Museums and Display Collections (Insects)

Insect collections are often oversimplified as either a precious and essential, rapidly developing treasure or a musty, dusty, moribund assemblage of archaic specimens. Those who now prefer the latter characterization have not been paying attention. Entomological collections and their curators are experiencing a steady, if not spectacular, evolution in the way collections operate, and perhaps the best is yet to come.
The term “insect collections” is often loosely used, and these collections usually contain other arthropods, including arachnids (e.g., spiders, mites), myriapods (e.g., centipedes, millipedes), and terrestrial crustaceans (e.g., sowbugs and pillbugs, amphipods). So most entomological collections are actually arthropod collections.
Collections of insects and related arthropods constitute an enormous resource for biological information and are an irreplaceable tapestry documenting Earth’s entomological natural history. The numbers of specimens in collections are staggering, as is the amount of work yet to be accomplished just describing and cataloging millions of new species. Despite the revolutionary changes energizing these collections, still daunting are the myriads of problems, particularly financial, that continue to debilitate many collections’ operations.

SCOPE OF THE WORLD’S INSECT COLLECTIONS

Insects are the largest, most diverse group of organisms in the world. Over 900,000 species have been described, and current estimates on the number still without names range as high as 30 million. That theoretical number is based on work in the New World tropics. However, more recent work testing that hypothesis, including the Old World tropics and measuring host specificity, now suggests a more modest but still astounding 4-6 million unnamed species. Reflecting the number of species potentially involved, insect collections maintain a large number of specimens. Based on numbers and extrapolations primarily from Arnett, Samuelson, and Nishida and adjusted for the last 8 years using an annual growth rate of 2% (average over a 20-year period), there are conservatively 724 million specimens in entomological collections worldwide. This figure does not include the unknown number of specimens in private collections, nor does it include a significant number of unprocessed specimens. In 1991 Miller reported the numbers of specimens for entomological collections in the United States and Canada and also included figures on unprocessed specimens (i.e., backlog). In 1976 reports indicated that 26% of specimens were reported unprocessed, increasing to 28% in 1981 and 30% in 1986. If these percentages are extrapolated worldwide and added to the processed specimens, there may be nearly a billion arthropod specimens housed in entomological collections.
As might be expected, a great many collections house the rather large number of specimens that have been amassed. The insects and spider collections of one Web site (http://www.bishopmuseum. org/bishop/ento/codens-inst.html) list 904 institutional or organizational insect collections. Despite the plethora of collections, the largest house a disproportionate number of the specimens. Table I lists the largest entomological collections, that is, those reporting over five million specimens in their holdings. The largest collections are found in Europe, North America, Australia, and New Zealand. The collections” locations are likely influenced by the historical origins of insect collections, centers for entomological research, cultural interests, and economic restrictions. These collections do not coincide geographically with the regions of highest insect biodiversity, which tend to be in the tropics.
The total number of specimens may appear excessive given the number of species described, but the total figure includes many undescribed species. Also, long series are required to study and account for the morphological, geographic, and seasonal variability within a species. The specimens are also widely spread throughout many collections, enabling multiple centers for study and providing insurance against loss of species representation in case of natural or man-made disaster.

BEGINNINGS OF INSECT COLLECTIONS

The beginnings of insect collections are lost in unrecorded history. The Chinese used silkworms as early as 4700 B.C., honey bees by the 5th century, and scale insects by the 13th century. A treatise describing insects and their pharmaceutical properties had been published in China by at least A.D. 200. Cuneiform texts found in Mesopotamia dating to earlier than 669-626 B.C. contain systematically arranged names of insects. Aristotle (384-322 B.C.) studied insects and taught entomology. In A.D. 77 Pliny produced an encyclopedia that included entries on insects. Insect collections were no doubt made during antiquity, but no record of them has been found.
The early periods saw interest in insects primarily for their practical use or as pests. European explorations in the 15th and 16th centuries opened up shipping lanes for commerce and trade. The explorers and adventurers brought back hordes of items including insect novelties, piquing the interest of many. The first entomological collections were included in the cabinets of “curiosities” assembled by wealthy Renaissance families to show to friends and associates. These cabinets were to eventually lead to modern natural history museums.
The first compound microscopes were made by Hans and Zacharias Jansen in Holland in 1590. This major technological advance, coupled with the improvements made by Antony van Leeuwenhoek in the late 1600s, permitted the observation of tiny insects and their minute parts, advancing their study.
As the number of curiosity cabinets continued to grow in the 16th and 17th centuries, a means to organize their contents became necessary. John Ray (1628-1705) attempted a classification of insects in 1705, which was published posthumously in 1710. Carolus Linnaeus (Carl von Linne) (1707-1778) published the first edition of his Systema Naturae in 1735, and the 10th edition, published in 1758, became the basis for modern insect classification.

aFrom Arnett, R. A., Jr., Samuelson, G. A., and Nishida, G. M. (1993). “The Insect and Spider Collections of the World.” 2nd ed. Sandhill Crane Press, Gainesville, FL and Miller, S. E. (1991). Entomological collections in the United States and Canada. Am. Entomol. 37, 77-84.
bCollections reporting over five million specimens; does not include large Russian collections such as Leningrad whose holdings are not available.
cIn 1993 Arnett, Samuelson, and Nishida reported an estimate of 100 million. However, this is generally considered to be in error, hence the more conservative figure provided here.

SOURCES OF EARLY SPECIMENS

Linnaeus surrounded himself with students not only to carry on his work but also to provide specimens for study. Linnaeus was particularly interested in obtaining species of practical use, and he arranged for his students to go on voyages and encouraged them to send material from their travels. From 1744 to 1796, students sent back to Linnaeus and his associates material not only from Europe but from the Middle East, Africa, India, Asia, South America, Africa, and the Pacific (Cook’s first two voyages).
Some of these students of Linnaeus eventually produced works of their own: for example, Fredrik Hasselquist’s Iter Palaestinum eller Resa til Heliga Landet in 1762 and Pehr Forsskal’s Descriptiones animalium in 1775. Other Linnaean students, for example, Johann Christian Fabricius (1745-1808), were extremely productive in discovering and describing new species, continuing the Linnaean traditions and fostering this era of cataloging.
Wealthy scholars and others amassed large collections that eventually wound up in institutional collections. Catherine the Great started Peter Simon Pallas on collecting and exploring travels throughout the Russian Empire between 1767 and 1810. A. M. F. J. Palisot de Beauvois described insects from Africa and America collected on his own travels from 1781 to 1797. Guillaume Antoine Olivier, sent on expedition to Turkey, Asia Minor, Persia, Egypt and the Mediterranean islands (1792-1798), later became a patron for other naturalists. Pierre Frangois Marie Auguste Dejean (17801845), a soldier of fortune, collected in Austria and by exchange or purchase amassed the greatest collection of beetles in the world at that time. Thomas Say (1787-1834), the father of American entomology was appointed naturalist for Long’s expeditions to the Far West and visited the Rocky Mountains and the sources of the St. Peters River in 1823. Victor Ivanovich Motschulsky (1810-1871) was a Russian military officer who traveled through Europe, the Caucasus, Siberia, the Kirghiz steppes, Egypt, India, the United States, and Panama. Thomas de Gray, Lord Walsingham (1843-1919), was an English nobleman wealthy enough to travel extensively (United States, North Africa, Europe) and also purchase specimens.
The 19th century was a fertile time for voyages and expeditions. Alexander von Humboldt visited the Spanish colonies of the American tropics between 1799 and 1804. Otto von Kotzebue sailed around the world from 1815 to 1818. On board was J. Friedrich von Eschscholtz who collected in California, Hawaii, the Philippines, Brazil, Chile, and other places. On a later voyage, again with Kotzebue, Eschscholtz amassed a large collection from the tropics, California, and Sitka (Alaska). Other important voyages for entomological specimens included those of the Astrolabe (1826-1829), the Astrolabe and the Zelee (1837-1840), the Swedish frigate Eugenie (1851-1853), and the Austrian frigate Novara (1857-1859). The U.S. Exploring Expedition (1838-1842) visited Madeira, Brazil, Chile, California, Oregon, Pacific Islands (including Hawaii, Australia, the Philippines, and Singapore), South Africa, and St. Helena. Sources of entomological collections mirrored the spread of empire and the pursuit of national interests.
Rather than circumnavigating, some targeted specific locations. For example, Henry Walter Bates spent the years 1851- 1870 in South America, mostly in the Amazon, collecting and sending material back to England. Giacomo Doria (1840-1913), who founded the Genoa Museum, funded expeditions to areas particularly rich in insect diversity (Africa, Southeast Asia, New Guinea, Indian Ocean islands). Others such as Lionel Walter Rothschild (1868- 1937)
focused on specific groups. Lord Rothschild concentrated on butterflies and moths and funded expeditions to the far corners of the world; in 50 years’ time he amassed the greatest personal collection ever (including 2.25 million butterflies and moths).
The amount of material grew exponentially, and as the Linnaean system became entrenched, secure and centrally located places to store the reference collections and unprocessed materials were sought.

DEVELOPMENT OF FORMAL COLLECTIONS

The first natural history museum probably was that of Conrad Gessner a scholar of mid-16th-century Zurich. Very few present-day natural history museums were established before the mid-18th century. The Museum National d’Histoire Naturelle in Paris was established in 1635 and was the first natural history museum established in the form we recognize today. Others were the Staatliches Museum fii” Tierkunde in Dresden established in 1650, the Zoologicheskii Instituti Zoologicheskii Muzei in Leningrad in 1727, the Zoologiska Museet in Lund in 1735, the Naturhistorisches Museum in Austria in 1748, and the British Museum in 1753. Scientific academies, beginning with the Accademia dei Lincei in Rome in 1603, fostered and often housed early collections. The Royal Society in London was founded in 1662, and the Academie Royale des Sciences of Paris in 1666. The Academy of Natural Sciences in Philadelphia, founded in 1812, is the oldest North American academy. The academies were later augmented by natural history societies that often performed similar functions. The First Aurelian Society (early insect collectors were known as “Aurelians”) was founded in London in 1745. The Entomological Society of Philadelphia, established in 1859, was the first American entomological society.
The great explosion of natural history museums occurred in the latter part of 18th century and into the 19th century, with the continuation of exploration and collecting. Coincidentally, this proliferation of museum collections coincided with the earliest use of persistent poisons such as arsenic to protect biological specimens from damage by the pests that had destroyed many earlier collections (a Western discovery, but the Chinese had written about the use of arsenic and mercury for control of human parasites in A.D. 100-200). Perhaps the concentration of the entomological collections in temperate Europe and North America was a result not only of European influence but also of the climate, which likely was less favorable to potential pests of museum specimens than in the warmer regions of the world.
Growth continued through the 20th century with the exception of periods of global conflict. The 19th and 20th centuries saw increasing participation of institutions and government in organizing and funding expeditions. Expatriates and professionals on foreign assignment were also great sources of collections. The 20th century later saw a focus on regional faunas, opportunistic trips, and taxon-based initiatives. Institutions became less involved with collecting efforts and individuals increased their efforts, particularly to aid their research goals. Toward the end of the 1900s, cooperative efforts returned as the cost of fieldwork increased. Large national inventories such as the Instituto Nacional de Biodiversidad (INBio) established in 1989 in Costa Rica were undertaken, and ATBIs (all taxa biological inventories) were begun to inventory areas with a combination of high biodiversity and high threat of loss due to that biodiversity.
As the great expeditions filled the collections’ coffers and the continuous additions provided more than enough work for taxonomists, collections also needed technological support to improve storage and retrieval capabilities.

TECHNOLOGICAL ADVANCES IN

METHODOLOGIES USED BY COLLECTIONS

Technological advances, from the microscope to finding effective pesticides, had and still have a profound influence on the development of entomological collections. Although the basic methods of collections and specimen preparation have not changed radically, new innovations usually made the process quicker, more efficient, and more inclusive. Steady changes have taken place in the past three decades, and in retrospect, a major revolution has occurred.
Many innovations have been implemented, including the use of glass-topped drawers for specimen storage rather than just simple boxes. It is likely that insects were placed in containers to take advantage of the efficacy of pesticides by maintaining the specimens in a closed environment. Dried specimens are still prepared with pins, and paper labels are affixed to the pin beneath the specimen. However, the materials used have been much improved. Insect pins are of higher quality and are less likely to corrode.
Along with the advances in technology, the last few decades have seen a concerted effort to introduce materials conservation techniques into collections management. Recent advances in storage technology in insect collections include the development of the unit tray system. This is a system of topless boxes made of cardboard and with a material that functions as a pinning base at the bottom of the box. This innovation permits the rapid rearrangement of the collections as new studies modify the organization of a group. Placing like elements in a single unit tray (e.g., specimens of a species all collected in one area) also permits the use of a header card, or tray identifier, that permits rapid recognition and retrieval of information. The material first selected for tray bottoms was cork. Within several decades, however, cork was found to be unacceptable because its acidic nature affected the pins and labels and even perhaps the specimens. A new material was searched for, and most collections have settled on a cross-linked polyethylene product that is inert and pliable.
In the late 19th century, new methods helped streamline the paper-making process. Unfortunately, the new papers are slightly more acidic and tended to break down faster, with the ironic result that older 17th-and 18th-century labels are more permanent. Labels have changed in both substance and content. Some early collections were not labeled
at all to show the origin of specimens. As systematic work progressed and some species were found to be restricted in their distribution, labels were added. These labels were laboriously handwritten in ink and often would indicate only a country, an island, or a region. As even more species of insects were discovered, classifications became larger, and more specimens were collected, labels became more specific, adding ecological data, collecting information, and details of the collecting locality. With the development of GPS (global positioning systems), collecting location coordinates are routinely being added to label data.
Hand-printed labels gave way to mass-printed forms. Typesetting took time, and so photoreduction methods were used to speed the process. Since the 1980s, the desktop computer has become a mainstay in collections work. Initial efforts to use the computer to generate labels were restricted to providing printed copies since the early printers did not have a font size small enough to fit all the necessary information onto the tiny specimen labels. As laserwriters developed, collections personnel began experimenting with producing labels on them. The first efforts were encouraging until it was discovered that the toner (laser cartridge “ink”) did not stick to the paper used for labels in fluid (ethanol) collections. At this time, inkjet printers seem to be a useful alternative.
The last two examples serve to show why collections often embrace technology slowly. Yet despite the pitfalls inherent in adopting new technologies, most collections today are in much better shape for long-term survival than they were before. Other advances in storage and maintenance include new or retrofitted buildings for many collections, use of climate control to reduce fluctuations in temperature and humidity, and installation of compactor storage systems to make better use of space and improve access to collections. Repellents used in collections that are potential human health risks, such as naphthalene (usage introduced in the late 19th century) and paradichlorobenzene, are being replaced with freezing procedures and integrated pest management monitoring techniques such as sticky traps to intercept possible problems sooner.
Collecting methods have improved and can easily overwhelm the preparation capabilities of most present-day collection staffs. Mass collecting techniques took a great leap forward with the invention of a flight intercept trap by Rene Malaise in 1937 (prototyped in 1933). The Malaise trap is a tent-like structure placed in a position to intercept flying insects and have them self-collect in strategically placed containers. Today’s arsenal of passive traps includes yellow pan traps, pitfall traps, Berlese samplers, and innumerable other specialty traps and methods, including modifications of the original Malaise trap. For those unwilling to wait for their specimens to come to them, proprietary devices (e.g., D-Vac) allow vacuuming of vegetation. Even more efficient is the use of pyrethrum fog to assemble vast quantities of specimens from tree canopies.
As collections techniques evolved, methods of studying and interpreting species have influenced collections also.

CHANGING ROLES OF COLLECTIONS

Modern entomological collections are rooted in Linnaean classification. The century following Linnaeus was devoted to describing and cataloging the massive amount of material gathered, but there were too many species and not enough taxonomists. Other disciplines began studies of arthropods, and many researchers had to develop taxonomic expertise on their own to have names for the organisms they were studying.
Around the mid-19th century, large-scale agriculture and expanding horticultural efforts underscored the importance of insects as pests and opened up an entirely new area for collections, namely,the role of identifying insect pests and establishing the authenticity of such identification. The use of parasitoid and predatory insects for biological control began a new type of biological exploration, sending professional entomologists around the world to find control agents which were subsequently reared and released. Governments established sections of entomology in agricultural divisions and often associated them with national collections such as the U.S. Department of Agriculture and the Smithsonian Institution or the Commonwealth Agricultural Bureaux and the British Museum of Natural History.
Between 1897 and 1900, Ronald Ross and Patrick Manson discovered and experimentally proved that mosquitoes act as vectors in transmitting malaria, launching yet another era in collections development: the collection and study of medically important arthropods. Identification and research units were often established within military units or centers, such as the Walter Reed Army Medical Center in the United States.
Evolutionary biology has had a profound influence on the development of insect collections. Both Charles Darwin and Alfred Russel Wallace had been influenced by insects when they proposed their theory of natural selection in 1858. Further evidence for evolution was sought within insects, enhancing collections in the process. In the past 50 years, areas such as genetics, population ecology, and even bioprospecting have used existing insect collections and developed additional collections as adjuncts to their research. Insect collections have provided support for unexpected areas such as medical forensics. Within the last two decades, molecular biology has been asserting its influence on entomological collections, similarly using available specimens and gathering more, making use of DNA evidence to establish better understanding of species relationships.
New approaches to taxonomic studies have appeared in the decades since 1980. Phenetics (sometimes referred to as numerical taxonomy) bases classifications on overall similarities. Cladistics places emphasis for classification on branching points of a phylog-eny. Evolutionary taxonomy adds degree of similarity to evolutionary origin. The advent of computers has helped the establishment of these systems by facilitating the manipulation of data. Ernst Mayr perhaps summed up the current status in insect classification best: “Taxonomy has been more active, more in ferment, in the last 50 years, than ever before in its history.” Today these words are even more applicable.
As these new sciences developed, positions in classical taxonomy dropped steadily, many workers transferred to the newer “cutting edge” sciences. An increase in efforts to stimulate appreciation of entomology was one of the responses to the perceived loss of positions and funding.

COLLECTIONS ON DISPLAY

Early collections were displayed in their entirety. In 1864 John Edward Gray of the British Museum proposed to store the collections away from public view, and Richard Owen eventually produced an “)ndex collection” that became the model for display of collections specimens. This began the period of exhibit collections, with only a small portion of the material placed on view and the remaining material devoted to research. With little variation, this was the extent of entomological specimen exhibition for the next century.
Toward the latter half of the 20th century, new entomological exhibits with educational themes began appearing in an effort to interest the public. As operating costs rose and income stagnated, museums began adding an entertainment component to their exhibits in hopes of attracting more visitors, and to this end they allied themselves more closely with educational institutions. Exhibitors and collections staff quickly discovered that people respond positively to the display of live arthropods.
In 1976 the first insect zoos (e.g., Smithsonian Insect Zoo) appeared in North America. These living exhibits were extremely successful, spawning dozens of replicates. The first butterfly house debuted in 1976 on the British island of Guernsey; over a hundred soon followed throughout the world. Determining the exact number of living insect exhibits throughout the world is difficult because many zoological parks have an insect component that is not readily apparent. Both conventional and insect zoos have live specimens on display, but whereas the older style zoos maintain special enclosures and habitats for the animals, butterfly houses permit visitors to walk through the enclosure. These two innovations sparked a flurry of activity in arthropod husbandry. An indication of the popularity of living collections just in North America is the number (328) of organizations represented at the year 2000 Invertebrates in Captivity Conference sponsored by SASI (Sonoran Arthropod Studies Institute).

SHIFTING FUNDING

As museums began appearing in the late 1700s and 1800s, funding for collections shifted from the province of wealthy patrons, who were largely replaced by institutions supported by government or public funds. As governments centralized and became more active, particularly in the areas of medicine and agriculture, funding support shifted. Beginning in the late 1800s, agriculture became a major source of economic support, and indeed, modern land grant college collections owe their existence to agricultural funding. Today most large museums in the United States survive on a mix of revenue from endowment, gifts, income from visitors, grants from government or private sources, and direct support from government. In the rest of the world, funding for collections more likely comes from government sources, with less dependence on private sources. Traditional sources of funding such as agriculture or military research have waned recently, as has government spending in general. Though it is likely that funding sources such as biodiversity or conservation have not yet realized their full potential, many insect collections are now seeking supporting funds from private foundations as well as continued support from customary sources such as the National Science Foundation.

FUTURE OF ENTOMOLOGICAL COLLECTIONS

Inventory of the world’s biodiversity is far from complete, and present work is being accomplished in the face of extraordinarily high rates of extinction. Despite the large holdings presently in collections, many more species probably have not been collected yet, or even discovered. Financing for large-scale inventory projects has been minimal at best. However, a revival of taxonomy is under way, with funding coming from more diverse sources than before and with entomological collections reasserting their roles. Interest remains in endangered species and interest in alien species and their impact is growing rapidly.
Collections have always been in the information business. Specimens are about data, and collections are in the business of brokering snformation and storing and retrieving data. Present information technologies are revolutionizing data-sharing capabilities, and many collections are furiously converting their older information retrieval systems (card files, specimen data, etc.) into electronic systems that can be used internally and shared internationally. Bioinformatics tools such as electronic catalogs [e.g., Biosystematic Database of World Diptera (http:// www.sel.barc.usda.gov/diptera/biosys.htm) or Orthoptera Species File Online (http://viceroy.eeb.uconn.edu/Orthoptera)] are rapidly coming online. Large clearing-houses for biological information such as the National Biological Information Infrastructure (NBII) are available on the World Wide Web.
The global availability of this information will provide more opportunities for cooperative ventures and at the very least will make the process of scientific inquiry a lot less time-consuming and less costly. Perhaps even more intriguing is the potential to overlay information from other disciplines—for example, adding geographic capabilities to enhance understanding of species distributions, or plant data to further understand host associations—and provide a historical perspective to boot. Ambitious systems such as Species 2000 and the Global Biodiversity Information Facility will permit this type of knowledge synthesis and interoperability. Perhaps an opportunity to better understand human impact on the world’s ecosystems from an arthropod perspective is finally at hand. This is an exciting time for insect museums.