42

Principes, 37(I), 1993, pp. 42-47

P R I N C I P E S [VoL. 37

Hypothesizing About Palm Weevil and PalmRhinoceros Beetle Larvae as TraditionalCuisine, Tropical W-aste Recycling, and

Pest and Disease Control on Coconut andOther Palms-Can They Be Integrated?

GnNa R. DrFormnrDept. of Entomology, 237 Russell Laboratories, 1630 Linden Drive, Madison, WI 53706

In their book on Cameroon cuisine" Gri-maldi and Bikia (1985) describe their rec-ipe for "coconut larvae" as a "favorite

dish offered only to good friends" (see rec-ipe, page 44). The flavor of o'palmworms"

(fat, legless larvae of the weevil genusRhynchophorus) has been appreciatedthroughout the tropical world for centu-ries. There are a number of species, butthe major ones from the standpoint of widedistribution and use as food are Rhyn-chophorus palmarum in the WesternHemisphere, R. phoenicis in Africa, andR. ferrugineus in Asia.

Newcomers to the Caribbean region wereparticularly effusive about palmworms.Bancroft (1769:239), in his "Natural His-tory of Guiana," wrote that the larvae are"esteemed a delicate morsel, not only bythe aboriginal Natives, but by many of theWhile Inhabitants, particularly rhe French,who roast them before the fire, and mixthem with crumbs of bread, salt, and pep-per." Smeathman (1781:I67-69), whowas working in

.West Africa at the time

and had taken a particular fancy to thetaste of the termite, Macrotennes belli-coszs, said of the termites, "they are some-thing sweeter, but not so fat and cloyingas the [palmworm] which is served up atall the luxurious tables of West Indianepicures, particularly ofthe French, as thegreatest dainty of the Western world."And Stedman (L796:22-23) in Suriname,remarked that, "However disgusting to

appearance, these worms are a delicioustreat to many people, and they are regu-larly sold at Paramaribo." Stedman laterrelated (p. II5) that: "'We here foundconcealed near the trunk of an old tree acase-bottle filled with excellent butter,which the rangers told me they made bymelting and clarifying the fat of the palm-tree worms: this fully answers all the pur-poses of European butter, and I found itin fact even more delicious to my taste."

Indigenous populations throughout thetropics have prized palmworms no less thanhave Europeans, and in the case of R.palmarurn, Chagnon (1968:30-32) inVenezuela/Brazil, Clastres (I97 2:I 6O-61)in Paraguay, and Beckerman (1977) andDufour (1987) in Colombia have reportedprimitive cultivation systems for the lar-vae. Chagnon reports: 'oThe Yanomamocome very close to practising 'animal

domestication' in their techniques ofexploiting this food. They deliberately cutthe palm tree down in order to providefodder for the insect. When they cut thetree, they also eat the heart of the palm,a very delicious, crunchy vegetable thatslighdy resembles the taste of celery hearts.One palm we cut yielded an edible heartof about 50 pounds. After the pith hasbeen allowed to decay for several months,it contains numerous large, fat, white grubs.The pith is dug out of the tree with sticks,broken open by hand, and the grubsextracted. . . . A fair-sized palm tree will

ree3l DEFOLIART: PALM BEETLE LARVAE

yield three or four pounds of grubs, someof them as large as a mouse. The grubsare wrapped in small packages of leavesand placed in the hot coals to roast." Cha-gnon was told by a missionary that thegrubs taste very much like bacon.

The Guayaki of Paraguay, according toClastres, consider the palm larvae as "more

than a food gathered by chance in theforest; rather, it is the product of a sortof cultivation. The Indians knock down thepalm tree, leaving a stump about 3 feethigh. They then generally cut the fallentrunk into sections l0 or 12 feet long,preparing the wood for the insects. . . .Each man is the owner of his larvae bed. . . .This private property is almost alwaysrespected and no one touches the larvaeof another. Later, the harvest is dividedand eaten collectively. Thus the Guayakidistribute a relatively abundant supply offood. . . . It is of great interest to see thatthe Guayaki, despite their being nomads,establish a fixed source of food to be gath-ered much later. In doing so, they areobliged to return to the cultivation areaafter many months of travelling. . . . Thiscultivation of guchurhercfore exerts a pro-found influence upon the wandering habitsof the Guayaki in that it gives an order totheir travels."

In Colombia, Beckerman ( I977)reported that the Bari Indians use onlyJessenia palm as a "grub farm." The treesare cut down and the logs left lying in theforest. "In two or three months the wholetrunk is infested with the edible larvae. . . .Several hundred grams of larvae can beextracted from a single trwrk. . . ." Dufour(1987) reported that "The Tatuyo felledpalms to harvest the fruits, and oftenreturned at a later date to harvest thelarvae which subsequently developed in thepith. Palms were also cut specifically withthe expectation that they would be invadedby weevils and the larvae ready to harvestin two or three months. Thus, the larvaewere both a by-product of the harvestingof palm fruits and 'cultivated."' Dufour

reported a live weight of 3-16 grams forthe grubs and a maximum acquisition rateof 2,000 g/how.

With this gustatory background, let uslook at another dimension of palm weevilsorestricting ourselves temporarily to theWestern Hemisphere. Rhynchophoruspalmarum is one of the most serious pestsof coconut and oil oalms in Latin Americaand the Caribbean, mining the trunks ofthe trees and transmitting the nematode,R hadinaphelenchus coco philus, which isthe causal agent of red-ring disease (RRD)(Morin et al. 1986, and others). The weevilinfests many other species of palms, bothwild and cultivated, as well as sugarcaneand several root and fruit crops (Hagley1965, and others). Hill (1983) describesthe damage from the weevils as follows:"The larvae burrow in the crown of thepalm, feeding on the young tissues, andsometimes destroy the growing point, whenthe palm will die. The leaves turn chloroticand die, and the trunk becomes tunnelledand weakened, and may break in a storm."

Schuiling and van Dinther (I9Bl) pro-vide a good entry to the extensive litera-ture on RRD. The coconut palm may diewithin 3-4 months after the appearanceof external symptoms which include yel-lowing of leaves and premature nutfall.Internally the stem tissue is discolored andnecrotic. There is evidence that only theadult weevils are involved in the trans-mission of the RRD nematode.

Hill (1983) lists recommended insecti-cides and several cultural control methodsthat are applied against R. palrnarum,including elimination of breeding sites byrestricting physical injury to palms, controlof Oryctes beetles, destruction of infestedpalms, and trapping of adult weevils. Morinet al. (1 986) describe procedures that havebeen successfully used in Para and Bahia,Brazil, since 1975. As adults are attractedfor feeding and reproduction to the odorof fermentation emanating from wounds inhealthy palms or from the decay of deador diseased palms, all injured or decaying

44 P R I N C I P E S [Vor-. 37

Cameroon cuisine - larves depalmiel

(From: La Cuisine Camerounaise, by Jean Grimaldiand Alexandrine Bikia, p. 136. Thanks to Dr. JaneHoman, UW International Agricultural Programs, forproviding a copy, and to Diane Landry for a trans-lation from the French.)

The larvae of certain coleoptera harvested fromthe oil palm and from the palm of genus Raphia areeaten in Cameroon. These larvae, called "Fos" inEwondo, are white (oil palm) or yellow (raphia palm).They are sometimes reared. Before any preparation,the larvae are washed in a lot of water and piercedin the abdomen with a sharp piece of bamboo betweeneach washing to let a white, fatty liquid escape. Inall regions they are prepared either by stewing, fryingin oil with salt and pepper, adding to squash seedpaste, or putting on brochettes grilled over coals.

Coconut larvae recipe

Larvae coming from oil palms or raphia palms,salt, pepper, onion, coconut,

Prenaration: Larvae washed and cut in half are

mixed with all the condiments cited. The coconuts

are chosen at half-hard stage, so that the inside,

completely globular, can be taken out of the husk

without being broken. The most pointed end of the

nut is cut in a way that forms a cap. The nuts are

emptied of their milk, then refilled with the larvae

and condiments and closed by attaching the caps

firmly.The nuts are stood straiSht up by some banana

leaves in a pot containing water. The amount of water

should be such that, during the course of cooking, it

cannot penetrate the nuts. The cooking is rather long.

After cooking, the nuts are cut into slices.This favorite dish is only offered to good friends

and is served with manioc sticks.

Bamoun preparation

Among the Bamoun. the larvae are strung up and

left to dry hanging under the trellis that is found

above the foyer. After they are well-smoked, they

can be incorporated, after being washed, into the

scuash seed paste.

trees are removed and traps are con-structed along the edge of a plantationfrom cut pieces of thinning, wild palms oruninfested parts of damaged or diseasedtrees. Whole trunks of oil-palms, whichare very thick, can be cut into cubes andleft in small heaps; but only the tenderapical I-2 meters of the. thinner buttougher trunks of wild and coconut palmsare used. They are split into longitudinalsections and intercrossed into piles withthe bud on top. Trap heaps should berenewed weekly, either by replacement withother palm pieces and burning of the oldinfested ones, or by spraying with palmsap to maintain attractiveness and also withO.l5% methomyl to prevent the piles frombecoming a source of infestation.

At the Paricatuba oilpalm estate in Para,Brazil, according to Schuiling and vanDinther (l98l), palm losses from RRDwere held to I.I4% of palms in the sus-ceptible age group through the programof phytosanitation, i.e., preventing wounds

and early elimination of palms showing dis-tinct growth disorders by felling and trans-porting the trunks to the oil factory wherethey were sawed into blocks and steamsterilized at 130'C for I hour, which killsthe nematodes. This program was consid-ered much more effective than insecti-cides, the efficacy of which, according tothe aulhors, is open lo question.

In Africa and Asia, Rhynchophorusphoenicis and R. ferrugineus, respec-tively, damage palms as does R. palma-rum in Latin America and the Caribbean.RRD, however, is apparently not foundoutside the Western Hemisphere.

The hypothetical scenario that can becreated from the foregoing has longintrigued this writer. Palmworms wouldcertainly seem worthy of wider publicizingas traditional cuisine of gourmet quality,the kind of delicacy that could be promotedas tourist and urban fare by the best res-taurants throughout the tropics and sub-tropics, and eventually, maybe, even as an

19931 DEFOLIART: PALM BEETLE LARVAE

item for export. Could such wider pro-motion and use create more opportunitiesfor employment and entrepreneurship inthe rural countryside? Could, in fact,expanded markets provide a basis forattempting to combine increased palm-worm production with more efficient recy-cling of dead and diseased palms, and aspart of reduced-pesticide integrated pestmanagement (IPM) programs and diseasecontrol on coconut and other palm species?

Taking a cue from how indigenous pop-ulations have done it for centuries, couldthe trap logs recommended for pest anddisease control, through a simple modifi-cation in procedure, be used simulta-neously for palmworm production? Thedesired harvest stage is the late-instar larva.Studies in Trinidad (Hagley 1965), Brazil(Morin et al. 1986) and Mexico (Gonzalezand Camino I97 4) have shown that theegg and larval stages of R. palmarumlast2-4 days and 40-61 days, respectively,at essentially ambient temperatures.Instead of burning trap logs at the end ofa week or spraying them with methomylto kill the larvae, as suggested by Morinet al., if left in place for approximately 45-50 days, the larvae would be ready forharvest. All would be large-sized, few wouldhave pupated and no adults would haveyet emerged. Possibly, logs could be reusedif desired by spraying with palm sap torenew attractiveness. If not, they could atthat point be burned or otherwise disposedof.

Greater efficiency might be achieved byadditionally seeding new trap logs with eggsfrom adult weevils caught in traps baitedwith coconut tissue. This should exert addi-tional control pressure within the planta-tion, while producing a higher density ofdeveloping larvae in the logs, thus pro-ducing more larvae per unit of substrate,more efficient recycling of the logs and areduced mass of material left for burning.Maharaj (1973), in Trinidad, described asimple aluminum trap that catches morethan twice as many weevils as the con-

ventional split-log trap and uses only aboutone-fifth as much coconut tissue as bait.To incorporate food production as part ofweevil IPM as hypothesized, trap logs wouldhave to remain in place about 7 weeksinstead of one, and thus would occupy 7times as much ground surface, but thatshould not be a huge problem in palmplantations.

The writer has not seen reports of "cul-

tivation" for either R. phoenicis or R.

ferrugineus, but the latter is attracted todying or damaged parts of palms, cut orsplit palm trunks, and even decaying sug-arcane (Kalshoven and van der Laan1981). The larval period, normally 2months or longer, has been reported asonfv 24 davs when feedine on the nutritious palm i'cabbage." So] enriching thelarval diet might have a place in increasingproduction as food.

A fourth species, Rhynchophorus bi-lineatus, the famous sago grub which isthe subject of feast and ritual among cer-tain Melanesians in Papua New Guinea, isalso "semi-cultivated" (Townsend 1970).In the opinion of at least one European,however, 'othe taste of the grub is fattyand oily and is no delicacy for the palateof a European" (Meyer-Rochow 1973).

Rhynchophorus larvae rank withwinged termites as among the richestsources of animal fat, a frequently scarceand needed commodity among tropicalrural populations. And insect fatty acids,in general, are highly unsaturated. Thehigh fat content of R. phoenicis is reflectedin its high energy value of 561 kcal/100g of insect (Oliveira et al. 1976). It is alsohigh in thiamine, riboflavin, and zinc andfairly high in iron.

For U.S. gourmets, it should be knownthat one species of Rhynchophorus, R.cruentatus, extends into the southeasternstates where its larval-feeding damage tothe terminal bud is a lethal problem intransplanting mature cabbage palmettos(Sabal palrnetto) and Canary Island datepalrns (P ho enix c anariens i.s) (Giblin-Davis

46 P R I N C I P E S lVoL. 3?

and Howard l9B9). At a length of 24-33

mm, it is the largest known weevil in the

United States.In even a brief discussion of major pests

of palms, the giant palm rhinoceros beetles,

primarily of the genus Oryctes (Scara-

baeidae: Dynastinae), must be mentioned.

The larvae of these beetles have also been

widely used as food in Africa and Asia. In

this case, it is the adult beetles that do the

serious damage, while the larvae are found

in all sorts of refuse (Bedford I9B0). Of

the three species reported as food in Africa,

Oryctes monoceros breeds in dead stand-

ing coconut and oil palms in western Africa

and in decaying coconut logs in eastern

Africa, O. boas breeds in rotting vegetation

and manure heaps (but not in rotting wood),

and O. owariensis in dead standing oil

palm, coconut and, Raphia trunls. Oryctesrhinoceros, in Asia and the western Pacific,

breeds in a wide variety of dead but not

yet decomposed plant material, including

the tops of dead standing coconut palms,

coconut stumps and logs on the ground,

and other types of decaying wood, as well

as compost, dung heaps, rotting straw, rot-

ting coconut husks, coffee and cacao pulp

waste, and refuse from sugar cane facto-

ries, ricemills, sawmills, and various other

types of agricultural products processing.

Larvae attain a length of 6-8 cm (Hill

1983) and Kalshoven and van der Laan(l 98 I :463-68), citing Leefmans in I920,

note that up to 50 grubs,/m3 may be found

in re{use dumps adjacent to towns and

larger villages. Although insecticides and

a promising baculovirus, Rhabdionuirus

oryctes, are available, control of rhinoc-eros beetles is based on sanitation and cul-

tural practices similar to those recom-

mended for Rhyncho phorus weevls. Thus,

i t seems hypothetical ly possible that

Oryctes could also be incorporated into

palm IPM programs, recycling an endless

variety of tropical wastes into animal pro-

tein and fat.Having a recipe from Cameroon was a

rather flimsy excuse for writing this article,

and I have done so with some trepidation'

The main problem is that I haven't been

in a palm plantation since becoming inter-

ested in insects as food, and have never

seen a palm grub or rhinoceros beetle larva

in situ. Many of our readers, however, are

surrounded by palms, and some are no

doubt knowledgeable about palm culture.

Maybe we can hear from some of you as

to the current situation and future possi-

bilities with palm weevils and rhinoceros

beetles.

LItrReruRE CIrnt

Bercnorr, E. 1769. An Essay on the NaturalHistory ofGuiana, in South America. London:Becket and De Hondt, p. 239.

Brcrrnlren, S. 1977. The use of palms by theBari Indians of the Maracaibo Basin. Principes2 l : I43 54 .

BronoRl,G.O. I980. Biology,ecologyandcontrolof nalm rhinocer os beetles. Annu. R eu. E nt o mol -25 :309-39.

CHAcNoN, N. A. 1968. Yanomamo: The FiercePeople. New York: Holt, Rhinehart and Win-ston, pp. 30-32.

CLASTRES, P. 1972. The Guayaki: In: Hunters andGatherersToday(M.G. Bicchieri, ed.), pp. 138?4. New York: Holt, Rhinehart and Winston.

DuFouR, D. L. 1987. Insects as food: a case studyfrom the northwest Amazon. Am- Anthropolo'gist 89:383-97.

Grerrx-Devrs, R. M. ar:lo F. W. Howeno. 1989.Vulnerability of stressed palms to attack byRhynchophorus cruentatus (Coleoptera: Cur-culionidae) and insecticidal control of the pest'

J . Econ. Entonol .82:1185 90.Goxzertz, N. A. AND L. M. CAMtNo. 1974. Bio-

logia y habitos del mayate prieto de la palma decoco, Rhynchophorus palmarum (L.) en laChontalpa, Tab. Folio Entomol. Mex. 197 4 (No.

28 ) : I 3 - I 9 .Gnrrr.retoI, J. axl A. BIKIA. I985. Le Grand Liore

de La Cuisine Camerounaise, p. 136.HAGLEY, E. A. C. 1965. On the life history and

habits of the palm weevil, Rhynchophorus pal-marum. Ann. Entomol. Soc. 4m.58:22-28,

HILL, D. S. 1983. Agricultural Insect Pests oftheTropics and Their Control. London: CambridgeUniv. Press, 516 pp.

KALSH0VEN. L. G. B. AND P. A. veN nrn LeeN.l98l. Pests ofCrops in Indonesia. Jakarta:P.T. Ichtiar-Van Hoeve, pp. 463-68.

MAHARAJ, S. 1973. A new design of trap for col-lecting the palm weevil, Rhynchophorus pal'

r9931

marum (L.). Ceylon Coconut Planters' Rea.7 ( I \ : 5 -7 .

MEyER-RocHow, V. B. 1973. Edible insects inthree different ethdc groups of Papua and NewGtrainea. Am- J. Clin. Nutr. 26:673-77.

MonrN, J. P. F. LuccHrNr, J. C. A. rn ARAUJO, J.M. S. Frnnrrne. eNo L. S. Fne.se. 1986.Rhynchophorus palmarum control using trapsmade from oil palm c,abes, Oleagineux 4I(2):57 -62 .

Ouvnnra, J. F. S., S. J. Passos DE CARvALKo, R.F. X. BRUNO DE SOUSA, AND M. MAGDALENASrtleo. 1976. The nutritional value of fourspecies of insects consmed in Angola. Ecol.Food Nutr .5:91-97.

ScsuruNc, M. aNn J. B. M. veN DINTHER. 1981.'Red ring direare'in the Paricatuba oilpalm estate,Para, Brazil. A case study. Zeut. Angew Ento-mol. 91:154-69.

Pr incipes,3T( l ) , 1993, pp.47 49

DEFOLIART: PALM BEETLE LARVAE t a

SltnarHlreN, H. 1781. Some account of the ter-mites, which are found in Africa and other hotclimates. Philosoph. Trans. Roy. Soc. London7 I : 139 -92 .

SrnoueN, J. G. 1796. Narratiue ofa Fiae Year'sExpedition Against the Reuolted Negroes ofSurinam, in Guiana, on the Wild Coast ofSouth America; From the Year 1772, to 1777. . . (2 vols. London, Vol. II, pp. 22 23.

Townsrno, P. K. W. I970. Subsistence and SocialOrganizations in a New Guinea Society. Ph.D.diss., Univ. Michigan.

Renrinted Irom: The Food Insects Nensletter. 199O.IlIi2\: 2-6.

A Needle Palm in the Northern Landscape

Jor Heennr261 Simard Dr., Chicopee, MA 01020

Even among cold-tolerant palms,Rhapidophyllum hystrix is legendary forits hardiness. Like most legends, this oneis part fact and part fallacy.

Reports of the needle palm survivingtemDeratures of - l5o F or even -20" Fhaue led some mail order nurseries to ratethe plant hardy to USDA zone 6. A SouthCarolina nursery listed a zone 6 rating forthe needle palm as recently as last year,but their latest catalog says the palm ishardy to Washington, D.C., inside zone 7 .

Why? For one thing, northerners whobought the plant often lost it during thecrucial first winter. I've noticed that mar-ginal trees and shrubs nearly always per-form better their second and third wintersin our soil, even when those winters aremore severe than the initial one. Accordingto what I've read in horticultural booksand articles-and later affirmed by exper-imenting-a plant requires at least a yearto acquaint itself with new soil. Until it

becomes acclimated an ornamental is sen-sitive to winter injury, drought stress, andthe limitations of its particular site (incom-patible soil types, lack of drainage, etc.).Of course plants grown at the edge of theirhardiness limit are especially at risk.

Though it is especially hardy, the needlepalm is a southern, heat-loving plant. Scat-tered populations may endure a night ortwo of abnormal cold in their native situ-ation, but that cold spell is usually shortlived. In the North, cold lingers, sometimesuntil April.

I first tried needle palms at a northernexposure because I'd had some successthere with broadleaved evergreens. Sincethe northern side of the house is alwaysshady, problems with winter sunscald areeliminated. My first needle palm, plantedten feet from the house, showed only alittle green by spring. It was alive when Idug it up, but died soon afterward. Thesecond needle palm I tried, this one planted