Gary, Norman E.

Mau, Ronald F.L.

Mitchell, Wallace C.

Proceedings of the Hawaiian Entomological Society

ScholarSpace at University of Hawai'i at Manoa

Vol. XXI, No. 2, December, 1972 205A Preliminary Study of Honey Bee Foraging Rangein Macadamia (Macadamia integrifolia,Maiden and Betche)1Norman E. Gary2, Ronald F. L. Mau3 andWallace C. Mitchell3The pollination requirements of macadamia {Macadamia integrifolia,Maiden and Betche) were reviewed by Urata (1954), who observed thathoney bees, Apis mellifera L. and several species of syrphid flies are the mostfrequent insect pollinators. The comparative value of these pollinatorshas not been determined. Honey bees appear to be the most abundantand active insects foraging on macadamia. It is difficult to determine theeconomic value of honey bees as pollinators of macadamia, although thereis evidence that some varieties apparently do benefit significantly fromhoney bee pollination, as reported by Shigeura (1967) and Shigeura, Lee,and Silva (1970).More efficient utilization of honey bees as pollinators requires moreinformation on the flight range, distribution within orchards, and foragingactivities. This information is needed to determine the optimum distribution of hives and the numbers of hives necessary to insure adequate pollination in all areas of orchards. Also, the population of feral honey beesshould be determined since abundant feral honey bee colonies are withinflight range of most macadamia orchards in Hawaii.The objectives of this research were to conduct a preliminary studyon the flight range of honey bees in a macadamia orchard and to estimateferal bee populations. Concurrently, the project provided an opportunityto conduct a preliminary experiment on a new magnetic capture/recapturemethod for determining the distribution and flight range of honey bees(Gary, 1971).Methods and MaterialsThe experiment was conducted in the 1,250 acre Keaau orchard ofthe Royal Hawaiian Macadamia Nut Company near Hilo, Hawaii. Fifty-one colonies of bees were placed on location at the edge of the orchard on21 February 1970 (Fig. 1). Consequently, the bees had adequate time toadjust to the foraging area prior to the experimental period (1-7 March).Tublished with the approval of the Director of the Hawaii Agricultural ExperimentStation as Journal Series No. 1461.2Dept. of Entomology, University of California, Davis, California 95616.3Dept. of Entomology, University of Hawaii, Honolulu, Hawaii 96822.206 Proceedings, Hawaiian Entomological SocietyFlight range data were obtained by the method of Gary (1971). Beeswere captured while foraging on the trees. Each bee was labeled with atiny, numbered, ferrous metal tag attached to the abdomen, and releasedapproximately 30 meters from the apiary. Preliminary experiments demonstrated that bees released near the apiary returned successfully to theirhives. When the tagged bees returned to their respective hives they passedthrough magnetic traps attached to the hive entrances. Magnets inthese traps pulled the metal labels from the bees and retained them asevidence of recapture. Control bees were treated identically, except theywere captured initially at the hive entrances of specific colonies, as theywere returning from foraging.Magnetic traps were installed on the hives on 28 February. On 1March, a preliminary flight range determination was made by taggingbees from five equidistant sampling areas along a line starting at sampleplot 1 (Fig. 2) and ending in Section G' approximately 1,280 m fromthe apiary (366 m beyond sample plot 6). Very few bees were recapturedfrom Section G\ Consequently, sample plots 1-6 (Fig. 2) were establishedat 150 m intervals along a line within the 915m range in Section G. Eachplot consisted of 15 trees, spaced at 7.6 m intervals, in a 3 X 5 tree block.The orchard contained interplanted varieties, and the varieties in sampleplots were as follows: 246 (53%), 386 (29%), 660 (7%), 425 (5%), 508(4%), and 333 (2%). Foraging bees were collected at each sample plotwithin 3 m from the ground by a long hose connected to a portable vacuumcleaner, powered by a 12 volt battery in a pull cart. Gentle suction wasused, just sufficient to pull bees from the flowers, and hold them againsta cloth filter positioned 1.3 cm inside the tip of the collection hose. Captured bees were immediately transferred to small holding cages and providedwith sugar candy as food. Samples were taken by one operator on 2 Marchand two operators on 5 and 6 March. Each operator began sampling atopposite ends of the line of sample plots, and proceeded in opposite directions. Samples of 10 bees were collected at each plot. Control bee sampleswere taken at the hives before and after field sampling. The bees weretaken indoors for tagging. They were anesthetized for 30-60 seconds withCO2, immediately chilled for 10 minutes at 2°C and tagged dorsally onthe abdomen. A paint dot was applied to the scutum of the thorax as asecondary identification mark to identify any bees that might be captureda second time, following initial release in the field. All tagged bees werereturned to holding cages. The 2 March sample was held overnight andreleased the next morning. Samples collected 5 and 6 March were releasedat approximately 5 pm on the day of capture. During confinement, somebees were lost from samples because of (a) mortality, (b) inability to flyat release time, or (c) loss of tag while confined. Successfully released beeswere those that retained tags during confinement and flew immediatelyafter being released.Vol. XXI, No. 2, December, 1972 207table 1. Recapture of taggedforaging bees in Keaaumacadamia orchard. 1970.aSamplePlot123456Total% RecoveryControls2 March0/83/97/93/105/91/519/5038.014/21Capture Date5 March5/1613/177/1510/2011/176/1852/10350.527/306 March8/1913/1913/199/1910/177/2060/11353.127/29Total13/4329/4527/4322/4926/4314/43131/26673/80% Recovery30.264.462.844.960.533.691.3aNumber recaptured/number released.The following meterological conditions prevailed during the study:temperature 17-28°C, humidity 61-95%, wind 3-12 km/hour, and partiallycloudy skies, with a trace of rainfall each day.Results and DiscussionThe data on recaptured bees are summarized in Table 1.Foraging bees from the apiary were distributed approximately uniformly within the sampled area except at plots 1 and 6. The sharp reductionof bees from the apiary at sample plot 6 suggests that this plot was nearthe outer edge of the area that was foraged most actively by bees from theapiary. Contrary to expectations, the highest proportion of bees originating from the apiary did not occur in plot 1 nearest the apiary. This couldindicate that there was greater competition from feral bees in the peripheralareas of the orchard, thereby making it more "profitable" for bees fromthe apiary to penetrate more deeply into the orchard. Another possibilityis that bees may fly a short distance from the apiary before foragingextensively.The ratio of bees originating from the apiary to feral bees originatingfrom nearby forest area was estimated by the percentage of recaptured beesin the samples, after making appropriate corrections based on the percentrecapture of control samples, shown in the following formula:a—— x 100 = % of bees originating from apiaryD/C /\ Q.a = number of recaptured foraging beesb = number of recaptured control beesc = number of released control beesd = number of released foraging beesFor example, 57.0% of the bees sampled on March 2 originated fromthe apiary (- 1914/21 X50 X 100). The remaining 43.0% of field bees208 Proceedings, Hawaiian Entomological SocietyFORES TApiaryF0RESTI kmfig. 1. Large scale map of 1,250 acre Keaau macadamic nut orchard nearHilo, Hawaii, showing apiary location and Section G where bee samples werecollected.must have been feral bees. Consequently, the calculated ratio of beesfrom the apiary to feral bees was 57: 43, 56: 44, and 57: 43 for 2, 5, and 6March, respectively. The feral bee population in the sampled area isestimated by calculation to be approximately 43%.A second method of estimating the apiary bee: feral bee ratio yieldsa similar result. According to Gary (1971), approximately 90% of releasedtagged bees normally are recaptured when all hives in the area have traps.Vol. XXI, No. 2, December, 1972 209NI200 mfig. 2. Small scale map of Section G showing sample plot locations.G is surrounded by high, dense windbreak composed of Norfolk pines.SectionApproximately 10% are lost owing to mortality in the field, tags that falloff, or other unknown causes. Consequently the difference between theactual recapture percent and the 90% expected recapture represents foraging bees that originated from colonies without traps. Since all hives inthe apiary had traps, the tagged bees that were not accounted for at theapiary must have originated from feral colonies in the nearby forest area.In this study, tags from 131 of 263 (49.8%) tagged and successfully released210 Proceedings, Hawaiian Entomological Society.SQ.£oGO100,8060.40200 250 500 750 1000Distance from Apiary (m)fig. 3. Proportion of bees originating from the apiary in foraging bee samplescaptured at various distances from the apiary.field bees were recaptured at the apiary. If this is corrected on the basisof the 90% expected return, the calculated percent of bees that originated49 ft0/from the apiary is 55.3% ( q^°qq = 53.3%), and the feral bee populationestimate becomes 44.7%.The percentage of foraging feral bees probably increased greatly asthe distance from the apiary increased beyond the "intensive foragingzone", located within approximately 915 m from the apiary, where apiarybees appeared dominant (Fig. 3). The edge of this zone appears to be inthe vicinity of plot 6, as indicated by the rapidly decreasing proportionof apiary bees in samples taken there. Since this zone occupies only asmall portion of the overall orchard (Fig. 1), we estimate that more thanhalf of all foraging bees in the orchard must have oriented from feralcolonies. It follows that the number of feral colonies in the thousandsof acres of forest surrounding the orchard greatly exceeds the number ofcolonies in the apiary.Only two paint-marked bees were recaptured in the field; this indicatedthat the possibility of tagging the same bees repeatedly is not a problem.Vol. XXI, No. 2, December, 1972 211Several problems were encountered in this preliminary study. Therelatively sparse flowers and low bee populations made it very difficultto obtain adequate samples of bees. Another problem concerned thepossibility that a small percentage of the tagged feral bees may have becomedisoriented by being released near the apiary, and may have been attractedto the apiary hives. A brief experiment was conducted to evaluate thispossibility. Fifty bees were captured on 7 March from several hives locatedin Hilo, located approximately 11 km from the orchard. These bees weretagged, along with 50 similarly captured bees from hives in the apiary atthe macadamia orchard. All bees were captured as they were returningto their respective hives. When released, 5 of 46 successfully released Hilobees were recaptured, compared to 34 of 46 apiary bees. These datasuggest that the frequency of entry of feral bees into the hives of the apiaryprobably was insignificant. All of the bees from Hilo should have beedisoriented because they were released in an unfamiliar area. However,most of the feral bees released at the apiary should have been familiar withthe surroundings and should have returned to their respective feral colonies.These preliminary data on foraging range of bees in macadamia suggestthat the orchard area would be within range of foraging bees wheneverapiaries are located so that orchard areas are within approximately a 1 kmradius from one or more apiaries. Also, in order to take maximum advantage of the feral and apiary bee populations, most of the hives shouldbe located at points most distant from the anticipated feral bee sources.If the orchard is surrounded by forest, apiaries could be placed near thecentral orchard area. The basic strategy is to minimize competition forforaging area between apiary and feral bees.The relatively high proportion of feral bees found in this preliminarysurvey suggests that macadamia pollination in Hawaii presently is accomplished primarily by feral bees. It seems inevitable that these populationswill decline in the future as nest sites are destroyed when forest land iscleared and developed, or pesticide usage reduces these populations.Commercial bee colonies can be manipulated more efficiently for pollination purposes, but the management of these colonies is contingent uponmore extensive studies that integrate data on the effects of many variables,e.g., apiary placement, numbers of hives per acre, flight range, and population density of foraging bees in the orchard.AcknowledgementsThe authors thank the Royal Hawaiian Macadamia Nut Companyfor the use of its orchards and facilities. The consulting services of Mr.Hiroshi Ooka were invaluable. Honey bee colonies were provided byMr. Roy Oness of Hilo, Hawaii. The research was supported in part by212 Proceedings, Hawaiian Entomological Societythe Hawaiian Agricultural Experiment Station, and the California Agricultural Experiment Station.REFERENCES CITEDGary, Norman E. 1971. Magnetic retrieval of ferrous labels in a capture-recapturesystem for honey bees and other insects. J. Econ. Entomol. 64(4): 961-965.Shigeura, G. T. 1967. Varietal nut set and suggestion of pollination requirement inmacadamia. Hawaii Macadamia Producers Assoc. Yr. Bk.Shigeura, Gordon, James Lee and James A. Silva. 1970. The role of honey bees inmacadamia nut (Macadamia integrifolia Maiden and Betche) production in Hawaii.J. Amer. Soc. Hort. Sci. 95(5): 544-546.Urata, Ukio. 1954. Pollination requirements of Macadamia. Hawaii Agr. Exp. Sta.Tech. Bull. 22.

A Preliminary Study of Honey Bee Foraging Range in Macadamia (Macadamia integrifolia, Maiden and Betche)

http://scholarspace.manoa.hawaii.edu/bitstream/10125/11004/1/21_205-212.pdf

A Preliminary Study of Honey Bee Foraging Range in Macadamia (Macadamia integrifolia, Maiden and Betche)

Abstract

Similar works

Full text

Available Versions

ScholarSpace at University of Hawai'i at Manoa