Color Pattern Elements Research Articles

Mating preferences act independently on different elements of visual signals in Heliconius butterflies

Abstract Mating cues are often comprised of several elements, which can act independently, or in concert to attract a suitable partner. Individual elements may also function in other contexts, such as anti-predator defense or camouflage. In Heliconius butterflies, wing patterns comprise several individual color pattern elements, which advertise the butterflies’ toxicity to predators. These wing patterns are also mating cues and males predominantly court females that possess the same wing pattern as their own. However, it is not known whether male preference is based on the full wing pattern or only individual pattern elements. We compared preferences of male H. erato lativitta between female models with the full wing pattern and those with some pattern elements removed. We found no differences in preference between the full wing pattern model and a model with pattern elements removed, indicating that the complete composition of all elements is not essential to the mating signal. Wing pattern preferences also contribute to pre-mating isolation between two other Heliconius taxa, H. erato cyrbia, and H. himera; therefore, we next compared preferences for the same models in these species. H. erato cyrbia and H. himera strongly differed in preferences for the models, potentially providing a mechanism for how pre-mating isolation acts between these species. These findings suggest that contrasting levels of selective constraint act on elements across the wing pattern.

Phenotypic and genomic dissection of colour pattern variation in a reef fish radiation.

Coral reefs rank among the most diverse species assemblages on Earth. A particularly striking aspect of coral reef communities is the variety of colour patterns displayed by reef fishes. Colour pattern is known to play a central role in the ecology and evolution of reef fishes through, for example, signalling or camouflage. Nevertheless, colour pattern is a complex trait in reef fishes-actually a collection of traits-that is difficult to analyse in a quantitative and standardized way. This is the challenge that we address in this study using the hamlets (Hypoplectrus spp., Serranidae) as a model system. Our approach involves a custom underwater camera system to take orientation- and size-standardized photographs in situ, colour correction, alignment of the fish images with a combination of landmarks and Bézier curves, and principal component analysis on the colour value of each pixel of each aligned fish. This approach identifies the major colour pattern elements that contribute to phenotypic variation in the group. Furthermore, we complement the image analysis with whole-genome sequencing to run a multivariate genome-wide association study for colour pattern variation. This second layer of analysis reveals sharp association peaks along the hamlet genome for each colour pattern element and allows to characterize the phenotypic effect of the single nucleotide polymorphisms that are most strongly associated with colour pattern variation at each association peak. Our results suggest that the diversity of colour patterns displayed by the hamlets is generated by a modular genomic and phenotypic architecture.

Four species in one: taxonomic revision of the Eirmocides helenita (Semper, 1879) complex (Lepidoptera: Lycaenidae) from Australia and New Guinea

AbstractTaxonomic investigations of the Eirmocides helenita (Semper, 1879) complex from north‐eastern Australia and mainland New Guinea based on adult morphology (male genitalia and wing colour pattern elements), together with a phylogenetic hypothesis of the genus (18 or 69% of the recognised species) based on molecular data (1 mitochondrial and 12 nuclear genes), and examination of type material, indicate that there are five species within this monophyletic lineage, here referred to as the E. helenita species‐group. Four of the species, previously classified under the name Eirmocides helenita (Semper, 1879) sensu lato and characterised by iridescent turquoise dorsal colouration in the male, are predominantly allopatric, as follows: Eirmocides callainus Braby & Müller, sp. nov., is endemic to the Wet Tropics biome of north‐eastern Queensland; Eirmocides helenita (Semper, 1879) sensu stricto is restricted to Cape York Peninsula of northern Queensland; Eirmocides rouku Braby & Müller, sp. nov., is endemic to the Western Province of southern Papua New Guinea; and Eirmocides dimorphus (Röber, 1886), stat. rev., occurs more widely throughout mainland New Guinea and its adjacent islands. The fifth member of the group, Eirmocides cupreus (Röber, 1886), is sympatric with E. dimorphus on mainland New Guinea. The taxonomic revision brings to 26 the total number of species recognised in Eirmocides and within the tribe Candalidini to 40 species. Lectotypes are designated for Plebeius dimorphus Röber, 1886, Plebeius dimorphus var. cupreus Röber, 1886, and Holochila subargentea Grose‐Smith & Kirby, 1896.

The genetic basis of wing spots in Pieris canidia butterflies

Spots in pierid butterflies and eyespots in nymphalid butterflies are likely non-homologous wing colour pattern elements, yet they share a few features in common. Both develop black scales that depend on the function of the gene spalt, and both might have central signalling cells. This suggests that both pattern elements may be sharing common genetic circuitry. Hundreds of genes have already been associated with the development of nymphalid butterfly eyespot patterns, but the genetic basis of the simpler spot patterns on the wings of pierid butterflies has not been investigated. To facilitate studies of pierid wing patterns, we report a high-quality draft genome assembly for Pieris canidia, the Indian cabbage white. We then conducted transcriptomic analyses of pupal wing tissues sampled from the spot and non-spot regions of P. canidia at 3-6 h post-pupation. A total of 1352 genes were differentially regulated between wing tissues with and without the black spot, including spalt, Krüppel-like factor 10, genes from the Toll, Notch, TGF-β, and FGFR signalling pathways, and several genes involved in the melanin biosynthetic pathway. We identified 14 genes that are up-regulated in both pierid spots and nymphalid eyespots and propose that spots and eyespots share regulatory modules despite their likely independent origins.

Color pattern complexity in dwarf minke whales (Balaenoptera acutorostrata) of the northern Great Barrier Reef of Australia

AbstractComplex color patterning is a characteristic feature of dwarf minke whales (DMWs; Balaenoptera acutorostrata) which has been used to photographically identify (photo‐ID) individuals and to research an aggregation on Australia's Great Barrier Reef (GBR). DMW color patterns have been described and applied in various studies, but a detailed and systematic analysis of their complexity is yet to be performed. Here, we applied a novel categorization tool to assess the variation, asymmetry, and association of several DMW color pattern elements, subelements, and their character states. Proportions, hierarchical clustering, and multiple correspondence analysis revealed a high level of asymmetric color pattern variation, with white markings dominant and associated on the right of the body. Our results will improve the citizen science driven photo‐ID of this little‐known cetacean as labor‐intensive manual methods transition to more efficient automated approaches. Such advancement will be challenging, yet beneficial for broader research into the poorly understood areas of DMW life history, evolution, genetics, social structure, and feeding. This could also potentially allow investigation into the functional significance of their color patterns.

Patterns of morphological variation highlight the effect of natural selection on eyespots modularity in the butterfly Morpho telemachus.

Morphological correlations can not only stem from developmental constraints but also from selective pressures. Butterfly eyespots are repeated wing color pattern elements, widespread across species. As developmental serial homologs, they are controlled by similar developmental pathways imposing correlations among eyespots: selection on a single eyespot may induce correlated responses in all eyespots. We study the variations in the ventral eyespots of Morpho telemachus, where two different selective regimes are likely to act: while most eyespots are always-visible, two eyespots are conditionally displayed: hidden at rest, they can be exposed when the butterflies are threatened, or during sexual interactions. We investigate how such contrasted selection across eyespots can alter the covariations imposed by their shared developmental origin. We quantified eyespots covariations within a large population of M. telemachus and compared the observed patterns to those found in M. helenor, where all eyespots are always-visible and thus probably affected by a similar selection regime. We found that M. telemachus conditionally displayed eyespots are less variable than always-visible eyespots and that these two eyespots form a separate variational module in this species, in contrast to M. helenor. Our results suggest that eyespots covariations were shaped by selection, highlighting how natural selection may promote the evolution of modularity.

Phenotypic Correlates of Pelvic Spine Coloration in the Threespine Stickleback (Gasterosteus aculeatus): Implications for Function and Evolution.

Animal color patches may be static or plastic in expression and concealable or continuously visible, yet the evolution and function of these aspects of coloration have seldom been studied together. We investigated such color pattern elements using the threespine stickleback (Gasterosteus aculeatus). Despite a rich history of study of stickleback nuptial color pattern evolution, disagreement persists regarding selection pressures and function and only limited research has addressed the role of pelvic spine coloration, a potentially important, and substantially concealable, color pattern element. We investigated (i) whether male pelvic spine (along with throat and body) coloration is relatively static or plastic across the reproductive cycle, (ii) when pelvic spines are raised versus concealed across behavioral contexts, and (iii) associations between color patches and behavior in males. We found no significant variation in spine color across reproductive stages whereas body color was more plastic and intensely red during courtship and egg/fry care. Conspicuousness of pelvic spine coloration instead varied behaviorally, through increased erection frequency during social interactions and in response to a model predator. Spine erection frequency was positively associated with behaviors that enhance spine color visibility, i.e. flees and leads to nest. These findings suggest that stickleback use pelvic spines to display an intensely red color patch facultatively, either as a complement to similar body coloration or possibly as a substitute.

Capturing and analyzing pattern diversity: an example using the melanistic spotted patterns of leopard geckos

Animal color patterns are widely studied in ecology, evolution, and through mathematical modeling. Patterns may vary among distinct body parts such as the head, trunk or tail. As large amounts of photographic data is becoming more easily available, there is a growing need for general quantitative methods for capturing and analyzing the full complexity and details of pattern variation. Detailed information on variation in color pattern elements is necessary to understand how patterns are produced and established during development, and which evolutionary forces may constrain such a variation. Here, we develop an approach to capture and analyze variation in melanistic color pattern elements in leopard geckos. We use this data to study the variation among different body parts of leopard geckos and to draw inferences about their development. We compare patterns using 14 different indices such as the ratio of melanistic versus total area, the ellipticity of spots, and the size of spots and use these to define a composite distance between two patterns. Pattern presence/absence among the different body parts indicates a clear pathway of pattern establishment from the head to the back legs. Together with weak within-individual correlation between leg patterns and main body patterns, this suggests that pattern establishment in the head and tail may be independent from the rest of the body. We found that patterns vary greatest in size and density of the spots among body parts and individuals, but little in their average shapes. We also found a correlation between the melanistic patterns of the two front legs, as well as the two back legs, and also between the head, tail and trunk, especially for the density and size of the spots, but not their shape or inter-spot distance. Our data collection and analysis approach can be applied to other organisms to study variation in color patterns between body parts and to address questions on pattern formation and establishment in animals.

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.

The Evolution of Color Pattern in Butterflyfishes (Chaetodontidae).

Coral reef fishes constitute one of the most diverse assemblages of vertebrates on the planet. Color patterns are known to serve a number of functions including intra- and inter-specific signaling, camouflage, mimicry, and defense. However, the relative importance of these and other factors in shaping color pattern evolution is poorly understood. Here we conduct a comparative phylogenetic analysis of color pattern evolution in the butterflyfishes (Chaetodontidae). Using recently developed tools for quantifying color pattern geometry as well as machine learning approaches, we investigate the tempo of evolution of color pattern elements and test whether ecological variables relating to defense, depth, and social behavior predict color pattern evolution. Butterflyfishes exhibit high diversity in measures of chromatic conspicuousness and the degrees of fine versus gross scale color patterning. Surprisingly, most diversity in color pattern was not predicted by any of the measures of ecology in our study, although we did find a significant but weak relationship between the level of fine scale patterning and some aspects of defensive morphology. We find that the tempo of color pattern diversification in butterflyfishes has increased toward the present and suggest that rapid evolution, presumably in response to evolutionary pressures surrounding speciation and lineage divergence, has effectively decoupled color pattern geometry from some aspects of ecology. Machine learning classification of color pattern appears to rely on a set of features that are weakly correlated with current color pattern geometry descriptors, but that may be better suited for the detection of discrete components of color pattern. A key challenge for future studies lies in determining whether rapid evolution has generally decoupled color patterns from ecology, or whether convergence in function produces convergence in color pattern at phylogenetic scales.

Stabilizing selection on individual pattern elements of aposematic signals.

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus, which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus, used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.

Genetic Basis of Melanin Pigmentation in Butterfly Wings.

Despite the variety, prominence, and adaptive significance of butterfly wing patterns, surprisingly little is known about the genetic basis of wing color diversity. Even though there is intense interest in wing pattern evolution and development, the technical challenge of genetically manipulating butterflies has slowed efforts to functionally characterize color pattern development genes. To identify candidate wing pigmentation genes, we used RNA sequencing to characterize transcription across multiple stages of butterfly wing development, and between different color pattern elements, in the painted lady butterfly Vanessa cardui This allowed us to pinpoint genes specifically associated with red and black pigment patterns. To test the functions of a subset of genes associated with presumptive melanin pigmentation, we used clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing in four different butterfly genera. pale, Ddc, and yellow knockouts displayed reduction of melanin pigmentation, consistent with previous findings in other insects. Interestingly, however, yellow-d, ebony, and black knockouts revealed that these genes have localized effects on tuning the color of red, brown, and ochre pattern elements. These results point to previously undescribed mechanisms for modulating the color of specific wing pattern elements in butterflies, and provide an expanded portrait of the insect melanin pathway.

Stripes, jewels and spines: further investigations into the evolution of defensive strategies in a chemically defended gecko radiation (Strophurus, Diplodactylidae)

The geckos in the genus Strophurus (Diplodactylidae) are one of only two squamate lineages with specialized caudal defensive glands. Many species in this genus also have distinctive caudal ornamentation combined with bright and/or contrasting colour pattern elements on the iris, tail and especially the lining of the mouth that are hypothesized to be adaptations for specialized (e.g. deimatic) defensive functions. We present the first multilocus, phylogenetic analysis of the biogeography and evolution of all recognized taxa of Strophurus. Contrary to previous phenotypic and ecological assessments, our phylogenetic analyses delineate four divergent lineages. Three lineages are relatively small (snout‐vent length [SVL] 40–60 mm), species‐poor (<5 recognized taxa), cryptically coloured (either striped or spotted) and lack precloacal pores (a secondary sexual trait) and putative deimatic elements. In contrast, the remaining lineage is comparatively species rich (at least 14 taxa), attains a larger body size (SVL 60–90 mm), possesses precloacal pores and shows extensive variation in caudal ornamentation and often bright and/or contrasting eye, tail and mouth colouration. The three less diverse lineages have smaller distributions and tend to be associated with spinifex (e.g. Triodia) hummock grasses or rocks, whereas the fourth lineage is much more widespread (including multiple biomes) and consistently reported to utilize more exposed diurnal microhabitats on shrubs and trees. Biogeographical analyses also indicate that – in contrast to many other Australian radiations – the arid biome is the ancestral area of occupation for Strophurus, with multiple inferred shifts into surrounding sclerophyll and monsoon biomes. This study emphasizes that – independent of caudal defensive glands – it appears to be a shift in microhabitat use that correlates with the accumulation of bright and contrasting colouration elements, secondary sexual characters and the widest geographic distribution.

Distal-less induces elemental color patterns in Junonia butterfly wings.

BackgroundThe border ocellus, or eyespot, is a conspicuous color pattern element in butterfly wings. For two decades, it has been hypothesized that transcription factors such as Distal-less (Dll) are responsible for eyespot pattern development in butterfly wings, based on their expression in the prospective eyespots. In particular, it has been suggested that Dll is a determinant for eyespot size. However, functional evidence for this hypothesis has remained incomplete, due to technical difficulties.ResultsHere, we show that ectopically expressed Dll induces ectopic elemental color patterns in the adult wings of the blue pansy butterfly, Junonia orithya (Lepidoptera, Nymphalidae). Using baculovirus-mediated gene transfer, we misexpressed Dll protein fused with green fluorescent protein (GFP) in pupal wings, resulting in ectopic color patterns, but not the formation of intact eyespots. Induced changes included clusters of black and orange scales (a basic feature of eyespot patterns), black and gray scales, and inhibition of cover scale development. In contrast, ectopic expression of GFP alone did not induce any color pattern changes using the same baculovirus-mediated gene transfer system.ConclusionsThese results suggest that Dll plays an instructive role in the development of color pattern elements in butterfly wings, although Dll alone may not be sufficient to induce a complete eyespot. This study thus experimentally supports the hypothesis of Dll function in eyespot development.

Evolutionary Novelty in a Butterfly Wing Pattern through Enhancer Shuffling.

An important goal in evolutionary biology is to understand the genetic changes underlying novel morphological structures. We investigated the origins of a complex wing pattern found among Amazonian Heliconius butterflies. Genome sequence data from 142 individuals across 17 species identified narrow regions associated with two distinct red colour pattern elements, dennis and ray. We hypothesise that these modules in non-coding sequence represent distinct cis-regulatory loci that control expression of the transcription factor optix, which in turn controls red pattern variation across Heliconius. Phylogenetic analysis of the two elements demonstrated that they have distinct evolutionary histories and that novel adaptive morphological variation was created by shuffling these cis-regulatory modules through recombination between divergent lineages. In addition, recombination of modules into different combinations within species further contributes to diversity. Analysis of the timing of diversification in these two regions supports the hypothesis of introgression moving regulatory modules between species, rather than shared ancestral variation. The dennis phenotype introgressed into Heliconius melpomene at about the same time that ray originated in this group, while ray introgressed back into H. elevatus much more recently. We show that shuffling of existing enhancer elements both within and between species provides a mechanism for rapid diversification and generation of novel morphological combinations during adaptive radiation.

Spatial patterns of correlated scale size and scale color in relation to color pattern elements in butterfly wings

Complex butterfly wing color patterns are coordinated throughout a wing by unknown mechanisms that provide undifferentiated immature scale cells with positional information for scale color. Because there is a reasonable level of correspondence between the color pattern element and scale size at least in Junonia orithya and Junonia oenone, a single morphogenic signal may contain positional information for both color and size. However, this color–size relationship has not been demonstrated in other species of the family Nymphalidae. Here, we investigated the distribution patterns of scale size in relation to color pattern elements on the hindwings of the peacock pansy butterfly Junonia almana, together with other nymphalid butterflies, Vanessa indica and Danaus chrysippus. In these species, we observed a general decrease in scale size from the basal to the distal areas, although the size gradient was small in D. chrysippus. Scales of dark color in color pattern elements, including eyespot black rings, parafocal elements, and submarginal bands, were larger than those of their surroundings. Within an eyespot, the largest scales were found at the focal white area, although there were exceptional cases. Similarly, ectopic eyespots that were induced by physical damage on the J. almana background area had larger scales than in the surrounding area. These results are consistent with the previous finding that scale color and size coordinate to form color pattern elements. We propose a ploidy hypothesis to explain the color–size relationship in which the putative morphogenic signal induces the polyploidization (genome amplification) of immature scale cells and that the degrees of ploidy (gene dosage) determine scale color and scale size simultaneously in butterfly wings.

An introgressed wing pattern acts as a mating cue.

Heliconius butterflies provide good examples of both homoploid hybrid speciation and ecological speciation. In particular, examples of adaptive introgression have been detected among the subspecies of Heliconius timareta, which acquired red color pattern elements from H. melpomene. We tested whether the introgression of red wing pattern elements into H. timareta florencia might also be associated with incipient reproductive isolation (RI) from its close relative, H. timareta subsp. nov., found in the eastern Andes. No choice experiments show a 50% reduction in mating between females of H. t. subsp. nov. and males of H .t. florencia, but not in the reciprocal direction. In choice experiments using wing models, males of H. timareta subsp. nov. approach and court red phenotypes less than their own, whereas males of H. t. florencia prefer models with a red phenotype. Intrinsic postzygotic isolation was not detected in crosses between these H. timareta races. These results suggest that a color pattern trait gained by introgression is triggering RI between H. timareta subsp. nov. and H. t. florencia.

Color pattern evolution in Vanessa butterflies (Nymphalidae: Nymphalini): non-eyespot characters.

A phylogenetic approach was used to study color pattern evolution in Vanessa butterflies. Twenty-four color pattern elements from the Nymphalid ground plan were identified on the dorsal and ventral surfaces of the fore- and hind wings. Eyespot characters were excluded and will be examined elsewhere. The evolution of each character was traced over a Bayesian phylogeny of Vanessa reconstructed from 7750 DNA base pairs from 10 genes. Generally, the correspondence between character states on the same surface of the two wings is stronger on the ventral side compared to the dorsal side. The evolution of character states on both sides of a wing correspond with each other in most extant species, but the correspondence between dorsal and ventral character states is much stronger in the forewing than in the hindwing. The dorsal hindwing of many species of Vanessa is covered with an extended Basal Symmetry System and the Discalis I pattern element is highly variable between species, making this wing surface dissimilar to the other wing surfaces. The Basal Symmetry System and Discalis I may contribute to behavioral thermoregulation in Vanessa. Overall, interspecific directional character state evolution of non-eyespot color patterns is relatively rare in Vanessa, with a majority of color pattern elements showing non-variable, non-directional, or ambiguous character state evolution. The ease with which the development of color patterns can be modified, including character state reversals, has likely made important contributions to the production of color pattern diversity in Vanessa and other butterfly groups.

Taxonomic revision of the Taractrocera ilia (Waterhouse) complex (Lepidoptera : Hesperiidae) from north-western Australia and mainland New Guinea based on morphological and molecular data

The taxonomy of the Taractrocera ilia complex is revised based on evidence from multiple sources, including phenotypic characters (wing colour pattern elements, morphology of adult and immature stages), ecology and molecular data. Three species are recognised in the complex: T. psammopetra Braby, sp. nov. is restricted to north-western Australia where it has a disjunct distribution (Kimberley and the central Arnhem Land plateau); T. ilia (Waterhouse, 1932) sensu stricto is endemic to the central Arnhem Land plateau where it is narrowly sympatric with T. psammopetra; while T. beta Evans, 1934, stat. nov. is allopatric and endemic to mainland New Guinea. Each species is illustrated and diagnosed based on comparative morphology of the adult stage, including androconia and male and female genitalia, and information on type material, biology, distribution and habitat is summarised and discussed. A phylogenetic hypothesis of the Australian species of Taractrocera based on combined analysis of molecular data (2.6 kb: mitochondrial COI and nuclear CAD, MDH, wingless) revealed that T. psammopetra is monophyletic and sister to T. ilia, with an overall mean divergence of 3.4% between the two species; the genus Taractrocera, however, emerged as polyphyletic. For T. psammopetra and T. ilia, the life history, including details of larval food plant specialisation and morphology of the immature stages, is described for the first time. Larvae of T. psammopetra and T. ilia specialise on ‘resurrection’ grasses, Micraira spp. (Poaceae), which typically grow as moss-like, mat-forming pioneer plants on shallow rock surfaces comprising open sandstone pavements or on rock ledges and under rock overhangs of sandstone cliffs. These food plants, together with the butterflies that they support, are a characteristic element of the sandstone plateaux of the Kimberley and central Arnhem Land, and they exemplify patterns of diversification, endemism and adaptation to these unique environments within the Australian monsoon tropics. Facultative larval diapause is recorded for both T. psammopetra and T. ilia in which larvae (all instars, but particularly the final instar) may suspend feeding for up to six months during the dry season when the food plants typically dehydrate. It is hypothesised that larval diapause may be the most flexible strategy to ameliorate seasonal adversity of the dry season and the onset, duration and inter-annual cycle of monsoon rainfall during the wet season, which is highly variable and unpredictable, given that Micraira can revive rapidly from a desiccated state after rainfall. http://zoobank.org/urn:lsid:zoobank.org:pub:51438A5E-048C-4C72-AD22-3FD176ECBA55

Taxonomic status of Delias aestiva smithersi Daniels, 2012 (Lepidoptera: Pieridae) comb. nov. from the Gulf Country of northern Australia, with description of the female

The female of Delias aestiva smithersi Daniels, 2012 comb. nov. from northern Australia is illustrated and described for the first time. The subspecies is diagnosed and its taxonomic status clarified. Several unique character states concerning wing colour pattern elements of D. aestiva smithersi, together with evidence of the male genitalia, support the hypothesis that the subspecies belongs to D. aestiva Butler, 1897 and not to D. mysis (Fabricius, 1775). The taxon appears to have a restricted geographical range, being limited to the eastern Gulf of Carpentaria on the western side of Cape York Peninsula, Queensland (from Weipa to Karumba), where it occurs in mangrove habitats in coastal lowland areas. Delias aestiva smithersi and the nominate subspecies, D. aestiva aestiva Butler, 1897 from the Top End, Northern Territory, are allopatric and geographically separated by the Gulf of Carpentaria, suggesting that this biogeographical barrier (the Carpentarian Gap) has facilitated differentiation within the species, either though vicariance or dispersal.