The Delightful December Moth

The December Moth, Poecilocampa populi, is found all over the UK. Because it is more resistant to cold than most other moths, the adults are common in parks, gardens and woodland during late autumn and winter.

Marvellous Moths

Many people don’t give moths a lot of thought. Most have incredible camouflage and they often fly at night, so we don’t tend to see them. When we do think of moths, it may be just as a kind of drab butterfly that sometimes eats our clothes. In reality, there is much more to the world of moths than we might think, and they are very important to our world.

Moths, together with butterflies, belong to the group of insects called the Lepidoptera (“scaly wings”) There are over 2,500 species of moth in the UK and only a very few will eat our clothes. Many of these moths are beautiful, either because of their spectacular colouration or because of the way their camouflage enables them to blend into their habitat.

Moths are important in ecosystems. Both adult moths and their caterpillars play crucial roles in food chains, feeding on plants and being eaten by bats, birds and other animals. It is estimated that about 35 million caterpillars are eaten by blue tit chicks every year! Moths also play a vital part in the reproduction of several plant species because of their role as pollinators.

‘Like a moth to a flame’

December moth showing black and brown colouration.

Adult December moths are night-flying and, like other moths, they are attracted to light at night. Entomologists are still not sure exactly why this is. One theory is that moths use the moon to navigate and can mistake a light for the moon. Another is that they normally fly with the lighter sky above them and a light source near the ground confuses them into flying downwards. This would explain why they are attracted to street lights and lit windows, and also why they fly downwards into light traps.

December moth, Poecilocampa populi. Photo: Ben Sale CC-BY 2.0

Life Cycle of the December Moth

Larvae and pupae of the December moth
Larvae and pupae of the December Moth in the HOPE Collection at the Museum

While adult December Moths can be found throughout autumn and winter, each individual is short-lived and does not feed. They mate and the females lay their eggs on food plants. The eggs overwinter and the larvae only emerge the following spring. These caterpillars can be found throughout spring and summer taking advantage of the new growth of leaves. They are active voracious feeders at this time and will eat the leaves of a wide range of deciduous trees. When they have gained enough weight, they pupate, with the adult moths emerging to repeat the cycle in late summer and autumn.

Pinned adult DEcember moths in the HOPE collection.

Moths are important indicator species: their presence tells us about the overall health of the environment.  Unfortunately, what moth populations seem to be telling us is that something is wrong.

Comparing the number and type of moths found in Britain today with those recorded in historic insect collections like the HOPE Collection at the Oxford University Museum of Natural History, shows us that moths have declined by about 40% in southern Britain. Over 60 moth species have become extinct in the UK over the last century and many more are at risk of disappearing forever.

Other animal species which rely on moths as food are also suffering, including a decline in bats flying over farmland and reduced numbers of cuckoos, which specialise in feeding on hairy moth caterpillars which other birds tend to avoid.

We need to do more research to fully understand exactly why moth species are declining in Britain, but it is likely to be because of a combination of factors including loss of habitat, farming practices such as clearing hedgerows and the use of pesticides, and climate change.

Adult December moths in the HOPE Collection

Ways we can help moths

Fortunately, many moth species under threat are found in parks and gardens, so we can all do things to help:

  • Not over-tidying gardens; a more natural look is much better for insects.
  • Growing a wide variety of large and small flowering plants and, if you have room, shrubs and trees.
  • Avoiding the use of weed killers and insecticides.
  • Reducing light pollution from outdoor lights
  • Reducing your carbon footprint, for example, by driving less and walking or cycling more.

If you enjoyed reading about the December Moth, you might like this post by Ben on Raising Poplar Hawk Moths.

Raising Moths

Ben brought in some Poplar Hawk Moths to show the other participants at our recent summer school. Here he describes how he raised them from eggs he received as a gift from his grandfather.

Last year during lockdown my Grandpa gave me 32 hawk moth eggs: 30 eyed and two privet. Not the most common of presents you might think, but these turned into the most enjoyable gift. I was very excited as I tore open the parcel and found the eggs safely packed in a small tube. It took roughly a week for the leafy-green eggs to turn into the most delightful little caterpillars. I decided to call them all Jim. The first thing they went towards was the fresh willow that lay in a small, water-filled jam-jar.

Poplar Hawk moth caterpillar with Ben’s hand for scale. Photo credit: Ben Atwell

Immediately, they started taking chunks the size of their heads out of the leaves until there were no leaves left inside the tank. I was very surprised by how much they ate in proportion to their size. Every day they grew bigger until, within 4 weeks, they were the length of my index finger! They were bright green with white stripes, pink spots and little pointy tails. To help them grow, they shed their skins every few days. Sadly, one little Jim got stuck in his skin whilst shedding and died. Willow-collecting took a lot of effort as it involved daily trips to the canal, but this was a welcome break from staring at my computer all day during online school.

Poplar Hawk Moth larva feeding. Photo credit: Ben Atwell

One morning we found that a lot of the caterpillars were wandering around, banging their heads on the bottom of the tank. They were also turning a darker green which (after a bit of research) we found out meant they needed to bury and become a chrysalis. We put a deep layer of soil into the tank and within minutes they had disappeared. We tucked them up in the shed for winter and waited.

After months of hibernation, they started emerging this spring with crumpled wings, looking very like dead leaves. After stretching out their wings we noticed that we couldn’t see the eyes that the eyed hawk moths are known for, but as we later realised, they only show the eyes as a defence mechanism if they were under attack. Normally it would take a while for the males to seek out the females using their fanned antenna, but because they were in a large tank, it was easy for them to find each other and mate. Within a few days they had laid over 1,000 little green eggs! So, the process of willow collecting began again, but this time, after checking with the county moth recorder, we released the little caterpillars (who this year I called Jeff) into our local wildlife reserve, hoping that they survive and go on to repeat the process in the wild this year.

Poplar hawk Moth adult. Photo credit: Ben Atwell

We are still waiting for the privet chrysalises to hatch, but to keep me busy, my Grandpa sent me 15 poplar hawk moth eggs this spring. These have already been through one cycle of eggs-caterpillars-chrysalis-moth-eggs and I gave some of the eggs to the museum during the Insect Investigators Summer School. I hope the staff have time to collect all that poplar!

The Poplar Hawk Moth, Laothoe populi, is a beautiful insect found thrououghout the UK and is common wherever their foodplants can be found: mainly the poplar trees from which they get their name, aspen and willows. Ben describes the voracious appetite of the larvae well. The adults don’t feed at all and so are short-lived. You can find the adult moth from May to July and the caterpillars from June to October. In Southern England there may be a second generation of adults in the autumn.

Make a butterfly feeder

In the last post Kate told us all about her favourite butterfly. In this post I will be showing you how to make your own butterfly feeder, from items you might commonly have at home, to help attract butterflies, and other insects, to your outside space. I had to raid my recycling bin for key materials.

Here are the same instructions on how to make a butterfly feeder, as can be seen in the video:

What you will need:

  • Cardboard
  • Coloured pens or paints
  • String or wool
  • Glue or sticky tape
  • Scissors
  • Bottle top
  • Hole Punch
  1. Take a piece of cardboard and draw a flower with five petals, roughly 20cm wide.
  2. Decorate your flower in any way you wish.
  3. Cut out your flower.
  4. Fix the bottle top to the middle of your flower using glue or sticky tape.
  5. Use a hole punch to make a hole at the edge of each petal of your flower.
  6. Cut five pieces of string or wool, each roughly 40cm long.
  7. Tie the five pieces of string together at one end.
  8. Turn your flower over and thread a piece of string through each hole, and tie the five pieces of string together.
  9. Tie an additional piece of string, or wool, to the knot.
  10. Hang your butterfly feeder in a sunny, but sheltered, spot outside.
  11. Mix together sugar and water, or take a small piece of overripe fruit (e.g. orange or banana), and put it in the bottle lid.

Watch to see any butterflies, or other insects, that visit your feeder. You could investigate which foods different species prefer.

Please tell us about your butterfly feeders and investigations. We would love to see photos of them. Contact us or email at hopelearning@oum.ox.ac.uk.

My Favourite Butterfly

This I-Spy Butterflies and Moths book was one of the reasons I became fascinated by insects as a child.  I loved the Red Admiral on the front cover, particularly because they were not so easy to find where I lived and so seeing one felt very special.  Here is a photograph I took last year of a Red Admiral near to where I grew up.  Maybe I am getting better at spotting them! 

Although the Red Admiral is a beautiful butterfly, it is not my absolute favourite.  The butterfly I came to love above all others, and the one that I look forward to seeing every year, is the Peacock butterfly, Aglais io.   These beautiful butterflies are out and about in our gardens, woodlands and open spaces right now.  On a sunny day, see if you can spot one basking in the sunshine.  Read on to find out why Peacocks are my favourite butterflies.

Masters of Disguise

One of the most distinctive of our butterflies, and surely one of the most beautiful, there is no mistaking the Peacock.  I just love their stunning wings with their dark red background topped with four iridescent eyes resembling the feathers of a peacock bird. In fact, the Peacock butterfly is a master of mimicry.  The eyes make it look like something much scarier than a butterfly. When you look at the body and the eyes together, they look, I think, remarkably like the face of an owl.  That would certainly put off a smaller bird from trying to have a peck! The underside of the Peacock is also worth mentioning as its woody, bark-like colour and patterns provide excellent camouflage when the butterfly’s wings are closed.

Peacock Butterfly – Ventral view (underside)

 

Don’t get stung

Looking for a Peacock caterpillar?  Then there is only one place you should look – in a bed of nettles!  Be careful not to get stung, this is where the adult females lay their eggs. What a great adaptation to use the plant’s stinging capabilities to protect your young!  Other species of butterfly also do this, including the Red Admiral and the Small Tortoiseshell.  This is one of the reasons why it is so important to allow nettles to grow in your gardens.  Without them, several important butterfly species have nowhere to lay their eggs.  Try to leave a wild area in your garden to encourage the widest variety of insects possible.  Pretty flowers are important but they are not the only plants that insects need! 

Peacock Caterpillar Flickr Mark Seton CC-BY-NC 2.0

Hidden Winter Treasures

Peacocks are one of the few butterflies in this country that hibernate in the winter as adults, emerging in the spring to mate and lay the eggs for the next generation. The other butterfly species that over-winter as adults are the Small Tortoiseshell (Aglais urticae), the Comma (Polygonia c-album), the Brimstone (Gonepteryx rhamni) and the Red Admiral (Vanessa atalanta). We may also be able to add the Large Tortoiseshell (Nymphalis polychloros) to this list.  Once widespread, this butterfly has been lost in the UK since the 1960s.  However, sightings in Southern England have been increasing and it is hoped that this butterfly is making a comeback.  To find out more, check out this interesting article Tracking down the Large Tortoiseshell.

Every now and again, you might be lucky enough to find a Peacock butterfly sheltering in a quiet corner of your house or in your garden shed during the winter.  If you do, don’t disturb them as they need to stay asleep until spring.  As a child, I remember finding a hibernating Peacock butterfly in the folds of some rarely-drawn curtains in the cold spare bedroom.  I kept peeking at it regularly until one early spring day, the butterfly was gone. 

Next week, check out Susie’s post showing you how to make a butterfly feeder to help attract butterflies to your outside space. 

Do you have a favourite butterfly?  I’d love to hear about it.  Contact us or email hopelearning@oum.ox.ac.uk