Cuticular Folds Research Articles

A New Species of Triumphalisnema (Nematoda: Coronostomatoidea) Parasite of Proculejus hirtus (Coleoptera: Passalidae) from Mexico, and the Position of the Family in the Oxyuridomorpha

A new species of the nematode Triumphalisnema Kloss, 1962 (Oxyuridomorpha), is described from the wood beetle Proculejus hirtus Truqui from the mountain mesophilic forest in Hidalgo State, Mexico. Triumphalisnema zuuei n. sp. is distinguished from the other 4 congeners species by the presence of an expanded cervical ring, well-developed lateral alae, an obtuse cauda with a short and bifurcated caudal appendage, series of cuticular folds at ventral and dorsal body surface from excretory pore level to anal region, and ellipsoidal eggs ornamented with numerous small mushroom-like structures over the surface. The phylogenetic position of the new species is inferred based on a Maximum Likelihood and Bayesian Inference analysis of partial sequences of 18S SSU rRNA. The phylogenetic analysis showed that Triumphalisnema zuuei n. sp., the only representative of the Traklosiidae in our study, is closely related to Coynema poeyi and species of Longior, Hystrignathus, and Lepidonema, all of them members of Hystrignathidae. These relationships are supported by high support values. The present study increases to 5 the number of species assigned to Triumphalisnema, all of them parasites of Passalidae. Additionally, a taxonomic key to the species of the genus is provided.

MORPHOFUNCTIONAL CHARACTERISTICS OF LEAVES AND FRUITS IN MALOIDEAE (ROSACEAE): b. THE ROLE OF SURFACE TISSUES IN THE FORMATION OF RESISTANCE TO FUNGAL DISEASES

Background. Resistance to the effects of plant biotic stressors is determined by a set of factors. Among them, the leading protective role is often assigned to the physiological and biochemical characteristics of the surface tissues. However, one cannot ignore the specificity of the microstructural organization of the plant surface, since the nature of interactions in phytopathogenic organisms is more complex than the chemical impact. Meanwhile, the information accumulated to date about the structure of the surface tissues of the vegetative and reproductive organs of plants, and the interface of mycobiota, is fragmentary.Objective. Mature leaves and fruits taken from representatives of the subfamily Maloideae Werber (Malus domestica Borkh., Pyrus communis L., Cydonia oblonga Mill. and Mespilus germanica L.) were selected for the study.Materials and methods. Samples for the research were taken from the middle part of the crown of model trees in 3 replications. In recent years, scanning electron microscopy (SEM) with cryofixation is considered the most promising technique and is used to analyze the surface of biological organisms and identification of species. It is particularly informative in the case of organisms with complex surface micromorphology and for studying the biodiversity of pathogens. However, in this work we combined the methods of light, electron (SEM, TEM) and confocal microscopy. The samples were also studied using phytopathological and histochemical techniques. Condensed polyphenols were detected using K2Cr2O7 and FeCl3 as well as 4-(Dimethylamino)cinnamaldehyde (DMACA, Sigma-Aldrich).Results. On the basis of the obtained phytopathological materials and published data an overview of fungal diseases afflicting leaves and fruits of M. domestica, P. communis, C. oblonga and M. germanica was made. It has been established that a common feature of the Maloideae fruits is the accumulation of condensed polyphenols, which play an important protective role against biotic stressors, in the cells of the pericarp’s outer tissues. Anatomical and morphological characteristics of passive immunity, or horizontal resistance to fungal pathogens, include the specific nature of waxy and cuticular deposits, features of the formation of cuticular folds and peristomatic rings in the stomata area and microstrands at the base of trichomes, thickness of the cuticle and cork tissue, and the development of lenticels on fruits.Conclusion. The studied model plants suffer from a sufficiently wide range of diseases with different etiologies; among them, the most widespread and harmful are mycoses. In view of this, their resistance to fungal pathogens correlates with the specificity of the leaf and fruit surface microstructure and the content of phenolic substances (polyphenols) in the cells of the pericarp’s surface tissues.

Molecular Phylogeny and Tribal Classification of Flanged Bombardier Beetles (Carabidae: Paussinae)

Members of the carabid subfamily Paussinae are known for their explosive defensive chemistry and their associations with ants, which vary from some species being facultative predators of adult ants to others being obligate predators of ant brood. This association with ants has driven extreme morphological adaptations in some lineages. Approximately 750 species are currently classified into four tribes: Metriini, Ozaenini, Protopaussini and Paussini. Here we use molecular sequence data from five genes (28S ribosomal DNA; 18S ribosomal DNA; wingless; carbamoyl phosphate synthetase domain of the rudimentary gene; and arginine kinase) to reveal patterns of deep divergence and provide a new tribal level classification reflecting evolutionary history. We recognize and describe two new tribes, and the tribe Ozaenini is redefined. Among other traits, members of each tribe has a characteristic shape of the cuticular fold at the posterolateral angle of both elytra, known as the flange of Coanda.

Interspecific variations in the surface wettability and morphological traits of petals across 125 plant species

Petal wettability is an important characteristic of flowering plants, as excess surface water on a petal can cause color loss and collapse of shape. However, few studies have examined natural variations in the wettability and the related morphological traits of petals. The present study investigated these characteristics across 125 species from a warm temperate habitat (Tokyo, Japan) by evaluating the contact angles (CAs) of water droplets on the petal epidermis as an index of surface wettability and cell curvature (= cell height/width) and the presence of epicellular structures, such as cuticular folds and trichomes as an index of the petal surface roughness. We found that more than half of the species possessed convex epidermal cells with epicellular structures. In addition, the majority of species had petals with low wettability (CAs varying between 90 and 140°), and only 2.4% and 12% of species possessed super-hydrophobic and hydrophilic petals, respectively. This natural distribution of petal wettability was less variable than that of leaves. Among the less wettable petals (CA > 90°), there was also a significant correlation between cell curvature and CA, and this relationship differed between the adaxial and abaxial sides. To assess the ecological importance of petal wettability, its relationships with life form and flower direction were examined. This showed that herbaceous plants have more convex epidermal cells than woody plants, but no significant difference was detected in their CAs. Besides, among upward-facing flowers, the adaxial side had a more convex and less wettable epidermis compared to the abaxial side, which may protect sky-facing adaxial epidermis from wetting by raindrops. However, there was no significant difference in these features between the adaxial and abaxial sides of sideward- and downward-facing flowers. The less clear tendency of petal wettability was attributable to multiple functions of the petal surface.

Influence of stomatal rings on movements of guard cells

The leaf stomata of some evergreen plants have cuticular rings. According to dynamic modeling, being the ribs of rigidity these rings are able to influence the stomatal mechanics. The cuticular folds are typical of the leaf surface of many flowering plant species. They are often present on the stomatal complex cells. The functions of such folds are still underinvestigated. This study aims to elucidate the role of the stomatal rings in guard cell mechanics. Light, scanning, and transmission electron microscopy were used to study the stomata of the leaf epidermis in Viburnum suspensum (Caprifoliaceae), Lauro-cerasus officinalis (Rosaceae), Exbucklandia populnea (Hamamelidaceae), and Acokanthera oblongifolia (Apocynaceae), which have stomatal rings. The rings are formed by cuticular folds and can be located either immediately on guard cell walls around the outer ledges (marginal stomatal rings), or on the outer ledges themselves (rings of ledges). To elucidate the role of the rings, we have applied dynamic modeling using the finite element method. The data on the shape of the guard cells, uneven thickness of their walls, localization and the relative sizes of stomatal ledges and rings were exactly reproduced during model stomata construction. The turgor pressure was simulated by creating the load distributed on the inner surface of the guard cells. The guard cells of all studied species are located on the subsidiary or neighboring cells. The modeling has shown that the presence of the marginal rings leads to sinking of the opening stomatal pores into epidermis. The depth of the sinking depends on mechanical characteristics of marginal rings. The rings of ledges rib the outer ledges and prevent the outer ledges aperture widening when the stoma is opening.

Two new onyсhiurid species (Collembola, Onychiurinae) inhabiting morel fruit bodies in southwest China.

Two new species Oligaphorura shifangensis sp. nov. and Onychiurus qingchuanensis sp. nov. living on mushrooms (morels) were reported from southwest China. Oligaphorura shifangensis sp. nov. is similar to known species O. schoetti (Lie-Pettersen, 1896), O. groenlandicus (Tullberg, 1876) and O. sibirica (Weiner Kaprus', 2014) as having the same pso formulae (32/133/33343 dorsally and 11/000/00000 ventrally), five papillae in AIIIO, subcoxae 1 of legs I-III with 1 pso each, 11 chaetae in the distal whorl of tibiotarsi, ms present on Th. II and III terga and the presence of anal spines; but they can easily be separated by the labial palp type, ventral psx formula, ratio of unguiculus/unguis and the presence/absence of cuticular fold in furcal remnant. Onychiurus qingchuanensis sp. nov. shares the number of dorsal pso with only three congeners, namely O. bhattii, O. fraterculi and O. steinmanni. They can easily be distinguished by the number of ventral and subcoxal pso, ventral psx and papillae on AIIIO.

Frequency of plant visits by the generalist ant Lasius niger depends on the surface microstructure of plant stems

The aim of this study was to analyze the visiting frequency of generalist ants to plants with different surface textures of their stems. We performed an experiment in which Lasius niger ants were attracted by sweet drops to flower stems of five plant species bearing different surface structures: Alchemilla mollis (wax projections and long tread-shaped trichomes), Lilium lancifolium (without wax, with ribbon-shaped trichomes and cuticular folds), Salvia nemorosa (without wax, with trichomes of various lengths and cuticular folds), Tulipa gesneriana (wax projections, no trichomes), and Paeonia lactiflora (neither of above surface features). As control samples, dry, smooth bamboo sticks were placed in the vicinity of experimental plant stems. Using cryo scanning electron microscopy, the micromorphology of stem surfaces was examined. The present study demonstrates that, on the one hand, ants avoid climbing wax-covered stems, if trichomes are lacking. On the other hand, some trichome-bearing stems having specific trichome micromorphologies were also ignored by ants. The strongest attractiveness was revealed in glossy stems and stems covered with soft/floppy trichomes. This experiment supports the hypothesis that when exposed to a diversity of plant stems in the field, generalist ants choose substrates where their locomotion is less hampered by obstacles or slipperiness of surface. Presumably, additional locomotory efforts needed to master climbing on “greasy” or “spiny” stems lead to an increase of costs-to-benefits ratio. However, since every type of stem surface was visited at least once during the experiment, it does not automatically mean that ants are not capable of walking on such challenging surfaces.

Ultrastructure and functional morphology of dermal glands in the freshwater mite Limnochares aquatica (L., 1758) (Acariformes, Limnocharidae)

This study is the first attempt to describe the ultrastructure and functional morphology of the dermal glands in Limnochares aquatica (L., 1758). The dermal glands were studied using light-optical, SEM and TEM microscopy methods during different stages of their activity. In contrast to the vast majority of other fresh water mites, dermal glands of the studied species are originally multiplied and scattered freely over the mite body surface. The opening of the glands is saddle-like, formed of several tight cuticular folds and oriented freely to the long axis of the mite body. Either a small cuticular spine or, rarely, a slim sensitive seta is placed on one pole of the opening. On the inside, the central gland portion is provided with a complex cuticular helicoid armature. The glands are composed of prismatic cells situated around the intra-alveolar lumen, variously present, and look like a fig-fruit with the basal surface facing the body cavity. The glands are provided with extremely numerous microtubules, frequently arranged in bundles, and totally devoid of synthetic apparatus such as RER cisterns and Golgi bodies. Three states of the gland morphology depending on their functional activity may be recognized: (i) glands without secretion with highly folded cell walls and numerous microtubules within the cytoplasm, (ii) glands with an electron-dense granular secretion in the expanded vacuoles and (iii) glands with the secretion totally extruded presenting giant empty vacuoles bordered with slim cytoplasmic strips on the periphery. Summer specimens usually show the first gland state, whereas winter specimens, conversely, more often demonstrate the second and the third states. This situation may depend on some factors like changes of the seasonal temperature, pH, or oxygenation of the ambient water. On the assumption of the morphological characters, dermal glands may be classified not as secretory but as a special additional excretory organ system of the body cavity. Despite the glands lack cambial cells, restoration of functions after releasing of ‘secretion’ looks possible. Organization of dermal glands is discussed in comparison to other water mites studied.

A new species of Microtetrameres (Nematoda, Tetrameridae) parasitizing Buteogallus urubitinga (Aves, Accipitridae) from northeastern Argentina.

A new tetramerid nematode, Microtetrameres urubitinga n. sp., is described from specimens recovered from the proventriculus of the great black-hawk, Buteogallus urubitinga (Aves: Accipitridae), from Formosa Province, Argentina. The males of the new species are characterized by having spicules unequal (length ratio of spicules 1:3.8-5.9) and dissimilar in shape (right spicule with a simple tip, left spicule with a symmetrical bifurcated tip), caudal papillae arranged asymmetrically (two pairs precloacal and two pairs postcloacal) and cloacal lips highly protruded forming a tube. The gravid females are permanently coiled clockwise or counterclockwise in a spiral and having a tail tapering gradually to a sharp point, with a cuticular fold. This is the first nominal species of Microtetrameres (Travassos, 1915) described parasitizing birds from Argentina. The relationship between the diet of B. urubitinga and the low prevalence of M. urubitinga n. sp. is discussed.

A Study on the Leaf Surfaces Micro-Morphological Characteristics in the Chenopodiaceae

The aim of the present study is to determine the micro-morphological properties of the leaf surfaces of nine species belonging to the family Chenopodiaceae, using scanning electron microscopy (SEM). Leaf surfaces were noticed to vary considerably with respect to cuticle structural types, stomatal pores position, guard cells cuticular ledges and types of trichomes. Lamellate and lamellate-reticulate cuticular types were recognized. These cuticular folds undergo various patterns, depth and orientation in the various species examined. Sunken, ridged, leveled, raised or depressed stomatal pores were encountered, whereas, the guard cells ledges were poorly or well- developed. In Suaeda vermiculata the stomatal pores are sunken in high longitudinal folds rendering the ledges indistinct. Non-glandular unbranched trichomes were detected in Bassia muricata, and collapsed salt bladders were reported in Atriplex leucoclada. The results showed that the micro-morphological characters of the leaf-surfaces examined are considered to be adaptations in response to arid conditions.

Functional micromorphology of petals of Chaenomeles japonica exposed to humid and cold season

In this study, micro- and nano-traits of petal epidermises of flowers of Chaenomeles japonica extended under environmental conditions, during the humid and cold period of the year, are presented. The outer (abaxial) and the inner (adaxial) epidermises of petals of C. japonica consist of convex and papillae cells, respectively, that are covered by epicuticular wrinkled relief further ornamented by submicron motifs, forming interfaces between floral tissues and environment. Structural epidermal features of the petal relief at the nanoscale level reveal different functionality on the two sides of the corolla. The cuticular folds of convex epidermal cells display declining water retention on the outer petal surface and the exposed side of the corolla to the environmental conditions. The cuticular folds of papillae epidermal cells increase in size the inner petal surface, in comparison with the outer surface; such traits facilitate light absorption and enhanced the contact area among folds and curvatures at the inner side of the corolla. It appears that nanometric surface structures of petals may be important adaptive features of C. japonica flowers, contributing to their performance in the field.

A new species of the recently established genus Setaphyes (Kinorhyncha, Allomalorhagida) from the Mediterranean with an identification key

A new species of the very recently erected kinorhynch genus Setaphyes is described here using scanning electron microscopy and differential interference contrast microscopy. Specimens of the new species were collected from the Mediterranean coast of Spain. Setaphyes cimarensis sp. nov. is distinguished from other congeners by the presence of unpaired paradorsal setae on segments 2–9, laterodorsal setae on segments 2–9 and ventromedial setae on segments 3–9, combined with the presence of a distinctive cuticular ornamentation at the anterior dorsal margin of segment 1 forming small, round depressions, as well as conspicuous longitudinal cuticular folds on both sides of segment 10. Moreover, the new species has a significantly larger total trunk length compared to its Mediterranean congeners. A key to all known species of Setaphyes is provided. The present contribution brings the total number of kinorhynch species around the Iberian Peninsula to 33.

Pollen and seed morphology of Zygophylum fabago and Peganum harmala (Zygophyllaceae) from Bulgaria

Scanning electron microscope (SEM) study of the pollenand seed morphology of Peganum harmala L. and Zygophyllumfabago L. (Zygophyllaceae), in native Bulgarian populations, wascarried out. Additionally, a light microscope (LM) investigation onpollen grains was made in order to elucidate the peculiarities of themajor parameters of pollen surface and size. It was established thatpollen grains in Z. fabago are pantoporate. Exine ornamentation isreticulate. The pollen grains of P. harmala are oblate, spheroidal, elongated,oval in shape, colporate, exine striato-rugulate. The seeds of P.harmala are oblong-oval and slightly flattened at the side (incorrecttetrahedral to rhomboid), with a peaked edge, arc-curve laterally. Theseed sculpture corresponds to the Tubular to Concave-type, whichis characterized by polygonal cells and reticulate tectum. The seedsof Z. fabago are oval-rhomboid in shape. The seed sculpture correspondsto Concave to Convex-type which is characterized with polygonalcells, ranging in size, with cuticular wax folds.

Attachment of honeybees and greenbottle flies to petal surfaces

Flower surfaces play a key role in the interaction with pollinators acting as signals and landing sites to attach to. To test attachment, Carniolan honeybees and greenbottle flies were used. Both species represent pollinators equipped with smooth or hairy tarsal attachment devices, respectively. A combination of microscopic methods and traction force measurements was applied in order to understand and evaluate the efficiency of pollinator attachment to a variety of petal surfaces. Although the petal surface texture influenced the attachment, coevolutionary relationships or adaptations between flower surfaces and pollinator tarsi could not be confirmed. Since pollinators appear to be opportunistic, they are expected to attach to a variety of flower surfaces. Rougher surfaces, including conical and papillate epidermal cells, significantly increased the foothold of flies and honeybees, while flat, tabular epidermal cells covered with microstructures like cuticular folds and epicuticular wax crystals impaired attachment. Carniolan honeybees generated larger forces than greenbottle flies, but the latter showed higher safety factors. However, tendencies in attachment ability toward sufficient and insufficient substrates are similar in flies and bees.

Study of petal topography of Lysimachia arvensis grown under natural conditions

The present study revealed that adaxial and abaxial petal epidermises of the blue-flowered Lysimachia arvensis consist of elongated, multi-micro-papillate cells, which may aid the rapid petal expansion. The epidermal cells are covered by a wrinkled relief, which is further ornamented by submicron features that increase in size the surface area of lobes; this may be a well-adapted mechanism of the small-sized flowers of L. arvensis with the short life span. The sculpturally increased surface area of adaxial epidermal cells of petals is expected to contribute to optical and adhesive properties, and wettability of the floral tissues. The adaxial and the abaxial petal surfaces of L. arvensis possess submicron cuticular folds, smaller than the sub-wavelength visible spectrum, which reflect radiation of shorter rather than longer wavelengths, whereas intense absorption was detected in the red spectral region. Also, three-celled capitate trichomes with a pigmented spherical head, which are densely distributed at the corolla margins of L. arvensis, may be involved in adhesive, defensive and functional properties of the floral tissues.

Position-dependent hearing in three species of bushcrickets (Tettigoniidae, Orthoptera).

A primary task of auditory systems is the localization of sound sources in space. Sound source localization in azimuth is usually based on temporal or intensity differences of sounds between the bilaterally arranged ears. In mammals, localization in elevation is possible by transfer functions at the ear, especially the pinnae. Although insects are able to locate sound sources, little attention is given to the mechanisms of acoustic orientation to elevated positions. Here we comparatively analyse the peripheral hearing thresholds of three species of bushcrickets in respect to sound source positions in space. The hearing thresholds across frequencies depend on the location of a sound source in the three-dimensional hearing space in front of the animal. Thresholds differ for different azimuthal positions and for different positions in elevation. This position-dependent frequency tuning is species specific. Largest differences in thresholds between positions are found in Ancylecha fenestrata. Correspondingly, A. fenestrata has a rather complex ear morphology including cuticular folds covering the anterior tympanal membrane. The position-dependent tuning might contribute to sound source localization in the habitats. Acoustic orientation might be a selective factor for the evolution of morphological structures at the bushcricket ear and, speculatively, even for frequency fractioning in the ear.

New records of marine tardigrades from Moorea, French Polynesia, with the description of Styraconyx turbinarium sp. nov. (Arthrotardigrada, Halechiniscidae).

Five marine arthrotardigrade species are recorded from Moorea, Society Islands, French Polynesia. Four were collected from coral sand; two, Dipodarctus anaholiensis Pollock, 1995 and Florarctus kwoni Chang & Rho, 1997, are new records for the region, and two, Halechiniscus perfectus Schulz, 1955 and Styraconyx kristenseni kristenseni Renaud-Mornant, 1981, have been previously reported. The fifth, a new species Styraconyx turbinarium sp. nov., is described and was collected from the drifting brown alga Turbinaria ornata. The new species is characterized by the presence of peduncles on all digits, an elongate primary clava, and the lateral cirrus A arising from a common pedestal and enveloped by a common membrane extending almost to the claval tip. The new species differs from the most similar species, Styraconyx tyrrhenus D'Addabbo Gallo, Morone De Lucia & de Zio Grimaldi, 1989, by having longer and differently shaped primary clavae which are elongated in the new species and club-shaped in S. tyrrhenus. By having a dorsal cuticle that is coarsely punctated but without folds or other ornamentations, the new species can be easily distinguished from S. craticulus (Pollock, 1983), a species with similar primary clavae, but with cuticular dorsal folds ornamented with a grid-like pattern.

Heth impalutiensis n. sp. (Nematoda: Ransomnematoidea: Hethidae)a millipede parasite from Central Mindanao, Philippines.

The nematode Heth impalutiensis n. sp. is described from an unidentified spirostreptid millipede (Harpagophoridae) from the Bukidnon Province of Mindanao, the Philippines. Based on morphological characters, H. impalutiensis n. sp. is closest to Asian-Pacific representatives of the genus. Females of H. impalutiensis n. sp. are close to H. dimorphum and H. vietnamensis in body size and form of the lateral lappets, but can be distinguished by the significantly longer tail. Males of H. impalutiensis n. sp. strongly resemble that of H. xaniophora by the presence of such a rare character combinations as mammiform papillae and a bursa-like cuticular fold, but can be easily differentiated by the numbers of genital papillae (7 vs 6 pairs, respectively). Heth impalutiensis n. sp. can be distinguished from all nominal species by hypertrophy of the anterior anal lip in females which overlaps the anal aperture. Phylogenetic analysis based on the newly obtained set of sequences did not provide an evidence of infraorder Rhigonematomorpha monophyly as two superfamilies Ransomnematoidea and Rhigonematoidea formed independent clades in the frames of ascaridid-spirurid-oxyurid super clade (Clade III of Nadler et al., 2007).

Is floral iridescence a biologically relevant cue in plant–pollinator signaling?

Is floral iridescence a biologically relevant cue in plant–pollinator signaling?

Cricket antennae shorten when bending (Acheta domesticus L.)

Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to “unfold” and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head.