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Richard
L. Lindroth In his classic children's book, The Very Hungry Caterpillar, Eric Carle describes the development of an increasingly voracious caterpillar, from egg hatch to metamorphosis into a beautiful butterfly. In addition to the character appeal of the larva and aesthetic quality of the illustrations, the book teaches some valuable lessons about the nutritional ecology of insect herbivores. The caterpillar hatched on Sunday; on Monday he ate through one apple, on Tuesday two pears ... and on Saturday "he ate through one piece of chocolate cake, one ice cream cone, one pickle, one slice of Swiss cheese, one slice of salami, one lollipop, one piece of cherry pie, one sausage, one cupcake, and one slice of watermelon. That night he had a stomachache!" What
are the lessons we can learn? First,
the older (and bigger) the insect is, the faster it eats.
Indeed, consumption and growth rates increase exponentially with
insect age. For example, leaf
consumption by the forest tent caterpillar (Malacosoma
disstria) is
approximately 0.05, 0.2, 0.8, 2.9 and 18.0 square inches for instars 1-5,
respectively. Second, the older an insect is, the more diversified its diet
may become. Most herbivorous
insects are specialists, feeding on only one or a few related species for
their entire lifespan. But
some insects are generalists; notable among these is the gypsy moth (Lymantria
dispar), which feeds on over 300 species of woody plants.
For these generalist feeders, diets typically become increasingly
diversified as maturity -affords both greater mobility and increased
capacity to detoxify the chemical defenses of plants.
Third, for caterpillars, as for humans, some foods or combinations
thereof may bring considerable discomfort. |
AD x ECD). In short, AD indicates how digestible a food is, whereas ECD and ECI indicate how efficient a herbivore is in converting that food into biomass. These efficiency values may b calculated for specific dietary nutrients as well as for the bulk die, For instance, nitrogen use efficiencies are informative because levels of plant nitrogen (an index of protein) are often times limiting to insect performance. Food conversion efficiencies may vary considerably within species. One cause of such variation involves homeostatic adjustment of consumption rates and efficiency parameters such that an insect can approach its "ideal" growth rate even with foods of different quality in various environments. For example, insects that experience reduced ECDs due to increased respiratory costs may be able to compensate by increasing consumption rates of digestion efficiencies (ADs). Not all changes are homeostatic however. For instance, many insects increase food consumption rates in response to low concentrations of critical nutrients such as protein. Increased consumption will accelerate passage of food through the gut and thereby reduce ADs. In our work with the gypsy moth we found that larvae reared on a protein deficient diet increased consumption rates by 3-4 fold, but overall ADs declined by nearly as much. Other nonhomeostatic changes in efficiency values may occur in response to plant allelochemicals. For example, compensatory feeding to increase intake of a limiting nutrient may simultaneously increase exposure to plant toxins, which in turn may reduce ECDs. In practice, however, it can be quite difficult to ascertain "cause" and "effect" responses with efficiency parameters. Does the insect eat more because digestibility is low, or is digestibility low because the insect is eating more? Efficiency parameters are so closely physiologically related that determination of "cause" and "effect" is not a trivial matter. Intraspecific variation in food conversion efficiencies may also be related to insect development. ADs generally decrease, whereas ECDs increase, from early to late instars. In other words older larvae digest their food less completely, but that which they do digest is more efficiently utilized for growth. One study showed that values for AD and ECD change from 46% to 27% and 38% to 60%, respectively, for early and late instars of the desert locust (Schislocerca gregaria). Factors contributing to such changes are still largely unknown, but may include shifts in food selection, digestive physiology, metabolic rates, and body composition. Food conversion efficiencies also vary greatly among species, and this variation is more closely related to feeding guilds than to taxonomic affinity. Insects that feed on nitrogen-rich foliage generally have higher consumption rates and assimilation efficiencies than do insects that feed on nitrogen-,poor foliage, and |
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Recent
Technical Paper Neupane,
F.P., R.B. Thapa, and M.N. Parajulee. 1990.
Life and seasonal histories of the eri silkworm, Samia cynthia ricini Hutt. (Lepidoptera: Saturniidae), in
Chitwan, Nepal. J.
Inst. Agric.
Anim. Sci. 11:113-120.
Institute of Agriculture and Animal Science, Chitwan, Nepal. Authors'
Abstract. The eri silkworm, Samia
cynthia ricini Hutt. (=Philosamia
ricini) produced six generations a year when reared on castor (Ricitius
communis L.) in Chitwan, Nepal. The
egg, larval feeding, and spinning + prepual + pupal periods from March
through September lasted 6-1 1, 15-21 and 14-20 days; from September
through November lasted 6-11, 16-21 and 26-31 days; and from November
through April lasted 25-27, 58-64 and 31-33 days, respectively.
It took 38-50 days
during March-September, 49-61 days during September-November and 114-126
days during November-April to complete a generation. The mean weights of a matured larva, a cocoon, a pupa and a
shell (silk) were 5.24-+0.86, 3.75±0.56, 3.09±0.51 and 0.61±0.19g
respectively, during July-August. Cassava
(Manihot esculenta L.), which is
a substitute food plant of the eri silkworm, also gave similar results.
But the mean weights of larvae, cocoons, pupae and shells (silk)
were slightly lower when reared on cassava compared to castor. Ericulture, after nearly disappearing for two decades in the eastern Tarai of Nepal, is slowly regaining popularity. The authors discuss |
various
benefits of ericulture and report the results of a two-year study on the
production biology of the insect. Quality
leaves of both castor and cassava are available throughout the year,
farmers can use their extra time for silkworm rearing and very little
investment is required, and even low-skilled children and older folks in a
family can participate in the rearing, thus enhancing employment and
economic status of poor and subsistence farmers.
There are additional advantages: castor bean oil has medicinal and
industrial value, while cassava roots are used as human food and animal
feed and the old plants as fuelwood.
Planting the trees in marginal lands helps prevent soil erosion. Mean
temperatures in the region are highest from April to September (above
30'C) and lowest from December to February (below 20'C).
Although fresh leaves are available throughout the year, rearing is
not advised during the cold months, November to April, because three
months is required to complete a cycle.
Pebrine disease (caused by Nosema
sp.) constitutes a problem during rearing, but is controlled by
treating the silkworm eggs and all rearing equipment with 2% formalin.
The mean number of eggs per female moth ranged from 149.9 to 398.3
from May through November, with maximum numbers being laid during October
and November. |
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EDITOR'S
CORNER The
National Research Council is talking about "microlivestock,"
rush of research dollars yet for edible insects John
Rennie's article on entomophagy in the August issue of Scientific American (page 20) wasn't included in our November
roundup of meritorious magazine articles because it was shorter and of
earlier vintage than the articles we mentioned.
But Rennie made an important point about the importance of the
American attitude that is too seldom made in the popular press.
The point was derived actually from a conversation that Rennie and
I had in New York. After noting the nutritional attributes of insects, and that
people in other cultures don't eat them just out of necessity but because
they enjoy them, Rennie's article states: "'Chacun
a son gout' [roughly 'Each to his own taste or preference'], some cvnics
might shrug, but DeFoliart argues that such narrowmindedness is harmful.
Because Americans and Europeans do not consider insects a food
source, few funds are available for research on the food uses of insects.
Such research could help identify particularly nourishing insects
and improve methods for raising and harvesting them." The old saying quoted above by Rennie expresses an admirable degree of tolerance, but it needs to be lengthened somewhat to accurately reflect what has long been the prevailing Western |
attitude
toward insects as food: "Each to his own taste, but don't expect us
to provide research support that would help you compound the error of
yourways." But things may be heading in the right direction.
In 199 1, The National Research Council/National Academy of
Sciences released a report titled, "Microlivestock: Little-known
Animals with a Promising Economic Future." I haven't seen the
original report, but it was summarized by Gibbons (199 1) in
Science. The title
sounded exciting. But, lo and
behold, the report wasn't talking about "micro" at all.
They were talking about "miniature," as in miniature
pigs, cows, sheep and goats. The
report states that large animals "such as cattle are too large for
the world's poorest people, they require too much space and expense."
The NRC panel annointed 40 down-sized animals, citing as their advantages
that they are less expensive to buy and feed, they take up less space,
reproduce quickly, and can be moved around easily. Conventional
livestock will certainly continue to have a place in animal agriculture,
but the move toward smallness appears to be a step in the right direction
for many situations. A second
step in the right direction is toward greater diversity. Several large rodents were among the 40 species which the
panel selected from a list of 150 proposed by 300 animal scientists in 80
countries. Relative to
rodents specifically, as summarized by Gibbons, they "are among the
world's most adaptable mammals -- and they breed like crazy." In all
likelihood, the inclusion of rodents required some painful cultural
adjustment on the part of some of the NRC panelists, despite the stated
adaptability of rodents and the fact that they are SEE EDITOR'S CORNER, P.11 |
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Letters Grasshopper
consumption by humans and free-range
chickens reduces pesticide use in The Philippines Edward
Litton of Manila writes, in part: "Grasshopper is a favorite food in
many parts of the Philippines and therefore it
is not destroyed with chemical insecticides.
It is also fed to chicken raised on pasture.
Pastured chickens in the Philippines are not fed commercial feed
and therefore have a delicious taste and are sold at a much higher price
than chickens fed with commercial feed. Insect
condiments for North Americans Tree
Willis of Venice, California was looking for sources of additional
information or confirmation when she wrote, in
part: "I've
become interested in utilizing insect [secretions] as a condiment for
foods after reading a passage in a book called Flowering
Plants of the Santa Monica
Mountains by Nancy Dale.
She writes, 'Indians in Placer County are reported to have put the
leaves near the entrance of red ant holes.
After the ants had swarmed on the leaves, they were shaken off
leaving a vinegary taste which was much relished.' The leaves mentioned
are of a plant in the Portulacaceae, called Claytonia
perfoliala.
I'm eager to try
it." Ed.:
Are there readers who can cite personal experience?
The following comment by Dr. Roger Akre is quoted from the March 1992
Newsletter (Letters section, p. 5): "Army (and Air Force)
survival schools in Washington also advocate the use of Formica
obscuripes and F. exsectoides [two
species of ants] as sources of formic acid as 'salad dressing' for any
greens such as pig weed, dandelion, or lambsquarter that can be collected
and eaten.
The formic acid gives the greens a better flavor, not quite so flat." A
first record of edible insects used in Macau? Emmett R. Easton, Convenor of Math and Science (but who also has a background in entomology) at the University of Macau, wrote recently to tell us that beetles of the aquatic families Dytiscidae and Hydrophilidae are commonly eaten in Macau. We wanted to get this in the newsletter before 1999 because Macau, a Portuguese outpost since 1557, will then revert to China and it would no 1011911 represent a new geographic record. Actually, to find that these aquatic beetles are used in Macau was not surprising because they are commonly eaten wherever cantonese dwell and Canton is only a short distance from Macau. But life gets harder even for old geography freaks like your editor. We were only vaguely aware that Macau is somewhere along the South China coast, so Emmett's report sent us to the bookshelf to pull out the 1990 Atlas and check things out. Right off, had trouble locating the city of Canton, which is now called Guangzhou. It is located in Guangdong Province (isn't this what used to be called Kwangtung Province?). Maybe the best way to pinpoint it is to simply say that Macau (formerly spelled Macao) is located across the mouth of the Zhu (also known as the Pearl) River from Hong Kong. |
The
San Francisco Insect Zoo's 14th Annual Open House
will be May 23, 1993 . January
25th from Ms. Leslie Saul, director of the Insect Zoo: "Enclosed
please find a check...to help defray publication costs for The Food Insects Newsletter which is a truly wonderful resource. "The
San Francisco Insect Zoo will be having our 14th Annual Insect "There
will be many other aspects of entomology also highlighted that day as
usual: butterfly/insect gardening, "Appreciating Arachnids",
insect-plant interactions (insectivorous plants, worm composting, garden
clinics), insects in amber, oh-mys from the California Academy of
Sciences.
This year, a representative from Food & Drug here in SF has
asked to participate and Peter Menzel has offered to do a photographic
presentation. "It
would be most appreciated if you could put a notice of our upcoming
bake-off in the new Newsletter issue
if it's timely.
Also, would it be possible to get reprints of nutritional
information on domestic crickets and mealworms if you have it.
We are getting more and more requests for detailed information.
Thanks very much.
Best regards." Ed.:
Leslie, "Amen" to your last paragraph.
We also hear from more and more people wanting more and more
detailed information.
The phone number for more information on the Open House is (415)
753-7053.
Mitchell Clark of San Francisco sent in some recent press coverage
of the Zoo's Open House, an article called " Putting the Bite on
Bugs," by Tara Aronson, in the San
Francisco
Chronicle of December 9,
1992. According
to the article, between 1000 and 3000peoplecrowd up to sample the edible
insect delights each year. Reader
suggests
that palm weevil culture has economic potential in Indonesia Ideas
for commercial development of palm weevil culture in Indonesia were
discussed in two long letters from Edgar Dresner of Vernon, Connecticut.
The following is extracted from the first letter, dated November 3,
1992: "In
the now distant past when I worked in Indonesia under U.S. Foreign Aid, I
was given the opportunity to eat cooked Curculio larvae; my reaction was
enthusiasm, but as you can imagine, I found SEE
LETTERS, P. 4 |
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Letters
(from page three) no
support by my U.S. or local associates for a program to make these a world
food crop. At that time there
were many technical difficulties in addition to the cultural antipathy. "My
introduction was palm weevil larvae, fairly large, tasty morsels.
Varying with species, these larvae attain up to 90 mm length,
diameter about 1/6 length. During
my introduction no adult beetles were presented, so I do not know the
species. There are at least
four large species in East Indonesia and possibly other nearby areas (K.W.
Dammerman, 1929, in The Agricultural
Zoology of the Malay Archipelago
(pp. 99- 10 1) listed three Indonesia area palm weevils:
Rhynchophorus ferrugeneus Fabr., R.
papuanus Kirsch and
Protocerius praetor Faust). "In
the copra production areas of East Indonesia back yard culture of the palm
weevil larvae is common. A
two- meter length of a fallen trunk is retained in a horizontal position
and in about two months the trunk is opened and the larvae and pulp are
removed. The larvae are
separated by washing, then cooked and feasted upon.
The trunk piece I saw included the growing tip but I believe the
beetles also oviposit in wound areas anywhere on the trunk. "Though
these larvae are locally esteemed, they did not usually enter commercial
marketing even within the country because at that time there was no rapid
transit from the field to the market; certainly there was no refrigeration
to preserve the crop for a later trip.
Perhaps equally important, the urban market consisted primarily of
people who would not consider eating insect larvae. This fare is forbidden by the Moslem code as well as
disapproved culturally by those who have embraced our Western culture. "In
spite of those negatives, I believe there is now a very large potential
market for these larvae both in urban Indonesia and in foreign markets.
In Indonesia the potential consumers include the more than four
million of Chinese background and the even larger number of Moslem
Indonesians who now eat in Chinese restaurants and now consume pork and
shrimp dishes. However, the
most important potential market is foreign sales to Singapore, Hong Kong,
and Japan, areas of wide ranging food acceptance.
It will take many years for production to satisfy the potential of
these markets before merchandising in the U.S. and Europe will be
required. I think demand in
these Western markets may come before the supply is ready. "In
contrast to the 50's when I worked in Indonesia, many of the rural areas
now have generators or even established electric power which could sustain
refrigerators; both sea and air transport has been greatly improved.
Commercial production of these larvae would be done in small or
larger town labs and the trunks could be transported the relatively short
distances to the labs. |
concentrated
through discs cut out of the green growing tips of the palms.
Eggs from a few days' oviposition would be held until hatching,
then placed in the culture medium, and after a calculated time, harvest of
the mature larvae. I expect,
but don't know for sure, the entire trunk could be used as a culture
medium. With most of the
coconut plantations in Indonesia now overage, 80 years plus, this program
would provide an incentive to cut down the old, less productive trees and
replace them with genetically selected high yielding plants.
In addition to coconut palms, these weevils infest sago, betel,
royal, and other palms." Ed-:
The July 1990 Newsletter contains an
article on palm weevils. Mr.
Dresner mentioned that, although now
retired, he would welcome any opportunity to investigate the potential for
commercial palm weevil culture in Indonesia. The
medicinal ant, Polyrhachis,
facing extinction in China? Under
date of 20 January 1993, Dr. Roger Akre of Washington State University
writes, in part: "On
page 4 of the most recent Food
Insects Newsletter is a reference to the Chinese eating ants.
I have a new student from China, Yi Chen (Charlie) who persuaded
his mother to send me a copy of the video "Value of Ants" which
is perhaps better titled the medicinal uses of ants .... Perhaps the most
interesting information on the video is that so many Polyrhachis
are eaten that there is a concern that the species may become extinct.
They have established formicaries to prevent this possibility. "I
enclosed a packet of powdered ants. These
were packaged by the hospital in Beijing.
The package is to be taken in three separate doses in water, hot
water, tea, coffee, or wine. It tastes a bit like pungent sand, but isn't too bad if you
add honey or sugar to your drink. Enjoy!" A
Canadian reports difficulty in
finding insect delicacies in
China Dr.
Yves Prevost, professor at Lakeland University in Thunder Bay, Ontario,
wrote (November 11, 1992) in part: "I
heard quite a bit about the successes of the New York Entomological
Society Banquet. As well, I
heard one interview with Vickie Gabereau of the Canadian Broadcasting
Corporation (CBC). That was
successful as well. We are
planning something similar, but not as elaborate for the icebreaker of our
upcoming annual meeting of the entomological Society of Canada in Sault
St. Marie, Ontario in October 1993. "This
past summer I was in China for the Entomology Congress among other things.
I was looking forward to eating many different insect preparations,
buying insects from street markets and whatever else I could imagine.
I would be visiting remote areas where they probably never have
seen a foreigner. I did not
know what to expect, but I did think this would be fertile ground for
feasting on insects, based on what I knew of Chinese food. This was
obviously my first
time in China. SEE
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From
a basketful of newspaper articles
sent in by readers But
please keep sending them. They
are helpful in ascertaining the amount and quality of media coverage of
the subject, and the popular press offers up-to-the-minute sociological
slants not as frequently found in technical papers. In
Mexico -- Insect-fortified tortillas A
United Press International article by Eda Chavez, datelined Mexico City.
Actual title: "Bug s May Be Added to Mexico's Tortillas."
Thanks to Ronald Sommers of San Leandro, California, for sending it: Mexicans
could find themselves munching on tortillas made with ground flies [Ed.:
meaning larvae or pupae?] or tacos filled with ants if scientists succeed
in their plans to raise the nutritional level of Mexican staples. Nutrition
specialists are investigating enriching basic foodstuffs with high-protein
substances from insects such as crickets, flies, worms, or termites.
"The tortilla is one of the basic dietary elements among
Mexican families because of its low cost, but it also has a low protein
content," said Pedro Valle, dietary researcher at the National
Autonomous University of Mexico. "By
adding animalderived protein, we could effectively lower the incidence of
malnutrition in the country," he said. Dr.
Julieta Ramos-Elorduy, an entomologist at the university, noted that 40%
of Mexicans suffer from malnutrition.
"And this will continue as the buying power of the average
Mexican decreases daily." Many peasants, especially among Indian
communities, exist on tortillas, black beans and hot chile peppers. They almost never eat meat or vegetables.
"Insects ensure a reliable alternative protein source and
would reduce the possibility of Mexico being a hungry nation in the
future," Elorduy said. [Ed.: Dr. Ramos-Elofduy's books and research
papers are cited frequently in the Newsletter.] Javier
Cordoba, researcher at the Institute of Agronomic Research, noting that
dietary customs may make whole insects repulsive, says, "But just by
using insect flour, we can convert any
type of snack into a product with high protein value." Dr.
Hector Burges, at the Institute of Nutrition, mentioned a wide range of
insect flavors resembling almonds, pine nuts, apples, a hot highly
seasoned flavor, and fried pork- rinds. In
Colombia -- For Tukanoans, it's yes to insects, no to chicken! This
short Associated Press article (titled "Where Little Bugs Are Great
Grub") was also sent in by Ron Sommers, and is reprinted in its
entirety. "Termites taste like fish, palm grubs resemble pork sausages, and ants can remind one of goose-liver pate," says anthropologist Darna Dufour. Sound tasty? Well, Dufour says "in the jungle, insects are good to eat." |
That
was the theme of her lecture on insect cuisine last week at the University
of Colorado Museum in Boulder. Dufour
dined on such delicacies as ants, termites, beetles and caterpillars
during a 16month study of the eating habits of the Tukanoan Indians of
eastern Colombia. In her
research along the Colombian-Brazilian border, Dufour found the Tukanoans
consumed insects as a food supplement and sometimes as a sole source of
nourishment when fish weren't available. Natives
preferred to harvest some of the insects, particularly termites and ants,
in larvae stages, "when they're highest in fat and protein
content," she said. Sometimes,
insects like ants are used as a spread for bread and the ants resembled
"bacon-bit sort of things," she said.
Although some caterpillars are saved, most of the insects collected
are eaten rapidly. "It's
a hand-to-mouth situation with insects," she said. Dufour
said that after overcoming some initial queasiness, she learned to like
some insects. While
Westerners are repulsed about consuming caterpillars, she added, the
Tukanoans don't particularly like some foods, either.
Eggs and chickens are out, because chickens are seen as scavengers. And milk, she said, "makes them want to vomit." Ed.:
The technical report describing the excellent research conducted by
Dr. Dufour in Colombia is: Dufour, D.L. 1987.
Insects as food: A case study from the northwest Amazon. American
Anthropologist 89(2):383-397. One
of the conclusions in her study was that, "the role of insect fauna
in the diet needs to be included in any evaluation of the adequacy of
protein resources in Amazonia." China
-- An investment opportunity in the health Field? A
Reuter dispatch, datelined Beijing. Thomas
Slone of Berkeley was the first to send it, as it appeared in The
San Francisco Examiner of March 15, 1992 under the title "Eating
termites like taking medicine." We offer only a brief summary as
there are no experimental results as yet: Yang
Siqi, director of the Yingtan Termite Research Institute, believes
termites can cure a variety of ills, according to the official New China
News Agency. He developed his
theory after orthodox treatments failed to cure his fever and gastritis. After three months of eating termites, "a miracle
happened," and doctors were amazed at how quickly his ailments had
disappeared, according to the report.
Yang has set up three companies to chutn out termite-based
medicines for the international mark-et. Zambia
-- Where armyworms are appreciated; maybe Kenya could export theirs Dateline
Rome. This article by Francis
Mwanza, titled, "Fancy a meal? -- catch a bug," as it appeared
in The Herald (Harare,
Zimbabwe), October 19,1988, was sent along several years ago by Dr. John
Phelps (some items simply get caught in the Newsletter. SEE
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Newspapers
(from page five) backlog).
We've extracted the latter part of the article, which pertains
primarily to Zambia: When
a plague invaded parts of Zambia, street vendors appeared with dried
locusts for sale. A spokesman
for the Zambian Ministry of Agriculture and Water Development issued a
warning that the locusts being sold were sprayed with chemicals. But
the buying and selling went on briskly.
Zambian nutritionists have long acknowledged that army worms, known
as ifishimu, and butterfly larvae are rich sources of protein.
Mothers are advised not to overlook the food value of ifishimu.
Nutritional posters in schools also show the insects as good
sources of protein. A
Zambian newspaper reader asked why Kenya, which is often badly affected by
army worm invasions, does not export them to Zambia. Termites, caught at the beginning of the rainy season, are
also eaten with gusto in Zambia and fetch a high price. Insects
are becoming more useful even in livestock feeds. Researchers at the University of the Philippines have
developed a chicken feedmeal from maggots of the common housefly to
replace fishmeal. The
maggots, which are dried, are reported to contain 53 percent crude protein
and 18 percent crude fat. And
a change of diet to include bugs, bees and beetles could mean that insects
are harvested rather than attacked by expensive insecticides. Ed.:
What is the scientific identity of the army worm(s) known as ifishimu?
Richards (1939) mentions ifishimu
as one of seven main kinds of edible caterpillars in Zambia.
I have not seen it mentioned elsewhere in the technical literature,
including Silow (1976), but have not seen the papers by Thompson (1954) or
White (1959). The
Philippines -- Hard times in the Cordilleras:
Back to insect-eating. The
above is the title of an article by Robert Domoguen, datelined La
Trinidad, Benquet. Like the
previous article, it has been caught for some time in the Newsletter
backlog. It was sent
(along with a letter dated September 9, 1990) by Dr. Chris Starr who
mentioned that it appeared in a Manila daily "a few years back."
The Cordillera is the highlands of northern Luzon, according to Chris: La
Trinidad, Benguet. Certain
edible insects are helping a growing number of folk in the Cordillera
uplands come by simple but protein-laden meals during these harsh economic
times. Mountain rice spiked,
laced or mixed with insect viands is becoming more common everyday fare
for highland families whose poverty prevents them from even thinking of
buying exorbitantly priced meat and fish. A survey conducted by
entomologists at the Mountain State Agriculture College (MSAC) in this
town found that the insect-eating provides the upland folk with their
daily protein and other nutrient needs. Lolita Colting, chairman of MSAC's plant protection department who is an entomologist, identified the more popular edible insects |
as
the June beetle, grasshopper, ant, mole cricket, water beetle, katydid,
locust and larvae of the dragonfly. She
said laboratory examinations show that such insects are "loaded"
with protein, fats, and calcium, thus providing nutrient needs of those
who eat them. The
insects are made palatable through various ways of cooking.
Some are fried in fat, broiled, sauteed with vegetables, turned
into "adobo" and "paksiw," Ms. Colting explained.
Size of the insects ranges from 0.25 millimeters to a few
centimeters and thus lots of them are needed to provide a person with the
required daily nutrients, she said. Colting
added that the Cordillera mountains abound with insects and there is not
going to be any shortage even if the entire upland population avail of
them as daily food. Eating
insects is an old custom among the various minority tribes in the
highlands of North Luzon. The
habit is due to food needs and a way of reducing pests which attack food
crops, according to entomologists. The
MSAC study, which is still going on, also discovered that a growing market
for edible insects has sprang up in a number of towns in the Cordillera
provinces of Benguet, Mt. Province,
Ifugao and Kalinga-Apayao. Some
enterprising folk- have taken to trapping the insects and selling them in
the markets. The common
measure is by the tin can-full, with costs ranging from PI to P2 per can
(25 pisos = US $ 1 J. The insects come out in full force during the middle
of the dry season and early weeks of the rainy months to feed on newly
planted food crops. Those who
trap them usually build fires in open spaces at onset of evening.
Basins full of water are placed around the fires.
Other trappers use nets, woven baskets or simply pick the insects
off the ground. Colting
said interviews with the insect-eaters elicited the information that the
latter have been introduced to such "eating delights" by their
parents and grandparents. Such
answers confirm that the uplanders have long been availing of insects as
protein sources, the MSAC entomologist said.
However, some respondents born and bred in the citified ways of
nearby Baguio City confessed that they have never eaten insects.
Colting said a few admitted that they did not know insects can
serve as human food. The
majority of respondents who said they eat insects come from the rural
areas. A
related development is the finding of staffers at the Sericulture Research
Training Center, located in the MSAC campus, that fried caterpillars are
"delicious." From Thailand -- Everything
you want to know about the giant water bug In
the November 29, 1992 edition of The
Nation (Bangkok newspaper), Martin Clutterbuck reviews a 63-page
booklet by Chaiya Yusoongnem which is apparently entirely devoted to the
giant water bug, Lethocerus indicus.
The title is Malaeng Daa Naa (Of
Edible Insects). It was
published by the Centre for Agricultural Texts, price Bt35 [25 baht = US $
1]. Among his early paragraphs, Clutterbuck says,
"Blissfully unaware of the revulsion experienced by those from other
cultures, Chaiya Uisoongnem uses this book to SEE
NEWSPAPERS, P. 8 |
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For
eri silk producers in India, unlike mulberry silk producers, the edible pupa is the prize and the
silk is the by-product. |
Request The BBC Natural History Unit in
Bristol, UK has recently embarked on a major new 6 x 30 minute series
about insects. The series
will take a "science fiction" style look at the alien world of
insects. Visually stunning
computer effects mixed with live action are one strength of the series.
The other is provided by the insects themselves - extraordinary
creatures carrying on extraordinary lives, most of which have never been
previously filmed. Our
aim is to seek out the most exciting and bizarre insect stories to include
in six programmes with the following themes: insect design, reproduction,
feeding, migration and dispersal, social insects and man versus insects.
If you have any insect stories that you would like to bring to our
attention please contact:
|
Insect snacks part of ESA's Insect Expo in Baltimore Following
its annual meeting held early in December, the ESA (Entomological Society
of America) sponsored Insect Expo, a day of hands-on education designed to
introduce children to entomology.
Held in the host city's Convention Center for an expected 3600
students from 43 Maryland schools, attendance was held to about 900
because of an early morning snow storm.
As described, in part, in the ESA Newsletter (January 1993):
"A six-foot, plush costumed ladybug greeted students as they roamed
through more than 30 hands-on display booths, attended puppet shows,
participated in the human caterpillar race, and stopped by the
entomological eatery for a handful of pan-fried mealworms ... [or] sampled
caterpillar crunch, a mixture of nuts and fried waxworm larvae."
|
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Letters
(from page four) "Most
Chinese looked at me very puzzled and asked me why I would want to eat
insects, when they could offer me eyeballs, stomaches, intestines and
heads of chicken, pigeon and turtle.
They believed that I was joking when inquiring about insects as
food. After a further discussion they finally admitted that some
people eat silkworm pupae and giant waterbugs, but it was not common.
Silkworm pupae are eaten only in the silkworm areas during harvest
of the silken cocoons when the cocoon-bearing pupae are placed in hot
water to kill them and to unravel the thread from the cocoon.
These pupae can be further processed by roasting in peanut oil. "During
the congress, a group of us decided to forage for edible insects in
Beijing restaurants. The only
animals that we ate which resembled insects were juvenile scorpions about
4 cm long. They were placed
on a bed of rice noodles and cost about $1.00 each. The specimens looked
ferocious, but tasted fine, probably like a potato chip.
Everyone was content with the experience, I went back for
seconds." Ed.:
Yves may have been looking in the wrong places or talking to the
wrong people. See
communications from Luo Ke and Chen Xiaoming, respectively, in the March
and July 1990 Newsletters. Newsletter
connects with the world of "rock" January
13, 1993 Although
I have never (knowingly) eaten an insect (but am open to the possibility),
I really enjoy reading the Newsletter.
Congratulations on putting out such a great publication. Sincerely,
[signed] James Martin, VOX Magazine |
"Our
bug debut didn't get the turnout we were hoping for, however, the weather
and the timing was not the most opportune.
Your technical and moral support has been most appreciated and
helpful. It enabled me to
produce some really good food. I
was quite surprised by the public's acceptance.
The majority of patrons that sampled our vittles were pleasantly
surprised with their gastronomic experience.
We'll continue to do free tastings for the next month or so. "I'm
sending along some of the invitations, menus and a copy of the article in
the Washinton Times. It wasn't flattering, but it wasn't a bashing either.
I guess insect cuisine will take some getting used to.
I'm not sure whether the 1 1/2 star rating is for the insects or
for our regular food. Oh
well, any press is good press, as they say.
We've also done two radio shows and the Washington
Business Journal will be in in the next few days to do an
interview...... Ed: More about this later. Details began arriving only shortly before press time and our space in this issue was already at a premium. It sounds like The Insect Club is loaded with "atmosphere." Newspaper
(from page six) tell
us everything we could possibly want to know about Thailand's favourite
edible insect." Many
"for instances" are given by Clutterbuck (only a few of which
are included here) concerning biology, harvesting, market prices, recipes
and other culinary uses. For
those wanting to be in Bangkok at the right time, tne selling season for malaeng daa is usually October-March. Male malaeng daa can
be sold wholesale for Bt35 apiece, while females fetch only 50-75 satang
[1 bhat = 100 satangs]. This
is because the male has the distinctive odor. "The
eggs can be eaten
on their own, raw or grilled, the result 'yet another form of
deliciousness.' The rather Tasteless female is best deep fried in batter
and dipped in itamjim. Alternately
she can be stuffed in pork and fried, or she can make a nice roast malaeng
daa curry. The male,
after a grilling to increase his flavour and removing his wings, is best
crushed in a mortar to make nam
phrik chili sauce. "Chaiya
recommends adding fish, prawn sauce (kapi),
the aubergine relative makheua or
the fermented plaa raa for
'tastiness you shouldn't tell anybody' about (aroi
yaa bork khral). This
writer [Clutterbuck] can confirm, that as a dip for grilled chicken, nam
phrik malaetig daa is indeed tasty and distinctive." Clutterbuck
concludes that, "For the adventurous, another world of flavour is
waiting, once they discard their conditioning." And one final useful
hint: "When buying, the best way to sex a malaeng
daa (and avoid being tricked by market women) is to look for the
female's egg-laying appratus." Ed.:
Thanks to Dr. Hugh Popenoe, Center for Tropical Agriculture,
University of Florida, who noticed the review during a recent trip to
Bangkok. This review seems to
confirm my impression that you want to have a Thai chef around when you
try giant water bug. |
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Food
Conversion
(from page one) as
a consequence grow and develop much faster.
The classic example here is the difference between forb- and
tree-feeders.
Forb leaves typically have high levels of nitrogen and water,
whereas tree leaves have lower levels of those substituents and higher
levels of poorly digestible compounds such as cellulose, lignin and
tannins.
Accordingly, insects that feed on mature tree leaves exhibit growth
rates half or less than those insects that feed on forbs.
The relatively poor nutritional quality of tree foliage has had
important consequences for insect life histories.
In temperate regions forbfeeders often have many more generations
per year than do treefeeders.
Among tree-feeders, numerous species have adapted to emerge and
feed only on the especially nutritious early spring foliage, and thus have
only one generation per year. Other
examples that demonstrate how the various efficiencies are strongly
influenced by food quality include wood- and
seed-feeding insects.
Wood is tough and nutritionally poor.
Thus wood-chewers have slow rates of consumption and digestion
(much of which is accomplished by symbiotic microbes).
The combination of these factors precludes all but slow growth
rates in wood-feeders.
In contrast, seeds are high in readily digestible carbohydrates and
protein and low in fibrous material. Thus seed-feeders exhibit high
ADs. Growth
rates are nonetheless only low to moderate, due to low consumption rates
and low ECDS.
Low ECDs may result from a requirement of these insects to
metabolize digested food in order to produce water. Understanding of these basic principles of nutritional ecology can enhance our appreciation of insects as a food resource. Environmentalists and others concerned about nutrition and world food resources have long decried the reliance of some people on large animal protein (e.g., beef) as a dietary staple. The reasoning is that production of such high-quality protein is very inefficient; |
more
food would be available if people ate the grain instead.
This debate is complex and beyond the scope of this paper.
Suffice it to say, however, that a major reason that large animals
are inefficient in transforming plant biomass into animal biomass is that
they have very high maintenance costs (i.e., low ECDS).
Large amounts of energy and nutrients are used to maintain constant
body temperatures.
Insects, being "cold-blooded,", are more efficient in
transforming plant biomass into animal biomass. Understanding
of basic nutritional ecology may also improve selection of insect and
plant species for large-scale insect production.
For example, production will be more rapid with forbfeeders than with
tree-feeders and with leaf-feeders than with wood-feeders, other
environmental factors equal.
Want to know what plant/insect characteristics may be limiting
production?
Some simple input/output and growth measurements will tell whether
production is limited by low consumption, poor digestibility, or
inefficient conversion of assimilated food into body mass.
Different corrective measures may be available for each situation. Acknowledgement This
article benefited greatly from the content and inspiration of excellent
reviews by Frank Slansky and Mark Scriber. Further
Reading Scriber,
J.M., and F. Slansky. 1991.
The nutritional ecology of immature insects. Annual Review of Entomology 26:183-211. Slansky,
F., and J.M. Scriber, 1982.
Selected bibliography and summary of quantitative food utilization
by immature insects.
Bulletin of the
Entomological Society of
America 28:43-55. |
|
A
FOLLOW-UP INTERVIEW WITH DR.
LINDROTH The
Newsletter has never used this journalistic technique before, but
it seems a good way of getting the most out of our invited experts while
we have their attention.
We'll designate the questioner as The FIN
(The Food
Insects
Newsletter).
It's too bad we're not in the fish business because it would
make a great acronym. The FIN: First, thank you Dr. Lindroth for accepting our invitation to set forth some basic principles of insect food conversion efficiency in the Newsletter and for taking additional time to respond to some questions. The food conversion efficiency of edible insects has important ecological and environmental implications. First question. Remembering that edible insects furnish not only protein, but fats, vitamins, and minerals, and. as a very high proportion of growth occurs in the last two larval or nymphal instars (about 95 % in lepidopterous larvae as shown with your example, M. disstria), can we assume that the combined ECI for the last two instars is a valid (and the simplest) statistic for comparing food conversion efficiency (let's shorten it to FCE) between or within species in different situations? A second, related |
question.
Do ecologists have any "rule-of-thumb" ECI level that is
considered good, or is everything comparative and dependent on the quality
of the food source? Dr.
Lindroth: If I had to select only one efficiency measure, ECI would be
a good candidate, as it represents efficiencies of both digestion and how
well digested food is converted to biomass.
Bear in mind though, that insects can compensate for low ECIs to
some degree simply by increasing their feeding rates.
Thus two insects could have the same growth rate, one achieves it
by eating less but being very efficient with what it eats, the other by
eating more but
being less efficient.
Because so much of an insect's feeding and growth occurs. in its
last few instars, FCEs from that period are a very useful comparative
measure.
Another caution here is that dietary characteristics (nutrient
deficiencies or toxins) may affect younger instars more than older
instars, and if the impact is great enough, you'll never see those insects
as older instars. SEE
INTERVIEW, P. 10 |
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Interview (from page nine) I'm reluctant to suggest what ECI values may be "good" or "bad"; they're really more useful in a comparative sense. What is "good" for one insect feeding on one substrate may or may not be "good" for another insect feeding on another substrate. What is most valuable is to compare different species (or races) feeding on the same food, or individuals of one species feeding on different foods. TheFIN: You pointed out that forb-feeders show higher FCEs than tree leaf-feeders because forbs are higher in nitrogen and water and lower in such hard-to-digest compounds as cellulose and lignin. I've seen combined ECI data (Scriber's) on only one forb-feeding edible insect, Spodoptera eridania (the southern armyworm). When tested on 10 varieties of alfalfa, combined ECIs ranged below 15% on six varieties, from 15.5-20.3% on three others, and showed an incredible 29.8% on Vernal alfalfa. Two questions. Do you know of any vertebrate meat animal that can come anywhere close to 29.8%? And secondly, how do you explain such great ECI differences at the plant varietal level? Dr. Lindroth: Yes. As you'll see below, poultry can attain this level of efficiency. But their food source is grain, which is even richer than alfalfa. Considerable variation in ECIs at the plant varietal level has not been well-studied, but may not be as unusual as one might expect For example, in a study with gypsy moth larvae feeding on individual aspen trees from a common habitat, we found ECI values that ranged from 6% to 16%. In our case among tree variation in levels of phenolic toxins greatly influenced ECIs and subsequent larval growth rates. I'm not at all surprised that differences of the magnitude you describe exist among plant varieties. Those differences probably result from differences in chemical or physical attributes of the varieties. The FIN: In scanning ECI data, one can dream up some wild schemes. For example, Scriberalso tested S. eridania on five kinds of clover and trefoil. The highest combined ECI was on Trifolium agrarium (yellow blossom sweetclover), 23.6%. Now, commercial pond fish producers are looking for good sources of long-chain w3 polyunsaturated fatty acids, and lepidopterous larvae, in general, would be a rich source if they could be feasibly exploited. Yellow blossom sweet clover must do very well on poor soils, because it's along roadsides all over the country. And S. eridania has multiple generations per year. Maybe it would pay the fish growers to hire a young entomologist (or maybe put some research money into your lab) to look into the possibilities. Maybe the armyworms should be harvested at the end of the penultimate (second to last) instar. Scriber's data showed an incredible ECI of 56.9% for that instar on YBSC (it was even higher, 58.3%, on Vernal alfalfa.) Dr. Lindroth: You're right, the possibilities are great. As you know better than I, a minor shift in one's thinking about insects as food can open up many new avenues of research and application. The FIN: Unfortunately, many more of the major edible insect groups seem to feed on trees and grasses, or even wood, than feed on forbs. Tests on two species of edible grasshoppers, Locustana |
migratoria and a species of Melanoplus, fed on several kinds of grasses showed combined ECIs in the range of 10-15% and 8-11%, respectively. Two questions. How do ECIs in the range of 10-15% compare with other grass-eaters such as cattle? (I believe there is a rule-of-thumb in cattle husbandry that 15 lbs of hay puts on a pound of gain). As grasshoppers are generalists, if they were reared on forbs, should we expect higher ECIs? Dr.
Lindroth: As I alluded to in the article, FECs are generally
higher for insects than for vertebrates.
One must be careful in making such comparisons, however. One problem is that insect values are reported on
the basis of dry weights, whereas livestock values are reported as
"gain" which typically includes 70% water. After adjusting for water weight, ballpark- figures for
efficiency of gain are seen below. Clearly,
the insects are superior to mammals when fed the same food.
FCEs of vertebrates can approach or even surpass those of insects
when they are fed especially nutritious and digestible food such as grain. About rearing grasshoppers on forbs: I would expect higher ECIs than when reared on grass. The FIN: Larvae of the giant silk moths (Family Saturniidae) are a major food insect group, especially in Africa. Most of these are tree-feeders, and as you indicated in general for tree-feeders, most have only one generation per year. I don't know of any ECI data on African species, but data by Scriber and Feeney on nine North American species on 21 host species showed combined ECIs ranging from 7.1 to 15.8 (ECIs above 10 on nine of the 21 larva/host combinations). Doesn't it seem that, even with ECIs at the relatively low range of 10-15%, if the forest was property managed for caterpillar (and termite) preservation (as has been recommended in several instances by researchers in Africa), it would be about as productive for animal agriculture as grassland? Is there a short answer for this complex question, or is the question not as complex as it seems? Dr. Lindroth: On the surface the reasoning seems sound. But a number of complicating factors come to mind; the answer really is complex. For example, because grasslands have coevolved with large grazing mammals grasses can recover remarkably well from extensive grazing. Remove the same percentage of green foliage from a forest habitat and you'll not have the forest for long. And then there are the practical matters of harvest, etc. It is probably much easier to harvest 1000 lbs of large animal biomass from a grassland than an equivalent amount of insect biomass from a forest! This is not to say that management of forests for insect production should not be considered, just that the comparison with grassland systems is frought with problems. The FIN: Several important food insect groups develop in wood, including decaying or rotten logs. As would be expected, most have SEE INTERVIEW, P. 11 |
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Interview
(from page ten) long
life cycles, one or more years, for example in the beetle families,
Buprestidae and Cerambycidae. Palm
weevils of the genus Rhynchophorus (Family Curculionidae), however, complete development
in only two or three months in palm logs. Is this an exception to the "feeding guilds"
principle that you mentioned (feeding guilds more important than taxonomic
affinity in determining food conversion efficiency), or what would explain
such relatively fast development on such poor food? Dr.
Lindroth: This is an interesting example.
I don't know the answer, but I can hazard a guess.
Most trees are dicotyledons and the woody tissue of these species
is loaded with lignins, tannins, etc.
Palm trees are monocotyledons: they are more closely related to
Kentucky bluegrass than to oaks or maples.
I know next to nothing about the chemical composition of palm logs,
but would suggest that they have higher levels of particular nutrients
(e.g., nitrogen, sugars) and/or lower levels of lignins and tannins than
occur in the wood of dicots. The
FIN: Thanks again, Rick, and a final question. Are forbs and herbs the same thing? Dr. Lindroth: Not quite. Herbs are non-woody plants, including both monocots and dicots. In temperate regions they "die back" to ground level at the end of the growing season. Forbs are herbs that are not grasses (dicots). |
Editor's
Corner (from page two) What
does all of this portend for the future of edible insects?
Maybe nothing. But, insects offer in profusion all of the features of
smallness deemed desirable in the NRC report (and they lack the
disadvantages cited for miniature animals in the report).
To elaborate a bit on one of the advantageous features, who knows
what might happen when the NRC bears about the reproductive capacity of
insects. Female crickets (Acheta domesticus), for example, chum out 1500 progeny per female
and they are ready for the pot 30-45 days later depending upon
temperature. No rodent can
come close to that. Nor can
rabbits. Objectivity
is supposed to be one of the prime virtues of science, but cultural
conditioning can be hard to overcome even for scientists.
Having given the okay to rodents, however, it shouldn't take too
much additional attitude adjustment for U.S. panels to give the okay to
insects. They, too, have long
been used as food by indigenous populations, and in at least some regions
where both rodents and insects have been used, the people preferred the
insects. GRD |
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Entomological
Society of Canada looking for outstanding new recipes for its
Annual Meeting Under
date of February 1, 1993, Dr. Yvres Prevost wrote: Enclosed
please find a recent article produced by the Globe and Mail.
M. LeGault did a great job on it.
As a consequence of this article I gave another interview to CBC
radio Sudbury in northeastern Ontario.
The preparations for our insect tasting at the Entomological
Society of Canada this September 25 to 29 in Sault Ste.
Marie, Ontario are moving along.
I have lined up silkworm pupae, house crickets, mealworms and
waxworms. I have ideas about
how to prepare these and still conserve the insect form, but if someone
has some outstanding recipes, I would like to hear from them.
I can be reached at School of Forestry, Lakehead University,
Thunder Bay, Ontario CANADA P7B 5EI. Ed.:
The Globe and Mail is for
Canada what USA Today is for the
U.S., sort of a national newspaper. The article is titled "The case for some grubs in our
grub," and subtitled "With billions of mouths to feed around the
world, there's one rich source of food we in North America have
completely overlooked -- insects. If
nothing else, it would certainly cut down on our use of harmful
pesticides. Pass the ants,
please. " I agree with
Yvres. It is one of the best
comprehensive newspaper articles I have seen on the subject.
To quote just one sentence by LeGault: "To a great extent, it
is a case that makes itself." |
The
Ralph M. Parsons Insect Zoo, a part of the Natural History Museum of Los
Angeles County, to present the 7th Annual Insect Fair on May 15 and 16. The
displays are designed to introduce the fascinating world of insects to
children of all ages. Both
live and preserved insects are included.
Exhibit themes include conservation, careers in
entomology, insect behavior, photography, specimen preparation, local
insects, giant tropical insects, and more.
Invited vendors offer collecting equipment, books, t-shirts, arts
and crafts, and other insect paraphernalia.
Guest speakers will talk- about a variety of insect subjects on May
15th. The Fair is held at
Arcadia, California and attracts more than 8000 people each year.
For more information, contact: Dr. Arthur V. Evans, Director, Ralph
M. Parsons Insect Zoo, Natural History Museum of Los Angeles County, 900
Exposition Boulevard, Los Angeles, CA 90007; (213) 744-3558.
Thanks to Kathy Burk-holder, Insect Zoo Technician, for furnishing
the above information. At
our press time, it was still uncertain whether insect goodies will be
offered at the Fair -- because of a technicality.
Regulations prohibit the Zoo staff from entering competition with
the regular food vendors. |