The Logic of Extinction: The Story of the Dutch Alcon Blue Butterfly
21 May 2021
By Rosanne van der Voet
By Rosanne van der Voet
Meijendel, summer of 1942. A faint golden sun is shining through dark grey clouds, yellowing the green and white landscape of sand, bush and trees. Standing out within the mass of rose- and orange-dotted green, the cross gentians bloom. Brightly dancing in the wind, the deep blue flowers break the silence. Their display attracts innocent visitors, bringing out lepidopterists like Barend Jan Lempke. He watches the butterflies return to their host plant, sucking out nectar from the flowers. The grey-blue wings look pale next to the bright flowers, their black spots darting as the butterflies fly from flower to flower.
For days, weeks, the man patiently observes the creatures, witnessing the insects laying their eggs on the remaining closed flower buds. Ten days later, he watches the caterpillars emerge, slowly but surely moving down to the centre of the flowers, eating every leaf that crosses their path. Without the nutrition of this specific plant, the caterpillars would not survive. While Lempke pins and studies a butterfly, the caterpillars drop to the ground and await the arrival of their host ant. Misleading the ants by adopting the surface chemistry of the ant brood, the caterpillars are disguised as ant larvae, taken to the ant’s nest and nurtured as their own.
The following summer, the cuckoo caterpillars will emerge from the ant’s nest as butterflies, and the same strange cycle of plant, butterfly, caterpillar and ant entanglement will be repeated. With the host ant species remaining unidentified, Lempke publishes his discovery of a new race of Alcon blue butterfly. The Dutch alcon blue, Maculinea alcon arenaria, a butterfly endemic to the Netherlands.
By 1979, the entire population of the Dutch alcon blue had disappeared. The locally specialised insects, dependent on one specific plant and ant species, could not survive in the rapidly deteriorating ecosystem, with anthropogenic changes to the landscape slowly encroaching on their fragile entanglements. While much coastal vegetation relies on natural dune function characterised by constantly shifting sand, water management against flooding and coastal erosion had begun to solidify the dunes which would otherwise have been in constant movement. Many dune-reliant plants could not adapt to the new conditions, causing the vegetation to decrease in biodiversity. Additionally, nitrogen pollution of the landscape favoured fast-growing plants, further reducing the chances of survival of slow-growing plants such as the cross gentian. Due to lack of natural grazing and mass mortality among rabbits, nothing stopped the grass from reaching up high, driving out nectar plants and starving the specialised butterflies in the process.
Today, the butterflies have been largely forgotten, but their absence is still tangible in the landscape if you know where to look. In their work Arts of Living on a Damaged Planet: Ghosts and Monsters of the Anthropocene, Anna Tsing, Heather Swanson, Elaine Gan and Nils Bubandt argue that extinct species still roam landscapes as ‘ghosts,’ their absence materially tangible in the severed ecosystem-specific entanglements left in their wake.
Though rare, between thorny bushes and marram grass, the cross gentian still grows in Meijendel today. Despite their deep blue colour, the flowers are not easy to see. The modest plant is usually standing on its own, lower and smaller than the plants it stands among. In the plant’s blue display, the butterfly’s absence is reflected, haunting the landscape. If you pay attention, you notice the indignant lonely blue of the flowers, echoing its call across the landscape. You see many insects answering, the flowers surrounded by buzzing pollinators. Yet the call to entanglement, to partnership between butterfly and plant, you still hear echoing across the landscape. You notice the cross gentian calling for that one creature after more than forty years without an answer. You notice that no one comes. That no more pale blue wings conclude its blue display. That no one lays eggs on the flower buds. That no caterpillar survives on just this plant. That no communities of unknown ants cluster any longer around its roots. Calling for its partner, the lonesome cross gentian still breaks the silence.
The legacy of the Dutch alcon blue, its disappearance only mourned by a small number of humans to begin with, was further discredited by research which claimed that the butterfly was in fact genetically identical to other alcon blues. Previously described as three distinct species of Dutch alcon blue, large alcon blue, and mountain alcon blue, all alcon blues turned out to be one and the same species. The butterfly’s status as a species endemic to the Netherlands being its one remedy against complete forgetfulness, its disappearance pinned it forever on the Sixth Extinction list. With the new revelations about its species, the Dutch alcon blue posthumously tumbled off its extinction pedestal, its status reversed, its extinction labelled an illusion.
The scientific discourse on the subject implied that the disappearance of the populations in Meijendel was insignificant now that it was known that genetically identical butterflies still roamed the rest of the continent. The focus on distinction in terms of (sub-)species left no room for more subtle differences, more local adaptions which made the butterflies of Meijendel unique. It conveniently masked the human eradication of the butterflies, rendering their disappearance meaningless. Yet the alcon blue of Meijendel flew out two weeks earlier than the large alcon blue. The morphological differences between the Dutch alcon blue and the large alcon blue turned out to be even bigger than between the large alcon blue and the mountain alcon blue.
Research from 2004, even though it determined all alcon blues were the same species, argued that the local ecological adaptations of the various populations were so divergent that they merited site-specific conservation measures. While some populations of alcon are hygrophilous, favouring damp conditions, others are xerophilous, living in dryer environments. These groups use different ant species as well as different foodplants. Regardless of these differences in behaviour, different populations of alcon blues are not treated separately for the purposes of conservation. Even though the butterflies have been considered endangered in Europe, their ecological status is now ‘of least concern,’ because they are treated as a homogeneous group.
An article from 2016 claims the various populations of alcon blue should be treated as behaviourally separate ecotypes, a much less strong distinction than that of subspecies. Although the different forms of alcon cannot be seen as ‘evolutionarily significant units,’ the authors conclude that ‘since they represent current ecological diversification of the group, and may have different evolutionary potentials (eg, through selection on different enzyme systems; Bereczki et al., 2015), they should continue to be treated as separate management units for long-term conservation.’
Whether we come to this conclusion directly through Lempke’s work or through the above-cited contemporary articles, it is evident that the butterflies of Meijendel constituted a separate population of alcon blue specifically adapted to the local dune landscape. It is indisputable that these butterflies have disappeared as a result of ecosystem decline due to human influence. The knowledge that the Meijendel butterflies were an ecotype rather than a subspecies of alcon blue does not discredit the tragedy of their disappearance. The approach that conflates the importance of the butterfly’s extinction with the question if they were a subspecies showcases an anthropocentric perspective that focusses on individual species rather than local species entanglements.
Viewing ourselves and the world around us as composed of individuals rather than symbiotically entangled beings echoes a linear worldview. However, although traditionally viewed as exceptions to the rule of individuality, research on microbes by scientists such as Lynn Margulis has pointed out that intricate symbiotic entanglements are rather the norm. As is evident in the story of the alcon blue butterflies, such entanglements can vary locally even among the same species. Countering the Anthropocene and the Sixth Extinction is thus not only about extinction of species, but also about the disappearance of locally specific ecological entanglements.
he case of the Dutch alcon blue shows that the scientific terminology on extinction should not be taken for granted – there is a need to reflect on the notion of extinction and the assumptions implied in the very term. For whether the plants and animals involved are fully extinct or not, the ecosystem of Meijendel remains impoverished by the disappearance of cross gentian, butterfly, and ant entanglement. The butterfly’s ant partner remaining forever unknown, the extent of what is lost is unclear. To focus on any one of the entangled beings would miss the point, for individuals are not the units of life. The flower buds of the cross gentian, slowly opening their bright blue leaves, reflect the missing grey-blue butterfly wings that should complete them. Until that happens, the plant remains a severed being.