Functional fibrillar interfaces: Biological hair as inspiration across scales.

Hair, or hair-like fibrillar structures, are ubiquitous in biology, from fur on the bodies of mammals, over trichomes of plants, to the mastigonemes on the flagella of single-celled organisms. While these long and slender protuberances are passive, they are multifunctional and help to mediate interactions with the environment. They provide thermal insulation, sensory information, reversible adhesion, and surface modulation (e.g., superhydrophobicity). This review will present various functions that biological hairs have been discovered to carry out, with the hairs spanning across six orders of magnitude in size, from the millimeter-thick fur of mammals down to the nanometer-thick fibrillar ultrastructures on bateriophages. The hairs are categorized according to their functions, including protection (e.g., thermal regulation and defense), locomotion, feeding, and sensing. By understanding the versatile functions of biological hairs, bio-inspired solutions may be developed across length scales.

Toe pad morphology and adhesion in the miniaturized gecko, Chatogekko amazonicus (Gekkota: Sphaerodactylidae).

Chatogekko amazonicus is a miniaturized gecko from northern South America and is among the smallest of toe pad bearing lizards. The toe pads of C. amazonicus are miniscule, between 18% and 27% of the plantar surface area. We aimed to investigate the relationship between adhesive toe pad morphology, body size, and adhesive capabilities. Using scanning electron microscopy, we determine that the adhesive pads of C. amazonicus exhibit branched setae similar to those of other geckos, but that are generally much smaller. When compared with other gecko taxa, we show that C. amazonicus setae occupy a similar range of seta length: snout-vent length ratio and aspect ratio as other gekkonoid species (i.e. Gekkonidae, Phyllodactylidae, and Sphaerodactylidae). We demonstrate that C. amazonicus-even with its relatively small toe pads-is capable of climbing a smooth glass surface at a nearly vertical angle. We suggest that sphaerodactylids like C. amazonicus offer an excellent system for studying toe pad morphology and function in relation to miniaturization.

Insect attachment on waxy plant surfaces: the effect of pad contamination by different waxes.

This study focuses on experimental testing of the contamination hypothesis and examines how the contamination of insect adhesive pads with three-dimensional epicuticular waxes of different plant species contributes to the reduction of insect attachment. We measured traction forces of tethered Chrysolina fastuosa male beetles having hairy adhesive pads on nine wax-bearing plant surfaces differing in both shape and dimensions of the wax structures and examined insect adhesive organs after they have contacted waxy substrates. For comparison, we performed the experiments with the same beetle individuals on a clean glass sample just before (gl1) and immediately after (gl2) the test on a plant surface. The tested insects showed a strong reduction of the maximum traction force on all waxy plant surfaces compared to the reference experiment on glass (gl1). After beetles have walked on waxy plant substrates, their adhesive pads were contaminated with wax material, however, to different extents depending on the plant species. The insects demonstrated significantly lower values of both the maximum traction force and the first peak of the traction force and needed significantly longer time to reach the maximum force value in the gl2 test than in the gl1 test. These effects were especially pronounced in cases of the plant surfaces covered with wax projections having higher aspect ratios. The data obtained clearly indicated the impact of waxy plant surfaces on the insect ability to subsequently attach to the clean smooth surface. This effect is caused by the contamination of adhesive pads and experimentally supports the contamination hypothesis.

A comparative study on the antennae morphology and ultrastructure of three mud crab species of the genus Scylla from Setiu Wetlands, Terengganu, Malaysia.

Crustaceans possess a range of sensory organs crucial in sensory perception, communication, and various ecological functions. Understanding morphological and functional differences in antennae among species could validate taxonomic differentiation and ecological adaptations. The antennae morphology and ultrastructure of mud crab species within the Scylla genus are poorly understood, and their role in ecological adaptation and species differentiation remains unexplored. This study aimed to describe and compare the morphology and ultrastructure of antennae in Scylla olivacea, Scylla tranquebarica, and Scylla paramamosain. Antennae were carefully excised from each crab and subjected to morphological, morphometric, and ultrastructural analysis. The study revealed that the antennae of Scylla species exhibit similar overall morphology, with a series of segments that tapered toward the upper end. All species possess non-branched single setae on the upper end of each segment. The number of antennae segments varied between species, with S. paramamosain having significantly more segments than S. olivacea. Additionally, the length and width of antenna segments differed among the species, with S. tranquebarica having a rougher antenna surface compared to S. olivacea and S. paramamosain. Our findings suggest that Scylla's antennae are distinct between species, especially in the number of segments and setae size. Such difference might be related to ecological adaptation. The role of antennae in sensory perception and social behavioral cues in mud crabs warrants further investigation. This study serves as a foundational reference for future research on the taxonomy, ecological adaptation, and sensory behaviors in the Scylla genus. RESEARCH HIGHLIGHTS: Variations and similarities in morphology and ultrastructure of three Scylla species can be found in the antennae. Scylla paramamosain had significantly higher number of segments than Scylla olivacea in morphology feature. The antennae surface of Scylla tranquebarica was rougher than that of S. olivacea and S. paramamosain. Antennae of three Scylla species possess non-branched single setae.

A case of panuveitis caused by caterpillar setae.

INTRODUCTION: Panuveitis is a serious inflammatory disease. Setae are fibers produced by many insects and plants. Many case reports have described caterpillar and spider fibers entering the eye. These hairs are covered with tiny barbs that help them enter and migrate into the eye tissue, leading to severe inflammation. Normally, they are buried mainly in the conjunctiva and cornea. However, in the present case, they entered the posterior segment of the eye, which is very rare. CASE DESCRIPTION: A female patient presented with a complaint of repeated foreign body sensation, redness, pain, and photophobia in the left eye for 9 years following initial exposure to caterpillars. She visited the doctor in January after aggravation of symptoms. Slit-lamp examination, ultrasound biomicroscopy, ultrasound B-scan, fluorescein angiography, and indocyanine green angiography revealed the presence of a foreign body in the vitreous, which caused discomfort in the patient's left eye and subsequently, panuveitis of the left eye. The symptoms improved significantly after foreign body removal using vitrectomy. Microscopic examination revealed that the foreign body was caterpillar setae. CONCLUSION: Clinicians should be more vigilant about history of contact with caterpillars while examining uveitis that has recurred for many years. Identification of the root cause of the disease can ensure better treatment.

Actin-templated Structures: Nature's Way to Hierarchical Surface Patterns (Gecko's Setae as Case Study).

The hierarchical design of the toe pad surface in geckos and its reversible adhesiveness have inspired material scientists for many years. Micro- and nano-patterned surfaces with impressive adhesive performance have been developed to mimic gecko's properties. While the adhesive performance achieved in some examples has surpassed living counterparts, the durability of the fabricated surfaces is limited and the capability to self-renew and restore function-inherent to biological systems-is unimaginable. Here the morphogenesis of gecko setae using skin samples from the Bibron´s gecko (Chondrodactylus bibronii) is studied. Gecko setae develop as specialized apical differentiation structures at a distinct cell-cell layer interface within the skin epidermis. A primary role for F-actin and microtubules as templating structural elements is necessary for the development of setae's hierarchical morphology, and a stabilization role of keratins and corneus beta proteins is identified. Setae grow from single cells in a bottom layer protruding into four neighboring cells in the upper layer. The resulting multicellular junction can play a role during shedding by facilitating fracture of the cell-cell interface and release of the high aspect ratio setae. The results contribute to the understanding of setae regeneration and may inspire future concepts to bioengineer self-renewable patterned adhesive surfaces.

Tenuipalpus Sensu Lato Donnadieu (Acari: Prostigmata: Tenuipalpidae); New Species Groups, a New Species, and Keys to the World Species.

Four new species groups of the Tenuipalpus sensu lato group are proposed in the present study based on the total number of dorsal opisthosomal setae, namely, carolinensis with ten pairs of setae (214 species), dubinini with nine pairs of setae (33 species), granati with eight pairs of setae (29 species), and barticanus with seven pairs of setae (7 species) Additionally, diagnostic keys to species groups and 273 species of the Tenuipalpus sensu lato are provided. Three species, T. lustrabilis Chaudhri, T. guptai Sadana and Gupta, and T. solanensis Sadana and Gupta, are synonymized with T. punicae Pritchard and Baker. One species, T. rodionovi Chalilova, is suggested as a junior synonym of T. granati Sayed, and eight species, T. chiococcae De Leon, T. costarricensis Salas and Ochoa, T. ephedrae Livschitz and Mitrofanov, T. molinai Evans, T. santae Manson, T. simplychus Cromroy, T. tetrazygiae De Leon, and T. oxalis (Flechtmann), belonging to the carolinensis species group, are not included in the key. Furthermore, a new species of Tenuipalpus sensu lato, T. jazanensis sp. nov., is described and illustrated based on females collected from the Chamaerops spp. (Arecaceae).

Atypically Shaped Setae in Gall Mites (Acariformes, Eriophyoidea) and Mitogenomics of the Genus Leipothrix Keifer (Eriophyidae).

The setae in Eriophyoidea are filiform, slightly bent and thickened near the base. Confocal microscopy indicates that their proximal and distal parts differ in light reflection and autofluorescence. Approximately 50 genera have atypically shaped setae: bifurcated, angled or swollen. These modifications are known in the basal part of prosomal setae u', ft', ft″, d, v, bv, ve, sc and caudal setae h2. We assessed the distribution of atypically shaped setae in Eriophyoidea and showed that they are scattered in different phylogenetic lineages. We hypothesized that the ancestral setae of eriophyoid mites were bifurcated before later simplifying into filiform setae. We also proposed that hypo-furcating setae are a synapomorphy that unites Eriophyoidea with Nematalycidae. We analyzed four new mitochondrial genomes of Leipothrix, the largest genus with bifurcated d, and showed that it is monophyletic and has a unique mitochondrial gene order with translocated trnK. We exclude Cereusacarus juniperensisn. comb. Xue and Yin, 2020 from Leipothrix and transfer five Epitrimerus spp. to Leipothrix: L. aegopodii (Liro 1941) n. comb., L. femoralis (Liro 1941) n. comb., L. geranii (Liro 1941) n. comb., L. ranunculi (Liro 1941) n. comb., and L. triquetra (Meyer 1990) n. comb.

Two new species of the genus Samarangopus and the first record of Eurypauropusjaponicus (Arthropoda, Myriapoda, Pauropoda, Eurypauropodidae) from China.

Two new species, Samarangopustestudineussp. nov. from Hunan, South China and S.rotundifoliussp. nov. from Zhejiang, East China, are described and illustrated. Samarangopustestudineussp. nov. is characterized by unusual testudinal patterns on the dorsal side of the body and well-differentiated marginal protuberances on tergites. Samarangopusrotundifoliussp. nov. features large, round, leaf-shaped marginal protuberances and small, candle-like dorsal protuberances on tergites. Both of these species are compared to similar species in detail. In addition, Eurypauropusjaponicus Hagino & Scheller, 1985 is newly recorded from China.

Ophthalmia nodosa secondary to intraocular, white-marked tussock caterpillar setae (Orgyia leucostigma) in a 15-year-old.

A 15-year-old female presented to the emergency department with a 1-day history of pain and swelling of her right eye following ocular contact with a caterpillar. Caterpillars of the white-marked tussock moth and other related species possess hairlike structures called setae, with angled barbs along their length, allowing them to travel linearly upon penetration of an enemy, resisting backward movement and becoming very difficult to extract once imbedded. When these fine, pointed hairs contact the surface of the eye, they can easily migrate in, eliciting movement of the globe, blinking, and rubbing of the eye in an attempt to remove the offending agent, potentially leading to ophthalmia nodosa. One of the most important aspects of ophthalmia nodosa diagnosis is a thorough history and prompt slit-lamp examination to identify the presence of foreign bodies and where they are located; this will help guide clinical management decisions. This case demonstrates that, depending on the number and location, more than one attempt may be required to remove all of the barbed setae. If ophthalmia nodosa is suspected, it is important to promptly refer to ophthalmology for a thorough eye exam, keep the eye clean, prescribe prophylactic topical antibiotics and/or steroids to reduce the potential for infection and inflammation, and emphasize the importance of keeping the eye protected during the healing process with an eye shield.

Suspect severe gastroenteritis associated with ingestion of caterpillar setae fragments in a cat.

A 6-month-old male neutered Domestic Shorthair cat was assessed for a 24-h history of anorexia, lethargy, depressed mentation, mild abdominal pain and persistent bradycardia. Abdominal ultrasound revealed marked thickening of the gastric wall, gastric distension, free abdominal fluid, distension and corrugation of the small intestine. Full-thickness histopathological biopsy of the gastric wall demonstrated intralesional chitinous structures whose morphology (size and presence of obvious barbs) supports these structures being urticating hairs (setae). A processionary caterpillar is considered most likely as these are the most common urticating caterpillars in Australia. This is the first case of suspected severe gastroenteritis associated with the ingestion of caterpillar setae fragments in a cat.

A Nonsurgical Approach to Management of Lepidopterism due to Woolly Bear Caterpillar Ingestion.

Systemic symptoms resulting from exposure to members of the Lepidoptera order, such as moths, butterflies, and caterpillars, are known as lepidopterism. Most cases of lepidopterism are mild and result from dermal exposure to urticating hairs; ingestion is less common and generally more medically significant because the hairs may get embedded in the patient's mouth, hypopharynx, or esophagus, leading to dysphagia, drooling, edema, and possible airway obstruction. In previous cases of symptomatic caterpillar ingestion reported in the literature, extensive efforts, including direct laryngoscopy, esophagoscopy, and bronchoscopy, were undertaken to remove these hairs. We review the case of a 19-mo-old previously healthy male infant who presented to the emergency department with vomiting and inconsolability after ingesting half of a woolly bear caterpillar (Pyrrharctia isabella). His initial examination was notable for embedded hairs in his lips, oral mucosa, and right tonsillar pillar. The patient underwent a bedside flexible laryngoscopy, which revealed a single hair embedded in the epiglottis, without significant edema. He was stable from a respiratory standpoint and, thus, was admitted for observation and IV dexamethasone without any attempt to remove the hairs. He was discharged in good condition after 48 h; at a follow-up visit 1 wk later, no remaining hairs were visible. This case demonstrates that lepidopterism secondary to caterpillar ingestion is amenable to conservative management and does not require routine removal of urticating hairs in patients who do not show signs of airway distress.

The diversity, evolution, and development of setal morphologies in bumble bees (Hymenoptera: Apidae: Bombus spp.).

Bumble bees are characterized by their thick setal pile that imparts aposematic color patterns often used for species-level identification. Like all bees, the single-celled setae of bumble bees are branched, an innovation thought important for pollen collection. To date no studies have quantified the types of setal morphologies and their distribution on these bees, information that can facilitate understanding of their adaptive ecological function. This study defines several major setal morphotypes in the common eastern bumble bee Bombus impatiens Cresson, revealing these setal types differ by location across the body. The positions of these types of setae are similar across individuals, castes, and sexes within species. We analyzed the distribution of the two most common setal types (plumose and spinulate) across the body dorsum of half of the described bumble bee species. This revealed consistently high density of plumose (long-branched) setae across bumble bees on the head and mesosoma, but considerable variation in the amount of metasomal plumosity. Variation on the metasoma shows strong phylogenetic signal at subgeneric and smaller group levels, making it a useful trait for species delimitation research, and plumosity has increased from early Bombus ancestors. The distribution of these setal types suggests these setae may serve several functions, including pollen-collecting and thermoregulatory roles, and probable mechanosensory functions. This study further examines how and when setae of the pile develop, evidence for mechanosensory function, and the timing of pigmentation as a foundation for future genetic and developmental research in these bees.

Setal descriptions, locations, and abundances: Their impacts on decorating behaviors in the spider crab Libinia (Crustacea: Epialtidae).

The setal abundances and distributions of the spider crab Libinia are examined, using two species. These spider crabs decorate their bodies with environmental materials and camouflage from predators. These decorations attach to hooked setae, but other types setae are prevalent in body regions where decorations occur. Adult crabs undergo a terminal molt and lose the ability to regrow setae. Little is known about setal changes over the lifetime in these crabs and if hooked setae abundance decreases with age, resulting in a loss of camouflage strategy in larger individuals. The objective of this study is to determine the prevalence and abundance of hooked and non-hooked setae in the decorated body regions and if these setal patterns vary by species and body size. Scanning electron microscopy is used along with computer software to describe, count, and measure the setal coverage of hooked and non-hooked setae in body regions. Small individuals have more hooked setae than larger individuals and the two species have different setal abundances of hooked and non-hooked setae. Non-hooked setae cover much surface areas of crabs, attach decorations, and remain on the crabs even when hooked setae are damaged and broken. Setal morphologies and fouling are described among different sized crabs and the two species, with setal types and morphologies being similar but fouling being different. Large individuals likely employ a different camouflage strategy than small individuals due to losing hooked setae but retaining non-hooked setae.

Diverse Localization Patterns of an R-Type Lectin in Marine Annelids.

Lectins facilitate cell-cell contact and are critical in many cellular processes. Studying lectins may help us understand the mechanisms underlying tissue regeneration. We investigated the localization of an R-type lectin in a marine annelid (Perinereis sp.) with remarkable tissue regeneration abilities. Perinereis nuntia lectin (PnL), a galactose-binding lectin with repeating Gln-X-Trp motifs, is derived from the ricin B-chain. An antiserum was raised against PnL to specifically detect a 32-kDa lectin in the crude extracts from homogenized lugworms. The antiserum detected PnL in the epidermis, setae, oblique muscle, acicula, nerve cord, and nephridium of the annelid. Some of these tissues and organs also produced Galactose (Gal) or N-acetylgalactosamine (GalNAc), which was detected by fluorescent-labeled plant lectin. These results indicated that the PnL was produced in the tissues originating from the endoderm, mesoderm, and ectoderm. Besides, the localizing pattern of PnL partially merged with the binding pattern of a fluorescent-labeled mushroom lectin that binds to Gal and GalNAc. It suggested that PnL co-localized with galactose-containing glycans in Annelid tissue; this might be the reason PnL needed to be extracted with haptenic sugar, such as d-galactose, in the buffer. Furthermore, we found that a fluorescein isothiocyanate-labeled Gal/GalNAc-binding mushroom lectin binding pattern in the annelid tissue overlapped with the localizing pattern of PnL. These findings suggest that lectin functions by interacting with Gal-containing glycoconjugates in the tissues.

Morphometric Analysis of Coptotermes spp. Soldier Caste (Blattodea: Rhinotermitidae) in Indonesia and Evidence of Coptotermes gestroi Extreme Head-Capsule Shapes.

Linear and geometric morphometrics approaches were conducted to analyze the head capsule (HC) shape of collected soldier caste specimens of Coptotermes from various locations in Indonesia. The soldiers' morphology was observed and measured. The results of the principal component analysis of the group of all species showed two important groups of variables, i.e., the body size and setae characteristics of the pronotum and head. The multicollinearity of the morphometric variables showed the importance of body measurements as well as important alternative characteristics such as the pronotum setae (PrS) and HC setae. Four trends of HC shape were observed across the species. Interestingly, three extreme shapes were depicted by geometric morphometrics of the C. gestroi HC. The phylogenetic tree inferred from 12S and 16S mitochondrial gene fragments showed high confidence for C. gestroi populations. The lateral expansion of the posterior part of the HC across the species was in accordance with the increasing of the number of hairlike setae on the pronotum and HC. These differences among species might be associated with mandible-force-related defensive labor and sensitivity to environmental stressors.

And thereby hangs a tail: morphology, developmental patterns and biomechanics of the adhesive tails of crested geckos (Correlophus ciliatus).

Among the most specialized integumentary outgrowths in amniotes are the adhesive, scale-like scansors and lamellae on the digits of anoles and geckos. Less well-known are adhesive tail pads exhibited by 21 gecko genera. While described over 120 years ago, no studies have quantified their possible adhesive function or described their embryonic development. Here, we characterize adult and embryonic morphology and adhesive performance of crested gecko (Correlophus ciliatus) tail pads. Additionally, we use embryonic data to test whether tail pads are serial homologues to toe pads. External morphology and histology of C. ciliatus tail pads are largely similar to tail pads of closely related geckos. Functionally, C. ciliatus tail pads exhibit impressive adhesive ability, hypothetically capable of holding up to five times their own mass. Tail pads develop at approximately the same time during embryogenesis as toe pads. Further, tail pads exhibit similar developmental patterns to toe pads, which are markedly different from non-adhesive gecko toes and tails. Our data provide support for the serial homology of adhesive tail pads with toe pads.

Variation of cleaning organ structures and setae of pedipalp tarsus in the family Phrynidae (Arachnida: Amblypygi).

The pedipalp tarsus of Amblypygi is used as a cleaning tool in grooming behavior and as a weapon in prey capture. The tarsus presents several structures with unknown functions that probably relate to both processes. The Amblypygi tarsus possesses a cleaning organ with two lines of projections and a group of setae distributed along the structure. We analyzed the morphological variation of the cleaning organ structures and the setae of the tarsus in species of the family Phrynidae using scanning electron microscopy (SEM). Additionally, we made histological sections to evaluate the sensory function of the structures. We found variation in the shape and size of the setae, projections and granular area of the cleaning organ; however, the observed differences do not allow for differentiation of taxonomic genera. The setae and projections of the cleaning organ have an internal structure similar to tip-pore sensilla. Externally, the setae are similar to the sensorial hairs in spiders and differ from the cleaning organ projections, which probably are modified setae. Mechanoreception function is evident in the setae, and is probable in projections of the cleaning organ; the evidence observed indicates that both structures may be considered as putative chemoreceptors.

Ultra-structural and physico-chemical characterization of eggs and egg hairs (setae) of the new invasive pest, fall armyworm, Spodoptera frugiperda (J. E. Smith) in India: A first report.

In this study, we report first time in India on the morphology, ultra-architectural pattern of the chorion in the egg and egg hair (setae). Further, physico-chemical characterizations of egg hairs (setae) were studied in the new invasive pest, fall armyworm, Spodoptera frugiperda. The egg is dome shaped with flattened base and curves upward to a broadly rounded point at the apex. HR-SEM micrographs revealed the surface ultrastructure of eggs chorion and shows structural elements of a marked rosette of petals surround the micropyle followed by micropylar rosette region around the micropyle plate. There was a small single micropylar opening along with 9 micropylar rosette cells and 13 micropylar rosette zones present near to the micropylar pit. In the egg the first order ribs were absent, but around 58-60 numbers of second order ribs were present. All the ventral and lateral cells of the eggs are connected by 19-22 cross striae and not forming a grid pattern, but joints with the longitudinal ribs at several of angles and totally 1,277-1,495 convex cells present at the egg's surface. The physico-chemical characteristics of egg hairs were studied using Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA) analysis. TGA results show that three weight losses occurred at 142, 418, and 880°C, respectively. FT-IR confirms the presence of amides, sulfoxide, and nitro compounds in egg hairs (setae).

Intra-lenticular caterpillar seta in ophthalmia nodosa.

PURPOSE: To report the clinical course of ophthalmia nodosa with a retained lenticular seta misdiagnosed and treated as non-infectious posterior uveitis for 7 consecutive years. METHODS: Meticulous clinical examination led to discovery of the caterpillar seta embedded in the crystalline lens and the intravitreal setae. RESULTS: Lens-sparing pars plana vitrectomy and removal of free-floating vitreal seta resulted in complete resolution of vitritis and uveitis. CONCLUSION: Embedded seta within a clear lens may remain sequestered, and may be left untouched under close observation, precluding a clear lens extraction in such patients.