More About Cutworm Moths and Grizzly Bears 

In the November 1992 Newsletter we reported, based on a short article in Newsweek that cutworm moths had been observed to be an important food of grizzly bears, now staging somewhat of a comeback in the northern Rocky Mountains.  The study mentioned In Newsweek was in the Absaroka Mountains east of Yellowstone National Park in Wyoming.  The specific identity of the moth or moths involved was not known, or at least not mentioned in the article. 

Now, as the result of yet another small world story, we have learned the identity of the moth and a little about its biology.  My wife and I were returning from the Portland, Oregon area last summer when, during a stop at the airport in Minneapolis for a connecting flight to Madison, we ran into Professor Bob Ruff, Department of Wildlife Ecology at the University of Wisconsin.  When we boarded the flight to Madison, as good luck would have it, Bob and I had seats across the aisle from each other.  He was returning from bear country in Wyoming, so I mentioned the grizzly-cutworm connection.  He had seen a report or two on it and said he would send over some information -- which turned out to be an article in the International Bear News by Don White, Jr. (Department of Biology, Montana State University, Bozeman, M'I) and Katherine Kendall (National Park Service, Glacier National Park, West Glacier, MT). 

In the spring of 1992, they initiated a three-year study on bear feeding ecology at moth aggregation sites in Glacier National Park.  Nine moth aggregation sites were identified in the alpine regions of the Park.  All of the moths collected at two of the study sites proved to be Euxoa auxiliaris Grote (Lepidoptera: Noctuidae).  Moths collected in mid-July 1992 averaged 24.4% protein and 34.4% fat;

mid-August collections averaged 18% protein and 35.4% fat.  Bear use of moth aggregation sites lasted at least from July 12 to September 3 in 1992, and 67% of bear activity on the talus slopes was directed toward moth feeding.  All bears were grizzlies, no black bears were observed.  Several species of birds also fed on the moths. 

The moth has an interesting life cycle.  It undergoes its development in the Great Plains where the eggs, about 2000 per female, are laid in the soil in the fall.  The larva, which has a total of seven instars, is in the first or second instar when it enters diapause.  It resumes feeding in the spring on plants such as alfalfa or small grains.  The larval period varies depending on temperature and location but may be as long as 25-32 days in Kansas and 43-63 days in Montana.  Pupation is in underground cells.  The adult moths emerge in early summer and migrate westward into the Rocky Mountains where they congregate above timberline.  The moths occupy the interstitia of talus slopes during the day and feed nocturnally, nectar sources being alpine and subalpine flowers.  The return migration to the plains occurs in late summer or early fall. 

White and Kendall mention several areas in the Rocky Mountains of Wyoming and Montana where grizzlies are known to feed on cutworm moths and other alpine insect aggregations.  In the Mission Mountains, grizzlies feed not only on E. auxiliaris, but also on ladybird beetles (Coccinnella and Hippodamia spp.). 

White, D.; Kendall, K. 1993.  Grizzly bears and army cutworm moths in the alpine of Glacier National Park, Montana.  Internat.  Bear News 2(3):2-3.

New Entomology Textbook Devotes Space to Entomophagy 

Gullan, P.J.; Cranston, P.S. The Insects: An Outline of Entomology.  Chapman & Hall, United Kingdom (In press). 

Dr. Penny Gullan, The Australian National University, sent a manuscript copy of a section titled, "Insects as human food: entomophagy," which will be part of the first chapter of this new general entomology textbook.  It is an excellent short discussion of the subject (6 manuscript pages).  We quote below two paragraphs that focus on implications and challenges for the future: 

"Large scale harvest or mass production of insects for human consumption brings some practical problems.  The small size of most insects presents difficulties in collection or rearing and in processing for sale.  Development of culture techniques also is necessary to overcome the unpredictability of many wild populations.  However, the encouragement of entomophagy in many rural societies, particularly those with a history of insect use, may help diversify peoples' diets.  By incorporating mass harvesting of pest insects into control programs, the use of pesticides can be reduced.  Furthermore, cultivating insects for protein should be less environmentally damaging

than cattle ranching, which devastates forests and native grasslands.  Insect farming is compatible with low input, sustainable agriculture and most insects have a high food conversion efficiency compared with conventional meat animals.  Perhaps the bugburger, cricketburger or beeburger will become acceptable alternatives to the well-known American hamburger.... 

"Clearly insects can form part of the nutritional base of people and their domesticated animals.  Further research is needed and a database with accurate identifications is required to handle biological information.  We must know which species we are dealing with in order to make use of information gathered elsewhere on the same or related insects.  Data on the nutritional value, seasonal occurrence, host plants or other dietary needs, and rearing or collecting methods must be collated for all actual or potential food insects.  Opportunities for insect food enterprises are numerous, given the immense diversity of insects."

Some Recent Articles in Professional Journals 

Fasoranti, J.O.; Ajiboye, D.O. 1993. Some edible insects of Kwara State, Nigeria.  Amer.  Entomologist 39(2):113-116, 6 figs.  Department of Biological Sciences, University of Ilorin, Ilorin, Kwara State, Nigeria. 

According to the authors, taboos - religious and other- are important among factors influencing entomophagy in West Africa.  The taboos are believed to run generally along ethnic lines, and the authors set out therefore to investigate beliefs militating against entomophagy among the four major tribes in Kwara State, the Yoruba, Ibira, Nupe and Baruba.  Seven species of insects are generally acceptable within these four dominant tribes.  A questionnaire was sent to all local government areas of Kwara State and followed up by personal interviews to clarify questions that arose from responses to these questionnaires. 

Macrotermes natalensis (termite): The winged reproductives, which are strongly attracted to light sources, are eaten by all age groups but are collected mainly by the women and children.  Termites are. sold in the markets when catches are large, while small collections are consumed at home.  They are fried or roasted.  The queen termite is considered a delicacy for adults only, but can be obtained only when a termitarium is destroyed. 

Brachytrupes membranaceus (cricket): These insects live in tunnels which are easily detected.  They turn a golden color when roasted.  Members of the Ire clan of the Yoruba tribe do not eat crickets for reasons discussed by the authors. 

Cyrtacanthacris aeruginosus unicolor and Zonocerus vatiegatus (grasshoppers): these are prepared in a manner similar to that for crickets and are consumed by all age groups of all tribes.  Grasshoppers are plentiful only periodically and were not observed being sold in the markets. 

Cirinaforda (moth larva): Popularly known as Kanni, this is perhaps the most important and widely marketed edible insect in Kwara State.  The larvae are starved for a day or two to eliminate the gut contents, then boiled for 2 hours, then sun-dried on mats.  Most tribes in Kwara State do not eat dried larvae of other insects, but Kanni is an essential ingredient in a vegetable soup, considered a delicacy, which also includes onion, melon, tomatoes, pepper oil, and salt to taste.  In the market, the dried larvae sold forNI9.50/kg (N1.00= US 300) compared with the 1986 price of N9.00/kg for beef. 

Rhynchophorus phoenicis (palm weevil larva): Palm trees under stress for any reason and fallen palms serve as breeding sites and can support hundreds of larvae.  Mature larvae are huge, measuring about 10.5 cm long and 5.5 cm wide.  Collected larvae are washed and fried; condiments added include onion, pepper and a little salt.  "Most people who were interviewed believe that this insect is very delicious."

Oryctes boas (scarabaeid beetle larva): Breeding sites such as dunghills and refuse of various kinds are searched for by all age groups, but more frequently by the women and children in the course of their other duties.  The larvae are even larger than palm weevil larvae.  After preparation, they are washed thoroughly and fried.  Acceptability of this insect is decreased because of the "dirty" nature of the breeding sites, but it is still popular among most insect eaters. 

The authors conclude that entomophagy should be promoted through education and that edible insects can help substantially in reducing the protein deficiency problem that exists in Kwara state.  They stress that only the development of artificial breeding methods, rather than relying on harvesting from natural populations, would ensure an abundant and continuous supply. 

The authors discuss several taboos, but relative to termite queens they state: "Children are forbidden to eat the queens for several reasons, not all of which have to do directly with safety to health.  Children form a large proportion of the farm hands, and the elders believe that if the young ones are allowed to eat the queens they will cherish the insects and spend so much of their time searching for them, that productivity in the fields will be reduced." From similar reasoning, children are discouraged from eating palm weevil larvae: "As the larvae taste so good, the young ones are likely to become preoccupied with felling palm trees to provide more breeding sites and a bumper harvest of larvae.  Indiscriminate felling of trees would deprive the community of primary palm products such as palm oil, palm kernals, and palm wine." 

Cherry, R.H. 199 1. Use of insects by Australian Aborigines.  Amer. Entomologist 37(l): 8-13.  Everglades Research and Education Center, University of Florida, Belle Glade FL 33430. 

The author discusses insects as part of Aborigine cultural beliefs and their use as food and medicine.  While most entomologists have ready access to ESA's American Entomologist, many of our readers do not, so we quote a large part of four paragraphs: "An interesting example of the mass harvesting of edible insects is the moth feasts that occurred in the Bogong mountains of New South Wales.  The Bogong moth, Agrotis injiisa (Boisduval), aestivated in large numbers every year on rock shelters of these mountains.  From November to January, hundreds of Aborigines from different tribes would gather for huge feasts on these adult moths.  Rock crevices were covered with layers of these moths, which were collected by dislodging and then collecting the moths from the cave or crevice floor.  Moths were then cooked in sand and stirred in hot ashes, which singed off the wings and legs.  Moths were then sifted in a net to remove their heads.  In this state, they were generally eaten, although sometimes they were ground into a paste and made into cakes.  As a food, the Bogong moth was rich in fat .... 

"Common (1970) states that the larva of Xyleutes leucomochla Turn. is the true witchety grub of the Aborigines.  Witchety grubs (larvae) are found in the roots of Acacia bushes, commonly known as the witchety bush in central Australia.  These grubs were the most important insect food of the desert and were a much valued staple in  

the diet of the Aborigines - especially women and children.  Men also loved the grubs, but would seldom dig them.  The grubs were collected by digging up the roots and chopping them to obtain the grubs within.  The grubs can be eaten raw or can be cooked in ashes.  Cooking causes the grubs to swell and their skins to stiffen.  Cooked witchety grubs frequently have been likened in taste to almonds (Isaacs 1987).  The larvae are rich in calories, protein, and fat.  Ten large grubs are sufficient to provide the daily needs of an adult (Australian National Commission of UNESCO 1973). 

"... honeypot ants were a highly valued food that provided a source of sugar for the Aborigines of central Australia.  Workers of the honeypot ants (Melophorus bagoti Lubbock and Camponotus spp.) gather honeydew from scale insects and psyllids, and feed it to other workers, which become mere nectar storage vessels with greatly enlarged abdomens.  These helpless replete ants, which regurgitate some of their nectar when solicited by other workers, are kept safe in deep underground galleries (Norris 1970).  The ants were obtained by scraping the surface of the ground to find the vertical shaft of the nest that led down to horizontal chambers where the honeypot ants were located.  Vertical shafts may be dug down to almost two meters (Mountford 1976). 

"Another popular source of sugar in the Aborigine's diet was the honeybag (hive) of stingless native bees (Trigona spp.). To locate the honeybag, the Aborigines caught a bee feeding on pollen, and after attaching to it a leaf or petal by means of sticky juices of certain plants, let it go.  The bee would fly straight to the hive and the item it was carrying not only would make it easy to see, but also would result in its flight being lower and slower, thus, it was easily followed by the hunter (Massola 1971).  Also, when looking for honey, Aborigines watched for small, black lizards, which often lived in honey trees and fed upon the bees as they returned to the hive.  To obtain the honeybag, a tree could be cut down or, if the tree were large, a hole could be cut in the tree under the hive.  A stick could then be poked into the hive and stirred about until the honey ran down the stick into a bark basket (Roughsey 1971).  When the honey was extracted from the hive, it usually was mixed up with honeycomb, bees, immature bees, and eggs.  The Aborigines put the lot into their mouths and spat out the inedible parts (Crawford 1968)." 

Cherry notes that the Aborigine population, estimated at more than 300,000 before 1770, is now down to about 160,000 and that about two-thirds of them now live in cities and have adopted suburban lifestyles.  This article was reprinted in Pest Control Technology, February 1992.  For more on the Bogong moth, see November 1992 Newsletter.  For more on Australian honey ants, see the March 1990 Newsletter. 

Ikeda, J.; Dugan, S.; Feldman, N.; Mitchell, R. 1993.  Native Americans in California surveyed on diets, nutrition needs.  Calif. Agric. 47(3):8-10. 

Some 500 descendants of the Miwok-speaking Native Americans live in Mariposa County, the county where Yosemite National Park is located.  Joanne Ikeda et al (1993) report that 50% of the families

live below the federal poverty level; "With little money and no access to major grocery chains, many families cannot buy the kind of food that supports an adequate diet...... We quote from two paragraphs in the report: 

"Some families augmented their food supply in traditional ways: 47% gathered wild berries, nuts, mushrooms and other plants; 67% said their grandparents and parents traditionally used wild plants as foods, and 8 1 % said this knowledge had been passed on to them by their elders ... [22% gardened, 26% fished, 14% hunted].... Many Miwok recalled foods their grandparents ate that they do not eat: insects such as pine tree worms, Monarch butterfly larvae [Ed.: questionable] and grasshoppers; animals like squirrel, Mono Lake shrimp, quail, deer, rabbit, bear and hedge hog; and plant foods such as acorn mush, pine nuts, wild vegetables and berries.  Some of these foods, particularly the insects, are not considered food by the dominant culture.  This may have influenced these native Americans to abandon them as food sources." 

(Ed.:        Thanks to David Strange, MD, Petaluma, California, for calling attention to this recent study.  Earlier studies of the Miwok had also reported the use of insect foods.     

Damerow, Gail. 1993 (August).  Wax worm fritters (and other edible delights).  Bee Culture 121 (8):448-449. 

Stating that "Beekeepers have ready access to two of the tastiest edibles, " this article focuses on the greater wax moth larva and bee brood, reprinting a recipe for wax worm fritters by Sharon Elliot, head chef New York Parties (this recipe was also printed in the July 1992 Newsletter).

Entomophagy Limits (from page one) 

a consequence of traumatic stimulation of the arthropod selected as a food item.  In general, the natural products synthesized by arthropods are externalized from glands and in a sense constitute the first line of chemical defense.  Furthermore, some species synthesize compounds that are often unique animal natural products but these compounds are not discharged from exocrine glands but rather, fortify the blood and of course the whole body.  As a consequence, the toxic effects of these products may not be realized until the insect is injured and the toxin-laden blood comes into contact with the predator's tissues. 

However, while these nonexocrine compounds are not discharged from specific glands, in some species they may nevertheless be externalized by autohemmorhage from weakened cuticular areas such as the legs, thorax, orelytra.  For example, hemolymph fortified with pharmacologically active natural products is characteristically elaborated by reflex bleeding in the case of species of adult Meloidae (Carrel and Eisner 1974) and Lampyridae (Blum and Sannasi 1974).  Indeed, the discharge of toxic blood by reflex bleeding appears to be far more characteristic of beetles than species of any other order. 

It is imperative that the insect gourmand learn to recognize both phanerotoxic and cryptotoxic species in order to avoid a traumatic assault on both the palate and the intestine.  Cryptotoxic species produce toxic nonexocrine secretions as previously described, but in some cases the active compound(s) may be localized in a single structure rather than fortifying the blood.  For example, females of the meloid Lyua vesicatoria localize cantharidin in the ovaries and eggs (Sierra et al. 1976), their cryptotoxicity becoming devastatingly evident when their reproductive system is exposed to the sensitive oral and enteric tissues of a naive predator.  On the other hand, a phanerotoxic species possesses an apparatus for synthesizing, storing, and injecting the venomous products.  Phanerotoxic species may not be readily evident, as is the case for the larvae of many satumiid species which possess clusters of venom-filled spines that are rendered invisible by being enveloped by dense hairs.  Obviously the poison apparatuses of bees, wasps, and ants are so conspicuously phanerotoxic--and distasteful--as to require little comment. 

Vesicants vs. Internal Toxicity For the entomophage, it is of great importance to be able to discriminate against toxic insect species before they become gastrointestinal disasters, the victim possibly subjected to exaggerated waves of reverse peristalsis, or worse.  Fortunately, a multitude of decidedly toxic insects advertise, as external vesicants, the adverse pharmacological effects of their natural products and they are clearly marked as species that should be immediately rejected as food items.  This is particularly true for lepidopterous larvae in a variety of families (Kawamoto and Kumacla 1984) and adult beetles in several families.  In short, the well-developed vesicatory properties of diverse insects often translate into considerable internal toxicity for a variety of toxinological reasons that will be discussed subsequently. 

Phanerotoxic vs. Cryptotoxic Species A large variety of insect species posses a true venom apparatus that generally includes a

poison gland, reservoir, venom duct, and a device for injecting the venom.  Venomous secretions are produced by species in the orders Hymenoptera, Hemiptera, and Lepidoptera, and their secretions are delivered by either retractile stings, piercing mouth parts, or urticating setae.  These obviously venomous insects are refer-red to as phanerotoxic species and contrast to cryptotoxic species whose toxicity is not manifested until the insect is ingested.  Often the toxins produced by phanerotoxic species are only active by injection and these venomous compounds are inactivated in the gastrointestinal tract.  However, as will be described in the next section, ingestion of some phanerotoxic insects could constitute a lot more than just a bad gustatory experience. 

Oral Vulnerability vs. Gastrointestinal Detoxicative Defense The larvae of many lepidopterans possess urticating spicule hairs which are powerful vesicants; similar reactions are caused by the spine hairs of larvae of moths in several families (Kawamoto and Kumada 1984).  In addition to these vesicatory hairs, the larvae of some saturniid species produce powerful fibrinolytic proteinases that have been implicated in a hemorrhagic syndrome in humans (Amarant et al. 199 1).  For the most part, the active compounds are believed to be proteins that should be readily inactivated in the gastrointestinal tract.  Despite enteric detoxication of these vesicatory toxins, a modicum of caution is recommended in order to ensure that disasterous larval revenge does not occur. 

Although the toxic compounds present in larval urticating hairs are in all probability proteinaceous constituents that can be facilely hydrolyzed (detoxified) in the intestine, major oral injuries can occur before the ingested larva becomes an intestinal victim.  In short, the oral cavity is probably very susceptible to the pernicious effects of these lepidopterous toxins.  The entomophage may also be vulnerable to the impaling of spines in the esophagous and elsewhere in the oral region, which could result in a real toxic overload.  It is advisable to know your larval lepidopteran (Blake and Wagner 1987) before ingesting it. 

When an Ingested Insect's Biochemical Constituents Become Toxins by Augmenting the Concentration of the Same Compounds in the Host When a human predator ingests an insect with which it shares a pharmacologically active agent, this compound can constitute a true toxin if applied in a toxic dose under Coca conditions (Vogt 1970).  For example, high concentrations of histamine, a known algogen, are characteristic of hymenopterous venoms and several biogenic amines have been identified in the venoms of wasps and honey bees (Owen 197 1).  The richest source of acetylcholine in the animal kingdom is the venom of Vespa crabro (Bhoola et al 1961), raising the question of what effect on an entomophage would result if a concentrated intrusion of this neurotransmitter was introduced into the gastrointestinal tract.  In short, insect-derived compounds may constitute cryptic toxins whose roles as dangerous physiological agents are not easily recognized because these biochemicals are identical to agents utilized by the host in relatively low concentrations.  "Too much of anything, however, especially biogenic amines, is not necessarily a good thing." 

SEE ENTOMOPHAGY LIMITS, P. 7

Paiute youths eating burgers and fries instead of ant pudding, laments a tribal elder. 

Paiute-Shoshone tribal members are considering whether to let the government store its radioactive nuclear waste on their reservation, creating badly needed jobs and economic growth, according to a story in The Sunday Oregonian of June 27, 1993.  The reservation is in a remote area at the Oregon-Nevada border.  Ernestine Coble, 46, tribal council chairwoman, who was quoted at length, believes that the old values are slipping away and she would like to save the ones that remain.  For instance, her grandmother would say, "Well, we're going to have ant pudding.  You'd better get ready.  We're going to have to leave when the sun comes up."  

Eight-year-old Ernestine's job was to put on warm clothing and to carry an empty coffee can.  They would hike around the res (short for reservation).  Her grandmother would spot a mound, lift the top like an old straw hat, and scoop out balls of cold-numbed ants.  They were put into the coffee can and cooked on the old wood stove.  Ernestine said that the ant pudding was not her favorite food, but it was a tradition and an anchor to a world of power and solidarity. 

The editor mentions this story for two reasons, first, I had not heard the term, "ant pudding" before, although ants and their pupae were widely eaten by Indian tribes in the West, and secondly, it reveals that the older generation of Paiutes in Oregon were still eating their insect foods as recently as 1955 (age 46 minus age 8 = 38 years ago).

Entomophagy Limits (from page six) 

Anabolic Steroids and Corticosteroids from Beetles--And a Lot More.  Coleopterans are preeminent in the biosynthesis of steroids other than ecdysteroids, and for the entomophage it is best to exercise considerable restraint before ingesting these insects.  For example, about 20 steroids have been identified as prothoracic gland products of species in the family Dytiscidae (Schildknect 1970), and many of these compounds are either identical to vertebrate steroids or constitute unique triterpenes that are closely related to these hormones.  Indeed, since dytiscid species in only seven genera have been subjected to analytical scrutiny (Blum 198 1), it is very likely that a host of steroidal surprises will be forthcoming when species in other genera are analyzed.  However, it is already evident that the dytiscid prothoracic glands rival the endocrine glands of vertebrates in biosynthesizing steroids with powerful physiological activity, for everything from fish to mammals.  Let the eclectic entomophage beware of dytiscids and other coleopterans as well! 

Anabolic steroids have been identified as exocrine products of Ilybius fenestratus and these include testosterone and 1,2-dehydrotestosterone (Schildknect 1970).  In addition, this secretion contains estrone and 17B-estradiol.  Conceivably, prolonged ingestion or sucking this beetle could result in a real anabolic effect characterized by nitrogen retention and skeletal muscle enlargement (Gilman et al 1980).  Although prolonged ingestion of dytiscid steroids may result in the entomophage possessing a body similar to that of Hercules, there may be untoward effects that militate against this means of achieving the perfect physique.  Younger males could experience serious disturbances of growth and sexual and osseous development. 

Edema, jaundice, and hepatic carcinoma can result from prolonged ingestion of anabolic steroids; azoospermia and impotence may also be the consequence of a long-term beetle diet containing these hormones.  For female entomophages, the danger of masculization is very real as a consequence of a diet of dytiscids fortified with these androgens (Gilman et al 1980).  Women may experience a deepening of the voice, develop body hair, and suddenly show a tendency toward baldness, probably too great a price to pay for the epicurean delight of dytiscids!

For vertebrates, steroids such as testosterone may constitute considerably more than anabolic stimulators.  When toads (Bufo and Pelobates spp.) ingested adults of two dytiscid species in the genus Ilybius, the beetles, often alive, were rapidly regurgitated, enveloped by a bloody slime (Schildknecht et al. 1967).  The prothoracic gland secretion of Ilybius species is dominated by testosterone and contains 1,2-dehydrotestosterone as well.  The protective role of anabolic steroids for vertebrates is also demonstrated by the fact that testosterone is a powerful stupaficient for goldfish, causing rapid paralysis of the carp.  These steroids have been presumably evolved to act as deterrents for fish and amphibians, two of the potentially major groups of predators for these water beetles. 

In addition to anabolic steroids, dytiscids generate a large variety of steroids, some of which are identical to well known vertebrate corticosteroids whereas others are novel triterpenes (Schildknecht 1970).  For example, about 0.4 mg of cortexone, the major steroid in the secretion of the beetle Dytiscus marginalis, is present in the prothoracic glands of an adult (Schildknecht et aL 1966).  This corresponds to the amount of steroid that can be extracted from I 000 ox suprarenal glands and suggests that these corficosteroids may constitute powerful deterrents for selected vertebrates.  Mineral cortical steroids such as cortexone are capable of destabilizing the sodium-potassium balance, and it is significant that pike and trout are rapidly narcotized by Dytiscus secretion or by cortexone, just as they are by testosterone (Schildknecht et al 1966). 

It is important to recognize that corticosteroids exhibit a potpourri of toxic effects that are observed either after withdrawal of the steroids or as a consequence of continued use of these compounds (Gilman et al. 1980).  Acute adrenal insufficiency can result from too rapid withdrawal of corticosteroids, whereas prolonged dytiscid tasting or ingestion could result in pituitary-adrenal suppression, increased susceptibility to infection, peptic ulceration, myopathy, and behavioral disturbances.  Although dytiscids may be delicious, it would seem advisable to avoid them as prey items. 

Steroids are produced by beetles in other families, and even though pharmacological data are lacking, it would seem desirable to discriminate against them as food items.  The cardiac glycosides pro- 

SEE ENTOMOPHAGY LIMITS, P. 8

Entomophagy Limits (from page seven)  

duced by chrysomelids (Pasteels and Daloze 1977) and the steroidal pyrones synthesized by lampyrids (Eisner et al. 1978), should serve to warn the entomophage that ingestion of these coleopterans may be hazardous to her health. 

A final word of dytiscid caution seems advisable for resolute entomophagous predators.  The steroidally fortified secretions of all species of Dytiscidae that have been analyzed consist of mixtures that may contain at least seven compounds.  It is not unlikely that interactive pharmacological effects may result from these mixtures, the steroids of which may be present in inordinately high concentration.  Conceivably, vertebrate predators that ingest dytiscids may experience considerably greater toxicity than would be anticipated based on the activity of individual steroids.  Feeding deterrency studies have almost invariably emphasized tests with single compounds, in spite of the fact that mixtures are, almost without exception, a defensive sine qua non.  So beware of mixtures--they can hurt you! 

A Cyanogenic Menu for Entomophagous Rejection A wellknown member of the snapper family, Lutjianus argentimaculatus, employs the same strategy as an archerfish in order to obtain food.  This mangrove snapper ejects ajet of water from its mouth which is aimed at a variety of animals that are on the leaves overhanging the stream in which L argentimaculatus is found.  While the archerfish technique for securing prey is admirable, it is not without life threatening hazards.  Sometimes the aqueous "bullet" launched by the mangrove snapper dislodges the millipede Polyconoceras allosus, a cyanogenic species.  Ingestion of this polydesmoid diplopod results in an almost instantaneous death for the snapper (Johannes 1981).  Cyanide-producing arthropods may be more than repellent for a predator--they may be deadly! 

Although hydrogen cyanide combines and inhibits a variety of mammalian enzymes (e.g., carbonic anhydrase, succinate dehydrogenase), the great toxicity of this compound primarily reflects its great affinity for ferric iron in cytochrome oxidase, the last enzyme in the cytochrome system (Curry 1992).  The binding of cyanide to cytochrome oxidase stops electron transport with a consequent fall in oxygen consumption and ATP production, a thoroughly perilous state of affairs.  The known distribution of cyanogenic animals is limited to species in three arthropodous classes--Chilopoda, Diplopoda, and Insecta (Duffey 198 1).  In the Insecta, cyanide-producing species have only been detected in selected taxa in the orders Lepidoptera (Jones et al. 1962) and Coleoptera (Moore 1967; Blum et al. 1981). Larvae of the moth Zygaena trifolii are very unusual in sequestering the same cyanogens from their host plant that they synthesize de novo (Nahrstedt and Davis 1986).  Cyanogenic lepidopterans (all stages) are also found in the Nymphalidae and Heliconidae, usually in species that are very aposematic or involved in mimicry complexes (Nahrstedt and Davis 198 1).  Although many of these species develop on plants that are fortified with toxic natural products (e.g., pyrrolizidine alkaloids), these lepidopterans do not sequester these compounds but rather biosynthesize cyanogens (Brown and Francini 1990).

Cyanogenic beetles have not been encountered frequently, having only been detected in species in the families Chrysomelidae and Cicindellidae.  It would appear that the cyanogenic chrysomelids in the genera Chrysophtharta and Paropsis (Moore 1967) are exceptional in producing defensive allomones that are atypical for members of this family.  The production of cyanide by adults of the tiger beetle Megacephala virginica (Blum et al. 1981) may also be regarded as unusual since no members of the closely related family Carabidae have been demonstrated to produce cyanogenic allomones. 

Should the adventurous entomophage eat these aposematic lepidopterans and beetles?  The levels of cyanide produced by individual insects should hardly constitute a real toxinological hazard, but in the absence of good information about cyanogenic insects being eminently benign, discretion would seem to be the best part of epicurean valor.  It is worth recognizing the possibility that the defensive arsenals of these sundry arthropods may contain more than cyanide, and they do! 

Beetles for Sniffing--And a Lot More The aromatic hydrocarbon toluene is widely used as a solvent for products such as varnishes and glues.  This compound is a central nervous system depressant and confusion, weakness, and fatigue can result from exposure to low concentrations (Gilman et al. 1980).  The CNS effects of solvents such as toluene are responsible for the practice of "glue sniffing" and demonstrate its considerable pharmacological activity when administered in the vapor phase.  Beetles in selected genera constitute real toluene factories, and as a consequence could be regarded as potential subjects for the practice of "beetle sniffing"! 

Longhorn beetles in the genera Stenocentrus and Syllitus produce toluene-dominated secretions in their mandibular glands and, in addition, the phenolic constituent o-cresol (Moore and Brown 197 1).  These defensive secretions, which constitute the only known sources of toluene in the Arthropoda, should probably be "off limits" for either "beetle sniffing" or ingestion.  Sniffing the secerambycids could result in the well-recognized toxic effects resulting from exposure to low levels of toluene.  These include ocular and respiratory irritation, dizziness, and decrement in motor performance (Sullivan and Van Ert 1992).  Major acute and chronic effects have also been reported after exposure to toluene.  Cresols have also been reported to cause significant public health effects such as dermal injury and in some cases central nervous system, kidney, and liver injury (Geehr and Salluzzo 1992).  All and all, these longhorn beetles can hardly be recommended for either sniffing or ingesting.

Vesicatory and Aposematic Staphylinids are not for Eating There are times when determined entomophagy must yield to insects that fairly scream their dangerous unpalatability.  This is certainly the case for the warningly colored beetles in the genus Paederus, the members of which contain a powerful vesicant that is detected when the beetles are crushed.  The major vesicant produced by these staphylinids is pederin, a novel amide that is the most complex nonproteinaceous compound identified in insects (Pavan 1975).  The 

SEE ENTOMOPHAGY LIMITS, P. 9