JOtlrnal of the Lepidopterists' Society 54(4), 2000, 137- 144

ON THE USE OF ULTRAVIOLET PHOTOGRAPHY AND ULTRAVIOLET WING PATTERNS IN MORPHOLOGY AND

HELGE KNDTTEL 1

AND

KONRAD FIEDLER Lehrstuhl Tierokologie I, Universitat Bayreuth, D-95440 Bayreuth, Germany email: [email protected]

ABSTRACT. In a series of feeding experiments we found that, depending on the larval food plant species or part of food plant ingested, individuals of the blue butterfly Polyommatus icarus () exhibit broad variation of wing patterns in the ultraviolet (UV) range of wave­ lengths which is invisible to humans. Such intraspecific variability in UV wing patterns has been underestimated thus far due to the rather de­ manding approach needed to study these patterns. We discuss methodological problems with the assessment of butterfly UV wing patterns by UV photography. Given proper standardization, UV photography is a suitable method to qualitatively assess UV wing patterns for possible use in morphology or systematics. Spectrophotometly should preferably be used as quantitative method when consideling UV wing patterns in a communication context. No higher value should be attached to UV wing patterns as compared to human visible wing patterns. Additional key words: Polyomnwtus, ultraviolet light, visual communication, color, phenotypiC plasticity.

Ultraviolet (UV) wing patterns have been widely human-visible wing patterns and morphology of geni­ used in butterfly systematics. Differences in UV re­ talia is possible (Gibbs 1980), yet the discovery of flectance patterns of butterfly wings proved helpful in marked differences in UV reflectance patterns was the revision of otherwise morphologically very similar taken even as evidence to suggest the existence of UV taxa, such as the genera Colias (Ferris 1973, Silber­ wing pattern-based isolating mechanisms (Meyer­ glied & Taylor 1973, 1978, Kudrna 1992) and Rochow 1991; for another case study in the genus Ly­ Gonepteryx (Nekrutenko 1964, Kudrna 1975, Brunton caena see Schaider (1988) versus van Oorschot & de et al. 1996). Differing UV wing patterns were sus­ Prins (1989)). Human lack of UV perception, and the pected to act as "isolating mechanisms" between processing of visual stimuli in other by nervous closely related species, e.g., by Meyer-Rochow (1991) systems which are completely different from our own, in , or shown to be involved in mate choice of make it very hard for the researcher to imagine what several species (e.g., Silberglied & Taylor 1973, 1978, the world may look like for other animals. But it seems Rutowski 1977, 1981). as if the lack of UV vision in humans and many other , in general, perceive UV light and UV vi­ mammals is the exception rather than the rule in the sion is an integral part of their visual capabilities kingdom (cf. Tovee 1995). (Eguchi et al. 1982, Silberglied 1984, Lunau & Maier In this paper we compare UV photography and 1995, Tovee 1995, Kelber & Pfaff 1999). The same is spectrophotometry as methods for assessing butterfly true for many visually guided butterfly predators such UV wing patterns. In particular, we discuss some as birds, lizards, and robberflies (Menzel & Backhaus methodological problems with the assessment of but­ ]99], Jacobs 1992, Fleishman et al. 1993, Tovee 1995). terfly UV wing patterns by UV photography. Finally, Therefore, UV coloration of butterfly wings has to be we point out an underestimate of individual variability considered as an essential part of overall wing patterns in UV wing patterns which may result from such in the spectral range of 300 nm to 700 nm, i.e., the en­ methodological problems as well as from the neglect of tire range of visual communication (Endler ]990, environmentally driven phenotypiC plasticity. Cuthill & Bennett 1993, Bennett et al. 1994b). Human observers cannot perceive UV light directly. This may MATERIALS AND METHODS be the reason why many researchers implicitly or ex­ Feeding experiments. Mated females of Polyom­ plicitly attached an extraordinary meaning to the col­ matus icarus (Rottemburg, 1775) (Lycaenidae) were oration of butterfly wings in the UV range of wave­ caught in summer 1997 at two locations in Northern lengths as compared to the human visible range. In the Bavaria, Germany and allowed to lay eggs. Caterpillars New Zealand Lycaena salustius (Lycaenidae) species used in this study were from the F1 or F2 generations of complex, for example, distinction of species based on these fe males. All larvae were reared in the same climate

I Present address: Universitatsbibliothek Regensburg, D-93042 chamber (25°C, 18 h light, 6 h dark). We kept the larvae Regensburg, Germany. in transparent plastiC boxes (125 m!) lined with moist pa- 138 JOURNAL OF THE LEPIDOPTERISTS' SOClETY per tissue. Fresh food plant material was available ad the range of 300 nm to 700 nm with a resolution of ap­ libitum and was supplied at least every two days. Food prox. 0.5 nm. A Spectralon™ 99 reflectance standard plants were either grown outside in a garden (Med­ was assumed as having 100% reflectance. For further icago sativa L. leaves) or collected locally from natural details of methods see Kntittel and Fiedler (2001). populations (!lowers of Trifolium repens L., flowers and leaves of Lotus comiculatus 1.) (all Fabaceae). We RESULTS killed the emerging butterflies with either HCN or by UV patterns strongly varied in both sexes of the Eu­ deep freezing. We measured spectral reflectance of ropean common blue butterfly, Polyommatus icarus the wings of these specimens and took UV pho­ (Figs. 1,2). We found consistent differences of UV re­ tographs. flectance among individuals that were fed different Ultraviolet photography. UV photographs were plant species or plant parts during their larval stages. taken with a Pentax Asahi Ultra-Achromatic-Takumar Reflectance in the UV was much lower for animals 85 mmlf 4,5 UV transmitting lens and Novoflex Auto­ reared on flowers of Trifolium repens and flowers or Bellows on Agfapan APX 100 film. To exclude all but leaves of Lotus comiculatus, as compared to animals ultraviolet light a combination of 3 mm Schott UCI reared on leaves of Medicago sativa (Figs. 1,2). These and 2 mm Schott BC38 filters was placed in front of differences were most pronounced in the white spots the lens for UV photographs. Illumination was pro­ (as seen with human eyes) but were apparent in the vided by two Metz Mecablitz 45 cn flash lights in underside ground coloration, too (Fig. 1). Overall, manual mode so that the same amount of light was judging from the UV photographs (Fig. 1), one might available for every exposure. Emission spectra of these be tempted to assign highly UV-reflecting specimens flash lights reach far enough into the UV range for the reared on M. sativa foliage to a different 'species'. No purpose of this study (data not shown). Photographic differences in UV reflectance were found for the up­ processing and development of film material was stan­ persides, the orange spots, and the black spots (Kntit­ dardized as much as possible. Films were developed tel & Fiedler 1999). for 5 min in 10% Agfa Neutol and fixed for 4 min in Altering photographic processing had a strong effect Tetenal fixing agent at 21°C. on the appearance of the resulting prints, a phenome­ To examine the effect of using different grades of non well known to any photographer. The influence of paper on the appearance of prints to be used for com­ using photographic paper of differing grades is illus­ paring UV patterns, we produced prints on different trated in Fig. 3. Even if processed from the identical grades of Agfa Broviro Speed glossy paper. These negative using the same chemicals, the resulting prints prints were then developed for 3 min with 10% Agfa of UV photographs may be quite different. We there­ Neutol and fixed for 15 min with Tetenal fixing agent fore included a calibrated gray scale, made from thick at 21°C. chromatography paper and dyed with various dilutions For purposes of comparison we took color pho­ of black India ink, in every photograph. Spectral re­ tographs of all objects on Kodak Elite II 100 slide film. flectance of the steps of the gray scale is illustrated in We used the same equipment as above but without the Fig. 4. Parts of a given photographic print that are of filters and with one flash light only. similar brightness, compared to the gray scale, will Spectrophotometry. We measured wing re­ have a similar reflectance value (Figs. 1 and 3). fl ectance with a L.O.T. Oriel spectrometer system (In­ The differences in wing patterns in the UV range, staSpec II diode array detector, MS 125 spectrograph among individuals reared on different plant species or with 400 Vmm grating, sighting optic) equipped with a plant parts, emerged from UV photographs and spec­ Zeiss Ultrafluar 10/0.20 UV transmitting objective at a trophotometric measurements alike. However, more right angle to the wing surface. Measuring spot diam­ subtle or gradual host plant-dependent color differ­ eter was 0.2 mm, numerical aperture of the measuring ences could better be visualized in the reflectance beam was 0.14. The measuring spot was illuminated at spectra (Fig. 2) . For example, only by studying the an angle of 45° to the wing surface via liquid light spectra is one able to identify the wavelength ranges guide by an Osram XBO 75 W/2 OFR lamp powered where individuals reared on M. sativa foliage converge by a L.OT. Oriel 68806 power supply. Numerical into the variation seen in individuals fed other food aperture of the illumination was 0.08. Wings were ori­ plants. Moreover, the small but consistent differences ented so that they were all illuminated from the same between food treatments in the human-visible range apical direction. With this setup we were able to were also only noticeable using spectrophotometric record spectral reflectance of individual wing spots in measurement data. VOLUME 54, l\'UMBER 4 139

FIC. 1. UV photographs of the undersides of Polyommatus icarus reared on different food plants. Differences in UV patterns seen in these individuals are representative for larger series. Individuals were reared on leaves of Lotus eomiculatus (upper left). leaves of Medicago sativa (upper right). flowers of Lotus corn-ieulatus (lower left), and flowers of Trifolium repens (lower right). Upper photograph: males, lower photo­ gra ph· females. 140 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY

DISCUSSION 100 --- Medicago leaves 1. Underestimate of individual variability in - . - . - Lotus leaves UV coloration ---Lotus flowers 80 -.. - Trifolium flowers Butterfly systematists are well aware of the large ex­ tent of intraspecific variation in wing patterns and col­ -.-.-.-.-.-.-.-.-~ oration within the human visible spectral range. In 60 ~. - - .. - - . . contrast, intraspecific variability in UV reflection pat­ terns has been underestimated so far. We feel that this mainly arises from the difficulty in studying UV wing 40 patterns, making the comparison of large series of c: specimens more laborious and demanding compared o U 20 to patterns seen in the human visible range. Since in Q) most studies UV photography applied to small samples ~ was used to assess UV wing reflectance, subtle differ­ a: o~~--~~~~--~~--~~ ences in UV reflectance of individuals may have fre­ 300 350 400 450 500 550 600 650 700 qucntly been missed. Wavelength [nm] Though only studied for a small range of butterfly species thus far, intraspecific variation of UV patterns may be as pronounced as , or even larger than that in 100 other ranges of wavelengths visible to humans (Brun­ --- Medicago leaves ton & Majerus 1995, Knlittel & Fiedler 1999, 2001, - . - . - Lotus leaves ---Lotus flowers this work). Yet, minor differences in UV patterns have 80 - .. - Trifolium flowers been sometimes taken as evidence for erecting new -~- . -.-.- . - ...,.~ .... ~. species or subspecies (e.g., Nekrutenko 1968, Schaider ,. _.. - .. - .. - . 1988, but see van Ooorschot & de Prins 1989), or as a ------... 60 I ,. later confirmation of taxonomic hypotheses originally ,".- 1'.. .., /' .­ proposed on the grounds of other data (e.g., Meyer­ / , , Rochow 1991, Coutsis & Ghavalas 1996). Ii,' 40 I '. Differences in UV wing patterns may be due to ge­ ,. / .' i netic or environmental reasons, but only genetically c ,. /: o '" ./ determined UV wing patterns are of systematic impor­ :g 20 /: tance. We demonstrated that high intraspecific varia­ Q) tion in UV wing patterns in Polyornrnatus icarus can be 05 a: OL--L--~~--~~L--L--~~ caused by different larval food plants under otherwise identical rearing conditions among individuals from 300 350 400 450 500 550 600 650 700 the same parents. Wavelength [nm] Flavonoids are a class of secondary plant compounds that highly absorb UV light (Harborne 1991, 1999). F TG . 2. Spectral reBection of the white spots of the undersides of Some Polyornrnatus species sequester flavonoids from the hindwings of Polyornmatus icarus reared on different food plants. Each curve is the mean of the measurements of 5 to 10 spots their larval food plants, and these pigments are de­ of a hind wing of one of the individuals illustrated in Fig. 1. Individ­ posited in thc wings during metamorphosis (Wilson uals were reared on leaves of Lotus comicu/atl1s ( .). leaves of 1987, Wiesen et al. 1994, Geuder et al. 1997, Korn­ Medicago sativa ( __ ), Bowers of Lotus comicl1latus ( _ ), and Bowers of Trifolium repens ( _ _ . ). Upper part: males, Lower part: maier 1999). Using artificial diets which only differed females. Conventions as in Fig. 1, in their Havonoid content but were othelWise identical in their chemical composition, Knlittel & Fiedler (1999, 2001) showed that flavonoids sequestered by the larvae alter wing refl ectance mainly in the UV that flavonoids are involved in mediating variation in range. In the polyphagous P icarus the types and UV wing patterns of P ica'rus feeding on different food amounts of Havonoids that are taken up and stored by plants in nature. the larvae vary strongly depending on the larval food It is important to emphasize that intraspeCific vari­ plants (Wiesen ct al. 1994, Burghardt et al. 1997, 2001, ability in UV reHectance in P icarus appears to be Schittko et al. 1999). Therefore, it seems very likely caused by chemical variation in the host plants, while VOLUME 54, NUMBER 4 141 variation in UV reflectance may be caused by structural flectance can be measured by spectrophotometry colors in other species (e.g., Colias eurytheme (Brun­ (Ghiradella et al. 1972, Endler 1990, Brunton & Ma­ ton & Majerus 199.5)). UV pattern variation in P icarus jerus 199.5 ). therefore must be regarded as a host-plant derived, Both UV photography and spectrophotometry have environmentally shaped form of phenotypic plasticity, advantages and disadvantages in their practical use. although heritable components cannot be fully ex­ When selecting a method to study UV wing patterns cluded. As different food plant species or plant parts the first step must be to answer the questions "What is are of varying value as a food source to P icarus, it the purpose of the study? What is it that UV patterns seems likely that UV wing patterns may be used in in­ should actually tell me?" Not all studies have ade­ traspecific visual communication, indicating other food quately addressed these questions. However, different plant-derived properties of individuals, such as nitro­ conclusions may have to be drawn from the use of dif­ gen content (Burghardt et al. 2001 ). Males of P icarus ferent methods. Therefore it is important to be clear discriminate between flavonoid-rich and flavonoid­ about the purpose of the study before chOOSing the free female dummies, preferring UV-absorbing, method. flavonoid -rich dummies (Burghardt et al. 2000, Knut­ UV patterns may be considered as a morphological tel & Fiedler 2001 ). feature like any other character. UV patterns result The differences shown here in the UV photographs from wing areas that differ from each other in UV re­ (Fig. 1) and quantitatively demonstrated in the accom­ flectance due to their physical and chemical constitu­ panying reflectance spectra (Fig. 2) very much resem­ tion. There is no conceptual difference to the refl ec­ ble the differences in UV reflectance claimed by Cout­ tions or colors in the human-visible range. Therefore, sis & Ghavalas (1996) as characters separating UV wing patterns may be used as regular morphologi­ Polyommatus icarus and the recently described P an­ cal characters in systematics, if they are assessed ap­ clronicus Coutsis & Ghavalas, 199.5. As differences of propriately. For example, if individuals within a such magnitude can be found within one species and species exhibit substantial variation in UV wing pat­ even among offspring of the same parents, they are terns, such as we found in P icarus, then UV wing pat­ unlikely to be sufficient to differentiate between ters may not be appropriate systematic characters. UV species. No quantitative data on spectral wing re­ photography done in the right way (see below) seems fl ectance are available for P anclrunicus, and the range a perfectly acceptable means for the description of UV of individual variation has not been documented statis­ wing patterns in this context. tically. Therefore we cannot presently assess whether On the other hand, UV wing patterns may serve as Significant differences in UV patterns may exist be­ Signals in a behavioral context. They may be important tween P anclronicus and P icarus. However, based on in mimetic or aposematic coloration (e.g., Beccaloni the UV photographs in Coutsis & Ghavalas (1996) it 1997) or in sexual selection (e.g., Brunton & Majerus seems unlikely that UV reflectance in P anclronicus 199.5), to give examples. But it is not sufficient to sim­ falls outside the range observed in the highly variable ply assume that UV patterns do have a function, for ex­ species P icarus. ample in mate recognition. This has to be proven in separate studies reaching farther than assessing differ­ 2. Problems related to the technical visualization of ences in UV reflectance only. Wheh conSidering the vi­ UV patterns sual physiology of butterflies (e.g., Eguchi et al. 1982) As humans cannot see ultraviolet light, UV wing or other visually guided species interacting with but­ patterns must be translated into a form of information terflies (e.g., Bennett et al. 1994a) it seems likely that that is accessible to us. This must be accomplished by UV light is important in the species' interactions. But appropriate technical means. UV photography or UV this is so only because UV sensitivity is an integral part videoviewing was chosen in most studies of UV wing of these species' visual systems and is not a conse­ patterns known to us (e.g., Ferris 1973, Rutowski quence of some putative special quality of UV light or 1977, 1981, Bowden & Kay 1979, Meyer-Hochow vision in the UV range. The mere possibility that UV 1991, Kudrna 1992, Couts is & Ghavalas 1996). Both patterns serve a function in communication gives them methods yield comparable spatial pattern information no special or "higher" value in systematic reasoning but almost no spectral information. Ultraviolet light (see e.g., Meyer-Rochow 1991, Brunton et al. 1996). from a broad range of wavelengths is reduced to a The same is true when comparing UV patterns to hu­ Single brightness value for every point or pixel in the man-visible color patterns. picture. Usually the spectral response of the picture­ To emphaSize this point: There is no reason at all to generating system is unknown. Alternatively, wing re- assign a higher value to UV patterns than to human- 142 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY

100

80

t*,

c o :.::; 20~ ____------() CD ;:;=: CD a: o~~--~~--~~~~--~~ 300 350 400 450 500 550 600 650 700 Wavelength [nm]

FIC. 4. Spectral reflection of the steps of the gray scale shown in Figs. 1 and 3. The higher the reflectance values the brighter the ar­ eas appear in the photographs. The curve for the darkest step almost falls in line "ith the abscissa. Mean spectral reflection for any given range of wavelengths may easily be obtained from the very Rat, al­ most horizontal curves. The UV range is from 300 nm to 400 nm and the visible range is from 400 nm to 700 nm. Abscissa: Wavelength in nanometers. Ordinate: Reflection in %, i.e. , the amount of light re­ fl ected at a given wavelength as compared to a white standard as­ sumed to reflect 100%. FTC. 3. UV photograph of the underside of one female l'oly­ omrnatus icarus reared on leaves of Lotus comicl1latus. Both prints were produced from the same negative out on photographic paper phy. For these reasons, in the study of communication of differing grades and accordingly illuminated for different time pe­ riods. They illustrate the inRuence of a minor change in photo­ or sexual selection (Bennett et al. 1994b), the method of graphic processing. A calibrated gray scale (cf. Fig. 4) included in choice is reflectance spectrophotometry. The whole the photographs allows for a comparison up to a certain degree de­ range of :300 nm to 700 mn needs to be covered by the spite the different appearance of the prints. Width of a step of the gray scale is .5 mOl. Upper print. Illumination for .5 ..5 sec, aperture measurements, that is from the ultraviolet to the red. .5.6 on grade 1 paper. Lower print: Illumination for lOsee, aperture Comparison of obtained spectra can be done by appro­ ,5.6 on grade .5 paper. priate statistical procedures (Endler 1990, Cuthill et al. 1999, Kntittel & Fiedler 2001). So far, for only very few species is information available on the phYSiology of visible wing patterns. And there is no reason to pre­ photoreceptors and associated neurons. For these suppose a special function of UV wing patterns as a species a phYSiological model closer to the processes oc­ Signal in visual communication. curring in the organisms may allow to calculate a classi­ More elaborate techniques must be applied when fication of colors. More details on the assessment of col­ studying UV wing patterns as Signals used in visual com­ ors in animal communication systems may be found in munication. Only when there are very strong differ­ the excellent works of Endler (1990), Cuthill and Ben­ ences, without intermediates in UV reflectance, will UV nett (1993), and Bennett et al. (1994b). photography be useful in such a context. This might be UV photography provides an easy method to assess the case when comparing wing patterns with and with­ the spatial distribution of areas of differing UV re­ out strongly reRecting structural colors. However, even flectance. Yet, in the majority of studies qualitative then UV photography will provide rather coarse qualita­ rather than quantitative results were obtained. This tive results only and individual variability of UV re­ means that wing areas were mostly classified as UV­ flectance may be missed (cf. Endler 1990, Brunton & reflecting vs. not UV-reRecting. However, reRectance Majerus 1995, this study). Variation in spectral informa­ is a continuous measure that may not easily be as­ tion within the UV range that may be important in com­ sessed in discrete steps (ef. Fig. 2). munication will also not be apparent with UV photogra- Moreover, comparisons between different pho- VOLUME 54, NUMBER 4 14.3

tographs and/or studies may be difficult without BRUNTON, C. F. A. & M. E. N. MAJERUS. 1995. Ultraviolet colours proper standardization. Brightness and contrast in in butterflies: intra- or inter-specific communication? Proc. R. Soc. Lond. B 260: 199-204. photographic prints depend on a number of parame­ BRUNTON. C. F. A .. P J. C. RUSSELL & M. E. N MAJERUS. 1996. ters, not all of which might be under the control of the Variation in ultraviolet wing patterns of brimstone butterflies investigator. Important parameters that contribute to (Gonepteryx: Pieridae) from Madeira and the Canary Islands. Entomologist 115:30-39. variation are amount and spectral composition of illu­ BURGHARDT, F. 2000. Stoffwechsel und okologische Funktion von minating light, spectral transmission of photographic Flavonoiden im Blauling Polyomrnatus icarus (: lenses and of UV transmitting filters, the film type, and Lycacnidae). iv, 192 pp. Ph.D. Dissertation. Bayerische Julius­ Maximilians-Universitat Wiirzburg, Germany. all kinds of influences on photographic processing in­ BURGHARDT, F., K. FIEDLER & P. PROKSCH. 1997. Uptake of cluding printing during publication. Variation in the flavonoids from Vicia villosa (Fabaceae) by the lycaenid hutter­ fly, Polyommatus icams (Lepidoptera: Lycaenidae). Biochem. appearance of UV photographs may arise from a minor Syst. E(:01. 25:527-536. difference in photographic processing as illustrated in BURGHARDT, F., H. KNDTTEL, M. BECKER & K. FIEDLER. 2000. Fig . .3. Therefore, a detailed description of optical in­ Flavonoid wing pigments increase attractiveness of female com­ strumentation, processing and film material should be mon blue (Polyommatus icarus) butterflies to mate-searching males. Naturwissenschaf'ten 87:304-307. given and, as a minimum standard, a gray scale of BURGHARDT, F., P PROKSCH & K. FIEDLER. 2001. Flavonoid known UV reflectance should be part of every UV sequestration by the common blue butterfly Polyommatus icarus: quantitative intraspecific variation in relation to larval photograph. Such a gray scale will allow comparisons hostplant, sex and body size. Biochem. Syst. Eco1. between photographs up to a certain degree because it 29:875- 889. provides a set of reflectance standards revealing inten­ COUTSIS, J. G. & N. CHAVALAS. 1996. Ultra-violet reflection pattern in Polyomrnatus andronicus Couts is & Ghavalas, 1995 and Poly­ tional and unintentional differences in brightness or ommatus icarus (Rottemburg, 1775) (Lepidoptera: Ly­ contrast between photographs (Figs. 1 and .3). This caenidae). Phegea 24:167-169. method is beautifully described in the pioneering work CUTHILL, I. C. & A. T. D. BENNEIT. 1993. Mimicry and the eye of of Daumer (1958) on the UV patterns of flowers. the beholder. Proc. R. Soc. Lond. B 253:203-204. CUTHILL,!. c., A. T. D. BENNETT, J. C. PARTRIDGE & E. J. MAIER. UV spectrophotometry yields very accurate quanti­ 1999. Plumage reflectance and the objective assessment of tative data but requires expensive equipment not avail­ avian sexual dichromatism. Am. Nat. 153:183-200. able to most systematists and a fair amount of com­ DAUMER, K. 1958. Blurnenfarben, wie sie die Bien en sehen. Z. verg!. Physiol. 41:49-110. putational data processing. Spectrophotometry is ECUCHI, E., K. WATANABE, T. HARIYAMA & K. YAMAMOTO. 1982. A superior whenever spectral information will be re­ comparison of electrophysiologically determined spectral re­ quired to answer biological questions. However, in sponses in 35 species of Lepidoptera. J. Physio!' 28:675-682. contrast to UV photography, spectrophotometry will ENDLER, J A. 1990. On the measurement and classification of not proVide eaSily comprehensible spatial pattern in­ colour in studies of animal colour patterns. BioI. J. Linn. Soc. formation. Hence, for taxonomic purposes where the 41:315--352. FERRIS, C. D. 1973. A revision of the Golias alexandra complex recognition and documentation of qualitative similari­ aided by UV reflectance photography with designation of a new ties and discrepancies in wing patterns is usually the subspecies. J. Lepid. Soc. 27:57-73. most important goal, properly standardized UV pho­ FLEISHMAN, L. J., E. R. LOEW & M. LEAL. 1993. Ultraviolet vision in lizards. Nature 365:397. tography will continue to be the preferred method, GEUDER, M., V. WRAY, K. FIEDLER & P. PROKSCH. 1997. Seques­ though at the cost of loss of quantitative information. tration and metabolism of host-plant flavonoids by the Iycaenid butterfly Polyommatus bellargus. J. Chem. Eco!. 23:1361-1372. GHIRADELL~, H., D. ANESHANSLEY, T. EISNER, R. E. SILIlERGLIED & ACKNOWLEDGMENTS H. E. HINTON. ] 972. Ultraviolet reRection of a male butterflv: We are indebted to Prof. Dr. Klaus Lunau who generously per­ interference color caused by thin-layer elaboration of wil~g mitted us to use his UV lens. 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