What is the point of moths?

Woodland Engagement Officer Michelle Stamp, shares more about why she loves moths and how you can get involved in observing moths.

There are approximately 2,500 species of moths in the UK of which 900 are macro-moths and the rest fitting in to the arbitrary category of micro-moths.  I say arbitrary because many micro-moths are larger than macros and the distinction is not based on any scientific observation, but rather convenience.  Many people find moths to be brown and drab and much prefer their daytime flying counterparts, the butterflies which are colourful and readily available to see nectaring on preferred food plants in the sunshine.

While butterflies and moths are both members of the Order Lepidoptera (meaning in Ancient Greek lepís “scale” + pterón “wing), butterflies are actually a branch of the moth family and compared to moths, the family of butterflies is quite small at only around 60 species in the UK.

It can be difficult to distinguish moths from butterflies because there are at least 130 day flying macro-moths and many hundreds more if micros are included. 

Moths can also be incredibly colourful like the Elephant Hawkmoth, while some butterflies are brown for example the Ringlet, or can look very moth-like such as the Skippers. 

Some people distinguish moths from butterflies by the clubbed antennae of butterflies, and feather like antennae that moth’s exhibit but there are exceptions in a few species. 

Butterflies normally fold their wings vertically over their backs while most moths hold their wings horizontally when at rest, but again there are exceptions with the Thorn moths which may also hold their wings vertically and the Skippers which hold their wings at an angle.

A common question about moths is, what is their point? 

Moths are important pollinators and are a food source especially for night flying mammals such as bats, and their caterpillars make up a large component of the diet of insectivorous animals. Blue Tits eat an estimated 50 billion moth caterpillars each year.  Many plants have evolved to utilize night flying moths to their advantage such as night scented stock, honeysuckles, evening primrose and some types of Jasmine.  Moths and butterflies are also important indicators of environmental quality and have been used for many years to study phenological and distributional changes in response to increasing temperatures.

Moth collecting has been a past time since the Victorian era with Victorians smearing tree trunks at dusk with brown sugar and beer, a practice termed “sugaring” which was a standard technique before light-traps were invented which first used candles to attract moths before Mercury vapour and Actinic bulbs became the norm. Many names of larger moths reflect their Victorian heritage with lavish, lush descriptions such as brocade, wainscot, footman and lutestring becoming part of their common names.  Rothamstead research has been running a light trap network since the 1960s to monitor changes in distributions of larger insects including moths and currently has a light-trap network comprising around 80 traps across the UK and Ireland with most of the traps run by volunteers. 

Today, the majority of moth trapping is carried out by people in their gardens and local areas who submit data to their county recorder or via iRecord. This data along with data collected by researchers has found that there has been a 33% decline in moth abundance over 50 years (1968–2017) and many have moved further north by 5km per year according to the State of Britain’s Larger Moths 2021 report

It was also found that warming climate is causing many moth species to emerge earlier in the year compared with the 1970s, which is benefitting some of them by allowing them to produce more than one brood of eggs per year. However, there may be ansynchronicity between caterpillar emergence and availability of their food plants which could account for some of the declines. Since 1900, 137 moth species have become established in the UK, including 53 this century alone which have arrived naturally, expanding their European range in response to climate change. This can have a detrimental effect on some of our native species of plants which aren’t equipped to cope with alien species.

What is moth trapping?

Most moth trapping is non-fatal to moths and once they have been counted and identified, they are released to carry on with their daily routines.  At the very basic you can leave a light on in your bathroom and the window open and see what has turned up in the morning.  You can also hang a white sheet on the washing line with a bright light behind it and watch the moths as they collect on the sheet.  Moth traps can also be bought from specialist shops and there are various types such as Robinson traps, Heath Traps and Skinner Traps with actinic, mercury vapour or LED lights which to the amateur can seem daunting, but various groups on social media such as moth traps UK can help the beginner get to grips with the lingo.  However, these traps can be quite expensive for those just starting out so there is the option to make your own trap like the Budget bucket moth trap from Butterfly Conservation, using materials from brewing shops like a brewers bucket with lid and a large funnel.  You can buy the electrics from various suppliers and websites such as those run by Paul Batty, who will provide help, advice and equipment to get you started. Some Butterfly Conservation groups also lend bucket moth traps to local members so check out your local group.

Tips for using your moth trap

Moth traps are filled with egg boxes for moths to hide in and are generally switched on at dusk and left out overnight in your garden.  Some people choose to stay with their traps but many moths don’t appear until between 1am and 3am with some moths having their own appearance times like Elephant Hawk moths mostly appearing around midnight.

If you choose to go to bed like I do, getting up early to check your trap can give more of a reward as many moths don’t make it in to the trap and will collect on the outside of the trap or land on the ground around the trap.  For this reason, I put a sheet on the ground so I don’t accidently stand on any but the sheet can also alert birds who will soon realize there is a potential buffet waiting for them. 

It is handy to have a soft paintbrush to gently move moths with and collection pots to keep your moths in while you identify them. These are especially useful when just starting out as identification of moths can be tricky and time consuming.

Moths can be kept in the fridge during the day to calm them down allowing you to take photos, ask for help from various people on social media or your county moth recorder and this will also protect them from overheating and risking predation from birds.  Keeping moths in the fridge does not harm them as they are ectothermic, meaning they can’t control their own body temperature so they will go in to a temporary torpor similar to how they overwinter. 

Approximately 1 hour before sunset, depending on the time of year and outside temperature, I remove the moths from the fridge to allow them to warm up for flight. In the middle of summer, they will be warm within a few minutes so adjust their removal from the fridge accordingly as larger moths will start flapping about in their pots and risk damaging their wings but you don’t want to set them free while the birds are still on the feeders.  Likewise in the winter they will take longer to warm up so you don’t want to be releasing them while they are unable to fly. 

I always release the moths in the same spot the trap was located so they aren’t disorientated and are back in their preferred locations from the night before. 

It is good practice not to trap on consecutive nights if you only have a small garden or in the same location on consecutive nights if you have large garden as you don’t want to risk trapping the same moths and disrupting their normal behaviour.  If you can trap in a different habitat or part of your garden then trapping over a few nights will give you an idea of how different types of moths use different areas and eventually you will learn their habits at different times of the year.

A few useful links for helping you to identify moths are

Twitter :@MothIDUK

General: Butterflies & Moths of Great Britain & Ireland

Borders: East Scottish Moths

Your records can be submitted to your county moth recorder who will verify your records and also help you with identication and input your records in to the national database where it will be used for long term monitoring of moths and assist with research.  Your county moth recorder can be found here.

Various identification books are also available some of which show life size images of the moths so you can hold you moth in its pot over the actual picture and see if it matches.  A list can be found here.

Moth trapping can become a highly addictive past time with the sheer variety of moths you will encounter throughout the year and it can be done all year round.  In winter numbers of moths will diminish but a few hardy specimens can still be found such as the Winter moth, November moth, and Dotted border who don thick furry coats to help them through winter. 

As spring and summer approach the vast array of disguises moths use become more apparent as you find a Buff tip that looks like a broken birch twig, a Poplar hawk moth that looks like a crumpled leaf and has incredibly sticky feet which won’t let go of your hand (but everyone has to have a go of holding a Poplar hawk), or the White ermine with its big white fluffy head and sweeping antennae who likes to play possum and make you think it’s dead like many of the larger moths but at the last minute will suddenly spring in to life when least expected.

Annual moth events include Moth night which is an annual celebration of our moths which happens every year and is a chance to collate data collected on the same night all across the country to give a snap shot of how populations are changing.  Moth week which was originally a US moth census but has now taken off globally also allows similar data to be collected.

If you would like to see moth trapping before you take the plunge various moth trapping events will be happening around the UK for National moth night up until the 25th July and Borders Forest Trust will be holding moth nights at some of our community woodlands over the next few weeks so get in touch if you would like to know more: Michelle@bordersforesttrust.org