What is happening to certain species of moths?

When I was a girl, and even much later in life, I used to feel rather joyful when I came across caterpillars and uncovering what species of butterfly or moth they would turn into.

I remember as a kid and also as a teenager, the common types that I could come upon in the garden or on my father or granddad’s allotments. I used to find caterpillars on the railway bank too.

Garden Tiger Moth

One species I have always loved is the Garden Tiger Moth (Arctia caja) with its large, very furry caterpillars that are known as woolly bears. The adult moths are spectacular too, with boldly patterned forewings of chocolate brown and white, and with hindwings of a bright orange dotted with blue black.

the garden tiger moth

It is one of the largest and most colorful of all the northern species. I remember finding the caterpillars on my dad’s rhubarb and often, you could see the holes they had eaten in the leaves.

Other times you might see one running across a path or in the lane in the summer sunshine. They were easy to feed if kept because they eat a very wide range of plants such as nettles, weeds like dandelions and dock, brambles, and cultivated vegetables such as cabbage.

In Potter County, where I lived until quite a few years back, the moth and its caterpillars were again commonly found in my garden and in the neighborhood. Recently though, I have read a number of reports claiming that this beautiful moth has gone into a rapid decline in the US and is vanishing from many places.

How could this be? It eats a wide range of food plants and the caterpillars are protected from predators by their long fur, while the adults are poisonous and put off enemies with their bright warning colors.

Something else is killing them off. Maybe it is the widespread use of pesticides and the practice of tidy gardening, with everything pruned just-so and neatly manicured lawns?

But perhaps it has to do with climate change? The Garden Tiger is a species that has a caterpillar that hibernates in winter, and a mild one would not cause the young insect to stay dormant so well.

It is not just the Garden Tiger. Many other once very common species are disappearing.

Magpie Moth

The Magpie Moth (Abraxas grossulariata) is another example. Something is killing off the once large numbers of this pretty moth too. This pretty moth is colorful in all stages of its lifecycle.

the magpie moth

As a caterpillar, which is of the “looper” or “inchworm” variety, it is mostly black and white and pinkish-red underneath. The pupa is black banded with dark yellow, and the adult moth has creamy white wings speckled with black dots and marked with yellow-orange bands. The body of the moth is black and orange.

Like with the Garden Tiger Moth, these are warning colors to tell would-be predators that the insect is poisonous. Like the Garden Tiger Moth the Magpie Moth, caterpillar hibernates while still small and completes its growth in spring.

I used to find loads of them on a flowering currant (Ribes sanguineum) bush in my grandparents garden, but they also eat other types of currant and Gooseberry (Ribes uva-crispa) bushes too. In the countryside they are, or were, common in hedges where they ate Blackthorn (Prunus spinosa) and Spindle (Euonymous europaeus).

In the countryside it can also live on mountainous areas and hillsides feeding on the Heather (Calluna vulgaris). These caterpillars can spin a thread that they can hang from, and can climb back up if they are dislodged from where they were hiding in the leaves.

They also move along by using the front legs to pull the rest of the body in a loop up to the front, rather than crawling like most other types of caterpillar. It seems very sad and strange to hear that these colorful and once common moths are having a struggle to survive in the US as it is now.

Some species are being maintained in captivity by insect enthusiasts and the businesses that breed and sell eggs, caterpillars and pupae. It seems a great shame that it has come to this.

Instead of being able to go out into your garden to find moths and their caterpillars, now you have to order them online from a company that will sell them to you.