Butterflies have captured the human imagination like no other insects. And we have collected butterflies in nets like no other insects. The Natural History Museum's collection of 10 million Lepidoptera - butterflies and moths - is the largest distinct collection in these buildings. This gallery showcases our collection and the stories that Lepidoptera tell about the world around us. These specimens are windows into evolution, ecology, natural history and the enthusiasm of collectors.
The wings of the purple emperor, Apatura iris, are vivid purple-blue from some angles and brown from other angles. This may have given rise to the genus name, from the Greek 'apatao' - 'to deceive'. Shifting, metallic colours such as this example derive from structural properties of the scales, which refract light at certain wavelengths.
Scales are involved in producing scents. Some butterflies have a 'sex brand', a patch of specialised androconial scales of the male fore wing that helps disperse pheromones emitted from tiny organs on the wings. The pattern of these scales makes it relatively easy to distinguish the males of the small skipper (Thymelicus sylvestris) (left) and Essex skipper (Thymelicus lineola) (right). Females are more difficult to separate, however, unless you get a good view of the underside of the antenna tip.
Within a lepidopteran wing pattern is a complicated network of veins that delimit cells. This can be seen most clearly on the mostly naked wing of a glasswing butterfly, Greta morgane oto. The patterns of wing veins have been used to infer the evolution of the Lepidoptera, as well as other insect orders.
The peppered moth, Biston betularia, is the most famous example of change in the frequency of colour patterns due to changes in the environment. In this case, the number of dark individuals increased when industrial pollution killed off lichens on tree trunks and deposited soot on the trunks. Geneticist Bernard Kettlewell carried out groundbreaking experiments on the genetics of colour morphs. Shown here are some of his bred specimens and his original notes. The story has become complex with the realisation that peppered moths don't normally rest on tree trunks. The genetics of this story are also complicated by the fact that there are two dark morph genotypes.
The African mocker swallowtail, Papilio dardanus, has been a model for evolutionary biologists for many years. Appearing in a number of morphs across different habitats, and with females mimicking less palatable species, one of the many intriguing stories involving this species concerns the difference between females and males. Differing selection pressures on the sexes result in females with wildly varying wing and mimicry patterns.
A small brown butterfly, the squinting bush brown (Bicyclus anynana), is the subject of a huge body of research investigating the effects of environment on the different colour morphs, including the appearance of eye spots and the influence of sexual selection in stabilizing wing patterns. From its African home, Bicyclus anynana has become a popular laboratory organism and is amongst an increasing number of butterflies to have had its entire genome sequenced.
If you have been light-trapping in Britain, you may have seen a moth land on a white sheet and transform into a piece of twig. The buff-tip, Phalera bucephala, is one of many species that have evolved to disappear into the background. Species such as the buff-tip look vastly different when pinned with wings outspread - hence names that refer to pale patches on the body rather than directly referencing their outlandish camouflage.
The painted lady, Vanessa cardui, undertakes one of the most remarkable migrations of European butterflies. When populations explode in North Africa, huge numbers move northwards. But it is not these individuals that reach us in Britain. Successive generations breed over the course of the summer, with offspring venturing further north. Then, remarkably, the butterflies emerging from eggs laid in Britain reverse this journey and move south, mirroring their ancestors from earlier in the year. Many details of this migration have been pieced together through citizen science, recording butterflies and their movements, and more high-tech use of radar and other techniques for tracking insect movements. These specimens demonstrate the wear and tear that accumulates over a butterfly's relatively brief life.
The most renowned butterfly migrant is the monarch, Danaus plexippus, journeying from large areas of North America to spend winter in their millions in Mexico and, to a lesser extent, California. The monarch's embarking on both the outward and return journeys is also highly unusual in the butterfly world.
Caterpillars are notoriously difficult to prepare as attractive pinned specimens. Unlike the adults, they are soft and they collapse and decay. The Museum has a relatively small collection of blown caterpillars, such as this swallowtail, Papilio machaon, whose insides have been squeezed out and the outer cuticle inflated and dried. It is more common nowadays to preserve larvae in alcohol.
In Britain, the lime hawkmoth, Mimas tiliae, almost always lives up to its name by eating the leaves of lime trees (Tilia species). But, further south in Europe, it will also happily eat birches (Betula). One theory is that it takes longer for the larvae to develop when eating relatively less nutritious birch leaves, so there simply isn't time in the short British summer for the life cycle to complete.
The silk moth, Bombyx mori, was domesticated in China millennia ago and is responsible for the vast majority of silk that we use. It produces silk to construct its cocoon. Bombyx mori has close relatives in the wild, but this species is now only known in domestication and cannot be found on its food-plant, mulberry, in the wild. After countless generations of silk moths having been bred in captivity, the larvae cannot locate food unless they are placed directly on the leaves, and the adults now have useless wings.
Caterpillars produce silk from spinnerets in their mouthparts. Silk from the silk moth is prized because it is laid down in a fine, continuous single strand to weave a cocoon. Moths that make cocoons underground tend to apply silk in large sweeps, like a plasterer, and their silk is unsuitable for fabrics.
Silk moth (Bombyx mori) pupae are commonly eaten as they are killed, and the silk can be harvested before the moth emerges and breaks the single silk strand. An African silk moth, Gonimbrasia belina, often known as the mopane worm, is also eaten in large quantities and can be bought by the bucketful in markets.
The origins of Cameraria ohridella were a mystery until herbarium samples of horse-chestnut leaves revealed that the moth had been living in the Balkans since the nineteenth century. The species presumably originated there, overlooked until it started stretching its wings and moving northwards. The adult is tiny but beautiful. Although a strong flyer, Cameraria ohridella is thought to have been inadvertently moved by vehicles over long distances.
The swallowtail, Papilio machaon, is the only British representative of a widespread family, the Papilionidae. Unlike its European relatives, the British population eats only milk parsley, Peucedanum palustre, in a few fens of Norfolk, although it used to be more widespread. Despite its low numbers, its specialist parasitoid, the ichneumonid Trogus lapidator, has clung on in Britain. Parasites and parasitoids are often seen as nuisances at best, but a healthy ecosystem should have a wide spectrum of parasites. Pupae that were parasitised can be recognised as the Trogus adult makes a neat emergence hole through the pupal wing case.
The usual suspect, responsible for many domestic clothes moth infestations, is the case-bearing clothes moth, Tinea pelionella. Its larvae feed in secluded spots on natural fibres. They require a warm climate and do well in centrally heated homes in Britain, especially given the recent mild winters.
The large heath, Coenonympha tullia, varies across its limited British range. Northern Scottish specimens have tiny spots or are entirely unspotted, while at the southern edge of their range in lowland Northern England, they are strongly spotted. Will this spotty pattern change over time? Genetic work on some British butterflies has shown that some genotypes are only present in museum collections, demonstrating that we have lost diversity within species as their populations have declined.
Through the enthusiastic collecting of a few naturalists, we have an unparalleled view of variation within discrete populations of a butterfly. The chalkhill blue, Polyommatus coridon, is rather local in Britain and restricted to one foodplant, the horseshoe vetch (Hippocrepis comosa). But where it occurs, populations can be sizeable and males conspicuous. A large series of specimens gives an idea of the variation within a species, which here include a hybrid with the Adonis blue, Polyommatus bellargus, and a rare gynandromorph - part female, part male.
Despite its English name, the New Forest burnet, Zygaena viciae, was last seen in the New Forest in 1927. Feared extinct in Britain, one population was eventually found on a ledge of a mountain slope in Scotland. The population has increased since its discovery in the 1960s but is still very localised.
Amassing the Museum's collections relies for the most part on the endeavours of committed amateur entomologists. Without the efforts of armies of collectors and recorders, we would have very little evidence for researchers to uncover change in the fortunes of our diverse flora and fauna. This chart shows the weekend spikes in collection dates for the orange-tips (Anthocharis cardamines) found in our collection.
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