Head lice are exclusive human parasitic blood-sucking insects. Distributed worldwide among school-age children, this parasitosis generates scalp irritation and sometimes social prejudice. Understanding how head lice detect and perceive their human hosts is crucial to control transmission. Here, we describe the sensory structures present on the mouthparts of Pediculus humanus capitis and their possible

Most brachyuran crabs use their pereiopods as walking legs, but there are also a number of species, in which the last (5th) pair of pereiopods (P5) are specialized to permit a unique mode of swimming. One of these P5-swimming crabs is Liocarcinus depurator, commonly found on European shores. We present 3-dimensional μCT-based reconstructions of the axial skeletons and 5th pereiopods (P5), including

The majority of extant arachnids are terrestrial, but other chelicerates are generally aquatic, including horseshoe crabs, sea spiders, and the extinct eurypterids. It is necessary to determine whether arachnids are exclusively descended from a single common ancestor (monophyly), because only that relationship is compatible with one land colonisation in chelicerate evolutionary history. Some studies

The leg regeneration capabilities of damselflies are understudied. Here we present the first data of regenerated limbs across a genus of damselfly based on adult specimens collected in the field to illustrate the prevalence of limb loss among nymphs. We show that this phenomenon is much more prevalent than previously thought, as 42 percent of individuals were found with regenerated limbs. Furthermore

Bess beetles are sapro-xillophagous insects that inhabit decaying logs. They display sub-social behavior and acoustic communication. Adults produce sounds with an abdomino-alary stridulatory system. The sixth abdominal tergum has lateral protuberances with spines (pars stridens), whereas the hind wings have spines in the radial cell (plectrum). The potential taxonomic utility of these spines has not

Beginning with the description by Withers in 1932, Eocarcinus praecursor from the Jurassic has long been considered the oldest representative of the Brachyura. In 2010 Feldmann and Schweitzer re-investigated the specimens of E. praecursor and expressed doubts about the brachyuran nature of this species. Among other characters, the suspected existence of small chelae in the 2nd or 3rd pereopods led

Among insect species, the male genitalia evolved many different anatomical features to ensure reproductive success. Males of primitive insects do not copulate but transfer sperm packaged in a spermatophore to the female, whereas males of the most advanced insects copulate and deliver free sperm to the storage organ, the spermatheca, in the female reproductive tract. Based on previous studies on several

In the present study, we describe the sperm morphology of 11 species of Elateriformia (9 elaterids, 1 lampyrid and 1 buprestid) using transmission electron microscopy. All species exhibited sperm that is not usually observed in insects in general. The most highlighted features are the displacement of the nucleus running parallel to the flagellar components, hitherto observed only in coccinellid and

The ability of ant colonies to transport, store, and distribute food resources through trophallaxis is a key advantage of social life. Nonetheless, how the structure of the digestive system has adapted across the ant phylogeny to facilitate these abilities is still not well understood. The crop and proventriculus, structures in the ant foregut (stomodeum), have received most attention for their roles

Arthropods operate in an outrageous diversity of environments. From the deep sea to dense tropical forests, to wide open arctic tundra, they have colonized almost every possible habitat. Within these environments, the presence of light is nearly ubiquitous, varying in intensity, wavelength, and polarization. Light provides critical information about the environment, such as time of day or where food

The horned gall aphid, Schlechtendalia chinensis, inhabits the productive species of Chinese gallnuts, which have economic value. Aphid wax glands are crucial for the survival of the insects, since the secreted waterproofing wax is important to protect the aphids from predators, pathogens and honeydew contamination. In this study, we investigated the structure of wax glands and their role in different

The intestinal system of unfed fresh-water mite larvae Limnesia maculata (O.F. Müller, 1776) (Acariformes, Limnesiidae) has been studied with transmission electron microscopy. The intestinal system is composed of the foregut, including the pharynx and the esophagus, the sac-like blind midgut and the excretory organ. The pharynx begins with the mouth covered by the labrum. The pharynx runs along the

Posture and walking require support of the body weight, which is thought to be detected by sensory receptors in the legs. Specificity in sensory encoding occurs through the numerical distribution, size and response range of sense organs. We have studied campaniform sensilla, receptors that detect forces as strains in the insect exoskeleton. The sites of mechanotransduction (cuticular caps) were imaged

Kissing bugs (Hemiptera: Reduviidae: Triatominae) are able to bend their rod-like maxillae while searching for blood vessels in the tissue of their vertebrate hosts. Little is known about the working mechanisms of these bending movements and the distal opening of the food channel. We compared the morphological structure of the stylets (mandibles and maxillae) of four triatomine species and analyzed

Coniopterygidae are the dwarfs among the Neuroptera. Despite their miniaturisation, the males are equipped with genital sclerites that are excessively heterogeneous. They function in copulation and sperm transfer and have been widely utilized for species identification, as well being considered of high phylogenetic relevance. The present study is the first to describe the musculature associated with

The covering by scales of the wings of Lepidoptera contributes to multiple functions that are critical for their survival and reproduction. In order to gain a better understanding about their distribution, we have exhaustively studied 4 specimens of Colias crocef (Geoffroy, 1785). We have quantified the sources of variability affecting scale density. The results indicate that the scale covering of

Here we describe in detail the late post-embryonic development of the common European scolopendromorph centipede Cryptops parisi. Canonical variate analyses of two groups of external morphological characters, viz., cephalic capsule characters (head length, length of the anterior and posterior paramedian cephalic sutures) and coxopleuron surface characters (number of pores in the coxal pore-field, number

Parameres are male genital structures found in many insects which are often used as clasping devices to exert dominance in copula. The asopines have evolved a remarkable additional pair of similar structures, often denominated processes, which combines with the parameres in a tweezers-like system. Processes in similar positions have also been found in other subfamilies of Pentatomidae, but smaller

Heteropterans communicate chemically through thoracic or abdominal glandular complexes. The dorso-abdominal scent glands (DAGs) are externalized by cuticular specialized structures forming the external scent efferent system (SES). Different groups in Heteroptera present other glands, such as the Asopinae (Pentatomidae), whose males can have ventral abdominal pheromonal glands externalized by cuticular

Endoparasitic larval stages of Eoxenos laboulbenei were documented with different techniques, with a main focus on the male tertiary larva. Two discrete endoparasitic stages occur, the secondary and the tertiary larva. The presence of large compound eyes and externally visible wing buds in the tertiary larva is a unique feature within Holometabola. The brain with large optic lobes is followed by a

Genitalia include some of the most complex and morphologically diverse structures in insects, finding extensive use in taxonomy, but ant taxonomy is female biased and knowledge of the males is little explored, potentially depriving ant taxonomy of valuable information. We examine the male genital morphology of six species of Dinoponera and the variation among species and within species is described

Stick insects have elaborate mechanosensory organs in their subgenual organ complex in the proximal tibia, particularly the distal organ with scolopidial sensilla in linear arrangement. For early postembryonic developmental stages of Sipyloidea sipylus (Phasmatodea: Necrosciinae), the neuroanatomy of the scolopidial organs in the subgenual organ complex and the campaniform sensilla is documented by

The spatial organization of digestion, which corresponds to the steps by which the ingested food is hydrolyzed in the different regions of the gut, was described in insects from the major insect orders. The pattern of digestion and absorption in the midgut shows a strong phylogenetic influence, modulated by adaptation to particular feeding habits. Based on this, basic digestive patterns were recognized

Terrestrial arthropods often colonized and became important in freshwater ecosystems, but did so less often and with little consequence in marine habitats. This pattern cannot be explained by the physical properties of water alone or by limitations of the terrestrial arthropod body plan alone. One hypothesis is that transitions among terrestrial, aquatic and marine ecosystems are unlikely when well-adapted

Megasecoptera is a late Paleozoic order of herbivorous insects with rostrum-like mouthparts and slender homonomous outstretched wings. Our knowledge of their morphology is mainly based on wings while other body parts are scarcely documented. Here we focus on the families Bardohymenidae and Aspidothoracidae. A new well preserved specimen of Sylvohymen cf. sibiricus is described and illustrated, particularly

The male reproductive system may provide significant evidence for the taxonomic and phylogenetic analyses of insects. However, current knowledge of the male reproductive system in Mecoptera is mainly concentrated on the external genitalia, and is rarely involved in the internal reproductive system. Here, we investigated the morphology and the fine structure of the vasa deferentia and associated structures

Cicadas and many of their relatives (Hemiptera: Cicadomorpha) generate vibroacoustic signals using tymbal organs located on their first two abdominal segments. Although tymbals are well-studied in Cicadidae, their systematic distribution in other Cicadomorpha and their possible homologies to the vibroacoustic mechanisms of other Hemiptera have been debated for more than a century. In the present study

The sperm of three coccinellid species belonging to the subfamilies Chilocorinae, Coccinellinae and Epilachninae were studied under light and transmission electron microscopy. The basic sperm structure of these ladybirds is common to that of the other previously studied species, especially the acrosome in front of the basal body and not the nucleus, with this latter running parallel with the flagellar

The ovipositor morphology of Trichophora (Hemiptera: Heteroptera) is revisited. Skeletomuscular structure of the ovipositor of selected species and outgroups is documented. Homologies of the structures are established, different homology hypotheses of previous authors are discussed and rejected. The groundplan of the trichophoran ovipositor is reconstructed, apomorphic conditions of each part of the

Reproduction is a critical feature in the search for means to manage the Asian citrus psyllid, vector of a devastating bacterial pathogen of citrus. The importance of accuracy in functional, anatomical descriptions and interpretations for use by other disciplines, particularly molecular genetics, cannot be overstressed. The term 'sperm pump' was coined by classical authors on observational appearance

Mate choice, copulation, genital morphology, and sperm storage are not very well understood in millipedes. The use of three-dimensional x-ray computed tomography (μCT) provides new morphological data regarding millipede reproductive systems in both the female and male, including chitinous sclerites and membranes, muscles, glands, oviducts, and sperm conduits. Here we present a complete integrated account

Copepoda is one of the crustacean taxa with still unresolved phylogenetic relationships within Tetraconata. Recent phylogenomic studies place them close to Malacostraca and Cirripedia. Little is known about the morphological details of the copepod nervous system, and the available data are sometimes contradictory. We investigated several representatives of the subgroup Calanoida using immunohistochemical

The sperm structure of several species belonging to different tribes of the large Carabidae family is described. Some species of Nebriinae, such as Nebria brevicollis and Notiophilus biguttatus, have free conventional insect sperm. Their sperm type can be regarded as the ancestral model for Carabidae. All the other species examined, either with isolated sperm such as Calomera nemoralis, Scarites sp

The thoracic morphology of the troglobiontic leiodid species Troglocharinus ferreri (Cholevinae, Leptodirini) is described and documented in detail. The features are mainly discussed with respect to modifications linked with subterranean habits. Troglocharinus is assigned to the moderately modified pholeuonoid morphotype. The body is elongated and slender compared to epigean leiodids and also cave-dwelling

The Asian corn borer Ostrinia furnacalis is one of the most destructive pests of maize throughout eastern Asia and the South Pacific. In the present study the fine structure of the compound eyes of adult O. furnacalis was investigated under light/dark adaptation using light and electron microscopy. The compound eyes of male and female O. furnacalis are superposition eyes with electron-lucent clear

Crustaceans detect chemical stimuli in the environment with aesthetasc sensilla, which are located on their 1st antennae. With the transition to other environments, chemoreception faces physical challenges. To provide a deeper understanding of the relation between the morphology of olfactory organs and different lifestyles, we studied the peripheral olfactory system of three amphipod species, the marine

It is known that the size of the scales covering the surface of the Lepidoptera wings is in correlation with body size: larger species possess larger scales. However, butterfly individuals representing the various generations of the same species but differing in body size were not investigated in this respect. Similarly, the question whether different scale size may influence structural color generation

Iridescence is an optical effect that produces angle dependent coloration in animals. Recently, studies have attempted to unveil structures behind such elaborated visual signals and associated behaviors in Odonata. Here, we studied males of the Amazonian damselfly Chalcopteryx scintillans, which have hindwings that exhibit pronounced iridescence. This optical feature is used by the damselflies for

The permeability of the peritrophic matrix, essential for its function, depends on its chemical composition. The objective was to determine if the permeability of the peritrophic matrix varies along the midgut and in the presence of anti-peritrophin-55 antibody in Melipona quadrifasciata and Apis mellifera bees. The thickness of the peritrophic matrix in both species varies between the anterior and

This paper tries to reveal the mechanism of the high-efficient adsorption of the sex pheromone by the trichoid sensilla of the male silk moth Bombyx mori. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to acquire the topographies and nanostructures of the surfaces of the trichoid sensilla. SEM and AFM images present mostly regular pore-ridge nanostructures on the sensilla

Many aphid species reproduce parthenogenetically throughout most of the year, with individuals having identical genomes. Nevertheless, aphid clones display a marked polyphenism with associated behavioural differences. Pea aphids (Acyrthosiphon pisum), when crowded, produce winged individuals, which have a larger dispersal range than wingless individuals. We examined here if brain structures linked

The morphology of the prognathous, host-seeking first-instar larvae of Stylops advarians was examined to advance our understanding of their adaptations to reach immature bee hosts, a process requiring temporal phoresy on an adult bee. Sensory structures on the larval head, including eye spots and two pairs of olfactory pits, evidently assist recognition of an adult bee and eventual detection of a permanent

Digger wasps of the family Crabronidae (Insecta: Hymenoptera) are generally known to use their sting to paralyze or kill a prey. However, only a few species of digger wasps transport their prey to the nest impaled on the sting. How sting morphology correlates with this peculiar type of prey carriage is still unclear. We examined the sting morphology of two phylogenetically closely-related species of

Morphological studies of insects can help us to understand the concomitant or sequential functionality of complex structures and may be used to hypothetize distinct levels of phylogenetic relationship among groups. Traditional morphological works, generally, have encompassed a set of elements, including descriptions of structures and their respective conditions, literature references and images, all

A mechanism involving interaction of the metathoracic wing and third abdominal segment of derbid planthoppers was first discovered over a century ago, and interpreted as a stridulatory organ for sound production. Although referred to occasionally in later taxonomic works, the detailed morphology, systematic distribution, and behavioural significance of this structure have remained unknown, and its

Nasonia, a genus of parasitoid wasps, is a promising model system in the study of developmental and evolutionary genetics, as well as complex traits such as learning. Of these "jewel wasps", the species Nasonia vitripennis is widely spread and widely studied. To accelerate neuroscientific research in this model species, fundamental knowledge of its nervous system is needed. To this end, we present

The knobbed setae on a small caterpillar in 45-55 million years old [Eocene] Baltic amber were studied and characterized as urticating, with evidence of liquid release implying the production of poisons. It is presumed that the caterpillar had been disturbed just prior to falling into the resin, as some of its setae showed defensive responses. The swollen tips of the setae are equipped with "trip hairs"

Termites have a rich set of exocrine glands. These glands are located all over the body, appearing in the head, thorax, legs and abdomen. Here, we describe the oral gland, a new gland formed by no more than a few tens of Class I secretory cells. The gland is divided into two secretory regions located just behind the mouth, on the dorsal and ventral side of the pharynx, respectively. The dominant secretory