Having a flutter: a lack of food for butterfly larvae has eaten into numbers. Photo: Getty
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Butterflies are beautiful but we need to love their larvae too

The numbers of monarch butterflies are at a record low and a large part of this is because of the disappearance of the milkweed plant, eaten by caterpillars.

Sometimes, to prove a point, you have to starve a larva. It’s all too easy to be bewitched by the beauty of a passing butterfly but not so easy to admire the foraging of a voracious caterpillar. We should, though: it turns out that the two are linked.

Researchers in the US have been putting monarch butterfly larvae on strict diets and observing the consequences for the butterflies they become. This kind of butterfly is in grave trouble. Every year, the insects perform an extraordinary 3,000-mile migration from Canada and the northern US down to central Mexico, where they gather on a few mountaintops for the winter.

In 2012, about 60 million monarchs arrived in the Mexican mountains. That was a record low until the 2013 figures came in – the number arriving was almost half that of the previous year. It was the lowest figure since records began in 1993.

A big problem is the widespread disappearance of the milkweed plant. Monarch larvae eat only milkweed and urbanisation and industrial farming practices have made it scarce.

Hence the research, which was published last April. The researchers found that restricting the monarch larva’s milkweed intake reduces the size of its wings when it emerges from the chrysalis. It is likely that this stunted growth makes the migration much harder work.

Monarchs also seem to need food to maintain their looks. The colours of the orange-and-black wing patterns are deeper, with more striking contrast, in monarchs covering the most distance. It may be that feeding up the larvae to produce better fliers will also produce more beautiful butterflies.

The aesthetic argument is one of very few available to conservationists. Researchers can’t point to any specific benefit that monarchs bring: they don’t seem to play a crucial role in any ecosystem and their removal from specific ecosystems “would probably not have lasting repercussions”, as one report put it. The monarchs don’t contribute anything apart from a beautiful spectacle when they migrate.

British butterflies are even worse off – they don’t have a spectacular migration. In March, the UK government issued a draft of its “pollinator strategy” document, which outlines what might be done about the severe decline in numbers of pollinating insects such as bees, butterflies and moths. The charity Butterfly Conservation said that it “strongly welcomes” the proposed strategy (though it dismisses as “ludicrous” the idea that pesticide companies should self-regulate).

Yet there is a slightly dejected tone to the charity’s chief executive’s observations. He points out that while bees are acknowledged to have economic value as pollinators of agricultural crops, butterflies are not and are therefore less likely to receive government help. In the age of market forces, it is not enough to be beautiful.

However, as the Intergovernmental Panel on Climate Change noted in March, butterflies’ relatively short life cycle and “high dispersal capacity” make them very useful markers of climate change.

That is certainly true of the British butterfly population, which, apart from a few cold-loving species, is thriving in our warming climate. In the past 20 years, for instance, the orange-and-black comma butterfly has spread 137 miles northwards.

If you lived in Edinburgh in the early 1990s, you would not have seen one. Now they’re not an uncommon sight: an effect of global warming that’s hard to complain about.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 14 April 2014 issue of the New Statesman, Easter Double

BBC
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Would the BBC's Nazi drama SS-GB have felt half so resonant a year ago?

This alternate history is freighted with meaning now we're facing the wurst-case scenario. 

Would SS-GB have felt half so resonant a year ago? Though the clever-after-the-fact Nostradamus types out there might disagree, I can’t believe that it would. When it comes to the Second World War, after all, the present has helpfully stepped in where memory is just beginning to leave off. The EU, in the process of fragmenting, is now more than ever powerless to act in the matter of rogue states, even among its own membership. In case you hadn’t noticed, Hungary, for instance, is already operating as a kind of proto-fascist state, led by Viktor Orbán, a man whom Jean-Claude Juncker, the president of the European Commission, jokingly likes to call “the dictator” – and where it goes, doubtless others will soon follow.

The series (Sundays, 9pm), adapted from Len Deighton’s novel, is set in 1941 in a Britain under Nazi occupation; Winston Churchill has been executed and the resistance is struggling to hold on to its last strongholds in the countryside. Sam Riley plays Douglas Archer, a detective at Scotland Yard, now under the control of the SS, and a character who appears in almost every scene. Riley has, for an actor, a somewhat unexpressive face, beautiful but unreadable. Here, however, his downturned mouth and impassive cheekbones are perfect: Archer, after all, operates (by which I mean, barely operates) in a world in which no one wants to give their true feelings away, whether to their landlady, their lover, or their boss, newly arrived from Himmler’s office and as Protestant as all hell (he hasn’t used the word “degenerate” yet, but he will, he will).

Archer is, of course, an ambiguous figure, neither (at present) a member of the resistance nor (we gather) a fully committed collaborator. He is – or so he tells himself – merely doing his job, biding his time until those braver or more foolhardy do something to restore the old order. Widowed, he has a small boy to bring up. Yet how long he can inhabit this dubious middle ground remains to be seen. Oskar Huth (Lars Eidinger), the new boss, is keen to finish off the resistance; the resistance, in turn, is determined to persuade Archer to join its cause.

It’s hard to find fault with the series; for the next month, I am going to look forward to Sunday nights mightily. I would, I suppose, have hoped for a slightly more charismatic actress than Kate Bosworth to play Barbara Barga, the American journalist who may or may not be involved with the British resistance. But everything else seems pretty perfect to me. London looks suitably dirty and its inhabitants’ meals suitably exiguous. Happiness is an extra egg for tea, smoking is practically a profession, and
the likes of Archer wear thick, white vests.

Swastikas adorn everything from the Palace of Westminster to Trafalgar Square, Buckingham Palace is half ruined, a memorial to what the Germans regard as Churchill’s folly, and the CGI is good enough for the sight of all these things to induce your heart to ache briefly. Nazi brutality is depicted here as almost quotidian – and doubtless it once was to some. Huth’s determination to have four new telephone lines installed in his office within the hour is at one end of this horrible ordinariness. At the other is the box in which Archer’s mutinous secretary Sylvia (Maeve Dermody) furiously stubs out her fag, full to the brim with yellow stars.

When I first heard about The Kettering Incident (Tuesdays, 12.20am; repeated Wednesdays, 10pm) I thought someone must have found out about that thing that happened one time I was driving north on the M1 with a more-than-usually terrible hangover. Turns out it’s a new Australian drama, which comes to us on Sky Atlantic. Anna (Elizabeth Debicki), a doctor working in London, pitches up back in Tasmania many years after her teenage friend Gillian disappeared into its Kettering forest, having seen a load of mysterious bright lights. Was Gillian abducted by aliens or was she, as some local people believe, murdered by Anna? To be honest, she could be working as a roadie for Kylie, for all I care. This ponderous, derivative show is what happens when a writer sacrifices character on the altar of plot. The more the plot thickens, the more jaw-achingly tedious it becomes.

Rachel Cooke trained as a reporter on The Sunday Times. She is now a writer at The Observer. In the 2006 British Press Awards, she was named Interviewer of the Year.

This article first appeared in the 24 February 2017 issue of the New Statesman, The world after Brexit