Area Of Ventral Surface Research Articles

Morphometric Analysis of Larval Instar Stages of Reared Red Palm Weevil, Rhynchophorus Ferrugineus (Oliver, 1790), (Coleoptera:Curcolionidae)

This study was conducted to explore alternative morphometric characters that could be used to estimate the larval age of red palm weevil (RPW), Rhynchophorus ferrugineus. A total of 14 characters explored in the study. Morphological characters were measured using Image J software and data were analyzed using One-way analysis of variance (ANOVA), principal components analysis (PCA), and discriminant function analysis (DFA). One-way ANOVA excluded characters that are not different among instars, which were distal head band (DB), basal head band (BB), distal tail width (DT), tail ratio (TR), and head band ratio (HBR). All other characters were found to be significant at p < 0.05. For PCA, cumulative variations of 88.7% from the first two principal components, evidenced by sharp decrease in slope of the scree plot, has resulted from high loadings in dorsal surface area (DSA), total surface area (TSA), ventral surface area (VSA), head capsule width (HW), body length (BL) ranging from 0.955 to 0.984. For DFA, only one function explained a canonical correlation of 0.986 with 94.9% variation, and Wilk’s Lambda statistics of (0.007). The highest character loadings were BL, DSA, and HW, and could be useful characters in distinguishing instar ages of RPW larvae.

Cling performance and surface area of attachment in plethodontid salamanders.

Plethodontid salamanders inhabit terrestrial, scansorial, arboreal and troglodytic habitats in which clinging and climbing allow them to access additional food and shelter as well as escape from unfavorable temperature and moisture conditions and ground-dwelling predators. Although salamanders lack claws and toe pads found in other taxa, they successfully cling to and climb on inclined, vertical and inverted substrates in nature. Maximum cling angle was tested on smooth acrylic, and the relationship between cling angle, body mass and surface area of attachment (contact area) was investigated. This study found that many salamander species can cling fully inverted using only a portion of their ventral surface area to attach. Salamanders fall into three functional groups based on mass and maximum cling angle: (1) high-performing, very small salamanders, (2) moderately high performing small and medium-sized salamanders and (3) low-performing large salamanders. They show significant differences in maximum cling angle, even between species of similar mass. In species of similar mass experiencing significantly different detachment stress (resulting from significantly different contact area), differences in morphology or behavior affect how much body surface is attached to the substrate. High performance in some species, such as Desmognathus quadramaculatus, is attributable to large contact area; low performance in a similarly sized species, Ensatina eschscholtzii, is due to behavior that negatively impacts contact area. There was no clear evidence of scaling of adhesive strength with increasing body size. Salamander maximum cling angle is the result of morphology and behavior impacting the detachment stresses experienced during clinging.

One new species of the genus Xizicus (Orthoptera: Tettigoniidae: Meconematinae) from Chongqing, China

The paper described one new species from Chongqing, China, i.e. Xizicus (Eoxizicus) simianshanensis sp. nov., it resembles Xizicus (Eoxizicus) divergentis (Liu & Zhang, 2000) and Xizicus (Eoxizicus) xiai (Liu & Zhang, 2000), but differs from the latter in: posterior processes of male tenth abdominal tergite straight; inner margin of base area of cerci with a notch, the other area of ventral surface after it enlarged inwards, with distinct edge; subgenital plate with posterior margin narrow, with styli stout and short.

Modelling skin surface areas involved in water transfer in the Palmate Newt (Lissotriton helveticus)

Magnetic resonance imaging (MRI) based 3D reconstructions were used to derive accurate quantitative data on body volume and functional skin surface areas involved in water transfer in the Palmate Newt (Lissotriton helveticus (Razoumovsky, 1789)). Body surface area can be functionally divided into evaporative surface area that interacts with the atmosphere and controls the transepidermal evaporative water loss (TEWL); ventral surface area in contact with the substratum that controls transepidermal water absorption (TWA); and skin surface area in contact with other skin surfaces when amphibians adopt water-conserving postures. We generated 3D geometries of the newts via volume-rendering by a “segmentation” process carried out using a graph-cuts algorithm and a Web-based interface. The geometries reproduced the two postures adopted by the newts, i.e., an I-shaped posture characterized by a straight body without tail coiling and an S-shaped posture where the body is huddled up with the tail coiling along it. As a guide to the quality of the surface area estimations, we compared measurements of TEWL rates between living newts and their agar replicas (reproducing their two postures) at 20 °C and 60% relative humidity. Whereas the newts did not show any physiological adaptations to restrain evaporation, they expressed an efficient S-shaped posture with a resulting water economy of 22.9%, which is very close to the 23.6% reduction in evaporative surface area measured using 3D analysis.

Manta Matcher: automated photographic identification of manta rays using keypoint features

For species which bear unique markings, such as natural spot patterning, field work has become increasingly more reliant on visual identification to recognize and catalog particular specimens or to monitor individuals within populations. While many species of interest exhibit characteristic markings that in principle allow individuals to be identified from photographs, scientists are often faced with the task of matching observations against databases of hundreds or thousands of images. We present a novel technique for automated identification of manta rays (Manta alfredi and Manta birostris) by means of a pattern-matching algorithm applied to images of their ventral surface area. Automated visual identification has recently been developed for several species. However, such methods are typically limited to animals that can be photographed above water, or whose markings exhibit high contrast and appear in regular constellations. While manta rays bear natural patterning across their ventral surface, these patterns vary greatly in their size, shape, contrast, and spatial distribution. Our method is the first to have proven successful at achieving high matching accuracies on a large corpus of manta ray images taken under challenging underwater conditions. Our method is based on automated extraction and matching of keypoint features using the Scale-Invariant Feature Transform (SIFT) algorithm. In order to cope with the considerable variation in quality of underwater photographs, we also incorporate preprocessing and image enhancement steps. Furthermore, we use a novel pattern-matching approach that results in better accuracy than the standard SIFT approach and other alternative methods. We present quantitative evaluation results on a data set of 720 images of manta rays taken under widely different conditions. We describe a novel automated pattern representation and matching method that can be used to identify individual manta rays from photographs. The method has been incorporated into a website (mantamatcher.org) which will serve as a global resource for ecological and conservation research. It will allow researchers to manage and track sightings data to establish important life-history parameters as well as determine other ecological data such as abundance, range, movement patterns, and structure of manta ray populations across the world.

Traits underpinning desiccation resistance explain distribution patterns of terrestrial isopods

Predicted changes in soil water availability regimes with climate and land-use change will impact the community of functionally important soil organisms, such as macro-detritivores. Identifying and quantifying the functional traits that underlie interspecific differences in desiccation resistance will enhance our ability to predict both macro-detritivore community responses to changing water regimes and the consequences of the associated species shifts for organic matter turnover. Using path analysis, we tested (1) how interspecific differences in desiccation resistance among 22 northwestern European terrestrial isopod species could be explained by three underlying traits measured under standard laboratory conditions, namely, body ventral surface area, water loss rate and fatal water loss; (2) whether these relationships were robust to contrasting experimental conditions and to the phylogenetic relatedness effects being excluded; (3) whether desiccation resistance and hypothesized underlying traits could explain species distribution patterns in relation to site water availability. Water loss rate and (secondarily) fatal water loss together explained 90% of the interspecific variation in desiccation resistance. Our path model indicated that body surface area affects desiccation resistance only indirectly via changes in water loss rate. Our results also show that soil moisture determines isopod species distributions by filtering them according to traits underpinning desiccation resistance. These findings reveal that it is possible to use functional traits measured under standard conditions to predict soil biota responses to water availability in the field over broad spatial scales. Taken together, our results demonstrate an increasing need to generate mechanistic models to predict the effect of global changes on functionally important organisms.

Anatomical connections of auditory and lateral line areas of the dorsal telencephalon (Dm) in the osteoglossomorph teleost, Gnathonemus petersii

Local field potentials evoked either by auditory or by mechanosensory (water displacement) lateral line stimuli were recorded in sensory subregions of the telencephalic nucleus dorsalis pars medialis (Dm) in the weakly electric fish Gnathonemus petersii. The neural tracer Neurobiotin was injected into these two physiologically defined subregions. A reciprocal connection between the two subregions of Dm, as well as cell bodies and terminals in other telencephalic regions, whose distribution was somewhat different for the two injection types, were found. The course of labeled fibers outside the telencephalon was similar after injections in both Dm regions. Fibers were seen running through the lateral forebrain bundle (lfb) to the ventral surface area of the brain within the diencephalic preglomerular region (PGv). Within a narrow streak along the ventral side of the brain densely arranged cell bodies were labeled. The locations of labeled cells within PGv were indistinguishable after tracer was injected into either acoustical or lateral line areas of Dm. Only after injection into the mechanosensory Dm region labeled cell bodies were found in the anterior preglomerular nucleus (PGa), in addition. When crystals of the fluorescent tracer DiI were inserted in the ventral part of PGv, a path of labeled fibers similar to that after telencephalic injections was found. Labeled terminals, but no cell bodies, were located both in the acoustical and in the mechanosensory regions of Dm as well as in several other telencephalic areas. Even though sensory regions in Dm that process acoustical and mechanical stimuli are segregated and unimodal, they both receive input from neurons of PGv. The specificity of the mechanosensory region of Dm might originate from the additional input from PGa and from other endbrain areas.

First Records of Hyalomma aegyptium (Acari: Ixodida: Ixodidae) from the Russian Spur-Thighed Tortoise, Testudo graeca nikolskii, with an Analysis of Tick Population Dynamics

During the fall of 1995 and the spring of 1996, 77 statistically comparable tick collections, comprising 792 specimens, were made from adults of the Russian spur-thighed tortoise, Testudo graeca nikolskii, at 4 sites along Russia's Black Sea coast. These are the first tick collections reported from T. g. nikolskii since its recognition as a taxonomic entity. All ticks were determined to be Hyalomma (Hyalomma) aegyptium, a common tortoise parasite in southern Russia that in 1930 was erroneously designated the type of subgenus Hyalommasta. Male ticks were recovered from more tortoises (67) than were females (57) or immatures (14), and nymphs were seen only in the fall. Significantly more ticks parasitized male tortoises than females, perhaps because males of T. g. nikolskii have larger home ranges. However, no functional relationship was found between tortoise ventral surface area and degree of tick infestation. Like other tortoise ticks, H. aegyptium is expected to decline in concert with its increasingly threatened hosts.

Alterations of phrenic nerve activity caused by stimulation of neuronal structures in rostral area of ventral surface of the medulla oblongata

Electrical stimulation of neuronal structures in a rostral area of the ventral bulbar surface alters central inspiratory activity in anesthetized rats, augmenting the amplitude and velocity of this activity during the periods of its increase and plateau. The reactions are more pronounced in rats with transected vagal nerves. Blockade of pulmonary mechanoreceptors eliminates the influence of rostral neuronal structures only on the temporal parameters of the plateau. Bilateral cooling of neuronal structures to 20°C results in complete block of central inspiratory activity.

CSF levels of prostaglandins, especially the level of prostaglandin D 2, are correlated with increasing propensity towards sleep in rats

The concentration of PGD 2, PGE 2, and of PGF 2 α was measured in the cerebrospinal fluid (CSF) collected from the cisterna magna of conscious rats ( n=29), which, chronically implanted with a catheter for the CSF sampling, underwent deprivation of daytime sleep. Significant elevation of the CSF level of PGD 2 was observed following 2.5-h sleep deprivation (SD), and the elevation became more marked following 5- and 10-h SD, apparently reaching the maximum at 5-h SD (703±140 pg/ml (mean±S.E.M.) for baseline vs. 1734±363 pg/ml for SD, n=10). The levels of PGE 2 and PGF 2 α also significantly increased following 5- and 10-h SD, but not following 2.5-h SD. It is unlikely that these changes were simply caused by some responses of the animals to stress stimuli, because stress stimuli derived from restraint of the animal at the supine position to a board for 1 h did not produce any acute responses in the CSF levels of prostaglandins ( n=13). In a different group of animals ( n=11) implanted with electrodes for recording electroencephalogram (EEG) and electromyogram (EMG) in addition to the catheter, the levels of the prostaglandins in CSF were determined for slow-wave sleep (SWS) and wakefulness in the day and for SWS and wakefulness in the night. The highest PGD 2 value was obtained at daytime SWS, whereas the lowest was at night wakefulness; furthermore, a significant difference was observed between SWS and wakefulness rather than between day and night. The CSF level of PGE 2 also showed a similar tendency. In an additional group of animals ( n=6), not only PGD 2 but also PGE 2 and PGF 2 α significantly increased the sleeping time of the animal when applied into the subarachnoid space underlying the ventral surface area of the rostral basal forebrain, the previously defined site of action for the sleep-promoting effect of PGD 2. The promotion of sleep by PGE 2 applied to the subarachnoid space was an effect completely opposite to the well-established awaking effect of the same prostaglandin demonstrated in the hypothalamic region in a series of previous studies. Based on these results, we conclude that increases in CSF levels of prostaglandins, especially that of PGD 2, are correlated in rats with heightened propensity towards sleep and further with the depth of sleep under normal as well as SD conditions. © 1997 Elsevier Science B.V. All rights reserved.

Morphogenesis of the murine node and notochordal plate

Development of the node and formation of the notochordal plate in gestational day 7-9 mice (Theiler stages 10-14) has been documented principally with scanning electron microscopy (SEM) and cell fate analyses utilizing DiI and/or CFSE as a cell label. With SEM, cells composing these two populations are initially identifiable at stage 10 at the ventral midline of the rostral half of the embryo. They can be recognized by their relatively small ventral surface area, as compared to that of the peripherally adjacent prospective gut endodermal cells, and by the presence on the ventral side of each cell of a prominent single, central cilium, which is lacking on endodermal cells. At stage 10, the node is located at the apex of the cup-shaped embryo. It represents the rostral end of the primitive streak (although its structure differs from that of the rest of the streak), and it consists of a localized two-layered area (i.e., epiblast and the most caudal aspect of the notochordal plate). By stage 11, the notochordal plate constitutes a relatively broad, circular area (at the level of the node) that tapers rostrally into a narrower midline strip (beneath the future floor plate of the neural tube). The tip of the notochordal plate terminates rostrally at the much broader prechordal plate, which underlies the future forebrain level of the neuraxis. The prechordal plate cells, like the ventral node and notochordal plate cells, each have a relatively small ventral surface area and displays a single central cilium on their ventral surface. The most caudal aspect of the notochordal plate remains morphologically distinct on the dorsal, midline surface of the open gut through stage 13; the more rostral levels progressively fold off from the roof of the gut to form the definitive notochord. Videomicroscopy reveals that the cilia extending from the ventral surfaces of the cells of node and of the prechordal and notochordal plates are motile. The potential significance of this motile behavior remains unknown. Labeling studies, which marked cells in both the dorsal and ventral layers of the node, reveal that the stage-10 node contributes cells to the notochordal plate and overlying midline ectodermal cells of the neural plate, the future floor plate of the neural tube.(ABSTRACT TRUNCATED AT 400 WORDS)

Light and Electron Microscopic Immunocytochemistry of TSH-like Cells Occurring in the Pars tuberalis of the Adult Male Rat Pituitary.

Morphological characteristics of TSH-immunoreactive cells (TSH-like cells) in the pars tuberalis (PT) of intact adult male rats were studied by light and electron microscopic immunocytochemistry. TSH-like cells in the rat PT can be classified into three types by light microscopy: 1) cells diffusely stained throughout the cytoplasm, 2) diffusely weak stained cells containing a strongly stained spot in the paranuclear region; 3) cells with a strongly stained spot in the paranuclear region without diffuse reaction. We call the latter two cell types "spot cells". Electron microscopic immunocytochemistry revealed that the latter two cells reacted very strongly in the Golgi apparatus. The spot cells were localized throughout the PT from rostral to caudal extremities as well as the ventral surface area of the pars distalis (PD) which was connected to the PT. The cytoplasm of the TSH-cells in the PD proper was strongly and diffusely stained with anti-TSH serum, while there was no spot-like staining in any cells. The spot cells demonstrated by electron microscopy contained a well developed Golgi apparatus, many microvesicles and a few secretory granules. These immunocytochemical results clearly showed two apparently distinct types of TSH-immunoreactive cells between the PT and PD in the intact adult male rat adenohypophysis. This morphological distinction of TSH-immunoreactive cells suggests functional differences in these cells.