Number Of Ocelli Research Articles

A long tail of truth and beauty: A zigzag pattern of feather formation determines the symmetry, complexity, and beauty of the peacock’s tail

Background Darwin assumed that the peacock’s long train was maladaptive and was the indirect effect of selection by female mate choice based on the train’s beauty. While a relationship between the feathers’ elaborate features and mating success has been shown, what features of the train females are attracted to remains controversial. Methods We used museum specimens to examine the anatomical plan underlying feather development responsible for the symmetry of the train. We developed a model based on an alternate arrangement of primordial feather buds during development and locations of concentric circles of symmetric eyespot distribution using the pattern seen on the train as a template. Results We observed a zigzag pattern of feather follicles that determined both the number and the hexagonal arrangement of eyespots on the train. Our model explained not only the alternate arrangement of feathers on the train but also the arrangement of the concentric color rings of the eyespots. While the zigzag pattern explains the symmetry, complexity, and structural beauty of the peacock’s train, it also precludes variation in eyespot number except by annual addition of new rows of feathers as a function of age. Conclusions Since eyespot number and feather length are developmentally correlated and an asymptotic function of a male’s age, their effects on female choice would be confounded and inseparable, and male vigor would be a crucial factor affecting male fitness. Females may not always choose males with the largest number of eyespots, as older males may lack vigor. We propose a multimodal model of female choice where females see eyespot and train size not as separate traits but as one complex trait combining both. The new model may be able to explain conflicting results and why eyespot number alone may not be sufficient to explain female choice.

Ultrabithorax modifies a regulatory network of genes essential for butterfly eyespot development in a wing sector-specific manner.

Nymphalid butterfly species often have a different number of eyespots in forewings and hindwings, but how the hindwing identity gene Ultrabithorax (Ubx) drives this asymmetry is not fully understood. We examined a three-gene regulatory network for eyespot development in the hindwings of Bicyclus anynana butterflies and compared it with the same network previously described for forewings. We also examined how Ubx interacts with each of these three eyespot-essential genes. We found similar genetic interactions between the three genes in fore- and hindwings, but we discovered three regulatory differences: Antennapedia (Antp) merely enhances spalt (sal) expression in the eyespot foci in hindwings, but is not essential for sal activation, as in forewings; Ubx upregulates Antp in all hindwing eyespot foci but represses Antp outside these wing regions; and Ubx regulates sal in a wing sector-specific manner, i.e. it activates sal expression only in the sectors that have hindwing-specific eyespots. We propose a model for how the regulatory connections between these four genes evolved to produce wing- and sector-specific variation in eyespot number.

Wing morphology and eyespot pattern of Erebia medusa (Lepidoptera, Nymphalidae) vary along an elevation gradient in the Carpathian Mountains

Wing morphology and eyespot pattern of Erebia medusa (Lepidoptera, Nymphalidae) vary along an elevation gradient in the Carpathian Mountains

Descriptors of a New Morphotype of One Stripe Spiny Eel, Macrognathus aral(Bloch & Schneider, 1801), Family: Mastacembelidae

The new ocelli variant of Macrognathus aral (Bloch & Schneider, 1801) under Mastacembelidae family was recorded from Gangetic Wetlands of North 24 Parganas, West Bengal, India. The new variant can be considered as a potential ornamental fish apart from high valued food fish, due its more number of ocelli in both dorsal and anal fin base of the body surface, which comparable to other commercially important M. aral.

Predation favours Bicyclus anynana butterflies with fewer forewing eyespots.

There are fewer eyespots on the forewings versus hindwings of nymphalids but the reasons for this uneven distribution remain unclear. One possibility is that, in many butterflies, the hindwing covers part of the ventral forewing at rest and there are fewer forewing sectors to display eyespots (covered eyespots are not continuously visible and are less likely to be under positive selection). A second explanation is that having fewer forewing eyespots confers a selective advantage against predators. We analysed wing overlap at rest in 275 nymphalid species with eyespots and found that many have exposed forewing sectors without eyespots: i.e. wing overlap does not constrain the forewing from having the same number or more eyespots than the hindwing. We performed two predation experiments with mantids to compare the relative fitness of and attack damage patterns on two forms of Bicyclus anynana butterflies, both with seven hindwing eyespots, but with two (in wild-type) or four (in Spotty) ventral forewing eyespots. Spotty experienced more intense predation on the forewings, were shorter-lived and laid fewer eggs. These results suggest that predation pressure limits forewing eyespot number in B. anynana. This may occur if attacks on forewing eyespots have more detrimental consequences for flight than attacks on hindwing eyespots.

Inter-Individual Differences in Ornamental Colouration in a Mediterranean Lizard in Relation to Altitude, Season, Sex, Age, and Body Traits

Animals frequently show complex colour patterns involved in social communication, which attracts great interest in evolutionary and behavioural ecology. Most researchers interpret that each colour in animals with multiple patches may either signal a different bearer’s trait or redundantly convey the same information. Colour signals, moreover, may vary geographically and according to bearer qualities. In this study, we analyse different sources of colour variation in the eastern clade of the lizard Psammodromus algirus. Sexual dichromatism markedly differs between clades; both possess lateral blue eyespots, but whereas males in the western populations display strikingly colourful orange-red throats during the breeding season, eastern lizards only show some commissure pigmentation and light yellow throats. We analyse how different colour traits (commissure and throat colouration, and the number of blue eyespots) vary according to body size, head size (an indicator of fighting ability), and sex along an elevational gradient. Our findings show that blue eyespots function independently from colour patches in the commissure and throat, which were interrelated. Males had more eyespots and orange commissures (which were yellow or colourless in females). Throat colour saturation and the presence of coloured commissures increased in older lizards. The number of eyespots, presence of a coloured commissure, and throat colour saturation positively related to head size. However, while the number of eyespots was maximal at lowlands, throat colour saturation increased with altitude. Overall, our results suggest that this lizard harbours several colour signals, which altitudinally differ in their importance, but generally provide redundant information. The relevance of each signal may depend on the context. For example, all signals indicate head size, but commissure colouration may work well at a short distance and when the lizard opens the mouth, while both throat and eyespots might work better at long distance. Meanwhile, throat colouration and eyespots probably work better in different light conditions, which might explain the altitudinal variation in the relative importance of each colour component.

First description of color variations in the annual killifish Millerichthys robustus, and preliminary observations about its geographical distribution

Millerichthys robustus is the only annual killifish distributed in America with phenotypic color variations, not yet described. Accordingly, we first describe the color pattern in both sexes to define its phenotypical variations. We then analyze the frequency of these phenotypes on a geographical scale, in four localities that represent opposite points of Millerichthys’s distribution in the Mexican southeast. Color analysis based on the RGB system allowed us to define five-color phenotypes in males continuously distributed in various perceptual units between two extreme colors (yellow-red): yellow, moderate orange, dark orange, strong orange and red. These color patterns found in M. robustus could be attributed to melanin, carotenoid, and pteridine pigments. The orange phenotypes was present in all localities studied. The yellow phenotype was present only in northeastern and northwestern locations, and the red phenotype was present only in northern populations. Female color variations were observed in the number of ocelli (from 1 to 15) at the base of the caudal peduncle and dorsal region. Ocelli have been associated with anti-predator functions because they resemble the eyes of vertebrates, thus shifting the target of predator attacks to less vital body parts. Females with 3 ocelli were the most frequent phenotype, and females with 13–15 ocelli occurred only in the northern populations. We concluded that male and female of M. robustus are not randomly distributed along their distribution range, which suggest that color phenotypes may react differently to biotic and abiotic factors that probably determine their distribution and frequency within the studied population.

Male mate choice in the annual killifish Millerichthys robustus and its relationship with female polymorphism, size and fecundity

In the classic theory of sexual roles, females are more careful in their choice of a mate because their reproductive investment is relatively higher. However, increasing evidence shows that males can also be choosy. Mate choice can be based on physical characteristics, such as body size and color ornaments, which have been documented as factors that also influence the maintenance of polymorphism. Here, we experimentally tested whether males of the annual killifish Millerichthys robustus preferentially choose females according to variations in ocelli number on the base of the caudal fin, or according to body size, in classical dual decision experiments. We demonstrated that there is a strong preference of the males of M. robustus for females with greater numbers of ocelli on the base of the caudal fin (females with 5–7 versus 1–2 ocelli) and for females of larger body size. We also tested whether female body size or number of ocelli are linked to higher fecundity or increased egg size, quantifying the number of embryos produced by the females of each experimental group and measuring the size of their eggs. Our results revealed that large females with more ocelli produced more and larger eggs than large females with fewer ocelli, and than small females regardless of the number of ocelli. These results may suggest that males of M. robustus that choose large-sized females can mate with genetic quality in parameters directly related to biological success, such as higher egg production of large-sized eggs. This is probably related to a higher hatching percentage, and larger subsequent larvae with rapid growth rates. We therefore propose that large body size and high number of ocelli on the base of the caudal fin in females could have evolved through male mate choice.

What Drives the Diversification of Eyespots in Morpho Butterflies? Disentangling Developmental and Selective Constraints From Neutral Evolution

Eyespots are wing colour pattern elements repeatedly observed in many butterflies, whose developmental genetics has been extensively documented. Nevertheless, the evolutionary forces shaping their diversification across species still remain largely unknown. Here we investigate the evolution of eyespots in the 30 species of the neotropical genus Morpho. Morpho butterflies display a series of eyespots located on the ventral side of their wings, highly variable among species, ranging from large, conspicuous structures to relictual spots. Applying geometric morphometrics to a large sample (N = 910) spanning all Morpho species and both sexes, we assess eyespots number, position, size and shape. We detect a divergence in eyespots position between understory and canopy species that opposes an L-shaped configuration in canopy species to a line pattern in understory species, where the eyespots tend to fuse and form a stripe in white and pale species. This effect is stronger than expected based on a Brownian motion model of phylogenetic divergence, suggesting an adaptation to the microhabitat and an influence of the wing colour on the evolution of pattern elements. Remarkably, this shift in colour pattern is strongly correlated with a shift in wing shape. However, using a thin-plate spline interpolation, we show that the shape change is insufficient to explain the evolution of eyespots position as a developmental side-effect of wing shape evolution, also pointing at an adaptive effect. Finally, we find a significant negative correlation between eyespot relative size and the within-species variation in eyespot number, position, size and shape, suggesting a relaxed or apostatic selection on small eyespots. We hypothesize that contrasted ecology may explain the observed differences between species: large and phenotypically stable eyespots might act as attack deflectors; small, variable faded eyespots might rather enhance crypsis; and pale species stripe pattern might disrupt the outline of the wing.

Multiple Loci Control Eyespot Number Variation on the Hindwings of Bicyclus anynana Butterflies.

The underlying genetic changes that regulate the appearance and disappearance of repeated traits, or serial homologs, remain poorly understood. One hypothesis is that variation in genomic regions flanking master regulatory genes, also known as input-output genes, controls variation in trait number, making the locus of evolution almost predictable. Another hypothesis implicates genetic variation in up- or downstream loci of master control genes. Here, we use the butterfly Bicyclus anynana, a species that exhibits natural variation in eyespot number on the dorsal hindwing, to test these two hypotheses. We first estimated the heritability of dorsal hindwing eyespot number by breeding multiple butterfly families differing in eyespot number and regressing eyespot numbers of offspring on midparent values. We then estimated the number and identity of independent genetic loci contributing to eyespot number variation by performing a genome-wide association study with restriction site-associated DNA sequencing from multiple individuals varying in number of eyespots sampled across a freely breeding laboratory population. We found that dorsal hindwing eyespot number has a moderately high heritability of ∼0.50 and is characterized by a polygenic architecture. Previously identified genomic regions involved in eyespot development, and novel ones, display high association with dorsal hindwing eyespot number, suggesting that homolog number variation is likely determined by regulatory changes at multiple loci that build the trait, and not by variation at single master regulators or input-output genes.

Interacting Effects of Eyespot Number and Ultraviolet Reflectivity on Predation Risk in Bicyclus anynana (Lepidoptera: Nymphalidae).

Small marginal eyespots on lepidopteran wings are conspicuous elements that attract a predator’s attention to deflect attacks away from the body, but the role of ultraviolet (UV) reflectivity at the center of these patterns and variation in eyespot number in altering the function of eyespots remains unclear. Here, we performed a field-based predation experiment with artificial prey items based on the appearance of squinting bush brown butterflies Bicyclus anynana (Butler, 1879). We tested how two visual properties of the wing pattern affect predation risk: i) the number of eyespots on the ventral forewing surface—two or four; and ii) the UV reflectivity of eyespot centers—normal (where the UV reflectivity of the centers contrasts strongly with that of the darker surrounding ring) or blocked (where this contrast is reduced). In total, 807 prey items were deployed at two sites. We found a significant interaction between the number of ventral forewing eyespots and UV reflectivity in the eyespot centers: in items with fewer eyespots, blocking UV resulted in increased predation risk whereas in items with more eyespots, blocking UV resulted in decreased predation risk. If higher predation of paper models can be equated with higher levels of wing margin/eyespot conspicuity, these results demonstrate that UV reflectivity is an important factor in making eyespots more conspicuous to predators and suggest that the fitness of particular butterfly eyespot number variants may depend on the presence or absence of UV in their centers and on the ability of local predator guilds to detect UV.

Use of Taxonomic and Trait-Based Approaches to Evaluate the Effects of Transgenic Cry1Ac Corn on the Community Characteristics of Soil Collembola.

Nontarget soil fauna in fields planted with transgenic Bt crops may be influenced by the Bt protein following crop establishment. Here, we investigated the effects of transgenic Cry1Ac corn Bt-799 on soil Collembola using both taxonomic and trait-based approaches in an experimental field in northeast China from 2014 to 2015. The relationship between the collembolan community and environmental variables (including corn type) was investigated using redundancy analysis (RDA). In May 2015, we found that collembolan species richness, Shannon-Wiener's index, and all trait values examined in transgenic Cry1Ac corn (Event Bt-799, Bt corn) were lower than in its near isoline (Zheng 58, non-Bt corn). However, this significant influence did not persist in the subsequent corn growth period. For all other sampling periods over 2-yr study, all indices based on taxonomic (abundance, species richness, and Shannon-Wiener's index) and trait-based (number of ocelli, body size, pigmentation, furcula development, and antennae length) approaches in Bt corn were not significantly different from non-Bt corn. The results showed no significant difference between the two corn types in the repeated-measures analysis of variance (ANOVA). Moreover, redundancy analysis (RDA) showed that corn type only explained 1% of the variation in the collembolan community. These results suggested that Bt corn did not affect collembolan community characteristics in the short term.

Apterous A specifies dorsal wing patterns and sexual traits in butterflies.

Butterflies have evolved different colour patterns on their dorsal and ventral wing surfaces to serve different signalling functions, yet the developmental mechanisms controlling surface-specific patterning are still unknown. Here, we mutate both copies of the transcription factor apterous in Bicyclus anynana butterflies using CRISPR/Cas9 and show that apterous A, expressed dorsally, functions both as a repressor and modifier of ventral wing colour patterns, as well as a promoter of dorsal sexual ornaments in males. We propose that the surface-specific diversification of wing patterns in butterflies proceeded via the co-option of apterous A or its downstream effectors into various gene regulatory networks involved in the differentiation of discrete wing traits. Further, interactions between apterous and sex-specific factors such as doublesex may have contributed to the origin of sexually dimorphic surface-specific patterns. Finally, we discuss the evolution of eyespot number diversity in the family Nymphalidae within the context of developmental constraints due to apterous regulation.

Post-Embryonic Development and Genital-Complex Formation in Three Species of Polyclad Flatworms.

Without the establishment of effective culturing systems, little can be known about the late developmental stages of polyclad flatworms. Here, we report a laboratory culturing system for three polyclad species: Comoplana pusilla, Notocomplana koreana, and Pseudostylochus obscurus, and we describe changes in their morphology from hatching to reproductive maturity. These species hatch out as lobe-less larvae with four eyespots, but the number of eyespots increases in later development. Cross-like and triangularly shaped larvae are observed in N. koreana and P. obscurus, respectively. After settlement, a pale area appears on the body of juveniles and then develops into the copulatory complexes. All three species could be successfully reared on brine shrimp, but only C. pusilla and N. koreana achieved reproductive maturation in such a culturing system. In P. obscurus, switching the food to the gastropod Monodonta labio induced sexual maturation.

A Quick View on Biology of Near Threatened Peacock Eel (<i>Macrognathus aculeatus</i>) in Khulna Region of Bangladesh

The Peacock eel, Macrognathus aculeatus is a near threatened highly valuable small indigenous species in Bangladesh. It is not only toothsome nutritive table fish but also notable aquarium species but still rely on natural stock. Keeping in mind the paucity of information on the biology which is crucial to develop artificial propagation and culture technique of this species, the present research was performed as an attempt to contribute to the information on the taxonomy and other biological aspects of M. aculeatus. Total 50 samples were collected from Khulna region during April to May 2014 to assay. The taxonomical study revealed that the total length, standard length, head length, eye diameter, pre and post orbital length; length of dorsal, anal and caudal fin; length of upper and lower jaw; body depth and width, distance between dorsal fin to caudal fin ranged from 17.00-21.00, 15.00-19.00, 0.80-3.00, 0.20-0.40, 0.50-2.10, 0.30-1.70, 3.10-6.70, 3.50-6.30, 0.50-1.50, 0.30-1.00, 0.70-1.80, 0.90-2.30, 0.60-1.20, 0.70-2.40 cm respectively, additionally meristic character’s formula appeared like D. 19 - 39, A. 11 - 18, C. 29 – 52, L. 11-15 and number of eye spots on dorsal fin, 3-10. Turning to the biological inquiry which showed that the fish weight (g), gonad weight (g), liver weight (g), gut weight (g), gonadosomatic, alimentosomatic and hepatosomatic index and condition factor ranged from 15.10-28.60, 2.32-3.18, 0.029-0.044, 0.64-1.08, 9.69-14.79, 2.58-4.15, 0.11-0.19 and 0.30-0.40 respectably. The mean values of hepatosomatic and alimentosomatic indices persuaded greater liver activity and feeding intensity in M. aculeatus. Moreover, stomach content depicted that the diet of peacock eel composed of small fish species, small prawn, prawn larvae, earthworm, water strider, insects pupae, Metaphire posthuma, Caenorhabditis, sand and mud for instance, which in brief expressed that M. aculeatus is omnivorous in its feeding habits. Indeed, this preliminary research outcome would be utile for the species identification, seed production, developing culture technologies as well as biodiversity conservation of this near threatened fish species.

The subgenus Monotarsobius in the Iberian Peninsula with a description of a new pseudo-cryptic species from Northern Spain revealed by an integrative revision of Lithobius crassipes L. Koch, 1862 (Chilopoda, Lithobiomorpha, Lithobiidae).

The widespread European centipede species Lithobius (Monotarsobius) crassipes L. Koch, 1862 was revised using an integrative approach incorporating sequence data and morphology. The partial mitochondrial cytochrome c oxidase subunit I (COI) barcoding gene was amplified and sequenced for 21 individuals from northern Spain, France and Germany as well as for individuals of three other species of the subgenus Monotarsobius Verhoeff, 1905. The dataset was used for molecular phylogenetic analysis and genetic distance determination. In addition, Monotarsobius specimens from more than 100 localities in northern Spain, France, and Germany were morphologically investigated. Both morphological and molecular data indicate that specimens from the Navarre and Gipuzkoa provinces, northern Spain, represent a distinct pseudo-cryptic species, only differing in some minor characters from L. crassipes. The new species L. (Monotarsobius) crassipesoides sp. n. is described and compared to L. crassipes in detail using morphology and morphometric statistics for body, head, and antennae length, number of ocelli and coxal pores, as well as the starting leg for legpair spines Vmt and DaP. The Iberian and European records of L. crassipes are discussed. The subspecies L. crassipes morenoi Garcia Ruiz, 2014 from Southern Spain is elevated to species as L. morenoi stat. n. A checklist, distribution map and key to all five species of Monotarsobius of the Iberian Peninsula are presented.

Relationship between land-use types and functional diversity of epigeic Collembola in Southern Brazil

Land-use change has been identified, among global changes, as the main threat causing biodiversity loss, locally and regionally. This is especially true in Southern Brazil with the two main biomes (Pampa and Atlantic forest) facing high conversion rate into agricultural land to meet increasing demand for food and fuel. Within this region, we focused on epigeic biota across three land-use types (forest, grassland and Eucalyptus plantation). We used both a taxonomical and a trait-based approach to depict the changes of Epigeic Collembola assemblages across land-use types. Furthermore, we tested trait-convergence and trait-divergence across land-use types to infer how the environmental filtering and biotic interactions can affect assembly rules and collembolan community composition. Results differed according to the approach used (either taxonomical or trait-based). In general, diversity indices based on the taxonomical approach did not significantly differ between forest and grassland, whereas Eucalyptus plantation showed significantly lower values. Functional diversity was significantly higher in forest and similar between grassland and Eucalyptus plantation. Furthermore, we found both convergence and divergence of subsets of traits related to the land-use types. The trait-convergence tended to be higher in grassland sites and rather linked to sensorial traits (number of ocelli, antenna length, and trichobothria), drought tolerance traits (body size) and habitat preference traits (pigmentation level, furca development, scale, number of ocelli, antenna length, and body size). On the opposite, Trait-divergence was only linked to sensorial traits (antenna length and postantennal organ) and greatest in forest sites. Our findings showed that a trait-based approach associated with a taxonomic one provides a better understanding of the collembolan community structuring in response to biotic and abiotic changes across different land-use types.

Genome editing in butterflies reveals that spalt promotes and Distal-less represses eyespot colour patterns.

Butterfly eyespot colour patterns are a key example of how a novel trait can appear in association with the co-option of developmental patterning genes. Little is known, however, about how, or even whether, co-opted genes function in eyespot development. Here we use CRISPR/Cas9 genome editing to determine the roles of two co-opted transcription factors that are expressed during early eyespot determination. We found that deletions in a single gene, spalt, are sufficient to reduce or completely delete eyespot colour patterns, thus demonstrating a positive regulatory role for this gene in eyespot determination. Conversely, and contrary to previous predictions, deletions in Distal-less (Dll) result in an increase in the size and number of eyespots, illustrating a repressive role for this gene in eyespot development. Altogether our results show that the presence, absence and shape of butterfly eyespots can be controlled by the activity of two co-opted transcription factors.

Austrobdella cairae n. sp., an Oioxenous Marine Leech (Clitellata: Piscicolidae) from the Banded Guitarfish, Zapteryx exasperata, in the Northeastern Pacific Ocean.

A new marine leech is herein described from specimens infecting the external surfaces, including the mouth and cloaca, of the banded guitarfish, Zapteryx exasperate, captured in the Gulf of California and eastern Pacific Ocean off the coast of San Diego, California. The leech is assigned to Austrobdella by possessing continuous contractile coelomic channels that lie outside the somatic musculature along the lateral edges of the urosome (marginal lacunae), clitellar gland cells densely packed in the urosome, 5 pairs of testisacs, and 6-annulate mid-body somites. The new leech is distinguished from its 6 congeners on the basis of body size (maximum 10 mm long) and shape (sub-cylindrical trachelosome distinctly demarcated from wider urosome that is ventrally flattened, convex dorsally, and narrowing toward caudal sucker that is narrow, 20-25% of maximum body width), number of eyespots (2 pairs), shape and arrangement of the ovisacs (pyriform and limited to somites XII/XIII), and characteristics of the midgut (1 pair of mycetomes, 6 pairs of simple thin-walled crop ceca, ventral postceca wanting, and 2 pairs of dendritic diverticula emerging from anterior portion of thick-walled intestine). The new species occurs in the northeastern Pacific Ocean on a benthic elasmobranch. Examination of host specificity for each Austrobdella species using the quantitative Index of Phylogenetic Host Specificity revealed that the new species is 1 of 4 oioxenous specialists in the genus, and the remaining 3 congeners are relative generalists herein classified as euryxenous. This is the first time host specificity for members of the Piscicolidae has been quantitatively assessed. The analysis suggests that associations between marine leeches belonging in Austrobdella and their vertebrate hosts are driven by ecological influences rather than host taxonomic placement.

Attack risk for butterflies changes with eyespot number and size.

Butterfly eyespots are known to function in predator deflection and predator intimidation, but it is still unclear what factors cause eyespots to serve one function over the other. Both functions have been demonstrated in different species that varied in eyespot size, eyespot number and wing size, leaving the contribution of each of these factors to butterfly survival unclear. Here, we study how each of these factors contributes to eyespot function by using paper butterfly models, where each factor is varied in turn, and exposing these models to predation in the field. We find that the presence of multiple, small eyespots results in high predation, whereas single large eyespots (larger than 6 mm in diameter) results in low predation. These data indicate that single large eyespots intimidate predators, whereas multiple small eyespots produce a conspicuous, but non-intimidating signal to predators. We propose that eyespots may gain an intimidation function by increasing in size. Our measurements of eyespot size in 255 nymphalid butterfly species show that large eyespots are relatively rare and occur predominantly on ventral wing surfaces. By mapping eyespot size on the phylogeny of the family Nymphalidae, we show that these large eyespots, with a potential intimidation function, are dispersed throughout multiple nymphalid lineages, indicating that phylogeny is not a strong predictor of eyespot size.