The roles of wing color pattern and geography in the evolution of Neotropical Preponini butterflies

Diversification rates and evolutionary trajectories are known to be influenced by phenotypic traits and the geographic history of the landscapes that organisms inhabit. One of the most conspicuous traits in butterflies is their wing color pattern, which has been shown to be important in speciation. The evolution of many taxa in the Neotropics has also been influenced by major geological events. Using a dated, species‐level molecular phylogenetic hypothesis for Preponini, a colorful Neotropical butterfly tribe, we evaluated whether diversification rates were constant or varied through time, and how they were influenced by color pattern evolution and biogeographical events. We found that Preponini originated approximately 28 million years ago and that diversification has increased through time consistent with major periods of Andean uplift. Even though some clades show evolutionarily rapid transitions in coloration, contrary to our expectations, these shifts were not correlated with shifts in diversification. Involvement in mimicry with other butterfly groups might explain the rapid changes in dorsal color patterns in this tribe, but such changes have not increased species diversification in this group. However, we found evidence for an influence of major Miocene and Pliocene geological events on the tribe''s evolution. Preponini apparently originated within South America, and range evolution has since been dynamic, congruent with Andean geologic activity, closure of the Panama Isthmus, and Miocene climate variability.     

Morphological study of alar androconia in Celastrina butterflies

Morphological studies of androconia were performed for 13 Celastrina species using a digital microscope with Z‐stacking mode. Whereas C. ladon lacked androconia, the remaining 12 species were found to possess fan‐shaped androconia on the dorsal wing surfaces. The androconia of these species shared the following common features: smaller size than standard color‐producing scales, absence of dentate termini and presence of crossrib perforations. In addition, some species were characterized by unique microstructures in their androconia. The androconia of C. argiolus iynteana possessed a rounded lamellar contour, while those of C. lavendularis himilcon and C. echo cinerea were tapered on the basal end. The average number of longitudinal ridges of C. argiolus ladonides and C. filipjevi (17.1) were greater than the average number of 12 species (14.3). These results suggest that the morphological traits of androconia in microdomain, such as the shape of the lamellar form and the average number of longitudinal ridges, are useful to identify species in the genus Celastrina.     

Species‐dependent microarchitectural traits of iridescent scales in the triad taxa of Ornithoptera birdwing butterflies

Ornithoptera birdwing butterflies have blue, green, or orange iridescent scales in different species or subspecies. To understand the species‐ or subspecies‐dependent scale color differences, we performed comparative morphometric analyses of iridescent scales from three closely related taxa: O. priamus priamus (green), O. priamus urvillianus (blue), and O. croesus (orange). The three types of Ornithoptera wings exhibited reversible color changes to longer wavelengths with different kinetics upon immersion in methanol, suggesting that their color differences are at least partly based on differences in the size of air cavities made by nanostructures. Cover scales of all three color types were visually semi‐transparent glass scales that exhibited color when placed on a dark background. The dorsoventral differences in coloration were observed in single scales, suggesting the optical importance of scale surfaces. Scanning electron microscopy of cover scales in cross section revealed that all color types exhibited finely sculpted tapered ridges and thick, irregular basal multilayers containing tandemly clustered granular objects and air cavities. Scale thickness, ridge height, and multilayer thickness were significantly different among the three color types, and granular object size was significantly different between orange scales and blue and green scales. We conclude that each of the three taxa of Ornithoptera butterflies possesses unique quantitative size values on tapered ridges and irregular multilayers with granular objects and air cavities to express unique structural color. These species‐ or subspecies‐dependent structural colors might have evolved via quantitative shifts in these microarchitectural traits rather than via changes in the basic developmental or architectural plan for color expression.     

Primers for the amplification of nuclear introns in Heliconius butterflies

I described the development of degenerate polymerase chain reaction (PCR) primers for intron‐containing regions of nine candidate wing patterning and pigmentation genes in Heliconius butterflies. Primers were developed by comparing sequence data from Drosophila melanogaster, Precis coenia, and a variety of other insects so they are likely to be applicable widely among the butterfly family Nymphalidae and perhaps Lepidoptera in general. The amplified regions are highly variable and should be useful for inferring relationships among closely related species and estimating the phylogeographical and population genetic structure of individual species.     

Wing colors based on arrangement of the multilayer structure of wing scales in lycaenid butterflies (Insecta: Lepidoptera)

Male wing colors and wing scale morphology were examined for three species of lycaenid butterflies: Chrysozephyrus ataxus, Favonius cognatus and F. jezoensis. Measurement of spectral reflectance on the wing surface with a spectrophotometer revealed species‐specific reflection spectra, with one or two peaks in the ultraviolet and/or green ranges. Observations of wing scales using an optical microscope revealed that light was reflected from the inter‐ridge regions, where transmission electron microscopy revealed a multilayer structure. Based on the multilayer dimensions obtained, three models were devised and compared to explain the measured reflectance spectrum. The results showed that the best fit is a model in which thicknesses of thin films of the multilayer system are not constant and air spaces between cuticle layers are more or less packed with cuticle spacers. This suggests that the specific wing colors of the species examined are produced by the species‐specific arrangement of the multilayer structure of wing scales.     

Comparative study of the morphology of stridulatory organs of the Iberian lycaenid butterfly pupae (Lepidoptera)

We compared the pupal stridulatory organs of 35 species and one subspecies of Iberian Lycaenidae using scanning electron microscopy. The studied species belong to the tribes Theclini, Eumaeini, Lycaenini, and Polyommatini. Nine species do not show stridulatory organs on the pupae but all other species possess them. Stridulatory organs are formed by a stridulatory plate (pars stridens) placed on the fifth abdominal segment and a file (plectron) in the sixth abdominal segment. The plate has tubercles in the Theclini and Lycaenini, tubercles, ridges, or undulations in the Eumaenini, and tubercles, teeth, or unspecialized structures in the Polyommatini. Morphological differences can be found in the files of the different tribes, regarding the number of teeth, their form and size. Cuticular formations of the organs were studied on a surface of 2,500 µm² and the average of ridges, tubercles, and teeth was measured searching for relevant taxonomic information. Stridulatory organs were thought to be an adaptation to myrmecophily but we show that they are present both in myrmecophilous and nonmyrmecophilous species; therefore, we suggest that this trait probably did not evolve in relation with myrmecophily, but may be used to enhance relationships with ants. J. Morphol. 275:414–430, 2014. © 2013 Wiley Periodicals, Inc.     

蛱蝶翅鳞片的超微结构观察

对我国东北地区典型常见蛱蝶科15属20种蝴蝶翅鳞片的超微结构进行了扫描电镜观察。结果显示：蛱蝶翅鳞片形态上可分为窄叶形、阔叶形和圆叶形3种,鳞片长65～135 μm,宽35～85 μm,间距48～112 μm。蛱蝶翅鳞片的超微结构可分为拱桥形、棋盘形和筛孔形3 种。拱桥形结构和棋盘形结构比较接近,二者与筛孔形结构差异较明显。在已观察的种类中,线蛱蝶属红线蛱蝶翅鳞片上的纵肋突起最小（200 nm×300 nm）,闪蛱蝶属柳紫闪蛱蝶翅鳞片上的纵肋突起最大（590 nm×560 nm）。鳞片具有相似的形状、结构和排列,尤其是同属蝴蝶翅鳞片超微结构的形状和尺寸差异较小,表明它们之间的亲缘关系接近。     

Microsatellite markers associated with genes expressed in developing wings of Bicyclus anynana butterflies

Deriving useful microsatellite markers in lepidopterans has been challenging when relying on scans of genomic DNA libraries, presumably due to repetitiveness in their genomes. We assayed 96 of 320 microsatellites identified in silico from a collection of Bicyclus anynana ESTs, in 11 independent individuals from a laboratory population. From the 68 successful assays, we identified 40 polymorphic markers including 22 with BLAST-based annotation. Nine of 12 selected polymorphic markers tested in a panel of 24 wild-caught individuals converted to successful assays and were all polymorphic. We discuss how microsatellite discovery in ESTs is an efficient strategy with important attendant advantages.     

Altitude and life‐history shape the evolution of Heliconius wings

Phenotypic divergence between closely related species has long interested biologists. Taxa that inhabit a range of environments and have diverse natural histories can help understand how selection drives phenotypic divergence. In butterflies, wing color patterns have been extensively studied but diversity in wing shape and size is less well understood. Here, we assess the relative importance of phylogenetic relatedness, natural history, and habitat on shaping wing morphology in a large dataset of over 3500 individuals, representing 13 Heliconius species from across the Neotropics. We find that both larval and adult behavioral ecology correlate with patterns of wing sexual dimorphism and adult size. Species with solitary larvae have larger adult males, in contrast to gregarious Heliconius species, and indeed most Lepidoptera, where females are larger. Species in the pupal‐mating clade are smaller than those in the adult‐mating clade. Interestingly, we find that high‐altitude species tend to have rounder wings and, in one of the two major Heliconius clades, are also bigger than their lowland relatives. Furthermore, within two widespread species, we find that high‐altitude populations also have rounder wings. Thus, we reveal novel adaptive wing morphological divergence among Heliconius species beyond that imposed by natural selection on aposematic wing coloration.     

Associations between lycaenid butterflies and ants in Australia

A comprehensive and critical review of all available literature on associations between Australian lycaenid butterflies and ants was undertaken to establish an accurate database of the partners involved. Collections and observations of lycaenids and ants were used to augment this review, resulting in a significant number of newly documented association (and non-association) records. Twenty published records considered to be erroneous or doubtful are noted, with justifications given for their deletion from the association database. In total, 265 different associations between lycaenids and ants, plus 65 non-attendance records are documented for Australia. Nearly 80% of the lycaenid species in Australia, for which the early stages are known, are recorded associating with ants and half of these are obligately ant-associated. Patterns of association are examined from the perspective of both lycaenids and ants, with a focus on ant systematics and ecology. Lycaenids are recorded with five ant subfamilies, including the first record of an association with the Pseudomyrmecinae. The Dolichoderinae, and to some extent the Formicinae, have a disproportionately high percentage of genera that associate with lycaenid butterflies. All ant species that tend lycaenids spend at least some portion of their time foraging on vegetation to collect plant and insect nectar. There is a robust relationship between the competitive status of ants within a community, and their frequency and degree of association with lycaenids. Obligate ant-association is accompanied by a high degree of specificity for ant partner, but two notable exceptions, Ogyris aenone and O. amaryllis are discussed. Facultative myrmecophiles tend to associate with a broad range of ants, although interactions with ecologically dominant ants are less frequent than might be expected based on the abundance of dominant ant species in Australian communities.     

Variation in cuticular lipid profiles of black butterflies of the genus Papilio in Japan

Insect (epi)cuticular lipids characterize sex and species and often play an important role in mating behavior. We previously revealed that two black-colored swallowtail butterflies, Papilio polytes and Papilio protenor, show sexual dimorphism and species specificity in cuticular lipid composition and that P. polytes males use specific monoene components for mate discrimination. These findings suggest that their closely related species may have different profiles of cuticular lipids. We examined the cuticular lipid compositions of five Papilio species (P. bianor, P. maackii, P. helenus, P. macilentus, and P. memnon), closely related and sympatric to P. polytes and P. protenor, and discussed whether it is possible to discriminate between sexes, and between species based on their chemical profiles. The cuticular lipids consist mainly of C23–C31 aliphatic hydrocarbons, in which n-tricosane, n-heptacosane, and n-nonacosane are predominant. Several aliphatic ketones, aliphatic acids, and oxygenated terpenoids were also identified as major components shared by several species. There were no components exclusive to a particular species. Conspecific males and females shared most of the components but were mostly distinguishable based on their composition. Moreover, P. helenus males, P. polytes females, and P. protenor females had two different phenotypes of lipid composition. Although unrelated to the genetic lineage, the seven species were classified into four clusters based on their lipid profiles. The first cluster was composed of only P. memnon. The other six species were broadly classified into three clusters consisting of subclusters for each species: 1) P. polytes, P. helenus, P. macilentus, and several P. protenor females; 2) P. bianor and P. protenor; and 3) P. maackii and several P. helenus males. These results indicate that cuticular lipid profiles characterize the species and sex of the Papilio species and may be responsible for mate discrimination among them.     

Irregular diapause, apparency and evaluating conservation status: anomalies from the Australian butterflies

Examples of irregular development (diapause regimes) are reported in three families (Lycaenidae, Nymphalidae, Papilionidae) of butterflies in Australia. The importance of understanding such irregularities is emphasized, and their relevance to interpreting conservation status and needs discussed. Expectations of incidence or abundance may not be met, and unexpected declines or losses resulting from irregular diapause can cause unnecessary conservation concerns.     

CLIMBER: Climatic niche characteristics of the butterflies in Europe

Detailed information on species’ ecological niche characteristics that can be related to declines and extinctions is indispensable for a better understanding of the relationship between the occurrence and performance of wild species and their environment and, moreover, for an improved assessment of the impacts of global change. Knowledge on species characteristics such as habitat requirements is already available in the ecological literature for butterflies, but information about their climatic requirements is still lacking. Here we present a unique dataset on the climatic niche characteristics of 397 European butterflies representing 91% of the European species (see Appendix). These characteristics were obtained by combining detailed information on butterfly distributions in Europe (which also led to the ‘Distribution Atlas of Butterflies in Europe’) and the corresponding climatic conditions. The presented dataset comprises information for the position and breadth of the following climatic niche characteristics: mean annual temperature, range in annual temperature, growing degree days, annual precipitation sum, range in annual precipitation and soil water content. The climatic niche position is indicated by the median and mean value for each climate variable across a species’ range, accompanied by the 95% confidence interval for the mean and the number of grid cells used for calculations. Climatic niche breadth is indicated by the standard deviation and the minimum and maximum values for each climatic variable across a species’ range. Database compilation was based on high quality standards and the data are ready to use for a broad range of applications.It is already evident that the information provided in this dataset is of great relevance for basic and applied ecology. Based on the species temperature index (STI, i.e. the mean temperature value per species), the community temperature index (CTI, i.e. the average STI value across the species in a community) was recently adopted as an indicator of climate change impact on biodiversity by the pan-European framework supporting the Convention on Biological Diversity (Streamlining European Biodiversity Indicators 2010) and has already been used in several scientific publications. The application potential of this database ranges from theoretical aspects such as assessments of past niche evolution or analyses of trait interdependencies to the very applied aspects of measuring, monitoring and projecting historical, ongoing and potential future responses to climate change using butterflies as an indicator.     

酢浆灰蝶生物学特性研究

通过野外观察、室内饲养等方法研究了酢浆灰蝶Pseudozizeeria maha(Kollar)的生活史及生物学特性。在南京地区,该蝶幼虫以酢浆草科Oxalidaceae的黄花酢浆草(Oxalis corniculataL.)为食,1年5代,世代交替发生。酢浆灰蝶在10月末以蛹在枯枝落叶或土壤表层浅洞中越冬,越冬代成虫次年5月始见、中旬为高峰期,5月中旬始见第1代卵及幼虫,6—10月间各月各虫态均同时发生,期间每月中下旬为成虫活动高峰期。幼虫共4龄,野外2～4龄幼虫具迁移、避热与适蚁行为。在室内饲养条件下,卵期为3～4d,幼虫期为22～26d,蛹期为6～7d。     

The scale of resource specialization and the distribution and abundance of lycaenid butterflies

Numerous hypotheses have been proposed for the commonly observed, positive relationship between local abundance and geographic distribution in groups of closely related species. Here I consider how hostplant specialization and abundance affect the relative abundance and distribution of lycaenid butterflies (Lepidoptera: Lycaenidae). I first discuss three components of specialization: local specialization, turnover of specialization across a species’ range, and the minimum number of resources (or habitats) required by a species. Within this framework, I then consider one dimension of a lycaenid species’ niche, larval hostplant specialization. In a subalpine region of Colorado, I surveyed 11 lycaenid species and their hostplants at 17 sites. I compare this local information to continental hostplant use and large-scale distributions of the lycaenids and their hostplants. Local abundance of a lycaenid species is positively correlated with its local distribution (the number of sites occupied), but not with its regional or continental distribution. Neither local specialization (the number of hostplants used within one habitat) nor continental specialization (the number of hostplants used across many habitats) is correlated with local lycaenid abundance. Continental specialization is positively correlated with a species’ continental distribution, however. Finally, while generalist butterflies tend to have more hostplant available to them, differences in resource availability do not explain the differences in butterfly abundance. Although local abundance is correlated only with local distribution, I suggest that abundance-distribution relationships might emerge at regional and continental scales if local abundance were averaged across many habitat types. Consideration of the scale of a species’ resource specialization (within or among habitats) appears to be key to understanding the relationships between resource specialization, resource availability, and a species’ abundance and distribution. Received: 1 September 1999 / Accepted: 12 December 1999     

Microsatellite markers to assess the influence of population size, isolation and demographic change on the genetic structure of the UK butterfly Polyommatus bellargus

Five microsatellite DNA markers were isolated and used to quantify population genetic structure among a subset of UK populations of the Adonis blue (Polyommatus bellargus Rottemburg). Specifically, whether population size, degree of isolation or history of bottlenecking in 1976-1978 can explain current patterns of genetic variation. The butterfly is at its northern range limit in the UK, where it exists as a highly fragmented metapopulation on isolated pockets of calcareous grassland. Most populations were affected by a severe bottleneck in the late 1970s, when a drought caused the host plant (Hippocrepis comosa) to wilt. Mantel tests and spatial autocorrelation analysis indicated a significant effect of isolation by distance among the UK populations, a relationship that broke down at greater geographical scales (> 23.85 km), probably because of large areas of unsuitable habitat presenting barriers to gene flow. Similarly, amova revealed that variation among geographical regions was almost double that observed within regions. Larger populations were found to support significantly higher levels of genetic diversity, suggesting that small populations may lose genetic diversity through drift. If, as in other butterfly species, low genetic diversity increases the probability of population extinction, then these populations are likely to be under threat. Neither isolation nor a history of bottlenecks appeared to influence genetic diversity. The results indicate that adequate population size a crucial factor in the conservation of genetic diversity in P. bellargus in the UK.     

Beak marks on the wings of butterflies and predation pressure in the field

Beak marks on butterfly wings have been used as an indicator of predation pressure. The relationship between butterflies and their predators in the field was examined to evaluate the beak mark rate as an indicator of predation pressure. Transect censuses were conducted to measure the beak mark rate on butterflies from May to November, 2010, in Shiga Prefecture, Japan. A total of 1216 butterflies of 42 species from five families were observed during the study period. The beak mark rate in the Papilionidae was significantly higher than those of all other families. Analysis of the monthly fluctuations in the beak mark rate and relative abundance of predators revealed that the higher beak mark rates observed for two butterfly families (Papilionidae and Nymphalidae) were significantly and positively related to predation pressure, while no significant relationship was found for other families (Lycaenidae, Pieridae and Hesperiidae). Beak marks in larger butterflies (Papilionidae and Nymphalidae) can be used as an indicator to evaluate the relative intensity of predation pressure in the field.     

Assessing priority areas by imperilled species: insights from the European butterflies

Biodiversity hotspots have been variously defined in terms of species richness, endemic species or imperilled species. The use of imperilled species to locate priority areas is particularly problematic, because an area that hosts a large number of imperilled species is likely to be under severe threats, making less effective conservation efforts. A possibly way to answer this problem is to assess species threats at two spatial scales. Then, areas which host concentrations of species that are imperilled at the larger scale, but not at the smaller scale, can be considered as priority areas where conservation efforts are expected to be more effective. An application of this procedure to the European butterfly fauna with the Biodiversity Conservation Concern index calculated with two IUCN red listings (European and national) allowed the construction of a four-celled model that reflects different types of conservation priority. This combined use of international and regional red lists may be a tool to make practical decisions (e.g. allocation of funds or legislative actions) to preserve imperilled species.