Butterfly Pollinators Research Articles

Butterfly pollination in Platycoryne (Orchidaceae): evidence for a key pollinator shift in the large Habenaria clade

Shifts between pollinator functional groups can explain major changes in floral phenotype. I document a novel case of butterfly pollination in Platycoryne, an African genus that is phylogenetically embedded in the very large Habenaria clade in the Orchidaceae. Most Habenaria species have green or white flowers and many of these have been shown to be pollinated by moths, but my observations of the orange-flowered species Platycorynus mediocris in south-central Africa showed that it is pollinated diurnally by butterflies. The nectar-producing spurs of this species are c. 15 mm in length and closely match the tongue lengths of nymphalid and pierid butterflies that visit the flowers. The rostellum arms flank the spur entrance and place sickle-shaped pollinaria on the eyes or palps of the butterflies. In contrast to the highly scented flowers of moth-pollinated Habenaria species, the flowers of P. mediocris emit very little scent. Anecdotal observations indicate that several other Platycoryne species with orange flowers are also pollinated by butterflies. I conclude that the flower colouration (orange without UV reflectance) and low emission of scent in P. mediocris reflect an important historical shift to butterfly pollination in African members of the Habenaria clade.

Konservasi Kupu-Kupu Penting Sebagai Penyerbuk di Kampung Wisata Isyo Hills Rhepang Muaif Nimbokrang, Kabupaten Jayapura

Butterflies are an important example of pollinating insects of the Order Lepidoptera. The presence of butterfly pollinating insects in nature is highly dependent or influenced by the availability of flowering plants visited in the ecosystem. The purpose of this study was to determine the diversity and abundance of butterfly pollinator in flowering plants. A direct survey method (visual) with a radius of ± 100-250 m² was done with scan sampling technique. Parameters measured were the abundance and the species richness of butterflies visited flowering plants as well as the species richness of flowering plants visited by butterflies pollinator. The data obtained were analyzed using the the Shannon-Wiener diversity index (H’). The results showed that at study sites in secondary forest habitats and yards, 25 species of butterfly pollinators were found consisting of 5 families with 308 individuals. Nine species of flowering plants visited by butterfly pollinators. The Jatropha integerrima was the most visited by butterfly pollinators with 11 species, followed by Hibiscus rosa-sinensis and Ixora coccinea (9 species), Clerodendron paniculatum (6 species), Mussaenda ralateensis (4 species), Bidens pilosa and Celosia argentea (3 species), Zinnia elegans visited by 2 species and Portulaca oleracea visited by 1 species of butterfly pollinators. Based on the calculation, the value of Shannon-Wiener index (H') is 2.946, which indicates that the level of diversity of butterfly pollinators in the medium category.

Characterizing each step of pollination in Phlox drummondii reveals a single butterfly species predominates the pollinator assemblage.

A central goal of pollination biology is to connect plants with the identity of their pollinator(s). While predictions based on floral syndrome traits are extremely useful, direct observation can reveal further details of a species' pollination biology. The wildflower, Phlox drummondii, has a floral syndrome consistent with Lepidoptera pollination. We test this prediction using empirical data. We observe each step of pollination in P. drummondii. First, we observe 55.5 hours of floral visitation across the species range. We use temporal pollinator exclusion to determine the contribution of diurnal and nocturnal pollination to reproductive output. We then quantify P. drummondii pollen transfer by the dominant floral visitor, Battus philenor. Finally, we test the effect of B. philenor visitation on P. drummondii reproduction by quantifying fruit set following single pollinator visits. B. philenor is the primary pollinator of P. drummondii. Pollination is largely diurnal, and we observe a variety of lepidopteran visitors during this period. However, B. philenor is the most frequent visitor, representing 88.5% of all observed visits. We show that B. philenor is an extremely common visitor and also an effective pollinator by demonstrating that individuals transfer pollen between flowers and that a single visit can elicit fruit set. Our data are consistent with the prediction of lepidopteran pollination and further reveal a single butterfly species, B. philenor, as the primary pollinator. Our study demonstrates the importance of empirical pollinator observations, adds to our understanding of pollination mechanics, and offers a specific case study of butterfly pollination. This article is protected by copyright. All rights reserved.

Diversity of butterfly pollinators in agroecosystems of Kumaun region

This study examined the diversity, abundance and evenness of butterfly pollinators in Kumaun region, Uttarakhand from March 2019 to February 2020. A total of 394 butterflies, representing 40 species and five families were collected. Nymphalidae was the most dominant family with 19 species, followed by Pieridae (9 species), Lycaenidae (9 species), Papilionidae (2 species), and Hesperiidae (1 species), respectively. Pieris canidia indica (Evans) was the most abundant species, constituting 38.3% of the total individuals. Shannon-Wiener diversity index was observed to be maximum in Site-1 (H’=1.37) than in Site-2 (H’=1.12). Similarly, evenness was maximum in Site-1 (E=0.457), than in Site-2 (E=0.333). In addition, significant pollinator species in crops have been identified in agroecosystems.

Papilio butterfly vs. hawkmoth pollination explains floral syndrome dichotomy in a clade of Lilium

Abstract Pollination niche shifts can drive remarkable floral divergence between closely related plant species. The Leucolirion clade of Lilium contains species with either tepal-recurved or trumpet-shaped flowers. The tepal-recurved flowers are bright orange and might be pollinated by butterflies and/or birds. The trumpet-shaped flowers are mostly pale and strongly fragrant and might permit visitation by a variety of hawkmoths. Lilium leucanthum has trumpet-shaped flowers, and some populations of this species show dark coloration on the floral outer surface, suggesting pollination by mammals. We identified pollinators and examined the dependence of reproduction on pollinators by floral visitor observations, pollen load analysis and pollination experiments. We also analysed floral traits to contrast the two floral syndromes involving different lepidopteran groups. The tepal-recurved lilies are specialized on a group of Papilio butterflies for pollination with pollen predominantly attached to the hindwings. The trumpet-shaped flowers are almost exclusively pollinated by hawkmoths, including diverse species with proboscises of different lengths. No mammal visitation was found to the populations of L. leucanthum with dark outer surfaces of flowers. Self-incompatibility prevails throughout the clade, including the populations in which pollinators were scarce. The butterfly- and hawkmoth-pollinated species display contrasting floral syndromes. Our findings confirmed that the dichotomy in floral syndrome in the Leucolirion clade is associated with Papilio butterfly vs. hawkmoth pollination, whereas intraspecific variation in colour of the floral outer surface of L. leucanthum many need a non-pollinator explanation.

The long spur of Impatiens macrovexilla may reflect adaptation to diurnal hawkmoth pollinators despite diversity of floral visitors

Many tropical and subtropical Impatiens species possess conspicuously long and narrow spurs and have been assigned to the butterfly pollination syndrome in investigations of floral evolution of this genus. However, this contradicts some previous studies documenting abundant hawkmoth visitors rather than butterflies. In this study, we explored the pollination ecology of Impatiens macrovexilla, a long-spurred species in Asia. We investigated a series of floral traits, tested the breeding system and contributions of different floral visitors to reproductive success, observed floral visitors and compared the spur length with the proboscis length of the nectar-collecting floral visitors. I. macrovexilla shows floral traits that cannot clearly be associated with a certain group of long-proboscid insects. Results showed that the species was visited by large nectar-collecting bees, diurnal hawkmoths, small pollen-collecting insects and rarely butterflies at different sites and in different years. Pollination treatments indicated that I. macrovexilla is self-compatible (Self-Incompatibility Index = 0.02) but completely relies on floral visitors for pollination. A treatment which excluded hawkmoths but permitted pollen-collecting insects to visit flowers revealed that diurnal hawkmoths contributed considerably to reproductive success of this species but that pollen-collecting insects acted as pollen thieves. Large bees firmly contacted anthers and stigmas when visiting flowers so probably also act as pollinators. The proboscises of large bees were shorter than half of the spur of I. macrovexilla in length, suggesting that they could only access the nectar accumulated near the mouth of the spur. However, hawkmoths can access most or all of the nectar because their proboscides match the length of the floral spur. Thus, the long nectar spur presumably reflects adaptation to diurnal hawkmoths. Using evidence from multiple lines of investigation, our study is the first to confirm the role of diurnal hawkmoths as pollinators in Impatiens.

Butterfly pollination of Bonatea cassidea (Orchidaceae): Solving a puzzle from the Darwin era

Although moths and butterflies are closely related, they tend to respond to different floral cues for foraging and thus select for different suites of floral traits. Shifts between moth and butterfly pollination in the same plant clade provide an opportunity to assess the traits that are required to impart a shift between these pollination systems. The orchid genus Bonatea consists mostly of night-scented moth-pollinated taxa, but here we document a butterfly pollination system in Bonatea cassidea, a century after Mansel Weale's initial observations of butterflies carrying pollinaria of this taxon in South Africa were communicated to the Linnean Society by Charles Darwin. We recorded visits by a number of species of butterflies from the family Hesperiidae and Pieridae, but contrary to Weale, we found that the majority of pollinaria were firmly affixed between the palpi and not on the sternum. Removal of pollinaria from flowers during the day, but not at night, suggested that moths do not contribute to pollination, despite the white flower colouration. Floral traits found in B. cassidea but not its moth-pollinated congeners include diurnal anthesis, scent emission which is weak in the day and virtually absent at night, and the production of small amounts of relatively dilute sucrose-rich nectar in short spurs. These features are consistent with those expected for butterfly-pollinated plants in general. This study represents the first detailed report of butterfly-pollination in Bonatea and one of very few cases of orchid pollination by pierid butterflies.

Variation in context-dependent foraging behavior across pollinators.

Pollinator foraging behavior has direct consequences for plant reproduction and has been implicated in driving floral trait evolution. Exploring the degree to which pollinators exhibit flexibility in foraging behavior will add to a mechanistic understanding of how pollinators can impose selection on plant traits. Although plants have evolved suites of floral traits to attract pollinators, flower color is a particularly important aspect of the floral display. Some pollinators show strong innate color preference, but many pollinators display flexibility in preference due to learning associations between rewards and color, or due to variable perception of color in different environments or plant communities. This study examines the flexibility in flower color preference of two groups of native butterfly pollinators under natural field conditions. We find that pipevine swallowtails (Battus philenor) and skippers (family Hesperiidae), the predominate pollinators of the two native Texas Phlox species, Phlox cuspidata and Phlox drummondii, display distinct patterns of color preferences across different contexts. Pipevine swallowtails exhibit highly flexible color preferences and likely utilize other floral traits to make foraging decisions. In contrast, skippers have consistent color preferences and likely use flower color as a primary cue for foraging. As a result of this variation in color preference flexibility, the two pollinator groups impose concordant selection on flower color in some contexts but discordant selection in other contexts. This variability could have profound implications for how flower traits respond to pollinator‐mediated selection. Our findings suggest that studying dynamics of behavior in natural field conditions is important for understanding plant–pollinator interactions.

Flower-Visiting Butterflies Avoid Predatory Stimuli and Larger Resident Butterflies: Testing in a Butterfly Pavilion.

The flower-visiting behaviors of pollinator species are affected not only by flower traits but also by cues of predators and resident pollinators. There is extensive research into the effects of predator cues and resident pollinators on the flower-visiting behaviors of bee pollinators. However, there is relatively little research into their effects on butterfly pollinators probably because of the difficulty in observing a large number of butterfly pollination events. We conducted a dual choice experiment using artificial flowers under semi-natural conditions in the butterfly pavilion at Tama Zoological Park to examine the effects of the presence of a dead mantis and resident butterflies have on the flower-visiting behavior of several butterfly species. From 173 hours of recorded video, we observed 3235 visitations by 16 butterfly species. Statistical analysis showed that (1) butterflies avoided visiting flowers occupied by a dead mantis, (2) butterflies avoided resident butterflies that were larger than the visitor, and (3) butterflies showed greater avoidance of a predator when the predator was present together with the resident butterfly than when the predator was located on the opposite flower of the resident. Finally, we discuss the similarities and differences in behavioral responses of butterfly pollinators and bees.

The ecological role of extremely long-proboscid Neotropical butterflies (Lepidoptera: Hesperiidae) in plant-pollinator networks

Extremely long proboscides of insect flower visitors have been regarded as an example of a coevolutionary arms race, assuming that these insects act as efficient pollinators for their nectar host plants. However, the effect of proboscis length on generalized or specialized flower use remains unclear and the efficiency of butterfly pollination is ambiguous. Neotropical Hesperiidae feature a surprising variation of proboscis length, which makes them a suitable study system to elucidate the role of extremely long-proboscid insects in plant-pollinator networks. The results of this study show that skippers with longer proboscides visit plant species with deep-tubed flowers to take up food, but do not pollinate them. Skippers equipped with extremely long proboscides seldom include short-tubed flowers in their diet nor visit more plant species than those with shorter proboscides. Our observations indicate that the extremely long-proboscid skippers steal nectar from their preferred nectar host plants, Calathea sp., instead of contributing to their pollination. Finally, we discuss the impact of nectar robbery by these butterflies on their nectar host plants and their legitimate pollinators, euglossine bees.

A Study on Coevolutionary Relationship of Four Plants With Their Butterfly Pollinators on Basis of Their Nectar Physiology

Present study is aimed to reveal the co evolutionary relationship of four butterfly pollinated flowers Cadaba fruticosa (L.) Druce, Caesalpinia pulcherrima (L.) Sw., Clerodendrum infortunatum L. and Clerodendrum phlomidis L.f. Not only the floral morphology, nectar quality the main energy source of insects including butterflies is also a promiscuous character which excludes other insects than specified. So, nectar characters of these flowers are studied and found a good correlation with butterfly preferred nectars. Here one-sided adaptation was there and it was described as “non-promiscuous”. It is one of the most significant events in organic evolution.

High specialisation in the pollination system of Mandevilla tenuifolia (J.C. Mikan) Woodson (Apocynaceae) drives the effectiveness of butterflies as pollinators

Butterfly pollination in the tropics is considered somewhat effective or solely effective in a few plant species. In the present study, we tested the hypothesis that Mandevilla tenuifolia (Apocynaceae), which has floral attributes associated with psychophily, has strategies adapted to pollination by butterflies, restricting other floral visitors and making these insects act as efficient pollinators. We analysed the floral and reproductive biology of M.tenuifolia, as well as the frequency and efficiency of its flower visitors. M.tenuifolia is an herb whose flowers have strong herkogamy and secondary pollen presentation on the style head, which corresponds to 60.4% of pollen on the anthers. Flower longevity and the long period of receptivity of the stigmatic region associated with the large amount of pollen removed in the first visits suggest that flowers remain functionally female during part of anthesis. Butterflies, mainly of the families Nymphalidae and Pieridae, are the only pollinators of M.tenuifolia. Despite being self-compatible, M.tenuifolia depends on biotic vectors for fruit production. A non-significant difference in fruit set between controlled treatments and natural conditions suggests that the pollinators are efficient. The inclination resulting from the landing of butterflies on flowers, together with flower morphology, guiding the insect proboscis inside the floral tube, as well as the frequency and efficiency of butterfly visits, are evidence of the close relationship between butterflies and M.tenuifolia, and also of the efficiency of these insects as pollinators.

Nectar sugars enhance fitness in male Coenonympha pamphilus butterflies by increasing longevity or realized reproduction

The principal components of floral nectar are water and the sugars sucrose, fructose and glucose. Several studies have shown the importance of nectar sugars for female butterfly fecundity, whereas to date little attention has been paid to the effect of nectar sugars on male butterfly reproduction. Clear evidence for an effect of nectar sugars on male realized reproductive success is still missing.In this study, we fed male Coenonympha pamphilus butterflies nectar mimics with low (5%), medium (20%) or high (30%) total sugar concentrations with a sucrose:glucose:fructose ratio of 2.7:1.1:1. Sugar solutions were made mimicking Knautia arvensis, an essential nectar plant for C. pamphilus and many other European butterflies. Realized male reproductive success for each treatment was measured indirectly via nuptial gifts, by recording reproductive parameters and by characterizing time patterns over the oviposition period of their female partner.Male butterflies fed high‐concentrated nectar sugars had a longer lifespan than males fed low‐concentrated nectar sugars. In contrast, offspring of males fed medium‐concentrated nectar sugars had a higher hatching mass than progeny of males fed low‐concentrated nectar sugars, indicating a tradeoff between somatic maintenance and reproduction in the use of nectar sugars. Thus, allocation patterns of nectar sugars differed according to sugar concentrations in adult food.The method used in this experiment took into account the indispensable role of female butterflies in passing male nutrients to offspring. With this comprehensive approach, we can show the general importance of nectar sugars for male butterfly fitness and support previous findings suggesting a coevolutionary process between butterflies and flowers dependent on butterfly pollination.

Pollinator-Mediated Selection on Flower Color Allele Drives Reinforcement

Reinforcement is the process by which reduced hybrid fitness generates selection favoring the evolution of stronger prezygotic reproductive barriers between emerging species. Using common-garden field experiments, we quantified the strength of reinforcing selection in nature by demonstrating strong selection favoring an allele conferring increased pigment intensity in the plant Phlox drummondii in areas of sympatry with the closely related species Phlox cuspidata. Incomplete hybrid sterility between the two species generates selection for traits that decrease interspecies hybridization. In contrast, selection on this locus is undetectable in the absence of P. cuspidata. We demonstrate that reinforcing selection is generated by nonrandom pollinator movement, in which pollinators move less frequently between intensely pigmented P. drummondii and P. cuspidata than between lightly pigmented P. drummondii and P. cuspidata.

Flower scent composition in diurnal Silene species (Caryophyllaceae): phylogenetic constraints or adaption to flower visitors?

A comparative analysis of the flower volatiles of 10 day-flowering Silene species native to Central Europe was made to improve the understanding of the pollination biology and evolution of floral odours in the genus. Floral scent was collected by dynamic headspace adsorption and analysed via gas chromatography–mass spectrometry. In total, 60 compounds could be identified by their mass spectra as well as by their relative retention times. The number of compounds per species ranged between 16 in Silene rupestris and 40 in S. viscaria. Main compounds in most species were fatty acid derivatives (FADs, cis-3-hexen-1-ol, cis-3-hexenyl acetate, n-nonanal), benzenoids (benzaldehyde, phenylacetaldehyde, methyl benzoate), and monoterpenes (limonene, linalool), accompanied by sesquiterpenes, and nitrogen-containing compounds. Nonmetric multidimensional scaling (CNESS, NMDS) based on relative amounts of single components leads to the same conclusion as visualization of similarities based on component classes reflecting to some degree biosynthetic pathways: differences in floral scent composition can be related to both the taxonomy and the pollination biology of the species investigated. In all but one species of the Silene group, and all species of the Lychnis group ( S. dioica, S. flos-cuculi, S. flos-jovis, S. pendula), the dominating compound classes are benzenoids followed by FADs. The relatively high amounts of aromatic compounds (e.g. benzaldehyde, phenylacetaldehyde, methyl benzoate) are indicative of an adaptation towards butterfly pollination. Species of the Viscaria and Eudianthe groups showed high relative amounts of FADs but a lower content of benzenoids. Relatively high amounts of monoterpenes (>10%) were found in S. alpestris, S. coeli-rosa, S. gallica, and S. viscaria. It is suggested that the high relative content of the most volatile monoterpene alkenes (e.g. limonene) in S. gallica and S. coeli-rosa may be indicative of an adaptation to bees as pollinators in these species.

Alien Abduction: Disruption of Native Plant‐Pollinator Interactions by Invasive Species

ABSTRACTThe indirect impacts of Shorea siamensis‐logging on the reproductive ecology of Dipterocarpus obtusifolius, a self‐incompatible butterfly‐, moth‐, and bird‐pollinated tree, were studied in tropical dry forest in Thailand. Pollinator activity at D. obtusifolius trees and subsequent seed production were recorded in three forest areas subject to differing intensities of S. siamensis extraction. The pollinator and plant understory communities in these areas were also noted. Forest areas subject to high S. siamensis extraction intensities had very high understory flowering plant cover, dominated by the exotic invader Chromolaena odorata. Activity of butterfly pollinators at D. obtusifolius trees decreased in these disturbed areas, although their abundance remained comparable to other forest areas subject to only moderate or no extraction. For sphingid moth pollinators, there was no difference across differentially disturbed forest areas in either abundance or in the proportion bearing pollen. Pollinator activity by birds increased at highly disturbed locations but was not sufficient to offset a decline in overall pollinator activity at D. obtusifolius canopies in areas of heavy 5. siamensis extraction. Thus, extraction of S. siamensis indirectly affected the pollination of D. obtusifolius, primarily by causing changes in the foraging behavior of butterfly pollinators rather than their abundance. A shift in the relative abundance of floral nectar resources from the canopy to the understory, a consequence of 5. siamensis extraction and invasion by C. odorata, led to a parallel shift in foraging location of the principal diurnal pollinators, the butterflies, toward the understory. Despite reduced pollination at disturbed sites, behavioral changes did not translate into a D. obtusifolius seed set effect, possibly because pollination by birds (or moths) at the disturbed site compensated for reduced butterfly pollination.

Alien Abduction: Disruption of Native Plant-Pollinator Interactions by Invasive Species1

ABSTRACT The indirect impacts of Shorea siamensis-logging on the reproductive ecology of Dipterocarpus obtusifolius, a self- incompatible butterfly-, moth-, and bird-pollinated tree, were studied in tropical dry forest in Thailand. Pollinator activity at D. obtusifolius trees and subsequent seed production were recorded in three forest areas subject to differing intensities of S. siamensis extraction. The pollinator and plant understory communities in these areas were also noted. Forest areas subject to high S. siamensis extraction intensities had very high understory flowering plant cover, dominated by the exotic invader Chromolaena odorata. Activity of butterfly pollinators at D. obtusifolius trees decreased in these disturbed areas, although their abundance remained comparable to other forest areas subject to only moderate or no extraction. For sphingid moth pollinators, there was no difference across differentially disturbed forest areas in either abundance or in the proportion bearing pollen. Pollina...

Evidence for Moth and Butterfly Pollination in Gladiolus (Iridaceae-Crocoideae)

Pollination strategies of Gladiolus, one of the largest genera of the monocot family Iridaceae, are unusually diverse, and include various bee species, foraging either for nectar or for pollen, passerine birds, long-proboscid flies foraging for nectar, hopliine beetles that use the flowers primarily as sites for assembly, and Lepidoptera. Pollination by insects of this order comprises two entirely different sets of pollinators, night-flying moths (Noctuidae or Sphingidae) and butterflies (evidently only one species of Satyridae). These lepidopteran-pollinated flowers have quite different floral adaptations and both types are specialist systems, although moth flowers may be pollinated by a range of different moths. In Gladiolus moth-pollinated flowers are usually large, long-tubed and pale-colored, or mottled dull purple to brown, are usually richly scented, often open fully only at night, and produce relatively concentrated nectar that is sucrose-rich. Butterfly flowers, in contrast, are fully open during the day, close partially or completely at night, are often bright crimson to scarlet, usually with prominent white splashes on the lower tepals, but are also large, have a long tube, and produce quantities of relatively dilute nectar, either sucrose-rich or hexose-rich. Comparing the pollination systems of related species, we infer that night-flying moth pollination arose 6 times in the genus, whereas butterfly pollination arose 3 times in the 165 species of southern Africa, and that the two lepidopteran pollination systems in Gladiolus arose quite independently of one another.

Evidence for phenotypic assortative mating for flower colour in periwinkle

AbstractTwo experiments were conducted with periwinkle, Catharanthus roseus, to determine the extent of natural outcrossing. Three white‐flowered, fully self‐fertile, monogenic recessive mutants, namely, dwarf, wavy leaf margin and curved leaf were used, together with their parental white‐flowered variety, ‘Nirmal’, and a normal pink‐flowered variety, PS‐1. The extent of total outcrossing ranged from 43.4 to 79.3% among mutants. Outcrossing between white × white‐flowered plants ranged from 28.3 to 65.3% and was two to four times greater than that between white × pink‐flowered plants in the three mutants. The extent of out‐crossing between white × pink‐flowered plants was similar “02.2‐15.0%” in all mutants and also similar to that in the normal white‐flowered variety,‘Nirmal’(00.4%), where white × white flower out‐crossing could not be estimated. There were no large differences in the number of seeds per fruit, percentage fruit set and germination percentage of seeds obtained from self, white × white and white × pink flower crosses made in the glasshouse. There were also no significant differences in the number of flowers produced by the genotypes used in the study. The observed higher frequency of white × white flower matings compared with white × pink flower matings appeared to be due to the constancy of flower colour exhibited by the butterfly pollinators Pachliopta hector and Catopsilia pyranthae during their flower visits. Observations made on the occurrence of natural self‐pollination revealed that automatic self‐pollination did not occur in periwinkle.

EVIDENCE FOR POLLINATION ECOTYPES IN THE YELLOW-FRINGED ORCHID, PLATANTHERA CILIARIS.

Platanthera ciliaris is a butterfly-pollinated, terrestrial orchid with a loose terminal raceme of 10-50 orange flowers, characterized by a long nectariferous spur. In the southeastern United States, P. ciliaris occurs in the Appalachian mountains and coastal-plain physiographic provinces, but it is found rarely in the intervening Piedmont. In 1983 and 1984, detailed observations of two populations within these disjunct areas revealed that the butterfly species that serve as the primary pollinators differ sharply. In the mountains, Papilio troilus (spicebush swallowtail) was the most frequent and effective visitor, whereas in the coastal plain, P. palamedes (palamedes swallowtail) was the predominant pollinator. Proboscis lengths of P. troilus (mean = 23.3 mm) were significantly shorter than those of P. palamedes (mean = 28.7 mm). Floral characters, most notably spur length, also differed significantly between mountain (mean = 23.8 mm) and coastal-plain (mean = 25.6 mm) plants. In both 1983 and 1984, levels of pollinator service, as assessed by rates of removal and insertion of pollinia, were higher in the mountains (0.81 and 0.86) than in the coastal plain (0.63 and 0.67). In addition, fruit-set was significantly greater in mountain (83.9% in 1983, 86.5% in 1984) than in coastal-plain (63.8% in 1983, 65.5% in 1984) populations. We hypothesize that selection pressure exerted through pollinator proboscis lengths has resulted in pollination ecotypes of P. ciliaris. The short-spurred mountain plants appear to be in equilibrium with their short-tongued butterfly pollinators, receiving high levels of effective pollination and achieving high levels of fruit-set. Coastal-plain plants produce flowers with longer spurs which, nevertheless, are shorter than optimal for insuring that very long-tongued butterflies make contact with their pollinia. Thus, effective pollinator service and fruit-set are reduced. Correlation analyses in 1984 showed a positive relationship between spur length and fruit-set only in the coastal plain. The presence of long-tongued nectar thieves in the coastal plain may also contribute to lower effective pollinator service and fruit-set. Results of reciprocal-transplant studies attempting to determine the genetic basis of floral characters, including spur length, were inconclusive but suggest that differences between mountain and coastal-plain plants are not due solely to phenotypic plasticity.