Butterflies are receding – and that could have dire consequences for life on earth


A symbol of beauty and metamorphosis, butterflies are one of the few generally popular insects. In fact, few would think of crushing a fly or spider, but butterflies inspire awe. Both the ancient Egyptians and the Aztecs believed that butterflies would greet the virtuous in the afterlife; several cultures around the world have associated butterflies with the soul. In western culture, they’re an eternally popular (albeit clichéd) tattoo choice.

Butterflies are so embedded in human culture that they can hardly imagine a planet without them. However, this seems to be the kind of world we are headed towards, based at least on current ecological trends.

“In the last 50 years our moth and butterfly populations have declined by more than 80 percent,” writes Josef H. Reichholf, an entomologist who recently wrote the book “The Disappearance of Butterflies”. “Perhaps only older people remember a time when meadows were full of colorful flowers and countless butterflies fluttered over them.”

Reichholf’s latest book is a hymn of praise for these beloved insects. In it he sees butterflies not only as a symbol of sensuality or visual splendor, but as animals with personalities. As Reichholf explains, they experience a complicated life cycle in which their bodies are constantly changing and changing, an existential ordeal that is probably incomprehensible to the human mind.

They are also, says Reichholf, astonishingly sophisticated in an unappreciated way. For example: their predilection for drugs.

“Butterflies can get drunk to some degree by sucking substances with psychopharmacological effects,” he told Salon.

I interviewed Reichholf by email about his book and the future of butterflies. As always, our interview was compressed and prepared for printing.

Can you explain the contrast between butterfly populations when you started studying them in the late 1950s with what they are today? What did you observe personally?

Very clear. I remember the many butterflies that flew over the meadows when I went to the river to watch birds [at] the Inn in southeast Bavaria in the early 1960s. The butterflies were of all kinds, from swallowtails to the then very abundant shades of blue, not just cabbage whites as is the case today. The investigation of the diversity and abundance of the night-flying Lepidoptera, the “moths”, however, revealed the continuing trends over the next few decades.

While the average biodiversity has halved in the last ten years, the abundance on the outskirts of the village in the south-eastern Bavarian region fell to up to 15 percent compared to the figures from 1969 to 1979.

While this study site is directly adjacent to the agricultural landscape, which has undergone extensive changes in the use and input of fertilizers and agrochemicals, there have been no significant changes in the biodiversity and abundance of butterflies and other insects in the river and forest near where I am running the same light traps on the same nights over and over since the early 1970s. And similar studies, which I carried out in the 1980s and from 2002 to 2010 in the city of Munich, showed no decline in spite of sometimes strong fluctuations in the frequency of nocturnal insects. It should be noted that the abundance of insects in Munich today is higher than in the agricultural countryside.

At one point you describe how purple emperors literally get drunk on toad poison. Can butterflies get as “drunk” as we do? Why do they do that?

Not only butterflies can get drunk to a certain extent by sucking on psychopharmacologically active substances, but as beetle collectors are also known, many types of beetles can be attracted with alcoholic juices, some of which are naturally produced when sugary juice is fermented by naturally occurring microbes . A number of mammals “like” alcoholic fruits, and so do birds. They have an enzyme in their liver that enables alcohol to be broken down, called alcohol dehydrogenase.

Can you break down the life cycle of an average butterfly? Most people believe that it is so easy for a caterpillar to create a cocoon and turn into a butterfly, but your book makes that a little difficult.

We have to take a closer look at the life cycles of butterflies, which are determined much more by the needs of the caterpillars than by those of the adult flight stage. The caterpillars are the “feeding phase” which precedes the “mating phase” of moths and butterflies when they emerge from the pupae. There are two very basic requirements for the feeding phase – namely the right food plants, as many Lepidoptera are quite specialized in their food choices; and a favorable microclimate in their habitat, the conditions of which can differ greatly from those officially measured at the meteorological stations.

In order to complete the annual cycles, the different species must also be able to survive the winter, which is present either as an egg, caterpillar, pupa or even as a hibernating butterfly (like sulfur). General meteorological trends therefore say little about the actual influence of weather on insects.

Like so many ecological disasters, this one can also be linked to industrial agriculture. What can we do to save her?

My studies, like so many others, show the overwhelming influence of agriculture on insect populations. Butterflies and moths are now trying better to live in cities than in rural areas.

However, the reduction in the amount of pesticides, as necessary and desirable as it is, is not followed closely enough to convince with an increase in the abundance of insects. The dominant factor, at least here in Central Europe, is the over-fertilization of the landscape. The availability of nitrogen compounds, which far exceeds the real requirement, favors the growth of a few plant species in addition to the crops, thus reducing the diversity of food crops and creating a much more humid and cooler microclimate than normal for the locations due to the excessive growth of vegetation. Greatly reduced food plant diversity and a too cold microclimate are the key factors for the extinction of butterflies and most species of moths and many other insects that are not agricultural pests.

Reducing the amount of fertilizer would therefore be of paramount importance in the policy strategy for more insect protection. Our nature reserves are too small and too prone to the side effects of modern agriculture to support a thriving population of butterflies, moths, and other coveted insects.

In view of the fact that more than a third of the agricultural products that people in Germany buy in supermarkets are disposed of in the garbage, a reduction in the level of agricultural production by around 25 percent would not affect people’s food security, but the use of fertilizers would and greatly reduce pesticides to maintain the now extremely high level of production.

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What would the world be without butterflies? Besides being less beautiful, how would it harm our ecosystem?

Butterflies, many species of moths as well as beetles and other insects, [are enjoyed by] many people. They are part of our environment and part of its quality. Nature-loving people. . . have the right to demand the preservation of the beauty and biodiversity of nature for their own sake, for us and for future generations.

Butterflies, even more so than the much more numerous moths and many other insects, are active and indispensable components of natural systems, ecosystems that provide free nature services such as pollination and bird food. Missing them or most of them would create a dull and depressing environment for us. Last but not least, the extremely high subsidies that we pay to agriculture from our taxes give us the right to demand an end to this destructive process, which is not necessary, only greed in the background.

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