Science & Nature

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GARDEN TIGER MOTH & CATERPILLAR

Alex Hennessy, Marketing and Communications Officer, Dorset Wildlife Trust

Caterpillars often inspire a flash of excitement as they are spotted creeping across a pathway or nestling among vegetation. Moth caterpillars are often much more colourful than the adult moths they grow into, but not the garden tiger – this moth is striking in all stages of life.

The striking caterpillars are large, black and covered in long, dense, black and ginger hairs and they are commonly called ‘woolly bears’. They feed on stinging nettles, dock leaves, burdocks and many garden plants. When the time comes to pupate, they form a thin cocoon in vegetation and later emerge in their adult form.

The garden tiger is well-protected against predators, with a selection of traits that help it survive. The hairs on the caterpillar are irritating, deterring birds as well as parasitic flies and wasps. The adult’s bright colours warn predators that it is unpalatable, while adults can also rub their wings together to create a rasping noise.

The garden tiger is a large, brightly coloured moth, on the wing towards the end of the summer during July and August. This night-flying moth favours scrub-covered sand dunes, woodland edges, wet meadows, parks and gardens. It has a chocolate-brown, furry body, brown and white patterned forewings, and bright red-orange hindwings with four or five large black spots each.

This species is common but has been in decline in many areas since the 1970s and 80s, particularly in the south-east of England. Its preferred habitats are more commonly ‘tidied’ or sprayed with weedkiller, reducing its choices for safe places to pupate, live, breed and feed.

You can help encourage moths like the garden tiger by leaving some plant debris around your garden instead of tidying it away, such as leaves and old plant stems. It’s important not to use pesticides or herbicides and growing a variety of different plants will help attract different moth species too. Discover more ways to help wildlife at dorsetwildlifetrust.org.uk/actions.

Garden tiger moth facts:

There are several tiger moths in the UK, which could be confused for a garden tiger. Here are some tips to identify them: • The wood tiger and cream-spot tiger have yellowy-orange hindwings instead of red. • The jersey tiger has white stripes on its black forewings. • The scarlet tiger has white spots on its black forewings.

Image: Amy Lewis

FLOODS, FIRE AND FURY

Tony Allen & Rob Bygrave, Sherborne Science Cafe

Professor Michael Lockwood is the Director of Research at the Meteorology at Reading University and a Fellow of the Royal Society. In May 2013 he gave a wide-ranging talk to the Sherborne Science Cafe on global warming and the possible causes. He talked about the history of measurements of the sun’s output and variability from tree rings to space born instrumentation. He highlighted the evidence that since reasonably accurate measurements have been available (approximately 200 years), though cyclical, the average output of the sun has not changed significantly. What has changed is the amount of greenhouse gases in the upper atmosphere, particularly CO2. This again has a cyclical component, but the average has increased dramatically in the last 40 years and very recently has reached 400ppm. Other gases have also increased but to a lesser extent. CFC’s have recently stopped increasing following the Montreal Protocol but the hole in the ozone layer has not yet started to decrease.

The reasons for the CO2 increase were discussed but apart from volcanic activity, responsible for about 10%, they are all man-made. Professor Lockwood then went on to discuss the possible consequences, partially prompted by questions from the audience. He had no firm conclusions but a number of views from his position of being in the centre of climate research.

The main subjects commented on were: •There is no evidence the Gulf Stream will be choked off any time soon. •Winter ice at the poles is reducing on average. •Average sea water height is very difficult to measure but has not increased significantly to date – it will increase due to ice melt and expansion due to temperature increase, about 50% from each cause. •El Nino affects the climate significantly but not global warming. •He does not believe the Earth is self-healing. It could finish up like Venus, but given the political will, it is possible to reverse the generation of greenhouse gases.

It may take a global catastrophe to kick-start a recovery.

Surprisingly, there were no questions from the known sceptics and the Professor received warm applause from the audience. TA

Since Professor Lockwood’s talk the global levels of the three main greenhouse gasses, carbon dioxide, methane and nitrous oxide

MDay Photography/shutterstock

Illustration: NOAA Global Monitoring Laboratory

have risen as shown by the data collected by the NOAA (National Oceanic and Atmospheric Administration) based in Washington D.C.

Carbon dioxide levels are now higher than at anytime in the past 3.6 million years.

Levels of the two most important anthropogenic greenhouse gases, carbon dioxide and methane, continued their unrelenting rise in 2020 despite the economic slowdown caused by the coronavirus pandemic response, NOAA announced today.

The graphs depict the mean global atmospheric burden of carbon dioxide as analysed from measurements collected by NOAA’s Global Greenhouse Gas Reference Network.

The atmospheric burden of CO₂ is now comparable to where it was during the Mid-Pliocene Warm Period around 3.6 million years ago, when concentrations of carbon dioxide ranged from about 380 to 450 parts per million.

During that time sea level was about 78 feet higher than today, the average temperature was 7 degrees Fahrenheit higher than in pre-industrial times, and studies indicate large forests occupied areas of the Arctic that are now tundra.

The Global Monitoring Laboratory makes highly accurate measurements of the three major greenhouse gases, carbon dioxide, methane, and nitrous oxide, from four baseline observatories in Hawaii, Alaska, American Samoa, and the South Pole, and from samples collected by volunteers at more than 50 other cooperative sampling sites around the world. These measurements are incorporated into the Global Greenhouse Gas Reference Network and are a vital reference widely used by international climate researchers.

At the time of writing floods deluge Japan, fires rage in Canada and California, and fury hits the Caribbean as hurricanes tear in earlier than usual. RB

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TIME TO ACT, NOT ARGUE

Peter Littlewood, Director, Young People’s Trust for the Environment

It is no good squabbling over who is responsible or who should pay. We shall only succeed in dealing with the problems through a vast international, co-operative effort.’

It’s amazing to think that these words, regarding the effects that the world’s greenhouse gas emissions were already having on the planet were spoken by Margaret Thatcher to the United Nations, back in 1989. She was a research chemist before turning to politics. Whatever you may think of her politics, she accurately predicted the situation we now find ourselves in, over thirty years later.

Recent weeks have seen record temperatures in the Pacific northwest regions of both the United States and Canada. And records weren’t just broken – they were smashed! Canada’s all-time record highest temperature stood at 45C, set in the dustbowl days of 1937. That was until a temperature of 49.6C was recorded in the village of Lytton, British Columbia on 29th June 2021. In fact, Lytton broke temperature records for three days in a row, as the effects of the extreme heat continued to build. Lytton is on a line of latitude that is only slightly to the south of London, perhaps warning us of things to come.

So what caused the prolonged extreme heat? Two high pressure systems, one from the Aleutian Islands in Alaska and the other from James Bay and Hudson Bay in Canada formed a ‘heat dome’, which acted rather like a lid and prevented heat from escaping. The heat dome brought high temperatures both day and night, coupled with largely cloudless skies. The heat extended high into the atmosphere, while the pressure systems effectively

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blocked the flow of cooling air from off the Pacific.

Whilst America as a continent is used to high temperatures, the Pacific north-west is not, and people there are less adapted to extreme heat than in other parts of the US. Homes there don’t generally have air-conditioning systems, so temperatures in houses and apartments quickly climbed to over 100F. Airconditioned rooms in hotels were soon selling for well above their usual nightly rates as people desperate to escape the heat and get some sleep in a cool space booked them up.

The high temperatures killed hundreds of people and they’re estimated to have killed billions of sea creatures. The heat buckled roads, melted power lines and caused wildfires and thunderstorms.

And temperature records aren’t just being broken in the US and Canada. Pakistan, Siberia, Estonia, Moscow and Helsinki have all recorded their highest ever temperatures in recent weeks.

As I write this and with much of California’s wildfire season yet to come, more high temperatures are on the way to the western and southwestern states of the US. Over 31 million people are in the path of a fresh heatwave, which according to the National Weather Service carries a ‘very high’ heat risk, bringing increased risk of heat-related illness.

These recent events have sounded alarm bells for climate scientists across the world. It looks like we’re going to see increasing instances of extreme heat across the world. Authors of a recent study have stated that the latest heatwaves have exceeded the worst-case scenarios of climate modelling. It now seems that the UK and other parts of the world could end up victim to similar extremes of temperature in the future.

What still remains unknown is whether the heatwave-affected areas were simply unlucky, or whether we have crossed some kind of climate threshold, where even small increases in global temperatures can lead to much more frequent instances of extreme heat. Climate scientists aren’t sure of the answers yet, but factors like the slowing of the jetstream could be making heatwaves both more likely and more potent than ever before.

Heatwaves were the deadliest weather disasters in both 2019 and 2020. The planet looks on course to suffer more devastating heat in the coming years. Architects and city planners are already starting to incorporate more green space and cooling areas into their designs.

We’re already at about 1.2C above pre-Industrial levels for global temperatures. By 2050, we could hit 2C above, which would make the western US heatwaves a reality every 5-10 years.

So, rapidly reducing greenhouse gas emissions is going to have to be an even greater priority for us all. With COP26 now just a few months away, we have to hope that the world’s leaders can agree on a clear pathway to net zero. And as Margaret Thatcher said so presciently 32 years ago, it’s not about squabbling over who is to blame for what and who needs to pay. It’s about recognising that there’s a problem that needs fixing and taking collective action to make a difference. The time for action is now.

HONEY HARVEST

Paula Carnell, Beekeeping Consultant, Writer and Speaker

‘From their bellies emerges a fluid of diverse colours, containing healing for the people…’ Qu’ran Verse 16, The Bee

As the last of the bramble blossoms become fruit, beekeepers across the land open their hives and collect the season’s honey harvest. For many, the quantity of honey harvested measures the success of the beekeeping year. ‘How many lbs or jars did you get this year?’ is a frequently asked question. For more and more, caring for bees is no longer all about the honey. The realisation that the balance is wrong and we need to do more to help bees is influencing those who are now called to work with bees. Ten years ago, the suggestion of having a tree hive seemed absurd to many, ’How do you take the honey?’ ‘We don’t.’ was my reply to an astonished questioner.

Now I am asked more and more about how to find tree hives, where to hang them, and how to entice the bees in.

I am not an extreme Natural Beekeeper. I believe in the connection of all things, an agreement between us and the bees. I ensure that I do all I can to provide

them with safe, nutritious forage, safe homes, and freedom to do what nature intends. In return they share rewards from the hive – propolis, wax and some honey.

When I had my first colony, I was stunned to learn that bees were fed with white sugar fondant after the harvest. Even if some honey was left in the brood box, this wouldn’t sustain a strong colony through the winter months. I am still mystified that anyone thought white sugar would. Imagine feeding our kids, or ourselves on sugar fondant for 6 months of the year – would we emerge from the winter months all healthy and nourished? I think not. I believe this is one of the many contributory factors behind the sicknesses that bees are suffering.

I recently spent two days judging honeys from around the world for the London International Honey awards. 90 honeys passed my lips and were waved under my nostrils, looking for hints of perfection, or adulteration. Thankfully, honey quality has improved since I first judged 3 years ago, and so only a couple of honeys forced me to exclaim a ‘eeuw’!

Even my ‘eeuw’ is someone else’s joy or medicine. The environment that the honey is harvested from, and how it’s harvested plays a big part in the aromas and taste. A heavily smoked hive extracting honey from aggressive bees, leaves a smokey aftertaste, which some are used to, others detest. A fine rare Arabic honey harvested on a goat farm, carries the aroma of farmyard to those of us far away from those desert bees. It instantly took me back to the remote Rustaq beekeepers in Oman, with their goats wandering freely amongst the hives, and the homes.

I have been on a quest to find the most delicious, medicinal and sustainable honeys from around the world, and my collection of single varieties is growing fast. I love running honey tastings and seeing the shock of how even a set of 4 honeys can have widely different aromas, flavours and consistency. A recent honey tasting at a local village school found that Spanish blackberry honey was by far the favourite when compared with Dorset hawthorn, Romanian sunflower, and Spanish almond. In the UK it’s not common to find single variety honeys. Partly due to the landscape, only small clumps of various plants, beekeeping practices, as well as lack of knowledge leave us with more regional blends than the exciting single varieties we could have – dandelion, clover, lime tree, hawthorn, bramble and borage. I have been on a personal mission to save the dandelion as it is by far my favourite honey. If only more knew of this distinctive bright yellow creamy delight – I am sure we’d see more lawns and fields covered in it, if only to maximise the honey crop! I started a Honey Tasting Club in June as a way of sharing the ranges of honeys available. To ensure I would have the exact varieties I wanted, I ordered the years supply for my members in advance, an expensive gamble that I am so grateful of now. Increased problems with importing honeys has meant a shortage as the extra paperwork and processing is delaying shipments by months. Honey I ordered from Canada in December, arrived in late June! There are still many incredible honeys from around the world that we cannot import into the UK, as they are produced by an ‘unrecognised’ species of bee. There are 11 species of honey bees around the world, and we only accept honey from Apis mellifera, the Western honey bee. It is a tragedy for rural communities around the world with excellent sustainable beekeeping practices, that they are excluded from trading their harvests with a large proportion of the world. Then in addition, there are countries that aren’t on the ‘accepted’ list, meaning that even Apis mellifera honey can’t enter our borders. I appreciate that agreements and rules need to be in place, however at the moment the rules favour the mass importation of tasteless, adulterated honey that only benefits the large organisations who can manage the bureaucracy, leaving many beekeepers exploited and in poverty. In the case of honey, local isn’t always the best. Our small islands have been polluted with toxic chemicals in industry and agriculture, our wildflower meadows and forests depleted as well as beekeeping practices outdated and causing stress to bees. I am enjoying supporting small producers who care for their bees, where the forage is clean and abundant, and my purchases put roofs on homes, send children to schools and give communities security. Manuka honey is a prime example of differing qualities within a single variety. Mauri beekeepers working in alignment with nature and the wild manuka flowers growing in their region, will have a completely different quality to the same named honey harvested from vast chemicallytreated monocultures of the same plant grown with chemical fertilisers in China. Where do you buy your honey, and do you know how it’s harvested? If a bee’s lifetime’s work is a tiny 1/12th of a teaspoon, please be sure to value that drop of liquid gold!