Fujii, Hisashi

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RIGHT:URL:CITATION:AUTHOR(S):ISSUE DATE:TITLE:Ethological Studies on the Flower-visitingBehavior of Luehdorfia Butterflies(Lepidoptera ; Papilionidae) (II) : Effects ofthe Size, Shape and Odor of FlowersFujii, HisashiFujii, Hisashi. Ethological Studies on the Flower-visiting Behavior of Luehdorfia Butterflies (Lepidoptera ; Papilionidae)(II) : Effects of the Size, Shape and Odor of Flowers. Memoirs of the Faculty of Science, Kyoto University. Series ofbiology. New series 1999, 16(2): 87-941999-12http://hdl.handle.net/2433/258929Mem, Fac. Sci. Kyoto Univ. (Sen Biol,), 16: g7-94. Dec., 1999Ethelogical Studies on the Flower-visiting Behavior of LuehdorLfia              Butterflies (Lepidoptera; Papilionidae)        II. Effects of the Size, Shape and Oder ef FlowersHlsAsHI FuJIIDepartment of Zoology, Faculty of Science, Kyoto University,          Sakyo, Kyoto, 606-8502 Japan           (Received November 5, 1999)Abstract Experiments were conducted to test whether Luehdolfia butterflies distinguish thesize, shape and odor of flowers. The results of the experiments suggested: l) larger fiowersattract more butterfiies, 2) total margin lengths might be rnore important than total area of thefiower, 3) the butterflies might recognize small flowers in mass, 4) the odor of fiowers attractsbutterfiies only when the fiower color is inappropriate, thus, 5) blue-violet refiection is ofprimary importance while the odor is of minor importance in the fiower-visiting behavior ofLuehdoi fia butterfiies.Key vvords Flower-visiting behavior, Luehdoijia, Papilionidae, Visual cue, Olfactory cueIntroductioR   Butterfiies exhibit color sense iit feeding and mating. Smail tiger swallowtails,Luehdorjfia puziloi and L. J'aponica, appear once a year iR early spring. They feed mainlyoR purplish fiowers blooming in sunny patches of deciduous broadleaf forests.    In {he previous study (Fujii 1999), I tested the following hypothesis: Luehdotfia but-terflies might distinguish fiower color and prefer one or several color(s) when feeding.The results ofcolor preference tests and spectroscopic analyses suggested:    (1) Butterfiies locate nectar sources in response to the colors of fiowers.    (2) Biue-violet is most attractive in both species, while yellow (or bee-purple) is lessattractive only in L. puziloi. Red is not attractive to both species.    (3) Reflection spectra of bluish papers are similar to those of bee-blue fiowers (orpurplish to humans) such as Erythronium J'aponicum: they have a peak refie6tion wave-iength around 450 nm.    (4) Luehdoifia butterflies visit purplish fiowers frequently in their natural habitat,because these flowers reflect blue-violet around 450 nm.    However, Luehdo(lria butterflies might also distinguish size, shape ancl/or odor offlowers when searching for nectar sources as is true in hoRey bees (e.g. Frisch 1914; Hertz1929, 1930, 193l; Manning 1956; Gould 1986). To test these hypotheses, Iconducted thefollowing experiments.88 HIsASHI FuJilMaterials and MethodsMaterials   Females ofLuehdoifiaJ'aponica were collec{ed in Tatekawa, Yamagata iR 1985. Eggswere obtained from these females. Eggs of L. puziloi inexpecta were collected in Aomorifrorn April to May l985 and 1987. Larvae of both species were reared in the laboratory.Pupae were stored in a refugerator till spriRg. Naive adults from these pupae were used inthe experimeBts.Experiments   The experimeRts were carried o"t iR an outdoor cage, in Hiraka, Aomori, from 3 to 6May 1986 (Series 1, 2 and 4) and from 30 April to 2 May 1988 (Series 3; for the structureof the cage see Fujii 1999). The weather was fair for the duration of the experiments. Iused 30-50 Raive adults iR each experiment. Behavior was recorded with 8 mm videocameras, a"d aAalyzed afterward.itome"]e-o[IIIi-v'apoefe'/t/"/211//•'i.,/}•ge;g,/k/\/aj/tt2iL•pueiiof'/lt,itefti-,g•/•ee,"Mt"l'ytw,tttti•st,//si,.,y,S"tkte"kg,ty, N. .  IO 5 2.5 L25 O. 625       Pavevs pvesentedFig. 1. Results ofexpertment Series 1.(cm)ot2    :i.;e- Nower-visiting Behaviour ofLuehdot17a IID i• /"panieaee L. pu"'leiei'"k''289i•' .,st                            e                o                     i$' n es . l'Illllillili.'                              Papers presented                      Fig. 2. Results ofexperiment Series 2.Series 1   To test the effect of size, 5 square papers (10 Å~ IO, 5 Å~ 5, 2.5 Å~ 2.5, 1.25 Å~ 1.25,O.625 Å~O.625 cm2) were arranged on the ground in order of descending size. Each paperwas half the length and a quater the area of the preceding paper (Fig. I). Vivid blue paperswere used because LuehdorLfia had been strongly attracted to this colored paper in theprevious study (Fujii 1999). The frequency of contacts was tabulated.Series 2   As the result of Series 1 was not in accord with my hypothesis (see Results), I ar-ranged this experiment to know which was of primary importance, blue area or marginallength of biue paper. I prepared 5 Å~ 5 cm2 papers each with a different size (O.5 Å~ O.5, 1Å~ 1, 2 Å~ 2, and 4 Å~ 4 cm2) white square in •the center (Fig. 2). The papers were attachedto the white square paper (15Å~ 15 cm2) and fixed to the ground. If blue area is importantfor Luehdoifia to locate nectar sources, the blue paper with smallest blank should attractthe most buttediies.90 HISASHI FUJIISeries 3   The results of Series 1 and 2 suggest that iarger fiower attracts more blltterflies (seeResults). However, LuehdorL17a butterflies also visit smaller flowers 1ike violets in naturalhabitats. As the size of Viola is 1 cm2 or less, vaola should be less attractive for Luehdocfiafrorn the results ofSeries l and 2. How can adults ofLuehdoifia find smalIer flowers inRatural habitats? Viola flowers usually bloom in groups iR a rather limited area. Butter-flies may perceive them as a mass. To test this hypo{hesis, 4 clusters ofblue square paperswere presented to LuehdorLfia. I numbered the clusters as follows: Cluster 1 composedfrom only oRe 5 Å~ 5 cm2 paper, Cluster 2 frorn four 2.5 Å~ 2.5 cm2 papers, Cluster 3 from16 1.25 Å~ 1.25 cm2 papers and Cluster 4 from 64 O.625 Å~ O.625 cm2 papers. Thus, thetotal blue areas of square pieces of the four clusters were equal (Fig. 3).Series 4   Butterflies may also perceive the odor of flowers. I prepared two sets of experimen-tal apparatus to test this hypothesis. Each set had two plastic cylinders: one containedflowers in water while another contained water only (control). The flowers of Speraeachamaedrifolia were used because of their strong odor. The tops of the cylinders werecovered with 5 Å~ 5 cm2 papers perforated with many small cuts. One set was coveredwith vivid blue papers, while another was covered with pale blue papers. Both sets appa-ratus were placed by the net window to control for wiRd direction (Fig. 4).!scl'."c•i-/esegev,.. ..'  ,,Cluster 1      Fig. 3.eext-'mameCluster 2 cluster 3 Cluster 4Results of experiment Series 3.Nower-visiting Behayiour ofLuehdoijia II 91     isfoi'?"         ajNteontained f}owevsÅ~ PerfopatedÅ~    Plasticin waterelored papercyllndercontaiBed water enlyFig. 4. Experimental apparatus used in Series 4.ResultsSeries 1   When blue squares of various sizes were presented, the butterflies of both speciesvisited the larger papers more frequently (Fig. 1). BecaBse the successively smaller paperwas one quarter the area of the previous paper, the number of contacts of the successivelysmaller paper should be one quarter of the previous paper if the butterfiies respondedmerely to the blue area. However, the results did not agree with this hypothesis. Instead,the number of coBtacts on the successively smaller paper was about one half. This sug-gests the butterflies may have responded to the lengths of the papers (e.g. marginal lengths)rather than the area.Series 2   When 5 Å~ 5 cm2 blue papers with the differnt-sized white squares were presented, thebuttetflies visited the. paper with larger white squares more frequently (Fig. 2). These datareject the hypothesis stating that butterfiies visit fiowers in response to the area of blue.The butterflies alighted on the paper and elongated their proboscises indicating they werebeing attracted to blue. They did not respond to the white square in the paper. The bluepapers presented in this experiment were equal in the Iength of outer margin, but varied inthe length of inRer margin. The numbers of contacts were proportional neither with thelengths of the outer margiR nor the inner margin. Instead, the number of contacts in-creased as the total length of both outer and iRner margins increased (Fig. 2).92 HIsAsHI FUJIISeries 3   Among the four masses of square blue papers, the butterflies visited the cluster con-sisting of four 2.5 Å~ 2.5 cm2 papers most frequently, while the 5 Å~ 5 cm2 paper attractedthe least number of butterflies (Fig. 3). As the masses of paper(s) had the same blue area,it appears that the butterflies did not respond only to the blue area. The total marginlength of CIuster N was twice of that of CIuster N+1: 20 cm for Cluster 1, 40 cm forCIuster 2, 80 cm for Cluster 3 and 160 cm for Cluster 4. The butterflies did not merelyrespond to the total margin Iengths of blue papers.Series 4   In the case of the set of cylinders covered with vivid blue papers, the butterfliescontacted equally the papers with odor and without odor (P>O.05, Chi-square test). Thebutterfiies in this case seem to have visited papers merely in response to the color ofpapers.   In contrast, the butterflies visited the paper with odor more frequently than that with-out odor when covered with pale blue papers (P<O.Ol). This would indicate that the odorattracted more butterfiies in this case (Fig. 5). xgT2Ee+edoe13+OdoryepafileaVivid blue Pa}e blue  Rsx2s  Rg'Y.2RI. pagilal                   ee                        +- +-                          Odop OderFig. 5. Results of experiment Series 4. Above: L. japonica, Below: L. puziloi, Left: covered with vivid bluepapers, and Right: covered with pale blue papers.Eower-visiting BehaviourofLttehdoijia II 93DiseussioR   Luehdoifia butterflies are able to locate nectar sources innately by approaching andthen alighting oR the blue-violet objects. They visit purpIish flowers most often in theirnatural habitat because those flowers have a peak refiection of blue-violet around 450 nmin wavelength (Fujii 1999). However, they do not visit purplish flowers equally: theyseem to have favorite flower species (e.g. Fukuda et at. 1982; Fajii 1999).   The results of this study have shown that Luehdoi fia butterflies distinguish severalpattems of blue--violet objects, and that they also sense the odor of fiowers.   In Series 1, the butterflies visited larger papers more frequently, but the numbers ofvisits were not in proportion to the blue area. Instead, it seems to have been proponionalto the total margin lengths of blue paper. Because the size of fiowers usually visited intheir natBral habitat is around 10-5e mm in length, the 10xlO cm2 paper seemed too largeand the O.625xO.625 cm2 paper seemed too srr}all for LuehdorLfia to visit. LuehdorLfiabutterflies might have a preference for size of flowers, but they still visit fiowers of ex-traordinary sizes. This preference seems adaptive in nature because they would be able tovisit larger andlor smaller flowers if they existed in their habitat.   It is interesting that a contradictory result was obtained in Series 2: the butteffliesvisited the papers with smaller blue area more frequently than those with larger blue ar-eas. However, this might be explained by the butterflies responding to the total lengths ofboth inner aRd outer margins of the blue paper. Because Luehdoifia butterflies usuallyalight on the edge of larger papers or larger fiowers like Erythronium, and then elongatetheir proboscises, the marginal areas seem more attractive than the total blue area. Tl}ismight also be as a result of the ability of compound eyes to distinguish edges as has beenshown with hoAey bees (Frisch 1914; Hertz 1929, 1930, 1931).   The result of Series 3 suggests that the butterflies do not respond to each paper oreach fiower, instead they respond to the papers or fiowers as a cluster. Though largerfiowers (e.g. Erythronium) attract more butterflies than smaller fiowers (e.g. Viola) dowhen blooming as single fiowers, a mass of smaller fiowers should attract more butter-flies than single large flowers.   The results of Series 4 could be explained as visual cue is of primary importancewhile olfactory cue is of minor importance. As shown in the previous study (Fujii 1999),vivid blue is the most attractive color for Luehdorfia while pale blue is less attractive.Therefore, it seems that the buttertlies visit blue-violet objects regardless of flower odor.However, they will visit pale blue objects frequently if they excrete the appropriate odor.LuehdorLfia butterflies might also use olfactory cues when visiting yellowish or whitishflowers in their habitat.94 HlsAsHl FUIIIAcknowledgements   The auther would 1ike to express his appreciation to Mr. Y. Kikuchi who kindly rearedmaterials and permitted rne to use his outdoor cage for experiments. This work wassupported in part by a Grant-in-aid (No. 58121003) for Special Project Research on Bio-logical Aspects of Optimal Strategy and Social Structure from the Japan Ministry of Edu-cation, Science and Culture.ReferencesFrisch, K. 1914 Der Fai:bensinn und Formensinn der Biene. 188pp., 5pls., Gustav Fischer,   JeRa.Fujii, H. 1999 Ethological studies on the fiovver-visiting behavior of Luehdo]fia butter-   flies (Lepidoptera; Papilionidae). I. Color preference of butterflies and reflection   spectra of flowers. Mem. Fac. Sci. Kyoto Uniu (Sen Biol.), 16: 67-86.Fukuda, H., E. Hama, T. Kuzuya, A. Takahashi, M. Takahashi, B. Tanaka, H. Tanaka, M.   Wakabayashi & Y. Watanabe 1982 The life histories of butterflies in Japan. Vol.I.   277pp., Hoikusha, Osaka (in Japanese with English summary).Gould, J. L. 1986 Pattern learRing by honey bees. Anim. Behav. 34: 990-997.Hertz, M. 1929 Pie Organisation des optischen Feldes bei Biene. I. Z. vergl. Physiol. 8:   693-748.Hertz, M. 1930 Die Organisation des optischen Feldes bei Biene. II. Z. vergl. Physiol. 11:    107-145.Hertz, M. 1931 Die Organisation des optischen Feldes bei Biene. III. Z. vergl. Physiol.    14: 629-674.Ilse, D. 1932 Zur "Forrnwahrnehmung" der Tagfalter. I. Spontane Bevorzugung von   Formmerkmalen. Z. vergl. Physiol. 17: 537-556.Manning, A. 1956 Tlie effect of honey-guides. Behaviour 9: 114-139.Swihart, C. A. 1971 Colour discrimination by the butterfly, Heliconius charitonius Linn.   Anim. Behav. 19: 156-164.

Ethological Studies on the Flower-visiting Behavior of Luehdorfia Butterflies (Lepidoptera ; Papilionidae) (II) : Effects of the Size, Shape and Odor of Flowers

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Ethological Studies on the Flower-visiting Behavior of Luehdorfia Butterflies (Lepidoptera ; Papilionidae) (II) : Effects of the Size, Shape and Odor of Flowers

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