Predaceous in Biological Control of Pests of North American Forests

Lorna C. Youngs

nts are common and usually ig- large and aggressive, colony populations budworm survival. The conclusions of nored members of forest com- frequently reach the hundreds of thou- Campbell et al. (1983) on the importance A munities, yet their activities af- sands, a wide variety of prey is taken, and of predation are contrary to those of fect forests in many ways. Their nesting colony activity can extend up to 200 days Markin (1979), who examined the in soil aids soil aeration, movement of soil per year in favorable climates (Finnegan number of budworm larvae and pupae particles to the surface, accumulation and 1974). A comprehensive review of the and the amount of defoliation on trees breakdown of organic matter, and nu- usefulness of ants in European forest pro- where ants were excluded and on trees trient recycling (Petal 1978). Ants influ- tection can be found in Adlung (1966). routinely foraged by ants. Except at very

ence vegetation patterns by dispersing Until recently, predaceous ants have re- high ant densities, he found no significant Downloaded from seed while foraging, and by creating fa- ceived little attention from North Amer- differences between trees, in budworm vorable or unfavorable microhabitats for ican forest entomologists. A few investi- numbers or defoliation. Because preda- plant growth near ant mounds. Ant for- gators have encountered species of both tion by birds was not prevented in his cx- aging, whether for plant or mate- Fonnica and Camponotus feeding on the periments, the compensatory mortality rial, can affect both the population dy- larvae or pupae of defoliating caterpillars from bird predation demonstrated by namics and the distribution of species and sawflies, but have not quantified the Campbell et al. (1983) may have masked http://besa.oxfordjournals.org/ commonly included in the ants' diet. Al- effects of ant predation on forest pests differences in budworm mortality be- though ants feed on a wide range of or- (Silver 1960, llnitzky and Mcleod 1965, tween ant-free and ant-foraged trees. ganic material, my discussion is confined Bradley and Hinks 1968, Allen et al. 1970, to those ant species that habitually prey Jennings 1971, Otvos 1977). History of the Use of Ants in on other -species that can play Research in the western United States Biological Control of Forest Pests an important role in the biological control on the population dynamics of the European efforts to use ants in biolog- of forest insect pests. western spruce budworm, ical control of forest pests have concen- The development of sociality has en- occidentalis Freeman, has revealed an im- trated on augmenting native species of the by guest on February 5, 2016 abled ants to interact with their environ- portant role for predaceous ants (Camp- F. rufa group. Considerable research has ment in ways unavailable to solitary in- bell and Torgersen 1982, Campbell et al. been devoted to methods of quantifying sects. Group foraging and food sharing 1983). Using exclusion techniques, the the minimum number of colonies per supply ant colonies with sufficient re- investigators measured the predation hectare necessary to promote forest pro· sources to support large populations, rates of insectivorous birds, predaceous tection and on methods of mass rearing, which in turn, through division of labor, ants (both Camponotus spp. and Fonnica transplantation, and protection of key ant permit the simultaneous performance of spp.), and both groups on budworm species (Gosswald 1951). Using the cri- all the tasks a solitary insect usually per- larvae and pupae across a range of bud· teria of large aggressive workers, large forms sequentially. Ants can modif)' the worm densities. At low budworm densi- colony size, colonial nest formation, and microhabitat at the nest site, thus reo ties, budworm numbers were 10- to 15- multiple queens per colony, researchers ducing losses of the vulnerable brood fold greater on trees protected from ant have selected F. polyctena (Foerster) as stage to environmental stress. The Ion· and bird predation, compared with trees the primary candidate for augmentation gevity of ant queens and the presence of accessible to both predator groups. At (Cotti 1963). Another species of the F. supplementary reproductives, in many high budworm densities, protected trees rufa group, F. lugubris Zetterstedt, has species, confers a kind of immortality on had twice as many budworms as accessible been augmented to a lesser extent, pri- ant colonies. Ant colonies are long-term trees. Either birds or ants caused similar marily in alpine forests where F. polyc- residents of forest stands. budworm mortality in the absence of the tena is less common and possibly less suc- other group, and predation by either or cessfui (Pavan 1960). both groups was the major source of mor- Research on the Role of Ant In North America, researchers have tality to the budworm in the late larval Predation in Forest Protection closely followed European techniques in and pupal stages (Campbell et al. 1983). their attempts to use ants in biological Research on ant predation on forest The work of Campbell and Torgersen pests has been conducted in Europe for quantifies the effect of ant predation on well over 100 years (Cotti 1963). This budworm survival and thus verifies the I O.G. Bain.Unpublishedreport."Twowood research has concentrated almost exclu- earlier investigation of Bain.I He found a ant speciesattackingwesternsprucebudworm sively on the mound-building species of high rate of budworm larval predation by Choristoneura occidentalis (Lepidoptera:Tor· the Fonnica tufa group, commonly called both obscuripes Forel and F. tricidae) in western Montana."Undated.On red wood ants. This group of species has criniventris Wheeler, although he did not file,PacificNorthwestForestand RangeExper- been singled out because the workers are quantify the effect of ant predation on imentStation,Corvallis,Oreg.8 pp.

WINTER1983 47 control of forest pests. In the early 1950s, ants were also effective in reducing pop- (1971 a,b) found a reduction of sycamore colonies of three Formica species, F. ulations of pine-defoliating caterpillars in sapling growth and a reduction of root fusca L.,F subnuda Emery, and F inte- southern Sweden (Wellenstein 1980). growth in lime samplings associated with groides Emery, were transplanted in New Studies frequently document the number high populations. He did not, how- Brunswick forests to assess their effects of insects captured by ant colonies ever, link aphid numbers to the degree of on the spruce budworm, Choristoneura (Horstman 1970, 1972) or the amount of ant tending. fumiferana (Clemens) (Morris 1963). defoliation occurring at various distances The association of ants with may The colonies did not become established, from ant mounds (laine and Niemela indirectly benefit forest protection. Hon- and the experiments were not repeated. 1980). eydew is a fairly stable food source that Finnegan (1974), in Quebec, has been ant colonies can exploit in periods of low a strong supporter of using ants in biolog- abundance. Other insect pred- Possible Disadvantages to Using Ants ical control. Using the European criteria ator-prey systems demonstrate that hon- in Biological Control for potentially effective ant species, he eydew provides an alternate food source (1971) surveyed the indigenous ant fauna Those that question the value of ant that sustains predator populations during of Quebec and concluded that none pos- predation in the control of forest pests do low prey density (Price et a!. 1980). sessed the necessary characteristics for not deny that ants eat large numbers of The effects of aphids cannot be casily augmentation programs like those in Eu- pest species. They point out, however, evaluated, because detrimental effects on rope. Therefore, Finnegan (1975) im- that ants do not feed exclusively on pests. tree growth depend not only on aphid ported F. lugubris from Italy and success- Beneficial insects such as parasitic wasps density, but also on the time of feeding fully established colonies in two sites in and flies are included in their diet (Adlung and the part of the tree under attack. The Quebec. Subsequently, Finnegan (1978) 1966). The impact of ant activity on other relation between ants and aphids can be

found up to 20% less defoliation by C beneficial insects is likely to be localized complex. Aphids themselves may become Downloaded from fumiferana on trees near F. lugubris near ant colonies, however, and would ant prey (Ayre 1959, Horstman 1970, mounds than on distant trees. McNeil et depend on the extent that the trees in the Skinner 1980), or one aphid species may al. (1978) studied the seasonal predatory area are foraged on by ants, and the extent be protected and another consumed activity of F lugubris and found that C that ant activity interferes with other ben- (Skinner and Whittaker 1981). Ant pre- fumiferana was the most common prey eficial insects. dation on other insects may also be a di- http://besa.oxfordjournals.org/ of this ant during peak budworm abun- The tendency for ant colonies to be rect result of aphid protection. Forest tent dance. clumped rather than randomly distributed caterpillars were attacked by Formica and Transplantation of indigenous ant spe- has supplied critics with an additional Camponotus species when larvae ven- cies was attempted later. Formica obscu- reason to question their usefulness in bi- tured too ncar ant-tended aphid colonies ripes colonies were successfully moved ological control of forest pests. Ants es- (Green and Sullivan 1950). from Manitoba into Quebec (Finnegan tablish foraging territories near their The habit of some carpenter ant species 1977). Previous work in Manitoba had nests, and they are frequently faithful to of nesting in both living and dead wood shown that colonies of F. obscuripes their foraging routes from year to year may limit the potential use of those spe-

could be transplanted from one part of a (Rosengren 1971, David and Wood cies in biological control. Sanders ( 1964) by guest on February 5, 2016 stand to another (Bradley 1972, 1973). 1980). Thus, the scope of their effective- found three Campo notus species in- Attempts to transplant indigenous For- ness may be limited to areas near the nest, festing live balsam fir and spruce in New mica species in the United States have not producing patches of trees free from in- Brunswick, and reported an attack rate in been successful. Wilkinson et al. (1980) sect damage, a so-called "green island" ef- New England and the Maritime Provinces moved F integra Nylander colonies from fect (laine and Niemela 1980). European of between 0.5 and 4.0% in balsam fir and Georgia into Florida slash pine planta- augmentation programs have been pri- between 0.5 and 1.0% in spruce. Thus, tions. Competition between F. integra marily aimed at reducing the degree of the degree to which tree-infesting car- and a local carpenter ant, Camponotus patchiness in ant distributions. penter ant species prey on forest pests abdominalis floridanus (Buckley), re- The association of many predaceous would need careful study before their use sulted in the destruction of the Formica ants with tree-feeding homopterans has in biological control could be recom- colonies. The investigators concluded added to the controversy over the bene- mended. that, because C abdominalis floridanus fits of ant predation on forest pests. Hon- Conclusion dominated the stand and is also preda- eydew, primarily from aphids, is prob- ceous, its potential in biological control ably the most widely exploited carbohy- Do predaceous ants have a future in bi- should be investigated. drate source of many ant species. The ological control of North American forest How much forest protection is afforded association between ants and aphids has pests? European research and augmenta- by ants is still a subject of controversy. led to various degrees of mutualism (Way tion efforts have been extensive, yet even Numerous accounts have been published 1963). Aphids that allow ants to solicit there the verdict is not in. Campbell and in Europe of red wood ants feeding honeydew frequently increase honeydew Torgersen have shown, for the western heavily on defoliating caterpillars and production when tended by ants. In turn, spruce budworm, that ant predation is a sawflies (e.g., Adlung 1966, Petal 1978), ants may provide some degree of protec- major mortality factor; this is one of the but many studies lack data on the effects tion for the aphids against natural.enemies few instances in North Americawhere the of ant predation on pest populations. (Flanders 1951). effect of ant predation on the population Some work in England, in hardwood for- Aphids tended by ants are often able to of a forest insect has been studied in ests, showed a significant reduction in maintain higher populations on trees for- depth. Although McNeil et al. evaluated wintermoth larvae and their damage, on aged on by ants (Bradley and Hinks 1968, the predatory activity of the introduced trees foraged on by red wood ants McNeil et al. 1977). High aphid numbers ant species, Formica lugubris, very little (Skinner and Whittaker 1981). Red wood may adversely affect tree growth. Dixon is known about the native ant species in-

48 BULLETIN OF THE ESA habiting North American forests. The States Spruce Budworms Program, Washing- mica lugubris (Hymenoptere: Formicides) work with western spruce budworm ton, D.C. Rev. Bimes. Rech. 33: 1.] Flanders, S. E. 1951. The role of the ant in shows that research directed toward References Cited the biological controt of homopterous in· quantifying the effects of native ant pre- sects. Can. Emomol. 83: 94-98. dation clearly could yield fruitful results. Adlung, K. G. 1966. A critical evaluation of GOsswald, K. 1951. Die rote Waldameise im What approach should we take to in- the European research on use of red wood Dienste der Waldhygiene. Forstwirtschaf- vestigate the potential use of ants in forest ants (Formica rufa group) for theprotection tliche, Bedeutung, Nutzung, Lebensweise, offorests against harmful insects. Z.Angew. Zucht, Vermehrung und Schutz. M. Kinau protection? Finnegan (1974) has advo- Entomol. 57: 167-189. Verlag, Liineberg. 160 pp. cated the European approach of colony Allen, D. C., F. B. Knight, and J. L. Foltz. Green, G. W., and C. R. Sullivan. 1950. Ants transplantation and the importation of For- 1970. Invertebrate predators of the jack- attacking larvae of the forest tent cater· mica rufu species. The silviculture prac- pine budworm, Choristoneura pinus, in pillar, Malacosoma disstria Hbn (Lepidop- Michigan Ann. Entomol. Soc. Am. 63: 59- tera: Lasiocampidae). Can. Entomol. 82: ticed in European forests is different from 64. 194-195. that practiced-or, often, not prac- Ayre, G. L. 1959. Food habits of Formica sub- Horstman, K. 1970. Untersuchungen uber ticed-in North American forests. Cen- nitens Creighton (: Formi- den Nahrungserwerb der Waldameisen turies of manipulation have created in- cidae) at Westbank, British Columbia. In- (Formica polyctena Foerster) im Eichen· tensely managed European stands, where sectes Sociaux 6: 105-114. watd. I. Zusammensetzung der Nahrung, Bradley, G. A. 1972. Transplanting Formica Abhiingigikeit von Witterungsfaktoren und the augmentation of ant populations by obscuripes and Dolichoderus tashenbergi von der Tageszeil Oecologia 5: 138-157. colony transplant or mass releases of lab- (Hymenoptera: Formicidae) colonies in 1972. Untersuchungen uber den Nahrung- oratory-reared queens is possible. North jack pine stands of southeastern Manitoba. serwerb der Waldameisen (Formica polyc· American forests, especially western for- Can. Entomol. 104: 245-249. tenaFoerster) imEichenwald II.Abhiingigi· 1973. Interference between nest popula- keit von fahresverlauf und von Nahrung- ests, are frequently unmanaged, inacces- tions of Formica obscuripes and Dolichod- sanRebot. Ibid. 8: 371-390. sible, and represent an extremely variable erus tashenbergi (Hymenoptera.· Formi- IInitzky, S., and J. M. McLeod. 1965. Notes Downloaded from environment. Finding a single Formica cidae). Can. Entomol. 105: 1525-1528. on ants associated with Neodiprion swainei species comparable to F. polyctena in Eu- Bradley, G. A., andJ. D. Hinks. 1968. Ants, Midd in jack pine stands in Quebec Can. rope that can be successfully established aphids and jack pine in Manitoba. Ibid. Dep. For. Bi-Mon.Prog. Rep. 21: 1-2. 100: 40-50. Jennings, D. T. 1971. Ants preying on dis- over such a wide range of conditions is Campbell, R. W., and T. R. Torgersen. 1982. lodgedjack·pine budworm larvae. Ann. En· unlikely. Some effects of predaceous ants on western tomol. Soc. Am. 64: 384- 385.

We need much more information about spruce budworm pupae in north central Laine, K.J., and P. Niemela. 1980. The in· http://besa.oxfordjournals.org/ the ant species native to North American Washington. Environ. Entomol. 11: I 11- fluence of ants on the survival of mountain 114. birches during an Oporinia autumnata (Lep., forests, their habitat requirements, their Campbell, R. W., T. R. Torgersen, and N. Geometridae) outbreak. Oecologia 47: geographic distribution, and most impor- Srivastava. 1983. A suggested role for pre· 39-42. tant, the degree to which they prey on daceous birds and ants in the population Markin, G. P. 1979. Ants as predators of the forest insect pests. From the limited in- dynamics of the western spruce budworm western spruce budworm Paper presented formation available for this review, both For. Sci. (in press). at 1979 Entomol. Soc. Am. Annu. Meet., Cotti, G. 1963. Bibliografia ragionata 1930- Denver, Colo. Formica and Camponotus apparently 1961 del Gruppo Formica rufa in Italiano, McNeil,}. N.,}. DeUsle, and R.}. Finnegan. contain predaceous species that may have Deutsch, English. Min. Agric. For. Roma, 1977. Inventory of aphids on seven potential for biological control. Many of Call. Verde 8. 413 pp. species in association with the introduced by guest on February 5, 2016 these species, especially the boreal Cam· David, C. T., and D. L. Wood. 1980. Orien- red wood ant Formica lugubris (Hymenop- tation to trails by a carpenter ant, Campon· tera: Formicidae). Can. Entomol. 109: ponotus species, are found over a range otus modoc (Hymenoptera.' Formicidae). 1199-1202. of forest conditions, and their distribution Can. Entomol. 112: 993-1000. 1978. Seasonal predatory activity of the could be extended by augmentation pro- Dixon, A. F. G. 1971a. The role of aphids in introduced red wood ant, Formica lugubris grams. Perhaps a complex of ant species wood formation I The effect of the syca- (Hymenoptera.· Formicidae), at Valcartier, would provide more effective control of more aphid, Drepanosiphon platanoides Quebec, in 1976. Can. Entomol. 110: 85-90. (Schr.) (Aphididae), on the growth of sy· Morris, R. F. 1963. Predation and the spruce forest pests than a single dominant spe- camore, Acer pseudoplatanus (L). ). Appl. budworm. In R. F. Morris [ed.], The dy· cies, and different complexes may be Ecol. 8: 165-179. namics of epidemic spruce budworm popu· more successful in controlling pests that 1971b. The role of aphids in wood for- lations. Mem. Entomol. Soc. Can. No. 31. are widely distributed, such as the spruce mation II The effect of the lime aphid, Eu- Otvos, I. S. 1977. Some parasites and insect callipterus tiliae L (Aphididae), on the predators of the blackheaded budworm in budworm. Perhaps also, silvicultural ma- growth of the lime, Tilia x vulgaris Hayne. Newfoundland Can. For. ServoBi·Mon. Res. nipulations-such as those that open the ). Appl. Ecol. 8: 393-409. Note 33: 11-12. stand or create more woody debris for Finnegan, R.J. 1971. An appraisal of indigo Pavan, M. 1960. Les transplantations de For· nesting sites-can augment ant popula· enous ants as limiting agents of forest pests mica lugubris sur les Apennins de la provo tions without costly colony transplanta. in Quebec Can. Entomol. 103: 1489-1493. ince de Pavie. Italy Min. Agric. For. Coll. 1974. Ants as predators of forest pests. En· Verde 7: 161-169. tion. But all of these possibilities remain tomophaga 7: 53-59. Petal,J. 1978. The role of ants in ecosystems. mere speculation until more research is 1975. Introduction of a predacious red wood In M.C. Brain [ed.j, Production ecology of done. ant Formica lugubris (Hymenoptera: For- ants and termites. Cambridge University micidae) from Italy to eastern Canada. Can. Press, Cambridge. Price, P. W., C. E. Bouton, P. Gross, B. A. Acknowledgment Entomol. 107: 1271-1274. 1977. Establishment of a predacious red McPheron, J. N. Thompson, and A. E. I thank David G. Fellin, U.S.Forest Service, wood ant Formica obscuripes (Hymenop· Weis. 1980. Interactions among three Forestry Sciences Laboratory, Missoula, Mont.; tera:Formicidae )from Manitoba to eastern trophic levels: influence of plants on her· Canada. Ibid. 109: 1145-1148. bivores and natural enemies. Annu. Rev. Max W. McFadden, U.S.Forest Service, Wash- 1978. Predation by Formica lugubris (Hy. Syst. 11: 41-65. ington, D.C.;and Daniel B.Twardus, Forest Pest menoptera.· Formicidae) on Choristoneura Rosengren, R. 1971. Route fidelity, visual Management, Portland, Oreg., for their review fumiferana (Lepidoptera.' Tortricidae). Bi- memory and recruitment behavior in for· of an earlier draft of this paper. Mon. Res. Note 34: 3-4. [Finnegan, R.). aging wood ants of the Formica (Hy· Work leading to this publication was funded 1977. Predation de Choristoneura fumi· menoptera: Formicidae). Acta Zool. Fenn. by the USDAForest Service, Canada/United ferana (Lepidoptera.' Tortricidae) par For· 133: 1-102.

WINTER1983 49 Sanders, c.J. 1964. The biology of carpenter rufa) and some tree·canopy herbivores. J. introduction into Florida. Fla. Entomol. 63: ants in New Brunswick Can. Entomol. 96: Anim. Ecol. 50: 313- 326. 142-146. 894-909. Way, M.J. 1963. Mutualism between ants and Silver, G. T. 1960. Notes on a spruce bUd· honeydew producing Homoptera. Annu. wonn infestation in British Columbia. For. Rev. Entomol. 8: 307-344. Chron. 36: 362-374. Wellenstein, G. 1980. Auswirkung hiigel· Skinner, G.J. 1980. Thefeeding habits of the bauender Waldameisen der Formica rufa- wood ant Formica rufa (Hymenoptera.· For· Gruppe auf forstschiidliche Raupen und das micidae) in limestone woodland in north· Wachstum der Waldbiiume. Z. fur Ange. En· Note: Received for publication 1 April west England]. Anim. Ecol. 49: 417-433. tarnal. 89: 144-157. 1983; accepted 15 August 1983. Skinner, G.J., andJ. B. Whittaker. 1981.An Wilkinson, R. c., A. P. Bhatkar, W. H. Whit· experimental investigation of interrela· comb, and W.J. 100ft. 1980. Formica in· Address: Dept. of Entomology, Oregon tionships between the wood ant (Formica tegra (Hymenoptera.· Fomlicidae). 3. Trial State University, Corvallis, OR 97331.

Value of Pollination to u.s. Agriculture

M. D. Levin

Abstract Honey bee pollinating activities are worth 143 times more than the value of honey and beeswax they produce ($18.9 Downloaded from billion vs. $140 million). Fruits and nuts, seeds and fiber, commodities from seeds requiring bee pollination and a portion of com· modities indirectly dependent on bee pollination are listed with their values, obtained from the USDA(1981).

he role of bee pollinators in the included in the USDA'sAgriculture Sta- 1 would have been greater if the farm

production of many economi- tistics (1981). No attempt was made to value of squash, pumpkin, safilower, buck- http://besa.oxfordjournals.org/ T cally important crops in the separate the crops according to depen- wheat, persimmon, mustard, rutabaga, United States has been the primary justi- dency on insect pollination. In many cases turnips, and many other minor crops had fication for much of the support provided the precise dependency is unknown, so been included. Some crops included in by government agencies to the bee· no exact calculation can be made (Mc- other lists were not included in Table 1 keeping industry. The concept has been Gregor 1976). In addition, the value of because the evidence for pollinator con· accepted that an adequate population of crops and commodities derived from seed tribution was obtained on cultivars and honey bee pollinators can only be main- produced by pollination is credited to under conditions not available in the tained in the framework of a thriving bee- pollinators on the principle that, without United States. keeping industry which obtains most of seed, the crop could not be grown, or As can be seen, the total value of crops by guest on February 5, 2016 its income from the production and sale that, without alfalfa hay, beef or milk resulting from pollinator activity in 1980 of honey and beeswax. In this context, the could not be produced as efficiently as approaches $20 billion, which compares honey price support program, the bee in- they are now. with ca. $140 million worth of honey and demnification program, and the bee re- Although the total value of crops and beeswax produced. These figures indicate search program of the Agricultural Re- commodities affected by the pollinating that the activity of bee pollinators is search Service have been carried out by activities of has reached an impres- worth 143 times as much to the American the U.S. Department of Agriculture sive figure on a national basis, the bee- economy as is the value of honey and (USDA)with the support and encourage- keepers who supply most of this service beeswax, on which most beekeepers must ment of Congress. receive very little monetary compensa· make their living. From time to time, attempts are made tion for it. A study made by the U.S.In· Much could also be said of the undoc- to quantify the importance of bees in the ternational Trade Commission (1976) re- umented contributions made by the pol· pollination of agricultural crops. In 1957, vealed that, of the total beekeeping in- linating activities of native species of bees crops dependent upon or requiring bee comes earned by 118 commercial and honey bees, both feral and domesti- pollination for seed or fruit were valued beekeepers in various states during cated, to crop plants and to thousands of at $4.5 billion (Metcalf et al. 1962). By 1971-1975, the proportion derived from wild plants (as forage, seed and fruit 1971, this value had increased to $7.6bil- pollination fees averaged only 9.7%. In sources, shelter, erosion control, etc.) for lion (Ware 1973). With increasing prices Washington, Oregon, and California, many forms of wild life that are integral for most crops, and some new crops rep· where use of pollination service is parts of natural ecosystems. resenting an increasing proportion of the greatest, some large commercial beekeep- Honey bees, of course, are not the only total acreage, this value has since in· ers earned about one· third of their in- insect pollinators contributing to the pro- creased dramatically, and a current re- come from pollination. In a few other duction referred to. A multimillion·dollar evaluation appears appropriate. areas (New England, the Mid·Atlantic industry has been developed in the Pacific An update is presented in Table 1 of the States, Texas, and Florida), pollination Northwest, where two other species of dollar values of crops and commodities fees contributed less to the income of bees (Megacbile rotundata and Nomia that were included among some 129 beekeepers; elsewhere, income from pol- melanderi) are managed successfully for crops listed by McGregor (1980) as de- lination fees was insignificant for most the pollination of alfalfa.With the advent pendent upon or benefiting from insect beekeepers. of monoculture, large-scale farming, and pollination and that, moreover, were also The total value of crops listed in Table other modern agricultural practices, many

50 BULLETIN OF THE ESA