Wing Margin Research Articles

Coloration principles of the Great purple emperor butterfly (Sasakia charonda)

The dorsal wings of male Sasakia charonda butterflies display a striking blue iridescent coloration, which is accentuated by white, orange-yellow and red spots, as well as by brown margins. The ventral wings also have a variegated, but more subdued, pattern. We investigated the optical basis of the various colors of intact wings as well as isolated wing scales by applying light and electron microscopy, imaging scatterometry and (micro)spectrophotometry. The prominent blue iridescence is due to scales with tightly packed, multilayered ridges that contain melanin pigment. The scales in the brown wing margins also contain melanin. Pigments extracted from the orange-yellow and red spots indicate the presence of 3-OH-kynurenine and ommochrome pigment. The scales in the white spots also have multilayered ridges but lack pigment. The lower lamina of the scales plays a so-far undervalued but often crucial role. Its thin-film properties color the majority of the ventral wing scales, which are unpigmented and have large windows. The lower lamina acting as a thin-film reflector generally contributes to the reflectance of the various scale types.

Emperors, admirals and giants, zebras, tigers and woolly bears: casting a broader net in exploring heparin effects on Lepidoptera wing patterns

Background:Studies of heparin effects on Lepidoptera wing patterns have been restricted to a small number of species. I report observations from experiments on a broader range of taxa, including first results from swallowtails, tiger moths and microlepidoptera.Methods:Heparin injections were made in prepupae and pupae ofJunonia coenia(common buckeyes),Agraulis vanillae(gulf fritillaries),Heliconius charithonia(zebra longwings),Asterocampa clyton(tawny emperors), Danaus plexippus(monarchs),Vanessa atalanta(red admirals);Heraclides cresphontes(giant swallowtails),Pterourus troilus(spicebush swallowtails),Protographium marcellus(zebra swallowtails),Battus polydamas(polydamas swallowtails);Hypercompe scribonia(giant leopard moths),Estigmene acrea(acrea moths),Hyphantria cunea(fall webworm moths), Utetheisa ornatrix(ornate bella moths);Glyphodes sibillalis(mulberry leaftier).Results:Heparin sometimes altered the entire pattern in a dramatic way, sometimes caused changes locally.In buckeyes, the previous heparin study conducted on pupae was compared to injections made at a prepupal stage. In gulf fritillaries, zebra longwings and tawny emperors, the dramatic changes occurred throughout their wings, while in monarchs, changes were restricted to wing margins. Changes achieved in red admirals, show that heparin action is unrelated to the original color. In swallowtails, transformations were restricted to border system, indicating higher levels of stability and compartmentalization of wing patterns. In mulberry leaftier, changes were restricted to the marginal bands. In tiger moths, elongation of black markings led to merging of spots; in the ornate bella moth, it was accompanied by an expansion of the surrounding white bands, and results were compared to the effects of colder temperatures.Conclusions:Using pharmaceutical intervention demonstrates that there are many similarities and some very significant differences in the ways wing patterns are formed in different Lepidoptera lineages. By creating a range of variation one can demonstrate how one pattern can easily evolve into another, aiding in understanding of speciation and adaptation processes.

Odonatans in lowermost Cenomanian Kachin amber: updated review and a new hemiphlebiid damselfly

Odonatans are rare in Cretaceous amber deposits, and only four fragmentary specimens were recorded in Lebanese, Jordanian, Charentes and South Dakota ambers except for Kachin amber. This study reviewed the odonatans in lowermost Cenomanian Kachin amber and commented 11 odonatans, which were previously placed in the family level. Until now, over 350 odonatans have been found in Kachin amber, including 38 species of three extant suborders, and representing the most diverse and abundant dragonfly assemblage in amber inclusions. The dominated odonatans include the damselflies Burmahemiphlebia zhangi and Mesomegaloprepus magnificus, and the damsel-dragonfly Burmaphlebia reifi, accounting for ca. 79% of all odonatans. The Kachin odonatans include the earliest records of the damselfly Perilestidae, Platycnemididae and Platystictidae, and the youngest records of the true dragonfly Araripegomphidae and Stenophlebiidae, contributing to exploring the origination and evolution of these families.Hemiphlebiidae is the dominant family in Kachin amber, represented by the species Burmahemiphlebia zhangi with ca. 160 species been recorded. It is surprising that the hemiphlebiid damselfly is abundant, but the diversity is very low with only two species been previously reported. Herein, a new hemiphlebiid damselfly, Kachinhemiphlebia lini gen. et sp. nov., is described by the unique characters: Arc slightly distal of Ax2 in both fore- and hindwings; and a well-defined AA ending on posterior wing margin below Ax2. This is the second genus of the Hemiphlebiidae in Kachin amber.

Role of Armadillo repeat 2 and kinesin-II motor subunit Klp64D for wingless signaling in Drosophila

Armadillo (Arm) is crucial for transducing Wingless (Wg) signaling. Previously, we have shown that Klp64D, a motor subunit of Drosophila kinesin-II, interacts with Arm for Wg signaling. Molecular basis for this interaction has remained unknown. Here we identify a critical Arm repeat (AR) required for binding Klp64D and Wg signaling. Arm/{varvec{beta}}-catenin family proteins contain a conserved domain of 12 Arm repeats (ARs). Five of these ARs can interact with Klp64D, but only the second AR (AR2) binds to the cargo/tail domain of Klp64D. Overexpression of AR2 in wing imaginal disc is sufficient to cause notched wing margin. This phenotype by AR2 is enhanced or suppressed by reducing or increasing Klp64D expression, respectively. AR2 overexpression inhibits Wg signaling activity in TopFlash assay, consistent with its dominant-negative effects on Klp64D-dependent Wg signaling. Overexpression of the Klp64D cargo domain also results in dominant-negative wing notching. Genetic rescue data indicate that both AR2 and Klp64D cargo regions are required for the function of Arm and Klp64D, respectively. AR2 overexpression leads to an accumulation of Arm with GM130 Golgi marker in Klp64D knockdown. This study suggests that Wg signaling for wing development is regulated by specific interaction between AR2 and the cargo domain of Klp64D.

A Survey of Chemoreceptive Responses on Different Mosquito Appendages.

Research on the functions of insect chemoreceptors have primarily focused on antennae (olfactory receptors) and mouthparts (gustatory receptors). However, chemoreceptive sensilla are also present on other appendages, such as the leg tarsi and the anterior wing margin, and their specific roles in chemoreception and mosquito behavior remain largely unknown. In this study, electrophysiological analyses in an electroantennogram recording format were performed on Aedes aegypti (L., Diptera: Culicidae) antennae, mouthparts, tarsi, and wings during exposure to a variety of insect repellent and attractant compounds. The results provide evidence that the tarsi and wings can sense chemicals in a gaseous form, and that the odors produce differing responses on different appendages. The most consistent and strongest response occurred when exposed to triethylamine (TEA). Antennae and mouthparts showed nearly identical responses pattern to all tested compounds, and their rank orders of effectiveness were similar to those of fore- and mid-leg tarsi. Hindleg tarsi only responded to TEA, indicating that the hind legs are not as chemoreceptive. Wings responded to a range of odorants, but with a different rank order and voltage amplitude. Insights gleaned into the function of these appendages in insect chemoreception are discussed.

Wingless and Archipelago, a fly E3 ubiquitin ligase and a homolog of human tumor suppressor FBW7, show an antagonistic relationship in wing development

BackgroundArchipelago (Ago) is a Drosophila homolog of mammalian F-box and WD repeat domain-containing 7 (FBW7, also known as FBXW7). In previous studies, FBW7 has been addressed as a tumor suppressor mediating ubiquitin-dependent proteolysis of several oncogenic proteins. Ubiquitination is a type of protein modification that directs protein for degradation as well as sorting. The level of beta-catenin (β-cat), an intracellular signal transducer in Wnt signaling pathway, is reduced upon overexpression of FBW7 in human cancer cell lines. Loss of function mutations in FBW7 and overactive Wnt signaling have been reported to be responsible for human cancers.ResultsWe found that Ago is important for the formation of shafts in chemosensory bristles at wing margin. This loss of shaft phenotype by knockdown of ago was rescued by knockdown of wingless (wg) whereas wing notching phenotype by knockdown of wg was rescued by knockdown of ago, establishing an antagonistic relationship between ago and wg. In line with this finding, knockdown of ago increased the level of Armadillo (Arm), a homolog of β-cat, in Drosophila tissue. Furthermore, knockdown of ago increased the level of Distal-less (Dll) and extracellular Wg in wing discs. In S2 cells, the amount of secreted Wg was increased by knockdown of Ago but decreased by Ago overexpression. Therefore, Ago plays a previously unidentified role in the inhibition of Wg secretion. Ago-overexpressing clones in wing discs exhibited accumulation of Wg in endoplasmic reticulum (ER), suggesting that Ago prevents Wg protein from moving to Golgi from ER.ConclusionsWe concluded that Ago plays dual roles in inhibiting Wg signaling. First, Ago decreases the level of Arm, by which Wg signaling is downregulated in Wg-responding cells. Second, Ago decreases the level of extracellular Wg by inhibiting movement of Wg from ER to Golgi in Wg-producing cells.

Four new species and one new subspecies of the Ghoria albocinerea Moore, 1878 species-group from northern Indochina and China (Lepidoptera, Erebidae, Arctiinae, Lithosiini).

The Ghoria albocinerea Moore, 1878 species-group is established for a complex of species having the characteristic silver whitish forewing coloration and pattern presented mostly by a broad longitudinal shade along the anal wing margin. Four new species and one new subspecies of the species-group are described: Ghoria nanlingica dytiko ssp. n. (China: Sichuan), Ghoria dammay sp. n. (North Vietnam), Ghoria longivesica sp. n. (China: Yunnan and North Thailand), Ghoria mubupa sp. n. (China: Yunnan) and Ghoria synnefo sp. n. (North Vietnam). Adults, male and female genitalia of the new taxa and the related Ghoria albocinerea (the central and eastern Himalayas), Ghoria nanlingica Dubatolov, Kishida Wang, 2012 (China: Guangdong) and Ghoria sinotibetica Dubatolov, Kishida Wang, 2012 (China: Sichuan) are illustrated.

Transcription factors underlying wing margin color patterns and pupal cuticle markings in butterflies

BackgroundThe diversity of butterfly color patterns can be attributed to a relatively small number of pattern elements that are homologous across Lepidoptera. Although genes involved in patterning some of these elements have been identified, the development of several major elements remains poorly understood. To identify genes underlying wing pupal cuticle markings and wing margin color patterns, we examined expression of the candidate transcription factors Engrailed/Invected (En/Inv), Distal-less (Dll), Cubitus interruptus (Ci), and Spalt in two nymphalids: Junonia coenia and Bicyclus anynana.ResultsWe found that En/Inv, Dll, and Ci mark domains on the J. coenia last-instar forewing disc that closely correspond to the position and shape of pupal cuticle markings. We also found that Spalt demarcates wing margin color patterns in both J. coenia and B. anynana, and that CRISPR/Cas9 deletions in the spalt gene result in reduction and loss of wing margin color patterns in J. coenia. These data demonstrate a role for spalt in promoting wing margin color patterning, in addition to its previously described role in eyespot patterning.ConclusionOur observations support the model that a core set of regulatory genes are redeployed multiple times, and in multiple roles, during butterfly wing pattern development. Of these genes, spalt is of special interest as it plays a dual role in both eyespot and margin color pattern development.

Biomechanical strategies underlying the durability of a wing-to-wing coupling mechanism

Insects thrived soon after they acquired the ability to fly. Beyond the reach of the non-flying competitors, flying insects colonized a wide variety of habitats. Although flight is an efficient way to disperse and escape predators, it is energetically costly. Hence, various strategies are served to enhance flight efficiency as much as possible. A striking example is the development of wing-to-wing coupling mechanisms in many neopterous insects to minimize the aerodynamic interference of fore and hind wings. However, it remains unclear how the seemingly delicate coupling mechanisms can withstand excessive mechanical stresses encountered during flight. Here we studied the complicated coupling mechanism of drone honey bees, which consists of a set of tiny hooks and a thickened membrane. We found that the durability of the coupling mechanism results from two complementary strategies. First, the angles at which hooks and membrane are coupled and uncoupled may be adjusted, so that the resulting stresses are minimized. Second, the out-of-plane structure, soft base and pronounced tip reduce the stress developed in the hooks, yet maintaining the coupling strength. We anticipate our study, which presents the first numerical model of insect wing coupling mechanisms, to be a starting point for the development of more sophisticated models in the future. Such models are particularly useful for comparative analysis of the influence of different morphological features on the functionality of complex coupling mechanisms. Statement of SignificanceHamuli, or ‘tiny hooks’, is the Greek term for hook-like structures on the anterior margin of honey bee hind wings. By fitting into the fold posterior margin of fore wings, the hooks couple the two wings to each other. Despite their seemingly fragile structure, the hooks withstand substantial mechanical stresses. We show that the out-of-plane structure, soft base and pronounced tip are morphological features that enhance the durability of the hooks, without compromising their function.

Prickle isoforms determine handedness of helical morphogenesis.

Subcellular asymmetry directed by the planar cell polarity (PCP) signaling pathway orients numerous morphogenetic events in both invertebrates and vertebrates. Here, we describe a morphogenetic movement in which the intertwined socket and shaft cells of the Drosophila anterior wing margin mechanosensory bristles undergo PCP-directed apical rotation, inducing twisting that results in a helical structure of defined chirality. We show that the Frizzled/Vang PCP signaling module coordinates polarity among and between bristles and surrounding cells to direct this rotation. Furthermore, we show that dynamic interplay between two isoforms of the Prickle protein determines right- or left-handed bristle morphogenesis. We provide evidence that, Frizzled/Vang signaling couples to the Fat/Dachsous PCP directional signal in opposite directions depending on whether Pkpk or Pksple predominates. Dynamic interplay between Pk isoforms is likely to be an important determinant of PCP outcomes in diverse contexts. Similar mechanisms may orient other lateralizing morphogenetic processes.

Lizards as Predators of Butterflies: Shape of Wing Damage and Effects of Eyespots

In warm climates, lizards may be important as predators of butterflies and thus exert selection pressure on butterfly colour patterns, including eyespots. However, this has received little attention. Two studies reported no evidence that butterfly eyespots deflect lizard attacks, while possible intimidating effects of butterfly eyespots on lizards have not been investigated. We exposed common evening brown butterflies (Melanitis leda) with a wide range of eyespot sizes (dry season forms with very small and faint eyespots, intermediate phenotypes with small eyespots, and wet season forms with large or very large eyespots) to house geckos, and recorded the location and shape of wing surface loss. We supplemented these data with direct observations of attacks of house geckos (Hemidactylus frenatus) and bronze skinks (Eutropis macularia) on common evening brown butterflies. We found that about three quarters of symmetrical wing surface loss, and about half of the non-symmetrical wing surface loss was rounded like the mouth of a gecko. Symmetrical as well as non-symmetrical wing surface loss was significantly more common in hindwings. We surmise that rounded wing surface loss and a bias in symmetrical wing surface loss to hindwings can be taken as evidence for failed lizard attacks. Rounded wing surface loss was more common in butterflies with small eyespots than in those with very small eyespots or with large eyespots. This suggests that small eyespots can deflect lizard attacks away from the head towards the wing margins, and that large eyespots can thwart lizard attacks. In four cases, skinks appeared to explore rather than attack butterfly eyespots. In contrast to earlier studies, our data provide evidence that butterfly eyespots can be an effective defence against lizards, and thus that predation by lizards can select for eyespots in butterflies.

Glycosylation of Specific Notch EGF Repeats by O-Fut1 and Fringe Regulates Notch Signaling in Drosophila

SUMMARYFringe glycosyltransferases differentially modulate the binding of Notch receptors to Delta/DLL versus Serrate/Jagged ligands by adding GlcNAc to O-linked fucose on Notch epidermal growth factor-like (EGF) repeats. Although Notch has 22 O-fucosylation sites, the biologically relevant sites affecting Notch activity during animal development in vivo in the presence or absence of Fringe are not known. Using a variety of assays, we find important roles in Drosophila Notch signaling for GlcNAc-fucose-O glycans on three sites: EGF8, EGF9, and EGF12. O-Fucose monosaccharide on EGF12 (in the absence of Fringe) is essential for Delta-mediated lateral inhibition in embryos. However, wing vein development depends on the addition of GlcNAc to EGF8 and EGF12 by Fringe, with a minor contribution from EGF9. Fringe modifications of EGF8 and EGF12 together prevent Notch from cis-inhibiting Serrate, thereby promoting normal wing margin formation. Our work shows the combinatorial and context-dependent roles of GlcNAc-fucose-O glycans on these sites in Drosophila Notch-ligand interactions.

<p><strong>An unusual new genus and species of beaded lacewings (Neuroptera: Berothidae) from the mid-Cretaceous Burmese amber</strong></p>

A new genus and species of the neuropteran family Berothidae from the mid-Cretaceous Burmese amber, namely Xiaoberotha bipunctata gen. et sp. nov., is described. In addition, an undetermined species of this new genus is also described. This new genus greatly differs from most known berothids by the presence of forewing ScA and the configuration of hind wing Cu that is not approximating posterior wing margin. The new genus superficially resembles Hemerobiidae by having the distinct, posteriorly curved forewing ScA and the two forewing cua-cup crossveins that are shared by many brown lacewing genera. However, no autapomorphy of Hemerobiidae could be confirmed to be present in the new species. Here we tentatively place this new genus in Berothidae by the configuration of the female gonocoxites 8, which is conspicuous and dorsoventrally extended. This unusual beaded lacewing genus highlights the morphological diversity of the extinct Berothidae.

<p><strong>A new genus and species of wasp (Hymenoptera: Evanioidea: Praeaulacidae) associated with an angiosperm flower in Burmese amber</strong></p>

A new genus and species of small wasp (body length, 4.3 mm, exclusive of antennae) of the extinct family Praeaulacidae (Hymenoptera: Evanioidea) is described in Burmese amber. Placement in the Praeaulacidae is based on the hind wing venation with RS, cu-a and apparent r-m present and a 10-celled forewing. Special forewing features are a large CuA cell and very narrow 3rm cell that is not aligned with 2r-m. The narrow hind wings have a unique venation with RS, M, Cu and A reaching the lower wing margin. The metasoma is attached to the propodium by a 1-segmented petiole. The ovipositor is long, exceeding the length of the metasoma. An angiosperm flower is adjacent to the wasp and the presence of herbivorous insect larvae on the flower may have attracted the female wasp.

Morphological and histological study of the forewing of Aleyrodes proletella (Linnaeus 1758) (Sternorrhyncha, Hemiptera) with a comparative analysis of forewings among Sternorrhyncha infraorders

Identification of whiteflies is based mainly on larval stages and generally very little is known about wings of these insects. Therefore, both sides of the forewings of Aleyrodes proletella were studied using histological methods, light and scanning electron microscopes. Studies confirm the occurrence of only three veins on forewings: the costal, radial and anal ones; only the anal vein lies under the anal fold. A campaniform and trichoid sensilla are present. The shape of wax secretions and wing margins is described. The comparative analysis of forewing structures contains new data for all Sternorrhyncha infraorders. The current results confirm the monophyly of the group, but place aphids closer to psyllids. The analysis of forewing base indicates that its general model is similar among Sternorrhyncha, but there occur some intergroup differences. Ways of wing folding depend on the structure of thorax.

Chemosensory sensilla of the Drosophila wing express a candidate ionotropic pheromone receptor

The Drosophila wing was proposed to be a taste organ more than 35 years ago, but there has been remarkably little study of its role in chemoreception. We carry out a differential RNA-seq analysis of a row of sensilla on the anterior wing margin and find expression of many genes associated with pheromone and chemical perception. To ask whether these sensilla might receive pheromonal input, we devised a dye-transfer paradigm and found that large, hydrophobic molecules comparable to pheromones can be transferred from one fly to the wing margin of another. One gene, Ionotropic receptor (IR)52a, is coexpressed in neurons of these sensilla with fruitless, a marker of sexual circuitry; IR52a is also expressed in legs. Mutation of IR52a and optogenetic silencing of IR52a+ neurons decrease levels of male sexual behavior. Optogenetic activation of IR52a+ neurons induces males to show courtship toward other males and, remarkably, toward females of another species. Surprisingly, IR52a is also required in females for normal sexual behavior. Optogenetic activation of IR52a+ neurons in mated females induces copulation, which normally occurs at very low levels. Unlike other chemoreceptors that act in males to inhibit male–male interactions and promote male–female interactions, IR52a acts in both males and females, and can promote male–male as well as male–female interactions. Moreover, IR52a+ neurons can override the circuitry that normally suppresses sexual behavior toward unproductive targets. Circuit mapping and Ca2+ imaging using the trans-Tango system reveals second-order projections of IR52a+ neurons in the subesophageal zone (SEZ), some of which are sexually dimorphic. Optogenetic activation of IR52a+ neurons in the wing activates second-order projections in the SEZ. Taken together, this study provides a molecular description of the chemosensory sensilla of a greatly understudied taste organ and defines a gene that regulates the sexual circuitry of the fly.

Paracaryum lalezarense (Boraginaceae), a new species from high alpine elevations of Lalezar Mountains, in Iran

Paracaryum lalezarense is described as a new species endemic to the Lalezar Mountains in southeastern Iran. The new species is characterized by its moderately incurved nutlet wings, glochidiate nutlet wing margins, smooth and shiny nutlet disks and rather small flowers (corolla 3.5–4 mm long) with corolla tube as long as limb. It is restricted to high alpine and nival elevations (4,000–4,260 m) that is an infrequent phenomenon amongst other species of the genus Paracaryum. Description, photographs of living plants and distribution map of the new species are provided and taxonomic relationships with its closest possible allied species and its conservation status are briefly discussed.

<p><strong>A holopsenelline wasp in mid-Cretaceous amber from Myanmar (Hymenoptera: Bethylidae)</strong></p>

A new genus and species of the basal bethylid subfamily Holopsenellinae is described and figured from a female in Burmese amber, the first occurrence of the lineage outside of the Early Cretaceous deposits of Lebanon. Holopsenelliscus pankowskiorum gen. and sp. nov., differs from other holopsenellines most notably in the discontinuous anterior wing margin and open subdiscal cell, among other traits. The genus and species are described in full and distinguished from Holopsenella primotica Engel et al. in Lebanese amber and Cretabythus sibiricus Evans in Taimyrian amber. A key to the genera of Holopsenellinae is provided.

Drosophila jumu modulates apoptosis via a JNK-dependent pathway and is required for other processes in wing development

Previous studies in several model organisms have revealed that members of the Forkhead (Fkh) transcription factor family have multiple functions. Drosophila Jumeau (Jumu), a member of this family, participates in cardiogenesis, hematopoiesis and immune system homeostasis. Here, we show that loss of jumu function positively regulates or triggers apoptosis via a JNK-dependent pathway in wing development. jumu mutants showed reduced wing size and increased apoptosis. Moreover, we observed a loss of the anterior cross vein (ACV) phenotype that was similar to that observed in wings in which JNK signaling has been ectopically activated. The JNK signaling markers puckered (puc) and p-JNK were also significantly increased in the wing discs of jumu mutants. In addition, apoptosis induced by the loss of jumu was rescued by knocking down JNK, indicating a role for JNK in reducing jumu-induced apoptosis. Jumu could also control wing margin development via the positive regulation of cut expression, and the observed wing margin defect did not result from a loss of jumu-induced apoptosis. Further, jumu deficiency in the pupal wing could induce multiple wing hairs via a Rho1-mediated planar cell polarity pathway, but abnormal Rho1 expression was not why jumu loss induced apoptosis via a JNK-dependent pathway in wing discs.

Taxonomic notes on dustywings of Aleuropteryginae (Insecta, Neuroptera, Coniopterygidae) from the mid-Cretaceous Burmese amber

Two new genera and three new species of the dustywings subfamily Aleuropteryginae are described from the Burmese amber (lowermost Cenomanian, mid-Cretaceous). Cycloconis maculata gen. et sp. nov. is tentatively placed in the tribe Fontenelleini and appears to be closely related to Libanoconis Engel, 2002, but it can be distinguished from the latter genus by the forks of forewing RP + MA and MP subequal in length and the trifurcated hind wing MP. Burmaleuropteryx meinanderi gen. et sp. nov. resembles Garnaconis Perrichot & Nel, 2014 (both genera with unclear placement of tribe), but can be separated from the latter genus by the forewing rp + ma-mp proximad branching point between RP and MA, the presence of forewing cua-cup, and the lack of stiff setae along distal and posterior margins of wings. Achlyoconis jiae sp. nov. is distinguished from Achlyoconis heptatrichia Engel, 2016 by the larger body size, the forewing with four pigmented spots, and the crossvein between RA and RP + MA slightly proximad branching point between forewing RP and MA. Achlyoconis heptatrichia Engel, 2016 is also re-described based on a series of new material, and its male genitalia is described in detail.