BEETLES (Coleoptera)

BEETLES(Coleoptera) WILLIAM L. KRINSKY

TAXONOMY 87 MORPHOLOGY 88 LIFE HISTORY 89 BEHAVIOR AND ECOLOGY 89 PUBLIC HEALTH IMPORTANCE 90 VETERINARY IMPORTANCE 96 PREVENTION AND CONTROL 100 REFERENCES AND FURTHER READING

TAXONOMY

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Beetles constitute the largest order of insects but are of relatively minor public health or veterinary importance. Adults and larvae of a few species occasionally bite, but more species secrete chemicals that can irritate the skin and eyes of humans and other animals. Beetles found in stored products can cause inhalational allergies, and some species found in dung and stored products act as intermediate hosts for helminths that cause pathology in domestic and wild animals. Many dung-inhabiting beetles are beneficial in interrupting the life cycles of mammalian parasitic worms and in acting as predators or parasitoids of pestiferous flies that breed in excrement. A few beetle species are ectoparasites or mutualistic symbionts on mammals, and a few are known to temporarily invade the skin of mammals.

The order Coleoptera is divided into four suborders: Archostemata, considered the most primitive; Adephaga, named for its carnivorous members; Myxophaga, which are algae-eaters; and Polyphaga, the largest suborder, encompassing 90% of beetle families, in which species with diverse feeding habits are grouped. The number of beetle families varies between 135 and 170, depending on whether family designations are based on larval or adult morphology (Crowson 1981, Lawrence and Newton 1995, Downie and Arnett 1996). About 112 families include species that occur in North America. More than 300,000 species of beetles have been described, representing 30-40% of all known insects. About 25,000 species of beetles occur in the United States and Canada (White 1983, Arnett 1990). Fewer than 100 species worldwide are known to be of public health or veterinary importance. Most of these are in the suborder Polyphaga. The species that have the greatest impact on the health of human and domestic animals are in the following families: Meloidae (blister beetles), Oedemeridae (false blister beeries), Staphylinidae (rove beetles), Tenebrionidae (darkling beetles), Dermestidae (larder beetles), and Scarabaeidae (scarab or dung beetles).

MEDICAL A N D VETERINARY ENTOMOLOGY

Copyright 2002, Elsevier Science (USA). All rights reserved.

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William L. Krinsky antenna

mandibles lab|al palpu] ._" ~\ maxillary:_ palpus t~

--

elytron

R3 r-m M1

M4 hind wing

abdomen

tibia

.~. {arsus

claws FIGURE 6.1 A representative adult beetle (Carabidae), dorsal view, with left elytron and wing spread. A, anal vein (2 nd, 3rd, 4th); C, costa; Cu, cubitus; M, media (M1 = i st branch, etc.); R, radius (R1, 1st branch, etc.); Rs, radial sector; Sc, subcosta; m-cu, medio-cubital cross-vein; r-m, radio-medial cross-vein. (Modified from Essig, 1942.)

MORPHOLOGY Adult beetles are distinguished from all other insects by the presence of hardened fore wings called elytra (singular elytron) that cover and protect the membranous hind wings (Fig. 6.1). Coleoptera means "sheath-winged" in Greek. The size range of beetles is impressive, varying from 0.25 to 150 mm; however, most species are 2 20 mm long. Black and brown are the most common colors seen in the Coleoptera, but exquisite bright colors, including metallic and iridescent hues, occur, especially in tiger beetles, ground beetles, plant beetles, metallic wood-boring beetles, long-horned beetles, and lady beeties. Beetles vary in shape from elongate, flattened, or cylindrical to oval or round. Their bodies are often hardened, like the elytra, but some families, such as the blister and false blister beetles, have soft elytra and soft body parts that are pliable and sometimes described as leatherlike.

The head of a beetle is usually conspicuous, and almost all beetles have some form of biting or chewing mouthparts. Even in specialized species adapted for piercing and sucldng plants, the mandibles are retained and are functional. The antennae vary greatly in shape from filiform to pectinate to clavate or clubbed and are usually composed of 11 visible segments. Two compound eyes are present in most species, and ocelli are rarely present. Part of the thorax is visible dorsally as the pronotum, just posterior to the head (Fig. 6.1). The divisions of the thorax are usually evident only on the ventral side. The legs vary greatly in shape, from thick paddles in swimming species to slender, flexible forms in running species. The paired elytra cover the folded, membranous pair of hind wings. They usually overlay the dorsum of the abdomen and often are all that is visible in the abdominal region when a beetle is viewed from above. In most species, the elytra are raised during flight. Some beetles have no hind wings and are flightless, and some beetles have very short

Beetles (Coleoptera) elytra so that the abdominal tergites are visible dorsally (e.g., rove beetles and some blister beetles). Most beetles have eight visible abdominal tergites which can be seen when the elytra and hind wings are raised. Defensive glands that secrete substances to repel predators are best developed in beetles in the suborder Adephaga. They are generally present as pygidialglands that open dorsally near the end of the abdomen. Secretions from these glands in the Adephaga are not known to cause notable ill effects in mammals. Within the Polyphaga, pygidial glands occur in a few families, such as the Tenebrionidae. In tenebrionids, the pygidial glands produce secretions that can deter small mammals and cause human skin irritation. The pygidial secretions of most other polyphagan species are not known to affect vertebrates. Beetles that contain chemicals that are especially irritating to humans and other animals have toxic substances dispersed throughout their bodies rather than sequestered in specialized glands. The blister beetles, paederine rove beetles, and lady beetles fall within this group.

LIFE HISTORY M1 beetles exhibit holometabolous development. Eggs are laid singly or in clusters on or in soil, living or dead plant matter, fabrics, water, and carrion and, rarely, on living animals. The larvae of most beetles have a distinct head with simple eyes (ocelli) and chewing, mandibulate mouthparts, and the abdomen has 8 to 10 segments. Beetle larvae exhibit diverse morphological types, from elongate-flattened forms (campodeiform) to cylindrical-flattened forms (elateriform), caterpillar-like forms (eruciform), and somewhat C-shaped soft forms (scarabaeiform). The larval body type usually is consistent in a particular family of beetles. In a few families, however, the larval form may vary from instar to instar in a given species, a life history progression called hypermetamorphosis. Certain blister beetle larvae, including scavengers in bee nests and ectoparasites or endoparasites of other insects, are hypermetamorphic. They emerge from the eggs as active campodeiform larvae, then molt into eruciform and scarabaeiform stages. Most beetle larvae molt at least three times before transforming into pupae. Mthough most temperate species undergo only one generation a year, species in warmer climates are often multivoltine. Depending upon the species, any developmental stage may overwinter, but overwintering most often occurs in the pupal or adult stage. Most species exhibit diapause in one or another stage, and those that have developmental cycles exceeding one warm season usually have an obligatory diapause, initiated by changes

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in photoperiod and temperature. Most adult beetles live for weeks to as long as a year. However, adults of some species may live for years, spending much of their lives in diapause during periods when food is scarce.

BEHAVIOR AND ECOLOGY Beetles live within all terrestrial and freshwater habitats. The great variation in beetle feeding behavior, whether saprophagous, herbivorous, carnivorous, or omnivorous, reflects the extremely diverse habitats in which these insects live. However, their mouthparts play a minor role in causing discomfort to humans and other animals. Beetle defense mechanisms, which involve the shedding or secretion of physically or chemically irritating materials, and beetle behavior that puts the insects in contact with developmental stages of parasitic helminths and vertebrates can lead to public health and veterinary problems. Larder or pantry beetles (Dermestidae) are ubiquitous in human and domestic animal environments, where the larval and adult beetles eat stored food, food debris, dead insects, and other organic matter. Setae that cause human skin irritation or act as respiratory allergens are loosely affixed to the larvae of many species. The setae are elaborately barbed so that their firm adherence to many substrates, including human skin, causes them to be dislodged from the crawling, living larvae. In some species, the larvae actively raise the abdomen and make striking movements in response to touch. Other active defensive behaviors are seen in blister beetles, some chrysomelid plant beetles, long-horned beetles, and lady beetles that exude irritant chemicals from the femoro-tibial joints of the legs or from glandular openings around the mouthparts when the beetles are handled or threatened. This reflex bleeding repels predators. One of the most dramatic defensive maneuvers is the explosion of boiling hot, acrid quinones from the anal glands of carabid beetles called bombardier beetles. These forceful expulsions, which are aimed with extreme accuracy at potential predators, cause minimal damage to humans and other large animals but can cause physical and chemical burns in insects and small vertebrates (Evans 1975). Most of the beetles that serve as intermediate hosts of helminths parasitic in domestic animals and humans are grain or dung feeders. These species ingest helminth eggs present in animal feces or fecal-contaminated food. Because of the proximity of the beetles to feeding animals, whole adult beetles are often incidentally ingested by potential vertebrate hosts. The tendency of many beetles to fly to artificial lights puts them in contact with human and domestic animal

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William L. Krinsky

habitats and increases the chances of vertebrate contact with species that may be the sources of skin irritations, allergies, or helminthic infestations.

PUBLIC HEALTH IMPORTANCE H u m a n health problems caused by beetles include skin, eye, ear, and nose irritations, respiratory allergies, and minor gastrointestinal discomfort. Beetle families known to cause public health problems are listed in Table I. The greatest human discomfort associated with beetles is caused by vesicating species that secrete irritating chemicals when the insects are handled or accidentally contact human skin or sense organs. Blister beetles, false blister beetles, some rove beetles, and some darkling beetles have these irritants in their secretions, hemolymph, or body parts. Larvae of larder beetles are covered with hairs that can act as skin or respiratory allergens.

Invasion of body tissues by beetle larvae is called canthariasis, whereas invasion of such tissues by adult beetles is called scarabiasis. These forms of infestation occur most often in tropical regions. Most clinical cases involve enteric canthariasis that results from the ingestion of foodstuffs infested with beetles, or the accidental ingestion of infested materials by children. Dermestid larvae, such as Trogodermaglabrum and T. ornatum, have been associated with enteric canthariasis in infants who showed signs of extreme digestive discomfort, which in one case was the result of ulcerative colitis. It is unlikely that larvae were the cause of the latter condition, although larval hairs may have exacerbated the symptoms. Larvae were recovered from the stools of these patients and from the dry cereal they ingested. Other grain-infesting beetles, such as Tenebrio molitor and T. obscurus, have been accidentally ingested without causing noticeable symptoms. Rarely, adult and larval beetles have been recovered from human nasal sinuses, and larvae have been recovered from the urethra. Small beetles in various families

TABLE I B e e t l e F a m i l i e s o f M e d i c a l / V e t e r i n a r y I m p o r t a n c e , L i s t e d in O r d e r o f R e l a t i v e I m p o r t a n c e Family

C o m m o n name

Clinical importance

Meloidae

Blister beeries

Cause eye irritation and blisters on skin; can poison and kill horses that ingest them.

Staphylinidae

Rove beetles

Paederine species cause skin and eye lesions and can poison livestock that ingest them; large species are known to bite humans; species attracted to dung feed on fly eggs, larvae, and pupae and are thereby beneficial in reducing pestiferous fly populations.

Scarabaeidae

Dung beetles and chafers

Spines cause irritation when adults enter ears; intermediate hosts of helminths; dung feeders are potential disseminators of pathogens; some dung feeders are beneficial in removing dung that is the source of pestiferous flies and that is infested with intermediate stages of vertebrate worm parasites.

Tenebrionidae

Darkling beetles and grain beetles

Cause skin and eye irritation; larvae and adults contain inhalational allergens; grainfeeding species are intermediate hosts of helminths and potential disseminators of pathogens.

Dermestidae

Larder beeries, pantry beetles, hide beetles, carpet beeries

Larval setae can cause skin, eye, ear, and nose irritation or gastrointestinal discomfort if ingested; larvae and adults can cause inhalational allergies; grain-feeding species are intermediate hosts of helminths; carrion-feeding species are potential disseminators of pathogens.

Histeridae

Hister beeries

Beneficial as predators of fly eggs and larvae developing in avian and mammalian manure.

Oedemeridae

False blister beetles

Cause skin and eye irritation.

Carabidae

Ground beeries

Intermediate hosts of poultry tapeworms.

Silphidae

Burying beeries or carrion beeries

Potential disseminators of pathogens.

Corylophidae

Minute fungus beetles

Cause eye lesions.

Coccinellidae

Ladybird beeries or ladybugs

Secretions can cause skin discoloration and irritation.

Cleridae

Checkered beetles

Can bite humans, causing temporary distress.

Cerambycidae

Long-horned beeries

Larger species can bite humans and other animals, causing temporary discomfort.

Merycidae

Old World cylindrical bark beetles

Can bite humans, causing temporary distress.

Curculionidae

Weevils

Grain-inhabiting species can cause inbalational allergies.

Beetles (Coleoptera) have been known to fly or crawl into human eyes and ears. Some of these cause minor physical irritation, while others may cause extreme burning sensations, presumably due to chemicals exuded by the insects. Painful, but temporary, eye lesions caused by tiny Orthoperus species (< 1 mm long) in the family Corylophidae have been seen in eastern Australia, where the condition has received several names: Canberra eye, Christmas eye, and harvester's keratitis. More than 40 species of beetles have been associated with human allergic reactions that result from inhaling beetle parts (e.g., larval setae) or excreta (Bellas 1989). Agricultural and research workers are most often affected by inhalational allergies, because most of the beetle species involved occur in large numbers in stored products. Dermestid beetles (Trogoderma angustum), tenebrionids (Tenebrio molitor and Tribolium species), and grain weevils (Sitophilus granarius) have been incriminated in many cases of respiratory distress, such as asthma. Beetles serve as intermediate hosts for more than 50 parasitic worms, including tapeworms (Cestoda), flukes (Trematoda), roundworms (Nematoda), and thornyheaded worms (Acanthocephala) (Hall 1929, Cheng 1973). These worms primarily parasitize nonhuman hosts. Only a few species, such as the rodent tapeworms Hymenolepis nana and H. diminuta and the Macracanthorhynchus species of acanthocephalan parasites, occasionally infest children. The intermediate hosts of Hymenolepis species are grain beetles (Tenebrionidae), and Macracanthorhynchus species undergo development in dung beetles (Scarabaeidae). Children become infested because of their poor hygienic practices or by accidental ingestion of the beetles. Intentional ingestion of living tenebrionids for medicinal purposes in Malaysia is also a potential route for human infestation with rodent tapeworms (Chu et al. 1977). Many beetles, such as scarabs, silphids, and dermestids that feed on dung and carrion have the potential to be mechanical vectors of pathogens, such as salmonellae and anthrax bacilli. Although there is experimental evidence for maintenance and excretion of some of these microbes by beetles, given the limited sizes of the inocula and the limited contact between humans and scavenger beetles, there is no indication that these beetles play a role in direct transmission to humans. Many families of beetles include species lmown to occasionally cause bites to humans. This may happen when the beetles are accidentally handled or when the beetles occur in such large numbers that many fly or crawl onto the body. Entomologists and others who pick up beetles are the persons most often bitten. Long-horned beetles (Cerambycidae), checkered beetles (Cleridae), rove beetles (Staphylinidae), and cylindrical bark beetles (Merycidae) are among those that have been reported as biting. The

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somewhat painful bites usually leave few or no skin marks and do not cause any long-lasting discomfort. Longhorned beetles feed on wood in their immature stages and are found as adults on flowers, dead and dying trees, and freshly cut timber. The larger species of rove beetles that can bite are predaceous on fly larvae and are often found on carrion or dung. Cylindrical bark beetles and checkered beetles are found under bark associated with wood-boring insects or fungus. Population increases and mass migrations of checkered beetles (Cleridae), fiat grain beetles (Cucujidae), and ground beetles (Carabidae) have all caused annoyance at times by their sheer numbers and, in some cases, by the strong odors of their defensive secretions.

MELOIDAE (BLISTERBEETLES) Blister beetles (Fig. 6.2) occur worldwide. Most, if not all, contain the terpene cantharidin (C10H1204), which can cause skin irritations. People usually develop blisters within 24 hr of contacting the secretions of these beetles or the body fluids from crushed beetles (Fig. 6.3). Often this is accompanied by tingling or burning sensations. The blisters may progress to vesicular dermatitis with itching and oozing lesions. At least 20 species of meloids have been associated with dermatitis (Table II). Cantharidin is present in the hemolymph and in the clear, yellow secretion that is exuded at the joints of the legs of these beeries by reflex bleeding. Reptiles and some predaceous insects are repelled by the fluid. Mthough cantharidin is irritating to humans, the chemical acts as a meloid courtship stimulant that is secreted by male accessory glands and passed to the female during copulation. The males, being the only source of cantharidin, generally have the highest concentrations of the chemical, with levels in female beeries varying with their mating histories. The meloid spermatophore is rich in cantharidin, and the eggs also contain the substance, presumably to deter predators. Blister-beetle dermatitis has been reported in Europe, Asia, Africa, North America, and Central America. The most famous blister beetle is the "Spanish fly" Lytta vesicatoria of the Mediterranean region, an insect that has been erroneously touted as a human aphrodisiac. Cantharidin is poisonous to humans and other animals when ingested and may cause kidney damage and death. Ingestion of powder made by grinding up dried beetles or any other source of cantharidin produces extremely toxic effects on the urogenital system. The resuiting inflammation causes painful urination, hematuria, and persistent penile erection (priapism), a condition mistakenly associated with increased sexual stimulation. Like many other naturally occurring toxins, cantharidin has been prescribed for centuries as a cure for various

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William L. Krinsky

FIGURE 6.2 Blister beetles (Meloidae). A, Black blister beetle (Epicauta pennsylvanica); B, Striped blister beetle (E. vittata); C, Spotted blister beetle (E. maculata); D, European "Spanish fly" (Lytta vesicatoria). (A-C, modified from White, 1983; D, from Harde, 1984.)

ailments, but it has never been proven to have a therapeutic effect. Meloid species most often associated with skin lesions in the United States and Mexico are members of the genus Epicauta. These include the striped blister beetle (Epicauta vittata) in the eastern states, the black blister beetle (E. pennsylvanica) found throughout most of the country, and the spotted blister beetle ( E. maculata) found in the western states (Fig. 6.2). Other species of Epicauta cause similar problems in India and Africa (Table II). The genus Cylindrothorax occurs over a vast area of the Old World, including Africa, the Near East, India, and parts of Southeast Asia. African species that cause blistering include Cylindrothorax bisignatus, C. dusalti,

FIGURE 6.3 Vesicularskin reaction caused by blister beetle, left cheek of human. (From Weinberg et al., 1975, reproduced with permission of the McGraw-Hill Companies.)

TABLE II Species o f Meloidae R e p o r t e d to Cause Blistering o f H u m a n Skin

Species

Geographic occurrence of clinical reports

Lytta vesicatoria

Europe

L. phalerata

China

Epicauta cinerea

United States (southwestern)

E. flavicornis

Senegal

E. hirticornis

India

E. maculata

United States (western)

E. pennsylvanica

United States, Mexico

E. sapphirina

Sudan

E. tomentosa

Sudan

E. vestita

Senegal

E. vittata

United States (eastern)

Cylindrothorax bisignatus

South Africa

C. dusalti

Senegal, Mali

C. melanocephalus

Gambia, Senegal

C. picticollis

Sudan

C. ruficollis

Sudan, India

Mylabris bifasciata

Nigeria

M. cichorii

India

Psalydolytta fusca

Gambia

P. substrigata

Gambia

Modified from Alexander (1984), with information from Selander (1988).

Beetles (Coleoptera) C. melanocephalus, and C. picticollis. A Lytta species in China also has been associated with human dermatitis (Table II). Blister beetles are found most often on flowers or foliage, where the beetles feed on pollen and other plant tissues. Epicauta species are usually abundant where grasshoppers flourish because the larvae of these meloids feed on grasshopper eggs. Most people who develop blister beetle lesions are agricultural workers or soldiers on maneuvers in areas where the beetles are common. Retention of cantharidin in frogs and birds that prey upon meloids may lead to human poisoning when these predators are used as human food. Nineteenth century medical reports of priapism in French legionnaires traced the cause of this clinical problem to the soldiers' ingestion of frogs that had eaten meloids. Humans have also developed signs of cantharidin poisoning following ingestion of cooked wild geese (Eisner et al. 1990).

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OEDEMERIDAE (FALSE BLISTER BEETLES) False blister beetles in the genera Oxycopis (Fig. 6.4), Oxacis and Alloxacis are known to cause vesicular or bullous dermatitis in the United States, Central America, and the Caribbean region. Sessinia kanak, a species that is commonly attracted to lights in the Solomon Islands, and S. lineata, a New Zealand species, cause similar irritating lesions. Blistering has been observed in people exposed to large numbers of swarming Eobia apicifusca in Australia. False blister beetles are attracted to flowers, where they feed on pollen. Immediate burning of the sldn following contact with Sessinia species swarming around coconut flowers has been reported on the Line Islands, south of Hawaii. As in meloids, cantharidin is the toxic substance in all of these oedemerids.

STAPHYLINIDAE ( R O V E BEETLES) Rove beetles (Fig. 6.5) in the genus Paederus contain pederin (C25H4sO9N), a toxin more potent than that of

FIGURE 6.4 Falseblister beetle, Oxycopismcdonaldi(Oedemeridae). (From Arnett, 1984.)

FIGURE 6.5 Blisterbeetle, Paederussabaeus(Meloidae), WestAfrica. (From Patton and Evans, 1929.)

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Latrodectus spider venom, and the most complex nonproteinaceous insect defensive secretion known. The beetles, which are mostly 7 - 1 3 mm long, are found in North, Central, and South America, Europe, Africa, Asia, and Australasia. Unlike most rove beetles, which are dullcolored, many Paederus species have an orange pronotum and orange basal segments of the abdomen, which contrast sharply with the often blue or green metallic elytra and brown or black coloration of the rest of the body. This color pattern may be a form of warning (aposematic) coloration, but a defensive function for pederin has not been demonstrated. At least 20 of the more than 600 described species of Paederus have been associated with dermatitis (Table III). Skin reactions to the beetles, named Ch'ing yao ch'ung, were described in China as early as AD 739. Most cases of dermatitis have involved tropical species, including Paederusfuscipes (widespread from the British

TABLEIII Species of Paederus (Staphylinidae) Reported to Cause Skin Lesions in Humans Geographic occurrence of clinical reports

Species Paederus alternans

India, Vietnam, Laos

P. amazonicus

Brazil

P. australis

Australia

P. brasiliensis

Brazil, Argentina

P. columbinus

Brazil, Venezuela

P. cruenticollis

Australia

P. eximius

Kenya

P. ferus

Argentina

P. fuscipes

Italy, Russia, Iran, India, China, Taiwan, Japan, Thailand, Vietnam, Laos, Indonesia Papua New Guinea Israel

P. nr. fuscipes P. ilsae

P. nr. intermedius

Philippines

P. laetus

Guatemala

P. melampus

India

P. ornaticornis

Ecuador

P. puncticollis

Uganda

P. riparius

Russia

P. rufocyaneus

Malawi

P. sabaeus

Sierra Leone, Nigeria, Zaire, Cameroon, Namibia, Tanzania, Uganda Guatemala, Panama

P. signaticornis P. tamulus

China

Paederus spp.

Malaysia, Ceylon

Modified from Frank and Kanamitsu (1987).

Isles east across Central Asia to Japan and southeast to Australia), P. sabaeus (Africa), P. cruenticollis and P. australis (Australasia), P. signaticornis (Central America), and P. columbinus and P. brasiliensis (South America). Species in South American countries are known by various names, such as bicho de fuego, pito, potb, podb, and

trepa-moleque. Unlike blister beetles, rove beetles do not exhibit reflex bleeding as a defensive reaction. Pederin contacts human skin only when a beetle is brushed vigorously over the skin or crushed. Because of their general appearance or misunderstandings about their etiology, the resulting skin lesions have been called dermatitis linearis, spider-lick (India and Sri Lanka), and whiplash dermatitis. The dermatitis may develop on any part of the body; however, exposed areas such as the head, arms, hands, and legs are most often affected. Mirror-image lesions may form where one pederin-contaminated skin surface touches another. Unlike meloid-induced dermatitis, which develops within 1 8 - 2 4 hr after contact, the paederine-induced reaction of itching and burning usually occurs 2 4 - 7 2 hr after contact with the beetle's body fluid. The affected skin appears reddened and vesicles form about 24 hr after the initial response. The vesicles may coalesce into blisters and become purulent, producing a reaction that is often more severe than that seen following exposure to meloids. The itching may last for a week, after which the blisters crust over, dry, and peel off, leaving red marks that may persist for months. Rubbing the eyes with beetle fluid or contaminated hands, or beetles flying or crawling into eyes, can cause pain, marked swelling of the eyelids and conjunctivae, excessive lacrimation, clouding of the cornea, and inflammation of the iris (iritis). Such ocular lesions seen in East Africa have been called Nairobi eye. Although eye involvement often is very irritating, permanent damage is not common. Rove beetles live in vegetable debris and under stones and other materials, such as leaf litter. They are predaceous on insects and other arthropods, or they may eat plant debris. Paederine staphylinids are most abundant in areas of moist soil, such as irrigated fields and other crop lands, where the adult beetles feed on various herbivorous insects. Consequently, agricultural workers and others working in fields and grassy areas are often affected. Because the beetles are attracted to lights, workers on brightly lit oil rigs and people occupying lighted dwellings in tropical areas are also commonly affected.

T E N E B R I O N I D A E ( D A R K L I N G BEETLES) Darkling beetles (Fig. 6.6) produce defensive secretions containing quinones. Adults of Blaps species found in

Beetles (Coleoptera)

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mostly scavengers on decaying or dry plant and animal matter. Dermestid larvae and adults are known to have crawled into human ears, causing itching and pain. The spearheaded setae of dermestid larvae have been observed on numerous occasions on cervical (Papanicolaou) smear slides and in sputum samples. In all of these cases the setae appear to have been contaminants that were not associated with any pathological changes in the patients (Bryant and Maslan 1994).

SCARABAEIDAE (SCARAB BEETLES)

FIGURE 6.6 Darklingbeetles (Tenebrionidae). (A) Confused flour beetle (Tribolium confusum); (B) Red flour beetle (T. castaneum). Defensive secretions containing quinones can cause skin irritation. (From Gorham, 1991.)

the Middle East and Europe secrete these chemicals that cause burning, blistering, and darkening of the sldn. Adult beetles of some cosmopolitan Tribolium species, including Tribolium confusum and T. castaneum, have been associated with severe itching. North American desert species in the genus Eleodes, when threatened, take a characteristic headstand pose and exude various quinones that repel small predators and cause mild irritation to humans who handle these beetles. Darkling beetles are found in diverse habitats, including under logs and stones, in rotting wood and other vegetation, in fungi, in termite and ant nests, and among debris in and outside of homes. Most species live in dry, often desert, environments, while pest species are found in stored products, such as grain and cereals. Most tenebrionids are scavengers on decaying or dry plant material, but a few feed on living plants.

DERMESTIDAE(LARDERBEETLES) Larvae of larder beeries, or pantry beetles (Fig. 6.7), are covered with barbed and spearlike setae that may cause allergic reactions in the form of pruritic, papulovesicular skin lesions. Dermestid larvae often are found living in household furnishings, such as carpets, rugs, and upholstery, or stored clothing of individuals suffering from these reactions, Larder beetles are named for their common occurrence as pantry pests, but they may also be found in grain storage facilities, in bird and mammal nests and burrows, and on carrion. The larvae and adults are

In some tropical regions where human and animal excrement are abundant in the vicinity of dwellings, scarab beetles living in the dung are sometimes accidentally ingested by young children. These beetles appear in the newly passed stools of children and may disperse from the excrement in a noisy fashion that has been described in Sri Lanka as beetle marasmus ("kurumini mandama"). Although some of these beeries may infest the fecal matter as it is passed or after it reaches the ground, it is quite likely, as local physicians claim, that the scarab beetles (e.g. Copris spp., Fig. 6.8) pass through the alimentary tract and remain alive, causing little or no discomfort to the children. Evidence for such durability among the scarabs comes from cases in which frogs, horses, and cattle have ingested scarabs, which then worked their way through the stomach wall and remained alive until the hosts were killed. In Asia and Africa, humans sometimes become infested with dung beetles (Onthophagus and Caccobius spp.) when these scarabs enter the anus and live within the rectum, causing physical discomfort and damage to the mucosa. Large numbers of the adult scarab beetles Cyclocephala borealis and Autoserica castanea invaded the ears of 186 boy scouts sleeping on the ground at a jamboree in Pennsylvania in 1957. The beeries caused pain and some slight bleeding as a result of the tearing action of their tibial spines. After the beeries were removed, there were very few cases of secondary infection (Mattuck and Fehn 1958).

COCCINELLIDAE

(LADYBEETLES)

Lady beetles, also called ladybird beetles, have been cited most often as causing priclding or slight stinging sensations, followed by the formation of mild erythematous lesions. These beetles may nip at the skin; however, given their small size, it is more likely that their defensive secretions cause the discomfort. The alkaloid secretions produced by reflex bleeding from the legs and around the

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FIGURE 6.7 Dermestidbeetles (Dermestidae). (A) Furniture carpet beetle (Anthrenusflavipes), adult; (B) same, larva, with hastate seta (enlarged); (C) Cabinet beetle (Trogodermasp.), adult; (D) Varied carpet beetle (A. verbasci), larva, with hastate seta (enlarged); (E) Common carpet beetle (A. scrophulariae), larva. (From Sweetman, 1965.)

mouthparts do stain human skin and can cause mild irritation. Lady beetles are c o m m o n in gardens in warm weather, where the beetles feed on aphids and scale insects on a variety of plants. Lady beetles also occur in large aggregations as they are crawling and flying from overwintering clusters.

intermediate hosts for helminthic parasites, direct injury to animals by ectoparasitic species, and structural damage to poultry facilities. Beetles also can be beneficial by playing an important role in the recycling of animal dung and as natural control agents, especially for dung-breeding flies.

I N G E S T I O N OF T O X I C B E E T L E S

VETERINARY IMPORTANCE Although not generally appreciated even by entomologists, beetles are involved in a variety of problems of a veterinary nature. These include toxicity to domestic animals on ingestion, mechanical transmission of disease agents,

Several blister beetles in the family Meloidae pose a hazard to livestock that feed on forage in which the living beetles are abundant. Horses that ingest quantities of these beetles are especially susceptible to cantharidin poisoning. Dead beetles and beetle parts retain their cantharidin

Beetles (Coleoptera)

FIGURE 6.8 Scarab beetles (Scarabaeidae). (A) Onthophagus

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the most commonly affected because the ldnds of forage they are fed are most often contaminated with beetles. Although the ruminant digestive tract is less susceptible to cantharidin poisoning, goats, sheep, and cattle have also died from cantharidin toxicosis. Horses and cattle have also been poisoned by pederin following ingestion of the tropical staphylinid P. fuscipes. Pederin can cause severe damage to the mucosa of the alimentary tract. Historically, there are reports of chickens, ducldings, goslings, and young turkeys dying as a direct result of ingesting the rose chafer (Macrodactylus subspinosus), a member of the Scarabaeidae (Lamson 1922). Although this North American species is abundant in the summer months, modern enclosed poultry production facilities may have greatly reduced the incidence of such poisonings.

polyphemi;(B) Coprisminutus. (From Woodruff, 1973.) TRANSMISSION OF PATHOGENS content so that forage crops that are harvested for livestock feed continue to be a source of the toxin. Blister beetles in alfalfa (Medicago sativa) fields contain enough cantharidin to provide lethal doses to horses that feed on this material when it is used as hay. Species that pose problems in the United States include the striped blister beetle ( Epicauta vittata), the black blister beetle (E. pennsylvanica) (Fig. 6.2), the margined blister beetle (E. pestifera), and the three-striped blister beetle ( E. lemniscata), as well as E. fabricii, E. occidentalis, and E. temexa. Individual beetles contain <0.1 to > 11 mg of cantharidin, equivalent to <0.1 to > 12% of their dry weights, with males of several species averaging >5%. The minimum lethal dose for a horse is about 1 m g / k g , which means that depending on the size of a horse and the cantharidin content of the beetles ingested, anywhere from 25 to 375 beetles are sufficient to cause death (Capinera et al. 1985). Horses have been poisoned by eating forage in the southern, midwestern, and western United States. Poisoning is not limited to a particular geographic area because contaminated forage is transported over long distances. Affected animals exhibit moderate to severe clinical signs, ranging from depression to shock that may be followed by death. Abdominal distress (colic), anorexia, depression, and oral irritation are commonly observed. These signs are accompanied by markedly decreased serum calcium and magnesium. Accelerated heart rate (tachycardia), increased respiratory rate (tachypnea), and increased creatinine kinase activity are indicative of severe toxicosis that is likely to lead to death. In most cases in which death has occurred, a horse has succumbed within 48 hr of the onset of clinical signs. Horses are

Darkling beeries (Tenebrionidae) inhabiting farm buildings can be mechanical vectors of animal pathogens. Tenebrionid beetles infesting feed in chicken houses may become infected with Salmonella bacteria passed in feces from infected chickens. Both larval and adult forms of the lesser mealworm beetle (Alphitobius diaperinus) (Fig. 6.9) have been found to maintain viable pathogens (e.g., Salmonella typhimurium and S. chester) on their external surfaces and in their digestive tracts. The bacteria survive for days after infection and are disseminated via beetle excreta. In chicken-breeding facilities, grain beetles are potential disseminators of these pathogens

FIGURE 6.9 Lessermealworm, Alphitobius diaperinus (Tenebrionidae), larvae and adults in poultry litter. (Photo by G. R. Mullen.)

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that can infect both chicks and adult birds. These organisms can cause gastroenteritis in human consumers. The lesser mealworm also is regarded as a potential disseminator of other bacteria (Escherichia, Bacillus, Streptococcus), fungi (Aspergillus), and the viruses causing Mar& disease, Newcastle disease, fowlpox, avian leucosis, and infectious bursitis(Gumboro disease). In addition, oocysts formed by protozoans in the genus Eimeria are ingested by lesser mealworm beeries and when the infected beetles are ingested by birds, the latter develop avian coccidiosis, a serious disease of poultry.

INTERMEDIATE HOSTS OF PARASITES Tapeworms (cestodes), flukes (trematodes), roundworms (nematodes), and thorny-headed worms (acanthocephalans) of many species that infest domestic and wild animals use beetles as intermediate hosts. Animals become infested by ingesting parasitized beeries that contaminate feed or bedding (tenebrionids, carabids) or that are attracted to animal dung (scarabaeids), or by ingesting water in which infective beetles have disintegrated. Two tapeworms that infest the small intestines of poultry are the broad-headed tapeworm ( Raillietina cesticillus) and Choanotaenia infundibulum. Both parasites cause enteritis and hemorrhaging in chickens, turkeys, pheasants, and guinea fowl. A few tenebrionids and scarabaeids and more than 35 species of carabid beetles, notably in the genera Amara and Pterostichus, are intermediate hosts for R. cesticillus (Cheng 1973). Some tenebrionid and dermestid species, including the lesser mealworm beetle, are intermediate hosts for C. infundibulum. Proglotrids or tapeworm eggs ingested by beetle larvae or adults develop into cystercerci (encysted larvae) that can then infest birds that eat the beetles. Chicks are most susceptible to serious infestations and often die from worm burdens. The beef tapeworm ( Taenia saginata) can use dung beetles and carabids as intermediate hosts, although they are not essential for transmission. Beetles associated with infective dung or debris can ingest proglottids or eggs, as in the case of poultry worms. Cattle and humans infested with the tapeworm may show mild symptoms such as weight loss, abdominal pain, and increased appetite. The dwarf tapeworms (Hymenolepis nana and H. diminuta) that usually infest rodents, especially rats and mice, can infest humans when the intermediate host beetles are accidentally ingested. Tenebrio molitor may act as an intermediate host for H. nana, although this worm is readily transmitted directly from one vertebrate host

to another. Several species of tenebrionids (Tenebrio spp. and Tribolium spp.) are required intermediate hosts for H. diminuta. Larval and adult beeries infesting grain and cereals ingest worm eggs that develop into cysticercoid stages that infest rodents or humans, usually children, who ingest the beetles. Dwarf tapeworms produce minimal symptoms in rodents and people, although heavy infestations in children may cause abdominal pain, diarrhea, convulsions, and dizziness. Beetles are known to be intermediate hosts for only a few trematodes. These are parasites of frogs that become infested by ingesting parasitized dytiscid beetles and pose no problem for other vertebrate animals. Many nematodes infest livestock and wildlife, but only a few use beetles as intermediate hosts. Spirurid nematodes of various species infest livestock and, rarely, humans. Physocephalus sexalatus and Ascarops strongylina eggs develop in many species of scarabaeid dung beetles ( Geotrupes spp., Onthophagus spp., and Scarabaeus spp.) that then may be ingested by pigs. Both wild and domestic swine can be infested with these stomach worms, which can cause digestive problems in heavily infested young animals. Gongylonema pulchrum is a parasite of the upper digestive tract of sheep, cattle, goats, and other ruminants, as well as horses, dogs, and humans. The worms burrow in the mucosa and submucosa of the oral cavity and esophagus and may cause bleeding, irritation, numbness, and pain in the mouth and chest. Scarabaeid and tenebrionid beetles serve as intermediate hosts for the larvae. Physaloptera caucasica, another spirurid, often parasitizes monkeys in tropical Africa, where humans are also commonly infested. This nematode causes digestive distress by infesting the alimentary tract from the esophagus to the terminal ileum. Scarabaeid dung beetles are its intermediate hosts. The acanthocephalans, aptly named for their thorny heads, include species found worldwide infesting swine, rodents, and carnivores, such as dogs. Macracanthorhynchus hirudinaceus, which attaches to the small intestines of swine, causes enteritis and produces intestinal nodules that lower the value of these tissues when they are sold to make sausage casings. Eggs of this parasite are ingested by scarab beetle larvae of species of various genera (Phyllophaga, Melolontha, Lachnosterna, Cetonia, Scarabaeus, and Xyloryctes), including May and June beeties, leaf chafers, dung beetles, and rhinoceros beetles. Infested beetle larvae, as well as the pupae and adults that develop from them, are infective to both pigs and humans. Humans and pigs often show no symptoms. However, in cases of heavy infestations, both human and porcine hosts may experience digestive problems, such as abdominal pain, loss of appetite, and diarrhea, which can lead to emaciation.

Beetles (Coleoptera) Two other acanthocephalan worms that parasitize the small intestines of their hosts use scarab beetles or tenebrionids as intermediate hosts. They are M. ingens, which infests raccoons and occasionally dogs and humans, and Moniliformis moniliformis, a parasite of rodents and dogs.

NEST ASSOCIATES AND ECTOPARASITES In addition to those beetles that occasionally invade the alimentary tracts or sense organs of animals, other species have evolved in close association with mammals as nest dwellers or ectoparasites. These species typically have reduced eyes and wings or have lost these structures completely. The family Leptinidae, known as mammal nest beetles, includes Platypsyllus spp., which live as larvae and adults on beavers, and Leptinus and Leptinillus spp., which live as adults on various small rodents. These species feed on skin debris or glandular secretions and have been associated with skin lesions on their hosts. Two other beetle groups, the Staphylinidae (Amblyopinini) and the Languriidae (Loberinae), have species that live on rodents and a few other mammals. These staphylinids, and possibly the languriids, appear to be mutualistically symbiotic with their mammalian hosts. The beetles infest mammalian fur to gain access to their prey, which are mammalian ectoparasites, such as fleas and mites, that live in rodent nests (Ashe and Timm 1987, Durden 1987). Some scarabaeid beetles are adapted to living in the fur around the anus of certain mammals. These beeries cling to the fur except when they leave to oviposit in the dung. Some of these scarabs (Trichillium spp.) are found on sloths and monkeys in South America and others (Macropocopris spp.) on marsupials in Australia. Larvae and adults of the lessermealworm beetle (Alphitobius diaperinus) have been found boring into and living in the scrotum of a rat, and feeding on sick domestic chicks and young pigeons. Similarly, the hide beetle (Dermestes maculatus) can feed on living poultry and has caused deep wounds in adult turkeys. In laboratory experiments, lesser mealworm beeries killed snakes and a salamander, all of which were devoured by the mealworms. The voracious and aggressive behavior of this commonly abundant tenebrionid makes it a significant pest in poultry houses. In addition to their direct attacks on birds, the lesser mealworm and hide beetle larvae are major causes of structural damage to poultry houses. After reaching their final instar, the larvae migrate into the insulation of poultry houses to seek pupation sites. The larval tunnels and holes produced in insulation and wood framing cause

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enough damage to alter temperature regulation in the houses, which reduces the efficiency of poultry production (Axtell and Arends 1990).

D U N G BEETLES AND BIOCONTKOL Many beetles that are attracted to avian and mammalian excrement should be viewed as beneficial insects. Scarabaeid beetles(including coprines) remove large quantifies of mammalian dung by scattering or burying the material during feeding or reproduction. The rapid removal of dung helps reduce the development of parasitic worms and pestiferous cyclorrhaphan flies that require dung for their survival and reproduction, and it also opens up grazing land that would be despoiled by the rotting excrement. Staphylinid beetles and histerid beetles that are attracted to mammalian and avian dung directly reduce muscoid fly populations by feeding on the immature stages of these flies and indirectly reduce these populations by introducing their phoretic mites, which prey upon fly eggs in the excrement. Dung beetle diversity is greatest in tropical regions, such as Africa, with its abundance of herbivores. More than 2000 scarabaeid species in many genera (e.g., Onthophagus, Euoniticellus, and Heliocopris) are known to feed and reproduce in dung in Africa. Less diverse dung feeders, such as Aphodius, Onthophagus, Canthon, and Phanaeus species, provide the same benefits in the United States. In Australia, the development of extensive cattle farming resulted in the production of millions of tons of dung that was not naturally removed, because the native coprophagous beetles were adapted to feeding only on marsupial dung. Within the last few decades, introductions of African beetles by sterile breeding programs have established several coprine species that have helped to open up grazing lands ruined by dung accumulation and to reduce the breeding source of the pestiferous bush fly (Musca vitustissima). Staphylinid beetlesof several species in the genus Philonthus feed as both larvae and adults on fly larvae living in animal excrement. These beetles are maintained as components in biological control programs against the face fly and horn fly. Staphylinid species of Aleochara are also helpful in reducing dung-breeding fly populations because the parasitoid larvae of these beetles penetrate fly puparia and destroy the fly pupae. Histerid beetles, especially Carcinops species, are found in confined animal production facilities, such as poultry houses. The larvae and adults of these beetles feed on eggs and larvae of muscoid flies. Any beetle species observed in animal production facilities should be identified to assess whether its presence is beneficial or detrimental

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to the m a i n t e n a n c e o f sanitary conditions and animal health.

PREVENTION AND CONTROL Preventing public health and veterinary p r o b l e m s associated with beetles requires education a b o u t which species are harmful. R e c o g n i t i o n o f m e l o i d , paederine, and oedemerid beeries allows one to immediately wash skin surfaces and eyes that c o m e into contact with the beetles, t h e r e b y r e m o v i n g the chemicals that cause dermatitis or inflammation o f the eyes. W i t h the exception o f the smallest species, beetles that are attracted to lights may be prev e n t e d from reaching h u m a n s or o t h e r animals by using screens and bed netting. C o n t r o l o f vesicating beetles occurring in natural and cultivated vegetation can be achieved with pesticides; however, the wide area over which these chemicals m u s t be broadcast generally makes such control impractical. H u m a n exposure can be p r e v e n t e d by c o m b i n i n g education a b o u t the p r o b l e m with personal protective measures and removal o f extraneous vegetation and decaying organic m a t t e r from a r o u n d agricultural fields and dwellings. Prevention o f blister beetle toxicosis o f farm animals involves care in the handling o f forage crops. Harvesting hay at times w h e n meloid beeries are rare, such as in late fall in temperate climates, helps prevent contamination o f dried, stored forage with dead beetles. Similarly, harvesting alfalfa before it produces the b l o o m s that attract meloids, or raking hay m o r e frequently after it is cut and allowing it to dry l o n g e r before it is c o n d i t i o n e d or crimped, will allow beetles to leave the hay before it is baled. Preventing and controlling dissemination o f p a t h o g e n s and transmission o f helminths o f veterinary i m p o r t a n c e can be achieved by a c o m b i n a t i o n o f strict sanitary and cultural practices. Removal o f d u n g and organic waste from animal enclosures, as well as sterilization o f man u r e before it is used as fertilizer, helps to i n t e r r u p t the transmission cycle o f parasites by reducing the chances o f beeries ingesting w o r m eggs. R o t a t i o n o f pastured animals also can limit contact b e t w e e n the definitive hosts and intermediate beetle hosts. Increased a b u n d a n c e o f scarabaeid d u n g beeries that aids in the rapid removal o f d u n g , by b o t h ingestion and burial, has been f o u n d beneficial in r e d u c i n g infestations with intestinal n e m a t o d e s that do n o t use beetles as intermediate hosts, but that are transmitted from animal to animal by d u n g ingestion (Fincher 1975). C o n t r o l o f destructive p o u l t r y - h o u s e beeries requires constant m o n i t o r i n g for the insects and strict sanitation.

Pesticides provide only t e m p o r a r y control and are m o s t beneficial w h e n applied to soil that larvae may b u r r o w in to pupate. Careful personal hygiene, use o f gowns and masks in beetle-rearing facilities, and regular v a c u u m i n g o f floors, floor coverings, and furniture in domestic settings help prevent exposure to dermestids and o t h e r beetles that can cause allergic responses.

REFERENCES AND FURTHER READING Alexander, J. O. (1984). Arthropods and human skin. Springer-Verlag, Berlin. Archibald, R. G., and King, H. H. (1919). Anote on the occurrence of a coleopterous larva in the urinary tract of man in the Anglo-Egyptian Sudan. Bull. Entomol. Res. 9, 255-256. Arnett, R. H., Jr. (1973). The beetles of the United States (a manual for identification). American Entomological Institute, Ann Arbor. Arnett R. H., Jr. (1984). The false blister beetles of Florida (Coleoptera: Oedemeridae). Fla. Dept. Agric. & Consumer Serv., Entomol. Circ. 259. Arnett, R. H., Jr. (1990). Present and future of systematics of the Coleoptera in North America. In: Systematics of the North American insects and arachnids: status and needs (M. Kosztarab and C. W. Schaefer, eds). pp. 165-173. Virginia Polytechnic Institute and State University, Blacksburg. Ashe, J. S., and Timm, R. M. (1987). Predation by and activity patterns of 'parasitic' beetles of the genus Amblyopinus (Coleoptera: Staphylinidae). J. Zool. Lond. 212, 429-437. Avancini, R. M. P., and Ueta, M. T. (1990). Manure breeding insects (Diptera and Coleoptera) responsible for cestoidosis in caged layer hens. J. Appl. Entomol. 110, 307-312. Axtell, R. C., and Arends, J. J. (1990). Ecology and management of arthropod pests of poultry. Annu. Rev. Entomol. 35, 101-126. Barrera, A. (1969). Notes on the behaviour of Loberopsyllus traubi, a cucujoid beetle associated with the volcano mouse, Neotomodon alstoni in Mexico. Proc. Entomol. Soc. Wash. 71,481-486. Bellas, T. E. (1989). Insects as a cause ofinhalational allergies: a bibliography 1900-1987. Canberra: CSIRO Div. Entomol. Blodgett, S. L., and Higgins, R. A. (1990). Blister beetles (Coleoptera: Meloidae) in Kansas alfalfa: influence of plant phenology and proximity to field edge. J. Econ. Entomol. 83, 1042-1048. Blume, R. R. (1985). A checklist, distributional record, and annotated bibliography of the insects associated with bovine droppings on pastures in America north of Mexico. Southwest. Entomol. Suppl. 9, 1-55. Bryant, J., and Maslan, A. M. (1994). Carpet beetle larval parts in Pap smears: report of two cases. South. Med. ]. 87, 763-764. Capinera, J. L., Gardner, D. R., and Stermitz, F. R. (1985). Cantharidin levels in blister beetles (Coleoptera: Meloidae) associated with alfalfa in Colorado. ]. Econ. Entomol. 78, 1052-1055. Cheng, T. C. (1973). General parasitology. Academic Press, New York. Chu, G. S. T., Palmieri, J. R., and Sullivan, J. T. (1977). Beetle-eating: a Malaysian folk medical practice and its public health implications. Trop. Geogr. Med. 29, 422-427. Clausen, C. P. (1940) (reprinted 1972). Entomophagous insects. Hafner, New York. Crook, P. G., Novak, J. A., and Spilman, T. J. (1980). The lesser mealworm, Alphitobius diaperinus, in the scrotum of Rattus norvegicus, with notes on other vertebrate associations (Coleoptera, Tenebrionidae; Rodentia, Muridae). Coleopts. Bull. 34, 393-396.

Beetles Crowson, R. A. (1981). The biology of the coleoptera. Academic Press, London. De las Casas, E., Harein, P. K., Deshmukh, D. R., and Pomeroy, B. S. (1976). Relationship between the lesser mealworm, fowl pox, and Newcastle disease virus in poultry. J. Econ. Entomol. 69, 775-779. Downie, N. M., and Arnett, R. H. (1996). The beetles of Northeastern North America. Vol. i and 2. Sandhill Crane Press, Gainesville. Durden, L. A. (1987). Predator-prey interactions between ectoparasites. Parasitol. Today 3, 306-308. Eisner, T., Conner, J., Carrel, J. E., McCormick, J. P., Slagle, A. J., Gans, C., and O'Reilly, J. C. (1990). Systematic retention of ingested cantharidin in frogs. Chemoecology 1,2, 57-62. Essig, E. O. (1942). College entomology. MacMillan Company, New York. Evans, G. (1975). The life of beetles. Hafner, New York. Fincher, G. T. (1975). Effects of dung beetle activity on the number of nematode parasites acquired by grazing cattle. J. Parasitol. 61, 759-766. Fincher, G. T. (1994). Predation on the horn fly by three exotic species of Philonthus. J. Agric. Entomol. 11, 45-48. Frank, J. H., and Kanamitsu, K. (1987). Paederus, sensu lato (Coleoptera: Staphylinidae): natural history and medical importance. J. Med. Entomol. 24, 155-191. Geden, C. J., Stinner, R. F., and Axtell, R. C. (1988). Predation by predators of the house fly in poultry manure: effects of predator density, feeding history, interspecific interference and field conditions. Environ. Entomol. 17, 320-329. Guglick, M. A., Macallister, C. G., and Panciera, R. (1996). Equine cantharidiasis. Compend. Cont. Educ. Pract. Vet. 18, 77-83. Hall, M. C. (1929). Arthropods as intermediate hosts of helminths. Smithsonian, Washington, DC. Hanski, I., and Cambefort, Y. (eds.) (1991). Dung beetle ecology. Princeton University Press, Princeton, NJ. Harde, K. W. (1984). A field guide in colour to beetles. Octopus Books Ltd., London. Helman, R. G., and Edwards, W. C. (1997). Clinical features of blister beetle poisoning in equids: 70 cases (1983-1996). J. Am. Vet. Med. Assoc. 211, 1018-1021. Lamson, G. H., Jr. (1922). The rose chafer as a cause of death of chickens. StorrsAgric. Exp. Sta. Bull. 110, 118-135. Lawrence, J. F., and Newton, A. F. (1995). Families and subfamilies of Coleoptera. In: Biology, phylogeny, and classification of Coleoptera: papers celebrating the 80th birthday of Roy A. Crowson (J. Pakaluk and S. A. Slipinski, eds.), pp. 779-1006. Muzeum i Instytut Zoologii PAN, Warsaw. Legner, E. F. (1995). Biological control of Diptera of medical and veterinary importance. J. Vector Ecol. 20: 59-120.

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Liggett, H. (1931). Parasitic infestations of the nose. J. Am. Med. Assoc. 96, 1571-1572. Marshall, A. G. (1981 ). The ecology of ectoparasitic insects. Academic Press, London. Mattuck, D. R., and Fehn, C. F. (1958). Human ear invasions by adult scarabaeid beetles. J. Econ. Entomol. 51,546-547. McAllister, J. C., Steelman, C. D., and Skeeles, J. K. (1994). Reservoir competence of the lesser mealworm (Coleoptera: Tenebrionidae) for Salmonella typhimurium (Eubacteriales: Enterobacteriaceae). J. Med. Entomol. 31, 369-372. Patton, W. S., and Evans, A. W. (1929). Insects, ticks, mites and Venomous animals. School of Tropical Medicine, Liverpool. Rajapakse, S. (1981). Letter from Sri Lanka: beetle marasmus. Br. Med. J. 283, 1316-1317. Samish, M., Argaman, Q., and Perlman, D. (1992). The hide beetle, Dermestes maculatus DeGeer (Dermestidae), feeds on live turkeys. Poultry Sci. 71,388-390. Schmitz, D. G. (1989). Cantharidin toxicosis in horses. J. Vet. Intern. Med. 3, 208-215. Schroeckenstein, D. C., Meier-Davis, S., and Bush, R. K. (1990). Occupational sensitivity to Tenebrio molitor Linnaeus (yellow mealworm). J. Allergy Clin. Immunol. 86, 182-188. Selander, R. B. (1988). An annotated catalog and summary of bionomics of blister beetles of the genus Cylindrothorax (Coleoptera: Meloidae). Trans. Am. Entomol. Soc. 114, 15-70. Southcott, R. V. (1989). Injuries from Coleoptera. Med. J. Aust. 151, 654-659. Sweetman, H. L. (1965). Recognition of structural pests and their damage. Wm. C. Brown Co., Dubuque. Th~odorid&, J. (1950). The parasitological, medical and veterinary importance of Coleoptera. Acta Trop. 7, 48-60. Waterhouse, D. F. (1974). The biological control of dung. Sci. Am. 230, 100-109. Weatherston, J., and Percy, J. E. (1978). Venoms of Coleoptera. In: Arthropod venoms (S. Bettini, ed.). pp. 511- 554. Springer-Verlag, Berlin. Weinberg, S., Leider, M., and Shapiro, L. (1975). Color atlas of pediatric dermatology. McGraw-Hill Book Company, New York. White, R. E. (1983). A field guide to the beetles of North America. Houghton Mifflin, Boston. Whitmore, R. W., and Pruess, K. P. (1982). Response of pheasant chicks to adult lady beetles (Coleoptera: Coccinellidae). J. Kansas Entomol. Soc. 55, 474-476. Woodruff, R. E. (1973). Scarab beetles of Florida (Coleoptera: Scarabaeidae), Part 1. Arthropods of Florida, vol. 8, Division of Plant Industry, Florida Department of Agriculture, Gainesville.