Priority of color over scent during flower visitation by adult <Emphasis Type="Italic">Vanessa indica</Emphasis> butterflies

Most flower visitors innately prefer a particular color and scent, and use them as cues for flower recognition and selection. However, in most cases, since color and scent serve as a combined signal, not only does the preference for an individual cue, but also the preference hierarchy among different cues, influence their flower visitation. In the present study, we attempted to reveal (1) the chromatic and (2) the olfactory cues that stimulate flower visiting, and (3) the preference hierarchy between these cues, using the naïve adult butterfly Vanessa indica. When we offered 12 different-colored (six chromatic and six achromatic) paper flower models, V. indica showed a color preference for yellow and blue. When we examined the proboscis extension reflex (PER) of V. indica towards 16 individual compounds identified in the floral scents from two nectar plants belonging to the family Compositae, Taraxacum officinale and Cirsium japonicum, six compounds were found to have relatively high PER-eliciting activities, including benzaldehyde, acetophenone, and (E+Z)-nerolidol. When we combined color and scent cues in two-choice bioassays, where butterflies were offered flower models that were purple (a relatively unattractive color), the models scented with these active compounds were significantly more attractive than the odorless controls. In addition, synthetic blends mimicking the floral scents of T. officinale and C. japonicum (at doses equivalent to that of ten flowers) enhanced the number of visits to the scented models. However, the effect of odorizing was not conspicuous in parallel bioassays when yellow flower models were used, and the butterflies also significantly preferred odorless yellow models to scented purple models. These results demonstrate that V. indica depends primarily on color and secondarily on scent during flower visitation.     

Associative Learning in Response to Color in the Parasitoid Wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

A parasitoid that can learn cues associated with the host microenvironment should have an increased chance of future host location and thereby increase its reproductive success. This study examines associative learning in response to simultaneous exposure to the colors yellow and blue in mated females of the parasitoid wasp Nasonia vitripennis. Preference was measured as the proportion of time spent on a color. When trained with one color rewarded with hosts and honey and the other unrewarded, females showed an increase in preference for the rewarded color with increasing number of training days (1, 3, and 7 days). Hosts and honey together produced a slightly greater preference toward the rewarded color than just hosts, which produced a greater preference than just honey. When trained with a variable reward on one color and a constant reward on the other, females preferred the color associated with the variable reward when it was yellow, but not when it was blue. Thus, relative to no reward, the presence of a variable reward decreased the strength of preference toward the constantly rewarded color. Finally, females trained with regular hosts on one color and used hosts on the other preferred the color associated with the regular hosts when that color was blue but showed no preference in the reverse situation. The presence of used hosts instead of no reward did not increase the strength of preference for the color associated with the regular hosts.     

Sunset,skylight polarization and the migratory orientation of yellow-rumped warblers,Dendroica coronata

Celestial light cues visible at sunset appear to play an important role in the nocturnal orientation of several species of night-migrating birds. The pattern of skylight polarization, an especially prominent geographical reference at sunrise and sunset, influences the orientation behaviour of migratory birds. Yellow-rumped warblers were capable of seasonally appropriate cage orientation at dusk and were sensitive to manipulation of the axis of skylight polarization (E-vector). A series of experimental treatments was designed to examine the relationship between sunset position and skylight polarization. The window panels of hexagonal enclosures were fitted with a depolarizer and a polaroid filter to rotate the E-vector, and mirrors to reflect the position of sunset. The results indicate that this migrant minimizes sunset position as an orientation relative to skylight polarization and may depend upon the latter to orient at dusk. The possibility that yellow-rumped warblers calibrate their sun compass in relation to polarized light remains a question for future research.     

Starvation and herbivore-induced plant volatiles affect the color preferences of parasitic wasps

Using light-emitting diode spotlights, we examined the responses of Cotesia vestalis, a parasitoid of diamondback moth (DBM), Plutella xylostella larvae, with different hunger level to different chromatic cues. Naïve satiated female wasps showed no significant preference for either green, yellow, orange, or red spotlighted areas over a control area with background fluorescent light. When starved for 2 h, female wasps preferred yellow and green light over the control area, but not orange or red light. We also tested the effects of DBM-larvae-induced cabbage-plant volatiles, which attract female wasps, on wasp responses to green versus yellow light. In control experiments with no plant volatiles, starved wasps showed no color preference. However, when synthetic volatiles were present, the wasps preferred green over yellow light. We concluded that both hunger level and herbivore-induced plant volatiles were important factors affecting the response of parasitic wasps to light of different color.     

Key Amino Acid Residues Responsible for the Color of Green and Yellow Fluorescent Proteins from the Coral Polyp Zoanthus sp.

Site-directed mutagenesis was used to study the structural basis of color diversity of fluorescent proteins by the example of two closely related proteins from one organism (coral polyp Zoanthus sp.), one of which produces green and the other, yellow fluorescence. As a result, the following conversions of emission colors were performed: from yellow to green, from yellow to a dual color (yellow and green), and from green to yellow. The saltatory character of the spectral transitions and the manifestation of the dual-color fluorescence suggest that chemically different fluorophores are responsible for the green and yellow fluorescence. The simultaneous presence of three residues, Gly63, Lys65, and Asp68, is necessary for the efficient formation of the yellow rather than green fluorophore.     

卷蛾分索赤眼蜂雌蜂的颜色偏好性

为了确定卷蛾分索赤眼蜂Trichogrammatoidea bactrae Nagaraja 雌蜂的颜色偏好性, 在室内通过在培养皿底部黏贴彩纸的方法测定卷蛾分索赤眼蜂雌蜂对红、 黄、 黑、 紫、 绿、 白、 蓝7种颜色的行为趋性反应。结果表明, 卷蛾分索赤眼蜂雌蜂在红、 黄、 紫、 绿和蓝5种颜色上的滞留时间都极显著地高于对照（P<0.01）, 在黑和白2种颜色上的滞留时间与对照没有显著差异（P>0.05）; 对黄色的首次选择率极显著高于对照(P< 0.01), 对红、 紫、 绿和蓝色的首次选择率均显著高于对照(P＜0.05), 对黑色和白色的首次选择率与对照没有显著差异。当雌蜂分别在黄与红、 紫、 绿和蓝两两颜色之间选择时, 雌蜂在黄色彩纸上的滞留时间显著长于其他4种颜色。当雌蜂对红、 紫、 绿、 蓝和黄色5种颜色一起选择时, 在首次选择率、 滞留次数上5种颜色间都没有明显差异(P＞0.05); 但在红色和蓝色上的滞留时间显著长于紫色(P＜0.05), 在这3种颜色上的滞留时间与在黄色和绿色上的滞留时间均无显著差异(P＞0.05)。卷蛾分索赤眼蜂雌蜂在7种颜色卵卡上分别与透明纸（对照）上的米蛾卵的选择寄生时, 在黄色卵卡上的寄生卵量极显著多于对照(P＜0.01), 黑色卵卡上的寄生卵量极显著少于对照(P＜0.01), 其他5种颜色的卵卡上的寄生卵量与对照没有显著差异(P＞0.05)。结果说明, 卷蛾分索赤眼蜂雌蜂对黄色最为偏好, 其次偏好红、 紫、 绿和蓝色, 较不喜好白色和黑色。     

Factors affecting the distribution of a predatory mite on greenhouse sweet pepper

The predatory mite Neoseiulus cucumeris is used for biological control of phytophagous mites and thrips on greenhouse cucumber and sweet pepper. In a previous study, N. cucumeris provided effective control of broad mite but was only rarely found on the sampled leaves, raising questions about the factors affecting N. cucumeris distribution. To determine the distribution of N. cucumeris, leaves of pepper plants were sampled three times per day: just after sunrise, at noon and just before sunset for two years and throughout a 24 h period in one year. The presence of other mites and insects was recorded. Biotic (pollen) and abiotic (temperature, humidity) factors were monitored from the three plant levels. The effect of direct and indirect sunlight on the mites was assessed. N. cucumeris was found primarily in flowers; however, the mite’s distribution was affected by other predators (intraguild predation); in the presence of the predatory bug Orius laevigatus virtually no mites occurred in the flowers. Whereas temperature and humidity varied from the top to the lower level of the plants, apparently neither these factors nor the presence of pollen outside the flowers influenced mite distribution. N. cucumeris was found to be negatively phototropic; therefore N. cucumeris were pre-conditioned to light by rearing under light conditions for 4 months before being released. The light-reared mites were initially more numerous during the noon sampling period, however, rearing conditions caused only a temporary and non-significant change in distribution.     

Associative Learning of Color by Males of the Parasitoid Wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

Males of the parasitoid wasp Nasonia vitripennis showed no innate preference for blue versus yellow or for green versus brown. They learned to associate color with mates, but their ability to do so depended on the color used and the strength of the reward. Specifically, males learned to associate brown or green with a reward of many virgin females. With fewer females, fewer training periods, or mated females as the reward, males still learned a preference for green but not for brown. Males did not learn to associate color with rewards of honey or water. Previous studies of color preference and associative learning in parasitoid wasps have focused almost entirely on females. This is the first demonstration of associative learning in response to visual cues by male parasitoid wasps.     

Hummingbird color preference within a natural hybrid population of Mimulus aurantiacus (Phrymaceae)

Hummingbird flowers are typically red in color but the reasons for this are not well understood. Relatively few studies have examined hummingbird flower color preferences under natural conditions in which flower color varies within a species. We recorded hummingbird visitation rates to flowers that vary in color from yellow to red in a natural hybrid population between red‐ and yellow‐flowered Mimulus aurantiacus subspecies. We also examined whether there were any correlations between color and flower size or nectar content. Finally, we reviewed the literature on hummingbird color choice tests using feeders and flowers. There were no correlations in this population between flower color and flower size, nectar volume, or sugar concentration. Nevertheless, hummingbirds undervisited the two most yellow color classes, overvisited orange flowers, and visited the two most red color classes in proportion to their frequency in the population. While Hummingbirds preferred flowers expressing red pigments to those that did not, the flowers with the most red hue were not the most attractive, as has been observed in similar studies with other species of Mimulus. While feeder studies generally fail to show hummingbird preference for red, all studies using flowers, including those that control all floral traits other than color, find consistent preference for red. Experiments are suggested that might help disentangle hypotheses for why hummingbirds exhibit this preference.     

Learning by the parasitoid wasp, Aphidius ervi (Hymenoptera: Braconidae), alters individual fixed preferences for pea aphid color morphs

Learning, defined as changes in behavior that occur due to past experience, has been well documented for nearly 20 species of hymenopterous parasitoids. Few studies, however, have explored the influence of learning on population-level patterns of host use by parasitoids in field populations. Our study explores learning in the parasitoid Aphidius ervi Haliday that attacks pea aphids, Acyrthosiphon pisum (Harris). We used a sequence of laboratory experiments to investigate whether there is a learned component in the selection of red or green aphid color morphs. We then used the results of these experiments to parameterize a model that examines whether learned behaviors can explain the changes in the rates of parasitism observed in field populations in South-central Wisconsin, USA. In the first of two experiments, we measured the sequence of host choice by A. ervi on pea aphid color morphs and analyzed this sequence for patterns in biased host selection. Parasitoids exhibited an inherent preference for green aphid morphs, but this preference was malleable; initial encounters with red aphids led to a greater chance of subsequent orientation towards red aphids than predicted by chance. In a second experiment, we found no evidence that parasitoids specialize on red or green morphs; for the same parasitoids tested in trials separated by 2 h, color preference in the first trial did not predict color preference in the second, as would be expected if they differed in fixed preferences or exhibited long-term (> 2 h) learning. Using data from the two experiments, we parameterized a population dynamics model and found that learning of the magnitude observed in our experiments leads to biased parasitism towards the most common color morph. This bias is sufficient to explain changes in the ratio of aphid color morphs observed in field sites over multiple years. Our study suggests that for even relatively simple organisms, learned behaviors may be important for explaining the population dynamics of their hosts.     

Cycling of clock genes entrained to the solar rhythm enables plants to tell time: data from arabidopsis

Background and Aims An endogenous rhythm synchronized to dawn cannot time photosynthesis-linked genes to peak consistently at noon since the interval between sunrise and noon changes seasonally. In this study, a solar clock model that circumvents this limitation is proposed using two daily timing references synchronized to noon and midnight. Other rhythmic genes that are not directly linked to photosynthesis, and which peak at other times, also find an adaptive advantage in entrainment to the solar rhythm.Methods Fourteen datasets extracted from three published papers were used in a meta-analysis to examine the cyclic behaviour of the Arabidopsis thaliana photosynthesis-related gene CAB2 and the clock oscillator genes TOC1 and LHY in T cycles and N–H cycles.Key Results Changes in the rhythms of CAB2, TOC1 and LHY in plants subjected to non-24-h light:dark cycles matched the hypothesized changes in their behaviour as predicted by the solar clock model, thus validating it. The analysis further showed that TOC1 expression peaked ∼5·5 h after mid-day, CAB2 peaked close to noon, while LHY peaked ∼7·5 h after midnight, regardless of the cycle period, the photoperiod or the light:dark period ratio. The solar clock model correctly predicted the zeitgeber timing of these genes under 11 different lighting regimes comprising combinations of seven light periods, nine dark periods, four cycle periods and four light:dark period ratios. In short cycles that terminated before LHY could be expressed, the solar clock correctly predicted zeitgeber timing of its expression in the following cycle.Conclusions Regulation of gene phases by the solar clock enables the plant to tell the time, by which means a large number of genes are regulated. This facilitates the initiation of gene expression even before the arrival of sunrise, sunset or noon, thus allowing the plant to ‘anticipate’ dawn, dusk or mid-day respectively, independently of the photoperiod.     

REPRODUCTIVE BIOLOGY OF PETAL COLOR VARIANTS IN WILD POPULATIONS OF RAPHANUS SATIVUS: I. POLLINATOR RESPONSE TO COLOR MORPHS

Pollinator response to petal color polymorphism in wild radish (Raphanus sativus) was investigated. Behavior of insect visitors was observed within experimental flower arrays, each containing two of the petal color forms seen intermixed in California populations: white, yellow, pink, and bronze. Honeybees, which accounted for almost 90% of all visits, typically preferred yellow or white flowers and discriminated against bronze. Their preference for white increased significantly as the Raphanus flowering season progressed. Syrphid flies were also frequent visitors and increased in abundance near the end of the season. Syrphids typically preferred pink to other colors. Individual honeybees tended to specialize on either yellow or pink flowers on a short-term basis. This foraging pattern provides the potential for positive assortative mating among plants with yellow or pink flowers. Intraspecific pollinator discrimination may influence genotypic frequencies as well as the relative maternal and paternal reproductive success of color morphs.     

Role of host fruit color in the behavior of the walnut fly Rhagoletis juglandis

Observations and sticky-trap tests were used to assess the effect of fruit color on the behavior of adult male and female Rhagoletis juglandis Cresson (Diptera: Tephritidae), a tephritid that infests husks of Arizona walnut in southeastern Arizona. In the first experiment, during which flies were observed foraging among walnut models suspended from small walnut trees, models were painted green to appear ripe and uninfested or yellow with brown patches to appear ripe and infested. Flies used for this first experiment were also of two types: prior to observations, one group of flies had access to real walnuts for 1.5 days (prior experience) while the other group of flies was held without real walnut fruits (no prior experience). Regardless of prior experience with real walnut fruits, female flies landed on green models more than yellow/brown models. Experienced males also were more likely to land on green models than on yellow/brown models. More interactions also occurred on green models, because there were more landings.In the field behavioral assay, flies from a natural population given a choice of green, yellow, and yellow/brown models landed most often on green models, and all interactions and oviposition attempts occurred on green models. Flies also distinguished models by color in field sticky trap assays.These results suggest that female response to ripeness cues is innate, while males develop a preference for green based on their encounter rate with females.     

Female preference for large males in sailfin mollies,<Emphasis Type="Italic"> Poecilia latipinna</Emphasis>: the importance of predation pressure and reproductive status

We examined the effect of predation risk on female association patterns in the live-bearing sailfin molly (Poecilia latipinna). We tested two classes of females, with and without the risk of predation by a green sunfish (Lepomis cyanellus): (1) postpartum females (maintained with males until visibly gravid, then isolated and tested within 24–48 h of dropping a brood); and (2) non-postpartum females (different females, isolated from males for >50 days). When there was no apparent risk of predation, postpartum females showed a significant preference for large over small males, whereas non-postpartum females showed no size preference at all. When there was an apparent risk of predation, postpartum females maintained their preference for larger males and non-postpartum females continued to show no preference for large or small males. These results suggest that reproductive status (receptivity) plays a greater role in mate preference than predation risk. For postpartum females, the cost of not choosing a preferred mate may outweigh the potential cost of predation. Non-postpartum females either do not benefit from mating or are being indecisive about mating and thus are less likely to be choosy whether or not a predator is present.Communicated by I. Schlupp     

Somatic hybridization between birdsfoot trefoil (Lotus corniculatus L.) and L. conimbricensis Willd

Summary Somatic hybrid plants were produced by fusion of birdsfoot trefoil (Lotus corniculatus) cv Leo and L. conimbricensis Willd. protoplasts. Birdsfoot trefoil etiolated hypocotyl protoplasts were inactivated with iodoacetate to inhibit cell division prior to fusion with L. conimbricensis suspension culture protoplasts. L. conimbricensis protoplasts divided to form callus which did not regenerate plants. Thus, plant regeneration from protoplast-derived callus was used to tentatively identify somatic hybrid cell lines. Plants regenerated from three cell lines exhibited additive combinations of parental isozymes of phosphoglucomutase, and L. conimbricensis-specific esterases indicating that they were somatic hybrids. The somatic chromosome number of one somatic hybrid was 36. The other somatic hybrid exhibited variable chromosome numbers ranging from 33 to 40. These observations approximate the expected combination of the birdsfoot trefoil (2n=4x=24) and L. conimbricensis (2n=2x=12) genomes. Somatic hybrid flowers were less yellow than birdsfoot trefoil flowers and had purple keel tips, a trait inherited from the white flowered L. conimbricensis. Somatic hybrids also had inflorescence structure that was intermediate to the parents. Fifteen somatic hybrid plants regenerated from the three callus lines were male sterile. Successul fertilization in backcrosses with birdsfoot trefoil pollen has not yet been obtained suggesting that the hybrids are also female sterile. This is the first example of somatic hybridization between these two sexually incompatible Lotus species.Formerly USDA-ARS, St. Paul, Minn, USA     

Effect of color properties on the selection of oviposition site by Ceratitis capitata

In laboratory experiments of the choice type, wild Mediterranean fruit flies, Ceratitis capitata (Wiedemann), originating from infested figs collected in the island of Chios, Greece, showed strong preference for oviposition in black, blue and red colored ceresin wax domes 18 mm in diameter. Green and orange domes were less preferred, while yellow and white domes received the least number of eggs when a preferred color was present. The observed preference for certain colors was found to depend on both the color hue and the intensity of the total reflected light (brightness), while the degree the colored domes contrasted with the background had little if any effect. The females visited the domes of the preferred colors most frequently, which indicates that some selection occurred before arrival on the domes.

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Zusammenfassung In Auswahlversuchen im Labor zeigten wilde Mittelmeerfruchtfliegen, Ceratitis capitata (Wiedemann), die aus infestierten Feigen der Insel Chios, Griechenland, stammten, eine starke Bevorzugung für schwarze, blaue und rote Ceresin Waxdome mit 18 mm Durchmesser. Grüne und orangefarbene Dome waren weniger bevorzugt, während gelbe und weisse Dome mit nur wenigen Eiern belegt wurden, wenn eine der bevorzugten Farben anwesend war. Die beobachtete Bevorzugung für gewisse Farben hängt vom Farbton und vom total reflektierten Licht (Helligkeit) ab, jedoch hatte die Stärke des Kontrastes der farbigen Dome vom Untergrund wenig oder keinen Einfluss. Die Weibchen besuchten öfter die Dome mit bevorzugten Farben, was darauf hindeutet, dass sie sie vor ihrer Ankunft auswählten.

     

Flower color affects tri-trophic-level biocontrol interactions

The adults of many parasitoid species require nectar for optimal fitness, but very little is known of flower recognition. Flight cage experiments showed that the adults of an egg parasitoid (Trichogramma carverae Oatman and Pinto) benefited from alyssum (Lobularia maritima L.) bearing white flowers to a greater extent than was the case for light pink, dark pink or purple flowered cultivars, despite all cultivars producing nectar. Survival and realised parasitism on all non-white flowers were no greater than when the parasitoids were caged on alyssum shoots from which flowers had been removed. The possibility that differences between alyssum cultivars were due to factors other than flower color, such as nectar quality, was excluded by dying white alyssum flowers by placing the roots of the plants in 5% food dye (blue or pink) solution. Survival of T. carverae was lower on dyed alyssum flowers than on undyed white flowers. Mixing the same dyes with honey in a third experiment conducted in the dark showed that the low level of feeding on dyed flowers was unlikely to be the result of olfactory or gustatory cues. Flower color appears, therefore, to be a critical factor in the choice of plants used to enhance biocontrol, and is likely also to be a factor in the role parasitoids play in structuring invertebrate communities.     

<Emphasis Type="Italic">Aphidius ervi</Emphasis> Preferentially Attacks the Green Morph of the Pea Aphid, <Emphasis Type="Italic">Acyrthosiphon pisum</Emphasis>

The pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae) is found in red and green color morphs. Previous work has suggested that the aphidiine parasitoid Aphidius ervi Haliday preferentially attacks green pea aphids in the field. It is not clear whether these results reflect a real preference, or some unknown clonal difference, such as in immunity, between the aphids used in the previous studies. We used three susceptibility-matched pairs of red and green morph pea aphid clones to test for preferences. In a no-choice situation, the parasitoids attacked equal proportions of each color morph. When provided with a choice, A. ervi was significantly more likely to oviposit into colonies formed from green morphs when the neighboring colony was formed from red morph aphids. In contrast, red morphs were less likely to be attacked when their neighboring colony was of the green morph. By preferentially attacking green colonies, A. ervi may reduce the likelihood of intraguild predation, as it is suggested that visually foraging predators preferentially attack red aphid colonies. Furthermore, if this host choice behavior is replicated in the field, we speculate that color morphs of the pea aphid may interact indirectly through their shared natural enemies, leading to intraspecific apparent competition.     

Effect of shape, size and color on selection of oviposition sites by Chaetorellia australis

The effect of shape, size and color on the selection of oviposition sites by females of Chaetorellia australis Hering (Diptera, Tephritidae) originating from infested yellow starthistle (YST) Centaurea solstitialis L. (Asteraceae, Cardueae) heads, was studied in the laboratory by direct observation of females sitting on or attempting to oviposit into different objects. Artificial substrates made of yellow-colored parafin was mimicking the natural oviposition sites (floral buds of YST), were used to study the effect of shape and size. The results revealed that spherical and conical objects of a total surface area of 310 mm², were visited more frequently than cylindrical and cubical ones of the same surface area. Also more females were observed and more oviposition attempts were recorded on spheres of 5 and 10 mm diameter than of 15 and 20 mm diameter. Yellow and orange dry YST heads, colored by dipping in molten colored ceresin wax, were preferred for oviposition to black, green, blue, red and white ones. The observed preference for certain colors depended primarily on the color hue and not on the intensity of the total reflected light. The females responded positively to hues reflecting maximally between 560 and 610 nm, optimum at 590 nm, while hues reflecting below 540 nm and especially between 400 and 500 nm appeared to have no positive effect.     

青斑蝶Tirumala limniace成虫颜色偏好性研究

【目的】明确青斑蝶Tirumala limniace雌、雄成虫对颜色的偏好性,可以为此蝴蝶人工饲养时的合理环境条件设定提供必要的理论支持。【方法】本研究通过在室内和野外对青斑蝶成虫对6种颜色(白色、红色、绿色、黄色、蓝色和紫色)光源的选择行为进行观察,明确青斑蝶成虫对不同颜色的偏好性。【结果】(1)在室内和在野外雌、雄成虫均优先选择黄色。(2)雌雄成虫在野外无其它光源干扰下对黄色的选择性强于室内。(3)单色光源照明和多种不同颜色光源同时存在下,成虫对颜色的偏好程度存在差异:当只有单色光源照明时,成虫对颜色的偏好程度为黄色>绿色=红色≥蓝色≥紫色;当不同颜色光源同时存在时,成虫对颜色的偏好程度则为黄色>蓝色≥绿色=红色≥紫色。(4)在不同颜色光源同时存在时,配对后的雌成虫表现出了比雄成虫更强的颜色选择性:雌成虫对黄色光源的选择性强于雄成虫,且其未产生颜色选择的成虫数量也少于雄成虫。【结论】青斑蝶成虫存在对黄色选择的颜色恒常性,野外成虫对颜色的选择性强于室内,雌、雄成虫对偏好颜色选择性存在性别差异。