ENDANGERED TERRESTRIAL INVERTEBRATES Mark Deyrup Archbold Biological Station

I. Evidence of Multitudes of Endangered Terrestrial entire lives (e.g., spiders) as opposed to animals that Invertebrates live in water for their entire lives (e.g., lobsters). II. Awareness and Understanding of Endangered Ter- There are also many amphibious animals that spend restrial Invertebrates part of their lives in both places (e.g., dragonflies). III. The Special Perils of Specialists terrestrial invertebrates Animals that are not verte- IV. The Significance of Endangered Terrestrial Inver- brates (such as fish, reptiles, amphibians, birds, and tebrates mammals) that live on land for their entire lives. V. No Second Chances Examples are all insects except for those with aquatic larvae; nonaquatic mites and nematodes; and all spiders, millipedes, centipedes, and scorpions. GLOSSARY alien invertebrates Invertebrates intentionally or acci- dentally imported by humans into new geographic SIMPLE STATEMENTS CAN RAISE the most compli- areas. cated questions. There are two simple facts about en- coevolution Long-term evolutionary adaptation of spe- dangered terrestrial invertebrates. The first is that there cies to each other (e.g., mutually beneficial relation- are great numbers of these endangered animals—many ships between bees and flowering plants). thousands of species. The second is that nobody knows endangered species Species that are likely to become enough to make a comprehensive list of these species. extinct in the near future because of normal human Without such a list, how is it possible to say whether activities. Examples of such activities are land clear- this list would be long or short and whether it would ing for agriculture or housing and accidental impor- really contain many thousands of species? What is the tation of invasive species through commerce. evidence that there are huge numbers of endangered endemic species Species confined to areas where they terrestrial invertebrates that are missing from lists of evolved (e.g., flightless crickets in the Hawaiian endangered species? Why aren’t biologists moving more Islands). quickly to add the missing names to the list? Are terres- habitat specialists Species found only in a specific hab- trial invertebrates particularly vulnerable to ongoing itat (e.g., species found only in forests of Sequoia rapid changes caused by our own species? If there are trees). such large numbers, what does this mean for the forests, terrestrial animals Animals that live on land for their fields, deserts, and other habitats that are threatened

Encyclopedia of Biodiversity, Volume 2 Copyright  2001 by Academic Press. All rights of reproduction in any form reserved. 487 488 ENDANGERED TERRESTRIAL INVERTEBRATES with the loss of these species? What does it mean for our own species?

I. EVIDENCE OF MULTITUDES OF ENDANGERED TERRESTRIAL INVERTEBRATES

The belief that there are very large numbers of endan- FIGURE 1 The Hawaiian tree snail Achatinella mustelina is1of41 gered terrestrial invertebrates is based on a combination species in its genus; 22 of these species are extinct, and the remaining 19 are severely threatened. These elegant, specialized, and slow- of knowledge and logic. The great majority of all ani- growing snails have been clobbered by a series of disasters. There mals are terrestrial invertebrates, in which are included was a shell-collecting frenzy of the 1800s, which also decimated at least three-fourths of the insects, most mites, terres- populations of Florida tree snails. This was followed by the destruc- trial mollusks, a large percentage of the nematodes, and tion of most of the forest habitat in which Achatinella species live. all the spiders, millipedes, and centipedes. The last three Finally, in 1955, a predatory snail species was introduced to combat an introduced species of African snail that is destructive to Hawaiian groups total more than all the vertebrates. If the factors agriculture. The killer snail quickly eliminated several species of that endanger other animals also affect terrestrial inver- Achatinella, and several other species survive only as captive colonies. tebrates, the number of endangered terrestrial invertebrates must be large indeed. These factors are primarily habitat destruction and the introduction of nonnative species into new areas, and it is known that they affect A. Logistical Problems terrestrial invertebrates. A major logistical problem is an insufficiency of experts. Hawaii, showcase of beleaguered biota, is a revealing There are so many species of terrestrial invertebrates example of these factors at work on terrestrial inverte- that it is easy to find groups with hundreds or thousands brates. Of the total number of animals that live on the of species that can only be identified by two or three Hawaiian Islands and in the surrounding sea, about people. Who can identify the dark-winged fungus gnats, three-fourths are terrestrial invertebrates, 99% of which Indonesian bark beetles, the egg parasites of tropical are found only on the Hawaiian Islands. The islands are sac spiders, the mites associated with millipedes, or any so strongly affected by habitat destruction that whole one of innumerable large groups of small organisms? habitat types, containing all their habitat-specific inver- The few people who do study these groups are generally tebrates, are considered endangered. Invasions of alien overwhelmed with species that are undescribed and plants and animals are so severe that whole groups of with species whose biology is almost completely un- invertebrates have been devastated, such as the Hawai- known. Recognizing any of these species as endangered ian land snails, which were originally believed to num- requires documentation of distribution and abun- ber approximately 1000 species but now number ap- dance—levels of information that will probably not be proximately 500, with most of the remaining species available for most terrestrial invertebrates for approxi- endangered. The Hawaiian Islands may provide the best mately another century (Fig. 2). opportunity to document relatively easily the scale of A second logistical problem is that specialized the threat to terrestrial invertebrates in especially vul- knowledge is needed not only for identifying most ter- nerable places, such as oceanic islands (Fig. 1). restrial invertebrates but also for finding and counting them. Species that are rare in museum collections are not necessarily rare in nature; they are frequently spe- II. AWARENESS AND cies that are difficult to find because their habits are unknown. Certain flightless pygmy mole crickets, for UNDERSTANDING OF ENDANGERED example, are very common in ancient dune areas in TERRESTRIAL INVERTEBRATES Florida, but until recently there were no specimens in museums because nobody knew to look for these insects Why is it taking so long to recognize and document just under the surface of the sand just after a heavy rain. endangered terrestrial invertebrates? There seem to be Many grasshoppers have species-specific songs which both logistical and strategic considerations involved. biologists must learn to study the abundance of the ENDANGERED TERRESTRIAL INVERTEBRATES 489

FIGURE 2 With regard to terrestrial invertebrates, there may be few people with the specialized knowledge to identify even large and easily characterized species. Many species could become rare or extinct without triggering alarms. The giant lacewing, Polystoechotes punctatus, apparently a common and widespread insect a century ago, is now so rare that few entomologists have seen a living individual. Nobody is writing distraught letters asking about the disappearance of this animal, and it does not appear on any list of endangered species. Nobody is doing any methodical surveys for this species; nobody knows how one would go about making such a survey because the ecology of the insect is poorly known. This species, which is relatively large (7-cm wingspread), distinctive, and of special interest because it is so primitive, has gone unrecognized as an endangered species. The great number of smaller and less conspicuous invertebrate species have that have become rare or extinct have even less of a chance of attracting attention.

adult insects; this has recently become a tool for studying endangered grasshoppers. Estimating the abundance of a species also requires specific knowledge of FIGURE 3 The red widow spider (Latrodectus bishoppi) is rare in life cycles and population dynamics. Many terrestrial the sense that it has a very small geographic range (a few areas of the invertebrates have a dormant period in the egg or pupal Florida peninsula) and a strict habitat requirement (Florida scrub). stage, during which they are almost impossible to find. Within its remnant patches of habitat, the red widow is sometimes Invertebrates often produce large numbers of offspring very common, whereas at other times it is extremely rare. This is probably due to predation by natural enemies such as spider wasps per female, and the percentage of survival of these off- and egg sac parasites. If one took a single survey in an area, one might spring may be strongly dependent on variable factors, conclude that this species was endangered or not at all endangered, such as weather or the population levels of certain pred- depending on the population level at the time of the survey. Is this ators. This means that populations may go through species endangered? Nobody knows. It depends on whether there frequent fluctuations of abundance and rarity, neither are factors that could wipe out populations when they are at their low point, since the habitat for the species is now in smaller patches of which may be good predictors of the long-term sur- that are farther apart. vival of a population (Fig. 3). Given all these logistical problems, however, there are still ways of quickly identifying large numbers of genuinely endangered invertebrates. There are whole tionships with other organisms and are endangered by groups of invertebrates that include many habitat spe- anything that threatens their host. Examples of these cialists and have poor dispersal abilities, and therefore excessively specialized invertebrates are most leaf-min- they are likely to be endangered if their habitat is re- ing and gall-making insects and mites, seed predator duced to small fragments. Examples of these unfortu- insects, insects and mites associated with plant genera nate animals are the land snails, millipedes, flightless that contain only one species, pollen feeders that visit beetles, flightless grasshoppers and crickets, and several one or a few species of flowers, and the fleas, lice, groups of primitive flies. It would be relatively easy feather mites, and den inhabitants of vertebrates. Since to compile a long list of endangered invertebrates by most species of endangered plants and vertebrate ani- surveying any old and distinctive habitat that is rapidly mals are likely to have at least one host-specific inverte- disappearing. There are some ecological groups of in- brate, it would be relatively easy to compile a long list of vertebrates that tend to have specific, coevolved rela- endangered invertebrates by studying the invertebrate 490 ENDANGERED TERRESTRIAL INVERTEBRATES associates of larger and better known endangered species. In summary, there are currently insurmountable dif- ficulties that prevent the recognition of more than a small percentage of the probable number of endangered terrestrial invertebrates. Even this small percentage of easily recognized species, however, is not receiving the intensive attention that one might expect, which sug- gests that there are additional problems with recognizing endangered invertebrates.

B. Strategic Considerations There are two species of bird lice (Franciscoloa thomp- soni and Neopsitticonirmus emersoni) that live only on the threatened Philippine cockatoo. These are examples of endangered invertebrates that might go unrecognized for strategic reasons. First, lice have no general appeal, and to say that this particular parrot is infested with unique and interesting species of lice is most unlikely to further spur efforts to save the bird. Simultaneously, there seems to be no strategic need to recognize the endangered species of lice because their survival depends on that of their host, whose status is already recognized. In the long run, however, it is important to understand that each species of organism represents a complex of ecological relationships, and the presence of a host-specific parasite is indicative of ancient se- quences of adaptation which add to the significance of the host species. Moreover, host animals may be molded by their parasites in ways that are just beginning to be acknowledged by biologists. Therefore, for example, mutual grooming behavior may have evolved through the presence of body parasites on places that are difficult to reach, and this mutual grooming may have a major role in social bonding between individuals. Some biolo- FIGURE 4 The sucking louse, Phthirpediculus propitheci, is a parasite gists also believe that strenuous courtship performances on the body of the endangered sifaka lemur, Propithecus diadema. and extravagant male ornamentation may evolve to This louse, which is indubitably endangered because of the status of demonstrate vigor and resilience in the face of the para- its host, seems an ideal candidate for Gilbert and Sullivan’s ‘‘little list site load that is borne by almost all wild animals (Fig. 4). of society offenders who might well be underground, and never would be missed!’’ Maybe not, however, because sifakas, like most other At a more general level of strategy, conservationists primates, do much of their socializing during episodes of mutual are caught in the same contradiction that afflicts all grooming, and the removal of the stimulus for this interaction could biological educators. On the one hand, simple messages change the intimate and supportive behavior of the species. are the most effective. On the other hand, life is irreduc- ibly complex. The story of the Florida scrub jay, for example, is complicated enough without considering such as terrestrial invertebrates. It may seem that this all the grasshoppers, beetles, millipedes, and other in- is an unscientific approach, one that panders to a per- vertebrates that are also restricted to Florida scrub habi- ceived bias against small, crawling creatures. In reality, tat. The choice is often made to focus on a few species it may be more a question of available information— whose protection through habitat preservation will au- both scientific information and information that is part tomatically protect a large number of other species, of our human heritage. The biology of the Florida scrub ENDANGERED TERRESTRIAL INVERTEBRATES 491 jay is known in great detail, including the complex of information on management and biogeography that is factors that threaten its existence, whereas the biology omitted when pandas or tigers are used as ‘‘umbrella of the Florida scrub millipede is almost completely un- species’’ whose protection helps to protect thousands known. Likewise, almost everybody has an intuitive of species that share the same habitat. A portion of the understanding of the significance of habitat loss to the earth’s endangered biota is contained in sites that do Florida scrub jay because this bird, like our own species, not support any endangered vertebrate species. The is relatively intelligent, home-loving, hierarchical, terri- endangered blue butterflies of the genus Maculinea of- torial, and lives in nuclear families. Accurate and de- ten occur in small sites in which there are no endan- tailed communication about the world of the Florida gered vertebrates. Certain small islands near the larger scrub millipede is not currently possible. If one were islands of New Zealand lack remaining endangered ver- to make the choice between studying a few endangered tebrates but have retained some endangered inverte- species in detail or studying many endangered species brates. Although some endangered invertebrates more superficially (a choice that few biologists actually quickly disappear from habitat fragments, others per- make), it might make sense to study a few species in- sist, together with endangered plants, long after the depth (Fig. 5). habitat-specific vertebrates have been extirpated. Man- In the long run, however, the study of a great variety agement of endangered invertebrates may require con- of endangered species provides a wealth of fine-grain sideration of microhabitat features that are less likely to be crucial to an endangered vertebrate, such as a species of crane or a species of antelope, because these larger animals have more general requirements. Maculi- nea butterflies provide a good example. Their caterpillars not only require certain food plants but also must spend part of their lives in the nests of particular species of Myrmica ants, which also have habitat requirements. Rotting tree trunks are a more generic example of a microhabitat; they are the only home for an enormous number of invertebrate species. The loss of this habitat type through salvage logging might have a small effect on vertebrate species but a great effect on invertebrates. Invasions of alien invertebrates are generally more of a threat to endangered invertebrates than to endangered vertebrates because these invaders are likely to be direct predators or competitors of native invertebrates.

III. THE SPECIAL PERILS OF SPECIALISTS

The very factors that have made the terrestrial invertebrates such a huge, successful group have guaranteed that large numbers of their species will become endan- FIGURE 5 The Florida scrub millipede, Floridobolus penneri,isa gered as humans change and destroy natural habitats. large gray species that burrows in the deep sand of Florida’s Lake Wales Ridge. It emerges at night to feed on dead scrub oak leaves and The small size of terrestrial invertebrates has allowed to disperse. This species is an example of an unrecognized endangered them to specialize on miniature resources. Huge num- invertebrate that receives some protection only because it occurs on bers of species, for example, feed on only one part of several sites on which the endangered Florida scrub jay also occurs. a single species or genus of plant. Many other species The Florida scrub millipede is absent, however, from most of the are internal parasites in a narrow range of insect hosts. range of the Florida scrub jay and is present in some small habitat fragments in which the jay is absent; therefore, the bird is not a truly The great advantage to this specialization is that it has effective ‘‘umbrella’’ for the invertebrate. Perhaps this millipede also allowed spectacular efficiency in finding and exploiting has some special microhabitat requirements. resources. The small bark beetle, Cactopinus hubbardi, 492 ENDANGERED TERRESTRIAL INVERTEBRATES which raises its larvae in the injured tissue lining the cavities made by woodpeckers in saguaro cactus, only needs to deal with the nutrients and defensive com- pounds of one kind of plant. It is probably able to zero in on its breeding sites, which are unlikely to be numerous in any one area, by following an odor plume emanating from the injured cactus. Since terrestrial invertebrates are able to rest in a dormant state with minimal energy expenditure, they can evolve life cycles synchronized with the availability of their resources, and this also increases the ability to specialize. The hundreds of species of solitary bees in arid habitats of Mexico and the southwestern United States can synchronize their emergence with the sea- sonal changes or the periodic rains that stimulate blooming in their plant hosts. This, combined with coevolution between the mouthparts of bees and the FIGURE 6 The Schaus swallowtail (Papilio aristodemus ponceanus), architecture of flowers, has led to many species-specific whose caterpillar feeds on young leaves of torchwood and wild lime, bee and flower relationships. The evolution of many is a good example of how specialization contributes to both the specializations is driven by the benefits of greater effi- evolution of species and the vulnerability of species. The young and ciency and less competition accrued by specialists. tender leaves and shoots of plants have concentrated nutrients and When humans disturb natural habitats, however, ex- are easy to chew, so they are usually greatly preferred by leaf-eating insects such as caterpillars. Plants, however, usually protect these treme specialization is a liability for many inhabitants young tissues with chemicals. Much of the diversity of butterflies because even temporary loss of a resource can eliminate and moths is based on species-specific adaptations: timing of the life the species that depended on that resource (Fig. 6). cycle to make the best use of growth spurts of plants and specialized The small size of terrestrial invertebrates allows them detoxification systems for particular plant poisons. The new growth to maintain thriving populations of habitat specialists of plants is concentrated at the top of the plant where there is the most light. Pollutants and pesticides, such as aerial sprays for adult in a small area, such as an isolated mountaintop with mosquitos, land mostly of the tops of the plants, where they are some alpine habitat that was colonized at the end of most likely to be consumed by caterpillars on young leaves. The a glacial period. Evolutionary biologists believe that Schaus swallowtail seems to quickly disappear in areas sprayed for speciation is most likely to occur in such isolated popu- mosquitos. lations peripheral to much larger populations. The isolated subspecies (really species in the making) of butterflies known as arctics (Oenis) and alpines (Erebia) show of species that are highly specialized or restricted to that this process can occur over a relatively short time. one or a few small patches of habitat. In areas in which there has been long-term isolation of habitat fragments, it is often possible to find isolated populations that have diverged so much that they are IV. THE SIGNIFICANCE OF clearly distinct species that could never merge, even if they were brought back together. Some groups of ENDANGERED TERRESTRIAL flightless Orthoptera provide good examples of this pro- INVERTEBRATES cess of speciation at work. Many of these distinctive forms and species of terrestrial invertebrates could per- A sparrow falls, Thou art mindful; A spider is sist indefinitely in the small areas of habitat where they gone, art Thou vexed? now occur, but these species and forms can be considered endangered because they could easily be elimi- Why should anybody be concerned about endangered nated by an episode of habitat destruction that would terrestrial invertebrates? Some people view this as a be small by current standards (Fig. 7). question of ethics: They believe that Homo sapiens is Terrestrial invertebrates as a group are not at risk not the only species with a right to exist, or they believe because there are many species that are generalists or that it is wrong to rob all future generations of the rich are widely distributed. A significant proportion of the biological heritage that was passed down to us. It is total diversity of invertebrates, however, is composed true that there have been previous waves of extinction ENDANGERED TERRESTRIAL INVERTEBRATES 493

duce useful chemicals. They might have innovative de- fenses against fungi or bacteria. They might have peculiar genetic systems or developmental pathways that are easy to analyze. Endangered species might inspire new areas of microengineering. They might display a variety of physiological mechanisms to deal with extreme environmental conditions. They may present more detailed evidence of evolutionary trends. They may be conve- nient indicators of environmental change. They might have novel types of mutualistic relationships with other animals or with plants. They may be remnant populations of formerly abundant species with important roles in restored ecosystems. Introduced pests might be con- trolled by invertebrates that are rare or endangered in their homeland. In addition to these potential material benefits, nonmaterial attributes of endangered invertebrates could have their own materialistic spin. Humans are willing to spend prodigious effort and money on nonmaterial things, such as entertainment, aesthetics, or the opportunity to make new discoveries. Many endangered species of terrestrial invertebrates might achieve their high- est value as examples of the beauty and intricacy of life; FIGURE 7 In Florida a series of isolated ancient dune fields have considering the psychological needs of our species, this their own species of grasshoppers that are unable to live in the is an offering that can never come too often or in too surrounding lowlands. Since these upland sites escape the flooding that is common in lower areas, they are well suited for housing and many guises. Already, the conservation of several spe- agriculture, and these grasshoppers have much reduced habitat and cies of butterflies is pushed by the market value of at least three appear to be endangered. Distinctive endemic species aesthetically pleasing specimens or of live specimens such as these grasshoppers also serve as biogeographic indicators, for butterfly houses that charge admission. showing that the areas they inhabit have been isolated for a long With regard to terrestrial invertebrates, we are cur- time and might have additional endemic plants and animals. The number of examples of endangered Florida invertebrates appearing rently in an inspiring but frustrating state of ignorance in this article is due to my familiarity with these species; there are in which any useful quality that we can imagine may many examples of endangered invertebrates almost everywhere. well be represented in the group, but our imaginations are clearly insufficient to the task. Second, the things that we care about are often de- of invertebrates caused by such events as ice ages or pendent on small, unconsidered details: the linchpin perhaps the impact of asteroids. Ethics, however, denies that holds the wheel on the axle or the knot at the end to us the innocence of an ice sheet or shooting star. A of the thread anchoring the stitching. From this truth, foundation stone of ethics is that we must endeavor to it is easy to postulate that there are ecological systems understand and take responsibility for the conse- that are tenuously held together by endangered inverte- quences of our actions. Since our species is strongly brates. Good examples might be found in old, isolated guided by ethics, ethical considerations may be as real systems with a very limited number of species, such as and important as the dictates of materialism. The origin a cave or an oceanic island. The situations in which a and nature of ethical attitudes toward other species single species has this linchpin role are likely to be few have been considered by several scientists, especially and exceptional. Most large-scale ecological systems, Edward Wilson. Even from a materialistic standpoint, such as a large area of rain forest in New Guinea or however, it makes sense to be concerned about endan- desert in Arizona, must have impressive built-in versa- gered invertebrates, for a variety of reasons. tility or they would not have survived the many natural First, endangered terrestrial invertebrates may be changes affecting the planet before the advent of our viewed as repositories of information. Currently, we species. On the other hand, biological systems of all have neither the time nor the skill to interpret this kinds can only withstand a certain degree of stress. It information. Some endangered invertebrates might pro- is difficult to recognize the approach of a breaking point, 494 ENDANGERED TERRESTRIAL INVERTEBRATES much less identify the relatively small events that could heavily settled areas; they seldom sweep out of large serve as triggers. tracts of natural habitat. In the future, invertebrates Third, although a single rare and endangered species might be endangered by genetically altered plants or of invertebrate is unlikely to determine the fate of a pathogens that carry self-replicating pesticides from ag- large ecological system, rare invertebrates may be im- ricultural areas into other habitats. One of the greatest portant in the aggregate (Fig. 8). In the remaining natu- threats to rare invertebrates today is invasion by exotic ral habitats of the world, especially those in warm and invertebrates. All these kinds of threats, which often warm-temperate climates, most of the total diversity occur in combinations, have a single general effect on of invertebrates is composed of relatively rare species. ecosystems: They replace many specialized invertebrate Many of these rare species could quickly become endan- species with a few generalists. The cumulative effect of gered species if their habitat changes in some major this loss of invertebrate diversity may be to threaten way. This change could be general habitat disturbance, populations of large, noticeable organisms, such as cer- or it could be habitat fragmentation. It could also be tain large vertebrates or plants. At a more basic level, caused by extensive contamination by pesticides to con- however, much of the efficiency and precision of energy trol agricultural pests. Aerial application of pesticides flow through ecosystems relies on the rarer and more to control biting insects is a special problem because a specialized species of invertebrates, just as the efficiency reduction in the incidence of human disease can be and precision in our communication relies on the avail- used to excuse even the most destructive of practices. ability of a huge number of rarely used and special- Most insect-borne diseases, however, are cycling in ized words.

V. NO SECOND CHANCES

Each species of endangered invertebrate is an old and irreplaceable entity. This seems like an obvious point, but one so often hears of ‘‘new’’ species of invertebrates that it is easy to unconsciously absorb the impression that invertebrates are evolving at a prodigious rate. These new species are always old species that are newly discovered. It is true that in special circumstances invertebrate populations can diverge relatively rapidly, evolving behavioral and physiological differences specific to the different conditions in different sites. Most invertebrate species, however, are distinguished by morpho- logical specializations that probably took a long time to evolve. This can be seen by examining the fauna of recently formed islands, such as the Bahamas. The Bahamas were submerged by the sea about 135,000 years ago and emerged again approximately 100,000 years ago. Although 100,000 years is a long time by human standards, it is evidently short by evolutionary standards—insufficient for the evolution of a major group of Bahamian species of terrestrial invertebrates FIGURE 8 General ecosystem functions, such as recycling of nutrients, are most efficiently done by many specialists rather than by a or terrestrial plants. few generalists. The plates that cover the shells of tortoises are made Recently, systematists (specialists who study the evo- of keratin—a protein that, because of its strong disulfide bonds, few lutionary relatedness of animals and plants) have put scavengers can digest. However, there is a moth, Ceratophaga vicinella, forward the argument that special attention should be whose caterpillar appears to have a specialized diet of the shells of dead given to endangered species that are the last remnants gopher tortoises. There are innumerable specialized invertebrates that feed on particular kinds of wood, bark, dung, and carrion. No single of evolutionary lines that largely disappeared millions one of these species is likely to be important in an ecosystem, but of years ago. It is noted that these relicts may have as a group they have a large impact. unusual kinds of adaptations and also provide glimpses ENDANGERED TERRESTRIAL INVERTEBRATES 495 of ancient life on our planet. Certain endangered terres- Bibliography trial invertebrates would be high on the list of species that would benefit from special consideration of relicts: Brown, K. S., Jr. (1997). Diversity, disturbance and sustainable use Onychophora, giant mites, redwood Thysanura, and of Neotropical forests: Insects as indicators for conservation monitoring. J. Insect Conserv. 1, 25–42. many primitive lineages known from small areas of the Collins, N. M., and Thomas, J. A. (Eds.) (1991). The Conservation tropics or south temperate areas. Although there is some of Insects and Their Habitats. Academic Press, San Diego. logic to priority for the most ancient and conservative Deyrup, M., and Franz, R. (Eds.) (1994). Rare and Endangered Biota of the endangered terrestrial invertebrates, unless sys- of Florida. Vol. IV. Invertebrates. Univ. Press of Florida, Gainesville. tematists are willing to work closely with ecologists, Elmes, G. W., Thomas, J. A., Wardlaw, J. C., Hochberg, M. E., Clarke, R. T., and Simcox, D. J. (1998). The ecology of Myrmica ants in the identification of relict lineages is not very useful. relation to the conservation of Maculinea butterflies. J. Insect Moreover, although ancient relicts may be important Conserv. 1, 25–42. for historical reasons and because they embody peculiar Gagne´, W. C. (1988). Conservation priorities in Hawaiian natural adaptations, they may have less relevance to modern systems: Increased public awareness and conservation action are systems than species that evolved from widespread lin- required. Bioscience 38, 264–271. Grove, S. J., and Stork, N. E. (1999). The conservation of saproxylic eages only a few million years ago. For example, useful insects in tropical forests: A research agenda. J. Insect Conserv. natural enemies of pests of solanaceous crops (such as 3, 67–74. potatoes, peppers, and tomatoes) are most likely to be Howarth, F. G., Sohmer, S. H., and Duckworth, W. D. (1988). Hawai- found among the large numbers of wasps and flies that ian natural history and conservation efforts: What’s left is worth attack insects on wild Solanaceae in some remnant habi- saving. Bioscience 38, 232–237. Matyot, P. (1998). The orthopteroids of the Seychelles: A threatened tat in the Andes Mountains. island fauna. J. Insect Conserv. 2, 235–246. In summary, terrestrial invertebrate species, once McKnight, B. N. (Ed.) (1993). Biological Pollution: The Control and lost, cannot ‘‘reevolve,’’ and the generation of new spe- Impact of Invasive Exotic Species. Indiana Academy of Science, Indi- cies that might restore lost diversity occurs on a time- anapolis. scale too long to be relevant to our own species. In other Middleton, S., and Liittschwager, D. (1994). Witness: Endangered Species of North America. Chronicle, San Francisco. words, every year there are fewer species of terrestrial New, T. R. (1991). Butterfly Conservation. Oxford Univ. Press, Oxford. invertebrates than ever before in human history; every Porter, S. D., and Savignano, D. A. (1990). Invasion of polygyne fire year there are more species of terrestrial invertebrates ants decimates native ants and disrupts arthropod community. than there ever will be again, even should human civili- Ecology 71, 2095–2106. zation endure 100,000 years. Riede, K. (1998). Acoustic monitoring of Orthoptera and its potential for conservation. J. Insect Conserv. 2, 217–223. Swengel, A. B., and Swengel, S. R. (1997). Co-occurrence of prairie and barrens butterflies: Applications to ecosystem conservation. See Also the Following Articles J. Insect Conserv. 1, 131–144. Tepedino, V. (1997). Wild bees and floral jewels. Wings 20, 8–11. ENDANGERED FRESHWATER INVERTEBRATES • Wilson, E. O. (1988). Biodiversity. National Academy Press, Washing- ENDANGERED MARINE INVERTEBRATES • ton, D.C. INVERTEBRATES, TERRESTRIAL, OVERVIEW • Wilson, E. O. (1992). The Diversity of Life. Belknap Press of Harvard TERRESTRIAL ECOSYSTEMS Univ. Press, Cambridge, MA.