation and Rothamstead Research assessed the status of Britain’s larger moths and showed a 28% decline in national moth numbers.

We have been operating a Rothamstead moth trap at our Allerton Project farm at Loddington since 1995, and our 18 years of data paints a rather different picture. Over this period the catches increased by 76.5% and of the 302 species showing trends, 181 increased and 121 decreased. In addition, the number of species captured per year showed an upward trend.

Typical examples of moths that have experienced major population changes include the garden tiger (-92%), buff arches (-80%), the green carpet (+230%) and the dingy footman (+1,851%) a lichen feeding species. Interestingly, several other lichen feeding species have shown similar increases, including the beautiful hook-tip, which has recently colonised Loddington.

Some moths are now flourishing on our Allerton Project farm. Nationally the straw dot moth has
not increased dramatically, but at Loddington, 25 were caught in the first nine years of trapping and 1,202 in the second nine. We believe this increase was in response to creating the species’ preferred habitat close to the trap, in the form of a 20 metre Stewardship grass margin incorporating three small ponds.

The stunning Merveille du Jour moth has also started to appear. This may be because we are planting a lot more oak (the larval food plant) in our woodland, a surprisingly scarce tree when we began managing the estate in 1992.

Over 2,400 species of moth have been recorded in the British Isles, of which about 900 fall into the larger moth category (macros), while the rest are placed in the small category (micros). If you are one of the many people who think that moths are boring, brown and offer little benefit to anything, then think again. Take the Silver Y moth, probably our most common migrant which comes from
as far away as north Africa to spend the summer months here. They select the fastest and most favourably directed airstreams, to enable them to migrate distances of between 300km and 400km per night, flying at speeds of more than 50km per hour.

Many moths are spectacularly beautiful, such as the large elephant hawk moth and the garden tiger moth. Also moths are a hugely important ‘link’ in the food chain as so many other creatures such as bats and birds feed on them or their caterpillars. Many species time the hatching of their chicks to coincide with peak caterpillar numbers. A blue tit chick, for instance, can eat up to 100 caterpillars a day, so to feed a brood of 10, the parents may need to find a staggering 1,000 caterpillars a day.

So, why not start to find out about moths? It does not matter where you are in the country; you can easily get to see them. Just by leaving an outside light on or using a light bulb and a white sheet you can attract moths. But ideally you need a moth trap, which you can buy ready made, or build yourself by getting hold of a few fairly cheap parts. It is a fabulous way to get children involved in wildlife as they thoroughly enjoy the excitement of checking out the ‘catch’ in the morning.

There is an amazing ‘mothy’ world out there waiting to be discovered.

Find out more about our pioneering Allerton Project >