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Sample records for arthropod vibratory communication

  1. Interference of Overlapping Insect Vibratory Communication Signals: An Eushistus heros Model

    PubMed Central

    Čokl, Andrej; Laumann, Raul Alberto; Žunič Kosi, Alenka; Blassioli-Moraes, Maria Carolina; Virant-Doberlet, Meta; Borges, Miguel

    2015-01-01

    Plants limit the range of insect substrate-borne vibratory communication by their architecture and mechanical properties that change transmitted signal time, amplitude and frequency characteristics. Stinkbugs gain higher signal-to-noise ratio and increase communication distance by emitting narrowband low frequency vibratory signals that are tuned with transmission properties of plants. The objective of the present study was to investigate hitherto overlooked consequences of duetting with mutually overlapped narrowband vibratory signals. The overlapped vibrations of the model stinkbug species Eushistus heros, produced naturally or induced artificially on different plants, have been analysed. They represent female and male strategies to preserve information within a complex masked signal. The brown stinkbugs E. heros communicate with species and gender specific vibratory signals that constitute characteristic duets in the calling, courtship and rivalry phases of mating behaviour. The calling female pulse overlaps the male vibratory response when the latency of the latter is shorter than the duration of the female triggering signal or when the male response does not inhibit the following female pulse. Overlapping of signals induces interference that changes their amplitude pattern to a sequence of regularly repeated pulses in which their duration and the difference between frequencies of overlapped vibrations are related inversely. Interference does not occur in overlapped narrow band female calling pulses and broadband male courtship pulse trains. In a duet with overlapped signals females and males change time parameters and increase the frequency difference between signals by changing the frequency level and frequency modulation pattern of their calls. PMID:26098637

  2. Deceptive vibratory communication: pupae of a beetle exploit the freeze response of larvae to protect themselves.

    PubMed

    Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

    2012-10-23

    It is argued that animal signals may have evolved so as to manipulate the response of receivers in a way that increases the fitness of the signallers. In deceptive communication, receivers incur costs by responding to false signals. Recently, we reported that pupae of the soil-inhabiting Japanese rhinoceros beetle Trypoxylus dichotoma produce vibratory signals to deter burrowing larvae, thereby protecting themselves. In the present study, monitoring of vibrations associated with larval movement revealed that T. dichotoma larvae remained motionless for ca 10 min when pupal vibratory signals were played back transiently (freeze response). Furthermore, pupal signals of T. dichotoma elicited a freeze response in three other scarabaeid species, whose pupae do not produce vibratory signals. This indicates that the freeze response to certain types of vibration evolved before the divergence of these species and has been evolutionarily conserved, presumably because of the fitness advantage in avoiding predators. Pupae of T. dichotoma have probably exploited pre-existing anti-predator responses of conspecific larvae to protect themselves by emitting deceptive vibratory signals.

  3. Mating Behaviour and Vibratory Signalling in Non-Hearing Cave Crickets Reflect Primitive Communication of Ensifera

    PubMed Central

    Stritih, Nataša; Čokl, Andrej

    2012-01-01

    In Ensifera, the lack of well-supported phylogeny and the focus on acoustic communication of the terminal taxa hinders understanding of the evolutionary history of their signalling behaviour and the related sensory structures. For Rhaphidophoridae, the most relic of ensiferans following morphology-based phylogenies, the signalling modes are still unknown. Together with a detailed description of their mating process, we provide evidence on vibratory signalling for the sympatric European species Troglophilus neglectus and T. cavicola. Despite their temporal shift in reproduction, the species’ behaviours differ significantly. Signalling by abdominal vibration constitutes an obligatory part of courtship in T. neglectus, while it is absent in T. cavicola. Whole-body vibration is expressed after copulation in both species. While courtship signalling appears to stimulate females for mating, the function of post-copulation signals remains unclear. Mating and signalling of both species were found to take place in most cases on bark, and less frequently on other available substrates, like moss and rock. The signals’ frequency spectra were substrate dependent, but with the dominant peak always expressed below 120 Hz. On rock, the intensity of T. neglectus courtship signals was below the species’ physiological detection range, presumably constraining the evolution of such signalling in caves. The species’ behavioural divergence appears to reflect their divergent mating habitats, in and outside caves. We propose that short-range tremulation signalling in courtship, such as is expressed by T. neglectus, represents the primitive mode and context of mechanical signalling in Ensifera. The absence of high-frequency components in the signals may be related to the absence of the crista acoustica homologue (CAH) in the vibratory tibial organ of Rhaphidophoridae. This indirectly supports the hypothesis proposing that the CAH, as an evolutionary precursor of the ear, evolved in

  4. Soluble proteins of chemical communication: an overview across arthropods

    PubMed Central

    Pelosi, Paolo; Iovinella, Immacolata; Felicioli, Antonio; Dani, Francesca R.

    2014-01-01

    Detection of chemical signals both in insects and in vertebrates is mediated by soluble proteins, highly concentrated in olfactory organs, which bind semiochemicals and activate, with still largely unknown mechanisms, specific chemoreceptors. The same proteins are often found in structures where pheromones are synthesized and released, where they likely perform a second role in solubilizing and delivering chemical messengers in the environment. A single class of soluble polypeptides, called Odorant-Binding Proteins (OBPs) is known in vertebrates, while two have been identified in insects, OBPs and CSPs (Chemosensory Proteins). Despite their common name, OBPs of vertebrates bear no structural similarity with those of insects. We observed that in arthropods OBPs are strictly limited to insects, while a few members of the CSP family have been found in crustacean and other arthropods, where however, based on their very limited numbers, a function in chemical communication seems unlikely. The question we address in this review is whether another class of soluble proteins may have been adopted by other arthropods to perform the role of OBPs and CSPs in insects. We propose that lipid-transporter proteins of the Niemann-Pick type C2 family could represent likely candidates and report the results of an analysis of their sequences in representative species of different arthropods. PMID:25221516

  5. Soluble proteins of chemical communication: an overview across arthropods.

    PubMed

    Pelosi, Paolo; Iovinella, Immacolata; Felicioli, Antonio; Dani, Francesca R

    2014-01-01

    Detection of chemical signals both in insects and in vertebrates is mediated by soluble proteins, highly concentrated in olfactory organs, which bind semiochemicals and activate, with still largely unknown mechanisms, specific chemoreceptors. The same proteins are often found in structures where pheromones are synthesized and released, where they likely perform a second role in solubilizing and delivering chemical messengers in the environment. A single class of soluble polypeptides, called Odorant-Binding Proteins (OBPs) is known in vertebrates, while two have been identified in insects, OBPs and CSPs (Chemosensory Proteins). Despite their common name, OBPs of vertebrates bear no structural similarity with those of insects. We observed that in arthropods OBPs are strictly limited to insects, while a few members of the CSP family have been found in crustacean and other arthropods, where however, based on their very limited numbers, a function in chemical communication seems unlikely. The question we address in this review is whether another class of soluble proteins may have been adopted by other arthropods to perform the role of OBPs and CSPs in insects. We propose that lipid-transporter proteins of the Niemann-Pick type C2 family could represent likely candidates and report the results of an analysis of their sequences in representative species of different arthropods.

  6. ELF communications system ecological monitoring program: Soil arthropods and earthworms

    NASA Astrophysics Data System (ADS)

    Snider, Richard J.; Snider, Renate M.

    1995-04-01

    Based on analysis of years grouped by pre-ELF and operational periods, density fluctuations of arthropods (Collembola and mites) were, in some taxa, significantly different between sites; in others, differences between year groups were significant within either of the study sites. No consistent patterns were seen at the level of species or higher taxa. In some species, effects of the 1988 drought may have carried over into 1989, the first year of antenna operation. Surface-active Collembola, velvet mites and carabid beetles did not alter their activity patterns following antenna activation (e.g., species predominantly spring-active remained spring-active). Although analyses routinely yielded significant differences with respect to total numbers captured in Test and Control, numbers alone were found to be unreliable estimators for disturbance, because a variety of potentially important factors other than EM fields were present. Weekly changes in relative numbers captured, however, showed that increases and decreases in activity were synchronous in the study sites. Carabid beetle activity, which is highly seasonal and governed mainly by reproductive processes, was not affected by EM fields.

  7. Temporal Processing of Vibratory Communication Signals at the Level of Ascending Interneurons in Nezara viridula (Hemiptera: Pentatomidae)

    PubMed Central

    Zorović, Maja

    2011-01-01

    During mating, males and females of N. viridula (Heteroptera: Pentatomidae) produce sex- and species-specific calling and courtship substrate-borne vibratory signals, grouped into songs. Recognition and localization of these signals are fundamental for successful mating. The recognition is mainly based on the temporal pattern, i.e. the amplitude modulation, while the frequency spectrum of the signals usually only plays a minor role. We examined the temporal selectivity for vibratory signals in four types of ascending vibratory interneurons in N. viridula. Using intracellular recording and labelling technique, we analyzed the neurons' responses to 30 pulse duration/interval duration (PD/ID) combinations. Two response arrays were created for each neuron type, showing the intensity of the responses either as time-averaged spike counts or as peak instantaneous spike rates. The mean spike rate response arrays showed preference of the neurons for short PDs (below 600 ms) and no selectivity towards interval duration; while the peak spike rate response arrays exhibited either short PD/long ID selectivity or no selectivity at all. The long PD/short ID combinations elicited the weakest responses in all neurons tested. No response arrays showed the receiver preference for either constant period or duty cycle. The vibratory song pattern selectivity matched the PD of N. viridula male vibratory signals, thus pointing to temporal filtering for the conspecific vibratory signals already at level of the ascending interneurons. In some neurons the responses elicited by the vibratory stimuli were followed by distinct, regular oscillations of the membrane potential. The distance between the oscillation peaks matched the temporal structure of the male calling song, indicating a possible resonance based mechanism for signal recognition. PMID:22053216

  8. Advanced turboprop vibratory characteristics

    NASA Technical Reports Server (NTRS)

    Srinivasan, A. V.; Fulton, G. B.

    1984-01-01

    The assembly of SR5 advanced turboprop blades to develop a structural dynamic data base for swept props is reported. Steady state blade deformation under centrifugal loading and vibratory characteristics of the rotor assembly were measured. Vibration was induced through a system of piezoelectric crystals attached to the blades. Data reduction procedures are used to provide deformation, mode shape, and frequencies of the assembly at predetermined speeds.

  9. Agonistic signals received by an arthropod filiform hair allude to the prevalence of near-field sound communication.

    PubMed

    Santer, Roger D; Hebets, Eileen A

    2008-02-22

    Arthropod filiform hairs respond to air particle movements and are among the most sensitive animal sensory organs. In many species, they are tuned to detect predators or prey and trigger escape or prey capture behaviours. Here we show for the first time that these hairs also receive intraspecific near-field sound signals in an arachnid. During agonistic encounters, whip spiders (Arachnida, Amblypygi) perform antenniform leg vibration (ALV) displays that have significantly longer duration in contest winners than losers. During an ALV display: (i) the vibrating antenniform leg of the displaying whip spider is positioned close to the trichobothria (filiform hairs) on its opponent's walking legs, (ii) the vibrating antenniform leg can excite these trichobothria via air movements and without direct contact, (iii) the antenniform leg of the displaying whip spider vibrates at a frequency that causes particularly strong, sustained excitation and little adaptation in the trichobothria, and (iv) the duration of an ALV display can be extracted from the response of a trichobothrium. Since filiform hairs are widespread among arthropods, communication via such hairs could be extremely prevalent.

  10. Vibratory tactile display for textures

    NASA Technical Reports Server (NTRS)

    Ikei, Yasushi; Ikeno, Akihisa; Fukuda, Shuichi

    1994-01-01

    We have developed a tactile display that produces vibratory stimulus to a fingertip in contact with a vibrating tactor matrix. The display depicts tactile surface textures while the user is exploring a virtual object surface. A piezoelectric actuator drives the individual tactor in accordance with both the finger movement and the surface texture being traced. Spatiotemporal display control schemes were examined for presenting the fundamental surface texture elements. The temporal duration of vibratory stimulus was experimentally optimized to simulate the adaptation process of cutaneous sensation. The selected duration time for presenting a single line edge agreed with the time threshold of tactile sensation. Then spatial stimulus disposition schemes were discussed for representation of other edge shapes. As an alternative means not relying on amplitude control, a method of augmented duration at the edge was investigated. Spatial resolution of the display was measured for the lines presented both in perpendicular and parallel to a finger axis. Discrimination of texture density was also measured on random dot textures.

  11. Non-inertial calibration of vibratory gyroscopes

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor)

    2003-01-01

    The electrostatic elements already present in a vibratory gyroscope are used to simulate the Coriolis forces. An artificial electrostatic rotation signal is added to the closed-loop force rebalance system. Because the Coriolis force is at the same frequency as the artificial electrostatic force, the simulated force may be introduced into the system to perform an inertial test on MEMS vibratory gyroscopes without the use of a rotation table.

  12. Pupal vibratory signals of a group-living beetle that deter larvae

    PubMed Central

    Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

    2012-01-01

    Pupae of some insects produce sounds or vibrations, but the function of the sounds/vibrations has not been clarified in most cases. Recently, we found vibratory communication between pupae and larvae of a group-living beetle Trypoxylus dichotoma, which live in humus soil. The vibratory signals produced by pupae were shown to deter approaching larvae, thereby protecting themselves. In the present study, we tested our hypothesis that pupal signals are mimics of vibratory noises associated with foraging of moles, the most common predators of T. dichotoma. Mole vibrations played back in laboratory experiments deterred larval approaches in the same way as pupal signals. These findings suggest that to deter conspecific larvae, pupae of T. dichotoma may have exploited a preexisting response of larvae to predator vibrations by emitting deceptive signals. PMID:22896788

  13. Evaluation of Vibratory Rollers for Bomb Damage Repair.

    DTIC Science & Technology

    1980-08-01

    Repair Base Course Bomb Damage Repair Crushed Stone Vibratory Rollers\\ Soil Compaction Unsurfaced Repairs 0. ABSTRACT (Continue on reveres aide if...3 Test Areas ....... ............. ............ 3 Vibratory Rollers............................... 3 Soils ...Roller Evaluation Tests ................. 16 Soil Preparation and Placement ................ 16 Compaction .................................... 16

  14. Arthropods in dermatology.

    PubMed

    Steen, Christopher J; Carbonaro, Paul A; Schwartz, Robert A

    2004-06-01

    Arthropods are important in medicine for a multitude of reasons. Their bites and stings may induce allergic reactions, ranging from annoying to life-threatening. Many arthropod products are also capable of inciting allergic responses in sensitized persons. In recent years, bites and stings have gained greater attention owing to increased concern about disease transmission. A common hypersensitivity response to arthropod bites, stings, and products is papular urticaria. This eruption occurs primarily in children, who eventually "outgrow" this disease, probably through desensitization after multiple arthropod exposures. Papular urticaria is most often caused by fleas or bedbugs, but virtually any arthropod is capable of inducing such a reaction. Two arthropod classes of medical importance are the Arachnida (spiders, scorpions, ticks, and mites) and the Insecta (lice, fleas, bedbugs, flies, bees, and ants). Animals in these two classes are probably responsible for more morbidity and mortality worldwide than are any other group of venomous creatures. In general, the diagnosis of arthropod bites and stings is dependent on maintenance of a high index of suspicion and familiarity with the arthropod fauna not only in one's region of practice, but also in the travel regions of one's patients. Learning objective At the completion of this learning activity, participants should be familiar with the clinical manifestations caused by a variety of arthropods as well as the treatment and possible sequelae of arthropod attacks.

  15. 21 CFR 884.4270 - Vibratory cervical dilators.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vibratory cervical dilators. 884.4270 Section 884....4270 Vibratory cervical dilators. (a) Identification. A vibratory cervical dilator is a device designed to dilate the cervical os by stretching it with a power-driven vibrating probe head. The device...

  16. Cloverleaf Vibratory Microgyroscope with Integrated Post

    NASA Technical Reports Server (NTRS)

    Tang, Tony K.; Gutierrez, Roman; Roger, Damien

    2003-01-01

    A modified design and fabrication sequence has been devised to improve the performance of a cloverleaf vibratory microgyroscope that includes an axial rod or post rigidly attached to the center of the cloverleaf structure. The basic concepts of cloverleaf vibratory microgyroscopes, without and with rods or posts, were described in two prior articles in NASA Tech Briefs, Vol. 21, No. 9 (September 1997): Micromachined Planar Vibratory Microgyroscopes (NPO-19713), page 68 and Planar Vibratory Microgyroscope: Alternative Configuration (NPO-19714), page 70. As described in more detail in the second-mentioned prior article, the cloverleaf-shaped structure and the rod or post are parts of a vibratory element that senses rotation via the effect of the Coriolis force upon its vibrations. Heretofore, the posts for devices of this type have been fabricated separately, then assembled manually onto the cloverleaf structures. The resulting imperfections in the assembled units have given rise to asymmetric stresses in the cloverleaf structures and, consequently, to changes in resonant frequencies of vibration and in shapes of vibration modes. These changes, in turn, have caused variations in performance among nominally identical devices. The modified design provides for the fabrication of the upper half of the post as an integral part of the cloverleaf structure; this is accomplished by reactive-ion etching of a single-piece half-post-and-cloverleaf structure from a wafer of silicon. The lower half of the post and a baseplate are also a single piece made by reactive-ion etching from a wafer of silicon. The two pieces are bonded together (see figure) by a thermal-compression metal-to-metal bonding technique to form a cloverleaf gyroscope with an integrated post structure..

  17. Continuous Tuning and Calibration of Vibratory Gyroscopes

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken

    2003-01-01

    A method of control and operation of an inertial reference unit (IRU) based on vibratory gyroscopes provides for continuously repeated cycles of tuning and calibration. The method is intended especially for application to an IRU containing vibratory gyroscopes that are integral parts of microelectromechanical systems (MEMS) and that have cloverleaf designs, as described in several previous NASA Tech Briefs articles. The method provides for minimization of several measures of spurious gyroscope output, including zero-rate offset (ZRO), angle random walk (ARW), and rate drift. These benefits are afforded both at startup and thereafter during continuing operation, in the presence of unknown rotation rates and changes in temperature. A vibratory gyroscope contains a precision mechanically resonant structure containing two normal modes of vibration nominally degenerate in frequency and strongly coupled via a Coriolis term. In the case of the cloverleaf design MEMS gyro, these normal modes of vibration are plate rocking modes. The rocking motion of the plate is described by giving two angles, theta(sub 1) and theta(sub 2). A proof mass consisting of a post orthogonal to the plate ensures a high degree of Coriolis coupling of vibratory energy from one mode into the other under inertial rotation. The plate is driven and sensed capacitively across a few-microns-wide gap, and the normal mode frequencies can be tuned electrostatically by DC voltages applied across this gap. In order to sense rotation, the resonator plate is caused to rock in the theta(sub 1) direction, then any small motions in the theta(sub 2) direction are sensed, rebalanced, and interpreted as inertial rotation. In this scenario, the "drive" has been assigned to the theta(sub 1) direction, and the "sense" has been assigned to the theta(sub 2) direction.

  18. Vibratory pumping of a free fluid stream

    DOEpatents

    Merrigan, M.A.; Woloshun, K.A.

    1990-11-13

    A vibratory fluid pump is described having a force generator for generating asymmetric periodic waves or oscillations connected to one end of one or more fluid conveyance means, such as filaments. The opposite ends of the filaments are connected to springs. Fluid introduced onto the filaments will traverse along the filaments according to the magnitude of the positive and negative excursions of the periodic waves or oscillations, and can be recovered from the filaments. 3 figs.

  19. Vibratory pumping of a free fluid stream

    DOEpatents

    Merrigan, Michael A.; Woloshun, Keith A.

    1990-01-01

    A vibratory fluid pump having a force generator for generating asymmetric periodic waves or oscillations connected to one end of one or more fluid conveyance means, such as filaments. The opposite ends of the filaments are connected to springs. Fluid introduced onto the filaments will traverse along the filaments according to the magnitude of the positive and negative excursions of the periodic waves or oscillations, and can be recovered from the filaments.

  20. Arthropods in Biological Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article reports the use of insect colloidal artificial diets suitable for the rearing of economically important arthropods, such as Lygus lineolaris, Lygus hesperus, Coleomegilla maculata, and Phytoseiulus persimilis The different diets contain key nutrients such as proteins, carbohydrates, vi...

  1. Making Precise Resonators for Mesoscale Vibratory Gyroscopes

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok

    2004-01-01

    An alternative approach to the design and fabrication of vibratory gyroscopes is founded on the use of fabrication techniques that yield best results in the mesoscopic size range, which is characterized by overall device dimensions of the order of a centimeter. This approach stands in contradistinction to prior approaches in (1) the macroscopic size range (the size range of conventional design and fabrication, characterized by overall device dimensions of many centimeters) and (2) the microscopic size range [the size range of microelectromechanical systems (MEMS), characterized by overall device dimensions of the order of a millimeter or less]. The mesoscale approach offers some of the advantage of the MEMS approach (sizes and power demands smaller than those of the macroscale approach) and some of the advantage of the macroscale approach (the possibility of achieving relative dimensional precision greater than that of the MEMS approach). Relative dimensional precision is a major issue in the operation of a vibratory gyroscope. The heart of a vibratory gyroscope is a mechanical resonator that is required to have a specified symmetry in a plane orthogonal to the axis about which rotation is to be measured. If the resonator could be perfectly symmetrical, then in the absence of rotation, a free vibration of the resonator could remain fixed along any orientation relative to its housing; that is, the gyroscope could exhibit zero drift. In practice, manufacturing imprecision gives rise to some asymmetry in mass, flexural stiffness or dissipation, resulting in a slight drift or beating motion of an initial vibration pattern that cannot be distinguished from rotation. In the mesoscale approach, one exploits the following concepts: For a given amount of dimensional error generated in manufacturing, the asymmetry and hence the rate-of-rotation drift of the gyroscope can be reduced by increasing the scale. The decrease in asymmetry also reduces coupling of vibrations to the

  2. Parametrically disciplined operation of a vibratory gyroscope

    NASA Technical Reports Server (NTRS)

    Shcheglov, Kirill V. (Inventor); Hayworth, Ken J. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2008-01-01

    Parametrically disciplined operation of a symmetric nearly degenerate mode vibratory gyroscope is disclosed. A parametrically-disciplined inertial wave gyroscope having a natural oscillation frequency in the neighborhood of a sub-harmonic of an external stable clock reference is produced by driving an electrostatic bias electrode at approximately twice this sub-harmonic frequency to achieve disciplined frequency and phase operation of the resonator. A nearly symmetric parametrically-disciplined inertial wave gyroscope that can oscillate in any transverse direction and has more than one bias electrostatic electrode that can be independently driven at twice its oscillation frequency at an amplitude and phase that disciplines its damping to zero in any vibration direction. In addition, operation of a parametrically-disciplined inertial wave gyroscope is taught in which the precession rate of the driven vibration pattern is digitally disciplined to a prescribed non-zero reference value.

  3. Fast Laser Shutters With Low Vibratory Disturbances

    NASA Technical Reports Server (NTRS)

    Brinza, David; Moore, Donald; Hochberg, Eric; Radey, Tom; Chen, Albert

    2005-01-01

    A prototype vacuum-compatible, fast-acting, long-life shutter unit that generates very little vibratory disturbance during switching is reviewed. This is one of a number of shutters designed to satisfy requirements specific to an experiment, to be performed aboard a spacecraft in flight, in which laser beams must be blocked rapidly and completely, without generating a vibratory disturbance large enough to adversely affect the power and frequency stability of the lasers. Commercial off-the-shelf laboratory shutter units -- typically containing electromagnet-coil-driven mechanisms -- were found not to satisfy the requirements because they are not vacuum-compatible, their actuators engage in uncompensated motions that generate significant vibrations, and their operational lifetimes are too short. Going beyond the initial outerspace application, the present vacuum-compatible, fast-acting, long-life shutter units could also be used in terrestrial settings in which there are requirements for their special characteristics. In designing these shutter units, unbalanced, electromagnetically driven mechanisms were replaced with balanced mechanisms that include commercial piezoelectric bending actuators. In each shutter unit, the piezoelectric bending actuators are configured symmetrically as opposing cantilever beams within a housing that contains integral mounts for lenses that focus a laser beam to a waist at the shutter location. In operation, the laser beam is blocked by titanium blades bonded near the free ends of the piezoelectric benders. The benders are driven by shaped electrical pulses with a maximum voltage differential of less than 60 V. Preliminary measurements indicate that rise and fall times are less than 1 ms.

  4. Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads

    NASA Technical Reports Server (NTRS)

    Amer, K. B.; Neff, J. R.

    1974-01-01

    The use of pendulum dynamic absorbers mounted on the blade root and operating in the vertical plane to minimize helicopter vibratory loads was discussed. A qualitative description was given of the concept of the dynamic absorbers and some results of analytical studies showing the degree of reduction in vibratory loads attainable are presented. Operational experience of vertical plane dynamic absorbers on the OH-6A helicopter is also discussed.

  5. Complex vibratory patterns in an elephant larynx.

    PubMed

    Herbst, Christian T; Svec, Jan G; Lohscheller, Jörg; Frey, Roland; Gumpenberger, Michaela; Stoeger, Angela S; Fitch, W Tecumseh

    2013-11-01

    Elephants' low-frequency vocalizations are produced by flow-induced self-sustaining oscillations of laryngeal tissue. To date, little is known in detail about the vibratory phenomena in the elephant larynx. Here, we provide a first descriptive report of the complex oscillatory features found in the excised larynx of a 25 year old female African elephant (Loxodonta africana), the largest animal sound generator ever studied experimentally. Sound production was documented with high-speed video, acoustic measurements, air flow and sound pressure level recordings. The anatomy of the larynx was studied with computed tomography (CT) and dissections. Elephant CT vocal anatomy data were further compared with the anatomy of an adult human male. We observed numerous unusual phenomena, not typically reported in human vocal fold vibrations. Phase delays along both the inferior-superior and anterior-posterior (A-P) dimension were commonly observed, as well as transverse travelling wave patterns along the A-P dimension, previously not documented in the literature. Acoustic energy was mainly created during the instant of glottal opening. The vestibular folds, when adducted, participated in tissue vibration, effectively increasing the generated sound pressure level by 12 dB. The complexity of the observed phenomena is partly attributed to the distinct laryngeal anatomy of the elephant larynx, which is not simply a large-scale version of its human counterpart. Travelling waves may be facilitated by low fundamental frequencies and increased vocal fold tension. A travelling wave model is proposed, to account for three types of phenomena: A-P travelling waves, 'conventional' standing wave patterns, and irregular vocal fold vibration.

  6. Methane production in terrestrial arthropods.

    PubMed Central

    Hackstein, J H; Stumm, C K

    1994-01-01

    We have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. We show that arthropod symbionts can contribute substantially to atmospheric methane. Images PMID:8202505

  7. Methane production in terrestrial arthropods

    SciTech Connect

    Hackstein, J.H.P.; Stumm, C.K. )

    1994-06-07

    The authors have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. The authors show that arthropod symbionts can contribute substantially to atmospheric methane.

  8. Analysis of rotor vibratory loads using higher harmonic pitch control

    NASA Technical Reports Server (NTRS)

    Quackenbush, Todd R.; Bliss, Donald B.; Boschitsch, Alexander H.; Wachspress, Daniel A.

    1992-01-01

    Experimental studies of isolated rotors in forward flight have indicated that higher harmonic pitch control can reduce rotor noise. These tests also show that such pitch inputs can generate substantial vibratory loads. The modification is summarized of the RotorCRAFT (Computation of Rotor Aerodynamics in Forward flighT) analysis of isolated rotors to study the vibratory loading generated by high frequency pitch inputs. The original RotorCRAFT code was developed for use in the computation of such loading, and uses a highly refined rotor wake model to facilitate this task. The extended version of RotorCRAFT incorporates a variety of new features including: arbitrary periodic root pitch control; computation of blade stresses and hub loads; improved modeling of near wake unsteady effects; and preliminary implementation of a coupled prediction of rotor airloads and noise. Correlation studies are carried out with existing blade stress and vibratory hub load data to assess the performance of the extended code.

  9. Vibratory compaction tests on graphite powders for neutron shielding

    SciTech Connect

    Morgan, W.C.

    1982-05-01

    Mistures of three size ranges of graphite powders have been vibratory packed to densities as high as 1.40 gm/cm/sup 3/, which is 87.5 percent of the design density for the graphte segment of the FMIT test cell shield. Ultrasonic resonance vibration of the particles was determined to be an impractical method for achieving the required density. Possible options for fabricating the shield are: (1) revert to solid graphite, rather than vibratory packed powder, or (2) develop the mechanical vibratory compaction method, which would require (a) designing for the higher heat-load attendant with the reduced graphite density, or (b) increasing the thickness of the graphite segment by 15 percent or (c) seeking a new source of graphite powder with higher particle density.

  10. Household Arthropod Allergens in Korea

    PubMed Central

    Jeong, Kyoung Yong

    2009-01-01

    Arthropods are important in human health, which can transmit pathogens to humans, parasitize, or produce important allergens. Allergy prevalence becomes higher in Korea recently as well as other developed countries in contrast to a decrease of infectious diseases. Allergic diseases caused by household arthropods have increased dramatically during the last few decades since human beings spend more their time for indoor activities in modernized life style. Household arthropods are one of the most common causes of allergic diseases. Biological characterization of household arthropods and researches on their allergens will provide better understanding of the pathogenesis of allergic diseases and suggest new therapeutic ways. Therefore, studies on arthropods of allergenic importance can be considered one of the major research areas in medical arthropodology and parasitology. Here, the biology of several household arthropods, including house dust mites and cockroaches, the 2 most well known arthropods living indoor together with humans worldwide, and characteristics of their allergens, especially the research activities on these allergens performed in Korea, are summarized. PMID:19885330

  11. Modifications of Fabrication of Vibratory Microgyroscopes

    NASA Technical Reports Server (NTRS)

    Bae, Sam Y.; Yee, Karl Y.; Wiberg, Dean

    2005-01-01

    A micromachining process for the fabrication of vibratory microgyroscopes from silicon wafers, and aspects of the microgyroscope design that are inextricably linked with the fabrication process, have been modified in an effort to increase production yields from perspectives of both quantity and quality. Prior to the modifications, the effective production yield of working microgyroscopes was limited to one or less per wafer. The modifications are part of a continuing effort to improve the design and increase production yields to more than 30 working microgyroscopes per wafer. A discussion of pertinent aspects of the unmodified design and the unmodified fabrication process is prerequisite to a meaningful description of the modifications. The design of the microgyroscope package was not conducive to high yield and rapid testing of many microgyroscopes. One of the major impediments to high yield and testing was found to lie in vibration- isolation beams around the four edges of each microgyroscope, which beams were found to be unnecessary for achieving high resonance quality factors (Q values) characterizing the vibrations of petallike cantilevers. The fabrication process included an 8- m-deep plasma etch. The purpose of the etch was to create 8- m vertical gaps, below which were to be placed large gold evaporated electrodes and sensing pads to drive and sense resonant vibrations of the "petals." The process also included a step in which bridges between dies were cut to separate the dies. The etched areas must be kept clean and smooth (free of debris and spikes), because any object close to 8 m high in those areas would stop the vibrations. However, it was found that after the etch, there remained some spikes with heights that were, variously, almost as high or as high as the etch depth. It also was found that the cutting of bridges created silicon debris, some of which lodged in the 8- m gaps and some of which landed on top of the petals. The masses added to the

  12. Laboratory identification of arthropod ectoparasites.

    PubMed

    Mathison, Blaine A; Pritt, Bobbi S

    2014-01-01

    The collection, handling, identification, and reporting of ectoparasitic arthropods in clinical and reference diagnostic laboratories are discussed in this review. Included are data on ticks, mites, lice, fleas, myiasis-causing flies, and bed bugs. The public health importance of these organisms is briefly discussed. The focus is on the morphological identification and proper handling and reporting of cases involving arthropod ectoparasites, particularly those encountered in the United States. Other arthropods and other organisms not of public health concern, but routinely submitted to laboratories for identification, are also briefly discussed.

  13. Arthropod neurons and nervous system.

    PubMed

    Smarandache-Wellmann, Carmen Ramona

    2016-10-24

    Arthropods are very diverse, come in many different forms with diverse adaptations, and through such diversity have populated all environmental niches on the planet. Almost 80% of the animals on planet Earth belong to this phylum. Despite their very diverse phenotypes they share fundamental similarities which were previously used to generate a phylogenetic tree. All arthropods have segmented bodies and possess jointed limbs at all or many of their body segments. An additional common feature of arthropods is their exoskeleton, made mainly of chitin and/or sclerotin.

  14. Laboratory Identification of Arthropod Ectoparasites

    PubMed Central

    Pritt, Bobbi S.

    2014-01-01

    SUMMARY The collection, handling, identification, and reporting of ectoparasitic arthropods in clinical and reference diagnostic laboratories are discussed in this review. Included are data on ticks, mites, lice, fleas, myiasis-causing flies, and bed bugs. The public health importance of these organisms is briefly discussed. The focus is on the morphological identification and proper handling and reporting of cases involving arthropod ectoparasites, particularly those encountered in the United States. Other arthropods and other organisms not of public health concern, but routinely submitted to laboratories for identification, are also briefly discussed. PMID:24396136

  15. 21 CFR 884.4270 - Vibratory cervical dilators.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vibratory cervical dilators. 884.4270 Section 884.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... used to gain access to the uterus or to induce abortion, but is not to be used during labor when...

  16. 21 CFR 884.4270 - Vibratory cervical dilators.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vibratory cervical dilators. 884.4270 Section 884.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... used to gain access to the uterus or to induce abortion, but is not to be used during labor when...

  17. 21 CFR 884.4270 - Vibratory cervical dilators.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vibratory cervical dilators. 884.4270 Section 884.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... used to gain access to the uterus or to induce abortion, but is not to be used during labor when...

  18. 21 CFR 884.4270 - Vibratory cervical dilators.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vibratory cervical dilators. 884.4270 Section 884.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... used to gain access to the uterus or to induce abortion, but is not to be used during labor when...

  19. Vibratory Urticaria Associated with a Missense Variant in ADGRE2

    PubMed Central

    Boyden, Steven E.; Desai, Avanti; Cruse, Glenn; Young, Michael L.; Bolan, Hyejeong C.; Scott, Linda M.; Eisch, A. Robin; Long, R. Daniel; Lee, Chyi-Chia R.; Satorius, Colleen L.; Pakstis, Andrew J.; Olivera, Ana; Mullikin, James C.; Chouery, Eliane; Mégarbané, André; Medlej-Hashim, Myrna; Kidd, Kenneth K.; Kastner, Daniel L.; Metcalfe, Dean D.; Komarow, Hirsh D.

    2016-01-01

    SUMMARY Patients with autosomal dominant vibratory urticaria have localized hives and systemic manifestations in response to dermal vibration, with coincident degranulation of mast cells and increased histamine levels in serum. We identified a previously unknown missense substitution in ADGRE2 (also known as EMR2), which was predicted to result in the replacement of cysteine with tyrosine at amino acid position 492 (p.C492Y), as the only nonsynonymous variant cosegregating with vibratory urticaria in two large kindreds. The ADGRE2 receptor undergoes autocatalytic cleavage, producing an extracellular subunit that noncovalently binds a transmembrane subunit. We showed that the variant probably destabilizes an autoinhibitory subunit interaction, sensitizing mast cells to IgE-independent vibration-induced degranulation. (Funded by the National Institutes of Health.) PMID:26841242

  20. Deburring die-castings by wet vibratory plant

    NASA Technical Reports Server (NTRS)

    Loeschbart, H. M.

    1980-01-01

    A wet vibratory procedure for the removal of burrs from die castings is described. In this process synthetic abrasive chips and detergent solutions are agitated with the work in such a way as to produce a spiral circulatory movement. Details of various forms of vibrator basin and shapes of abrasive are illustrated. The automation of deburring is illustrated through the application of vibrators of spiral design in combination with transport and drying devices.

  1. Characterization of the bell-shaped vibratory angular rate gyro.

    PubMed

    Liu, Ning; Su, Zhong; Li, Qing; Fu, MengYin; Liu, Hong; Fan, JunFang

    2013-08-07

    The bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a novel shell vibratory gyroscope, which is inspired by the Chinese traditional bell. It sensitizes angular velocity through the standing wave precession effect. The bell-shaped resonator is a core component of the BVG and looks like the millimeter-grade Chinese traditional bell, such as QianLong Bell and Yongle Bell. It is made of Ni43CrTi, which is a constant modulus alloy. The exciting element, control element and detection element are uniformly distributed and attached to the resonator, respectively. This work presents the design, analysis and experimentation on the BVG. It is most important to analyze the vibratory character of the bell-shaped resonator. The strain equation, internal force and the resonator's equilibrium differential equation are derived in the orthogonal curvilinear coordinate system. When the input angular velocity is existent on the sensitive axis, an analysis of the vibratory character is performed using the theory of thin shells. On this basis, the mode shape function and the simplified second order normal vibration mode dynamical equation are obtained. The coriolis coupling relationship about the primary mode and secondary mode is established. The methods of the signal processing and control loop are presented. Analyzing the impact resistance property of the bell-shaped resonator, which is compared with other shell resonators using the Finite Element Method, demonstrates that BVG has the advantage of a better impact resistance property. A reasonable means of installation and a prototypal gyro are designed. The gyroscopic effect of the BVG is characterized through experiments. Experimental results show that the BVG has not only the advantages of low cost, low power, long work life, high sensitivity, and so on, but, also, of a simple structure and a better impact resistance property for low and medium angular velocity measurements.

  2. Arthropod use of invertebrate carrion

    SciTech Connect

    Seastedt, T.R.; Mameli, L.; Gridley, K.

    1980-08-01

    Arthropods associated with cricket carcasses placed on top and within deciduous forest litter were collected over a 12 month interval. Vespid wasps and ants quickly removed carcasses left on top of forest litter, but carcasses placed within litter persisted throughout the study. Major consumers of carcasses in litter varied seasonally; maggots dominated on fresh carcasses in summer, but fresh carcasses placed in litter in autumn were consumed by other arthropods. A gamasid mite, Hypoaspis (Laelaspis) johnieae dominated the microarthropod fauna found on exoskeleton fragments. A method for collecting invertebrate carrion feeders and measuring carrion disappearance is presented.

  3. Arthropod use of invertebrate carrion

    SciTech Connect

    Seastedt, T.R.; Mameli, L.; Gridley, K.

    1981-01-01

    Arthropods associated with cricket carcasses placed on top and within deciduous forest litter were collected for 12 months. Vespid wasps and ants quickly removed carcasses left on top of forest litter, but carcasses placed within litter persisted throughout the study. Major consumers of carcasses in litter varied seasonally; maggots dominated on fresh carcasses in summer, but fresh carcasses placed in litter in autumn were consumed by other arthropods. A gamasid mite, Hypoaspis (Laelaspis) johnieae, dominated the microarthropod fauna found on exoskeleton fragments. A method for collecting invertebrate carrion feeders and measuring carrion disappearance is presented. 15 references, 2 tables.

  4. Innovative decontamination technology by abrasion in vibratory vessels

    SciTech Connect

    Fabbri, Silvio; Ilarri, Sergio

    2007-07-01

    Available in abstract form only. Full text of publication follows: The possibility of using conventional vibratory vessel technology as a decontamination technique is the motivation for the development of this project. The objective is to explore the feasibility of applying the vibratory vessel technology for decontamination of radioactively-contaminated materials such as pipes and metal structures. The research and development of this technology was granted by the U.S. Department of Energy (DOE). Abrasion processes in vibratory vessels are widely used in the manufacture of metals, ceramics, and plastics. Samples to be treated, solid abrasive media and liquid media are set up into a vessel. Erosion results from the repeated impact of the abrasive particles on the surface of the body being treated. A liquid media, generally detergents or surfactants aid the abrasive action. The amount of material removed increases with the time of treatment. The design and construction of the machine were provided by Vibro, Argentina private company. Tests with radioactively-contaminated aluminum tubes and a stainless steel bar, were performed at laboratory level. Tests showed that it is possible to clean both the external and the internal surface of contaminated tubes. Results show a decontamination factor around 10 after the first 30 minutes of the cleaning time. (authors)

  5. Reconstruction and separation of vibratory field using structural holography

    NASA Astrophysics Data System (ADS)

    Chesnais, C.; Totaro, N.; Thomas, J.-H.; Guyader, J.-L.

    2017-02-01

    A method for reconstructing and separating vibratory field on a plate-like structure is presented. The method, called ;Structural Holography; is derived from classical Near-field Acoustic Holography (NAH) but in the vibratory domain. In this case, the plate displacement is measured on one-dimensional lines (the holograms) and used to reconstruct the entire two-dimensional displacement field. As a consequence, remote measurements on non directly accessible zones are possible with Structural Holography. Moreover, as it is based on the decomposition of the field into forth and back waves, Structural Holography permits to separate forces in the case of multi-sources excitation. The theoretical background of the Structural Holography method is described first. Then, to illustrate the process and the possibilities of Structural Holography, the academic test case of an infinite plate excited by few point forces is presented. With the principle of vibratory field separation, the displacement fields produced by each point force separately is reconstructed. However, the displacement field is not always meaningful and some additional treatments are mandatory to localize the position of point forces for example. From the simple example of an infinite plate, a post-processing based on the reconstruction of the structural intensity field is thus proposed. Finally, Structural Holography is generalized to finite plates and applied to real experimental measurements

  6. Carnivorous arthropods after spring flood

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spring flooding is a common practice in Wisconsin cranberries, but flooding as insect control produces variable results among marshes. This project is aimed at figuring out why it works, and why it sometimes doesn’t. We have focused on tracking arthropod populations to explain the observed patterns ...

  7. Arthropod diversity in a tropical forest.

    PubMed

    Basset, Yves; Cizek, Lukas; Cuénoud, Philippe; Didham, Raphael K; Guilhaumon, François; Missa, Olivier; Novotny, Vojtech; Ødegaard, Frode; Roslin, Tomas; Schmidl, Jürgen; Tishechkin, Alexey K; Winchester, Neville N; Roubik, David W; Aberlenc, Henri-Pierre; Bail, Johannes; Barrios, Héctor; Bridle, Jon R; Castaño-Meneses, Gabriela; Corbara, Bruno; Curletti, Gianfranco; Duarte da Rocha, Wesley; De Bakker, Domir; Delabie, Jacques H C; Dejean, Alain; Fagan, Laura L; Floren, Andreas; Kitching, Roger L; Medianero, Enrique; Miller, Scott E; Gama de Oliveira, Evandro; Orivel, Jérôme; Pollet, Marc; Rapp, Mathieu; Ribeiro, Sérvio P; Roisin, Yves; Schmidt, Jesper B; Sørensen, Line; Leponce, Maurice

    2012-12-14

    Most eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields >60% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.

  8. Chaotic behavior on in-phase vibratory conveyors

    SciTech Connect

    Raski, J.Z.

    1998-07-01

    One of the basic building blocks of IBM's computer technology is the thin-film interstitial metallized ceramic (IMC) substrate. The packaging of these substrates employs small input/output (IO) pins to provide both mechanical and electrical connection to the printed circuit board. In the automated manufacturing of the substrate, the input and output pins are individually conveyed by in-line vibratory conveyors. However, a nonperiodic motion of these pins is observed at certain angles of conveyor table tilt that cannot be explained by classical models of friction. This paper models the motion of a single I/O pin on an in-phase, linearly oscillating conveyor using the classical model of friction and compares that result with experimental observations. It is shown here, analytically and experimentally, that when the vibratory conveyor table amplitude and the coefficient of friction between the pin and the table are sufficiently large, the pin is conveyed forward with some velocity. If the conveyor table's angle of tilt is sufficiently large and the coefficient of friction is sufficiently low, the pin may slip backwards just as fast as the conveyor table drives it forward, resulting in a net pin velocity of zero. Surrounding the condition at which the net velocity of the pin is zero is a chaotic basin of attraction in which the pin motion is non-periodic. This basin of attraction was experimentally determined to be bracketed within a range of values of the coefficient of friction. The implications of these theoretical and experimental results are discussed in terms of the practical application of in-phase vibratory conveyors in manufacturing.

  9. Quantitative phase imaging of arthropods

    PubMed Central

    Sridharan, Shamira; Katz, Aron; Soto-Adames, Felipe; Popescu, Gabriel

    2015-01-01

    Abstract. Classification of arthropods is performed by characterization of fine features such as setae and cuticles. An unstained whole arthropod specimen mounted on a slide can be preserved for many decades, but is difficult to study since current methods require sample manipulation or tedious image processing. Spatial light interference microscopy (SLIM) is a quantitative phase imaging (QPI) technique that is an add-on module to a commercial phase contrast microscope. We use SLIM to image a whole organism springtail Ceratophysella denticulata mounted on a slide. This is the first time, to our knowledge, that an entire organism has been imaged using QPI. We also demonstrate the ability of SLIM to image fine structures in addition to providing quantitative data that cannot be obtained by traditional bright field microscopy. PMID:26334858

  10. Investigation of the Effect of Blade Sweep on Rotor Vibratory Loads

    NASA Technical Reports Server (NTRS)

    Tarzanin, F. J., Jr.; Vlaminck, R. R.

    1983-01-01

    The effect of helicopter rotor blade planform sweep on rotor vibratory hub, blade, and control system loads has been analytically investigated. The importance of sweep angle, sweep initiation radius, flap bending stiffness and torsion bending stiffness is discussed. The mechanism by which sweep influences the vibratory hub loads is investigated.

  11. Knowledge of Arthropod Carnivory and Herbivory: Factors Influencing Preservice Elementary Teacher's Attitudes and Beliefs toward Arthropods

    ERIC Educational Resources Information Center

    Wagler, Ron; Wagler, Amy

    2013-01-01

    Human negativity toward arthropods has been well documented but the factors that contribute to this negativity have been elusive. This study explored knowledge of arthropod carnivory and herbivory as possible casual factors that contribute to the negative tendencies preservice elementary teachers have toward most arthropods. Specifically, this…

  12. [Tularemia transmitted by arthropod bites].

    PubMed

    Misić-Majerus, L; Bujić, N; Madarić, V

    1996-01-01

    The authors present four patients affected with tularaemia in Koprivnica-Krizevci region. The disease occurred in the period from April to September 1994, in 3 males and 1 female patient, aged 9-49 years. In all affected persons the infections were transmitted after bites of arthropods, ticks or other insects. The disease was clinically manifested as ulceroglandular form, without complications and relapses. The diagnosis was established by anamnestic and epidemiological data, clinical picture, the course of the disease, laboratory findings, tularin test and specific agglutination test (two samples). All patients were successfully treated with doxycyclin.

  13. Adaptive control of a vibratory angle measuring gyroscope.

    PubMed

    Park, Sungsu

    2010-01-01

    This paper presents an adaptive control algorithm for realizing a vibratory angle measuring gyroscope so that rotation angle can be directly measured without integration of angular rate, thus eliminating the accumulation of numerical integration errors. The proposed control algorithm uses a trajectory following approach and the reference trajectory is generated by an ideal angle measuring gyroscope driven by the estimate of angular rate and the auxiliary sinusoidal input so that the persistent excitation condition is satisfied. The developed control algorithm can compensate for all types of fabrication imperfections such as coupled damping and stiffness, and mismatched stiffness and un-equal damping term in an on-line fashion. The simulation results show the feasibility and effectiveness of the developed control algorithm that is capable of directly measuring rotation angle without the integration of angular rate.

  14. Analysis of the vibratory excitation arising from spiral bevel gears

    NASA Technical Reports Server (NTRS)

    Mark, William D.

    1987-01-01

    Tools required to understand and predict in terms of its underlying causes the vibratory excitation arising from meshing spiral bevel gears are developed. A generalized three component transmission error of meshing spiral bevel gears is defined. Equations are derived that yield the three components of the generalized transmission error in terms of deviations of tooth running surfaces from equispaced perfect spherical involute surfaces and tooth/gearbody elastic deformations arising from the three components of the generalized force transmitted by the meshing gears. A method for incorporating these equations into the equations of motion of a gear system is described. Equations are derived for the three components of the generalized force transmitted by the gears which are valid whenever inertial effects of the meshing gears and their supports are negligible. Bearing offsets from the positions occupied by the shaft centerlines of perfect spherical involute bevel gears and bearing/bearing support flexibilities enter into the computation of these forces.

  15. Split-Resonator, Integrated-Post Vibratory Microgyroscope

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam; Hayworth, Ken; Shcheglov, Kirill

    2005-01-01

    An improved design for a capacitive-sensing, rocking-mode vibratory microgyroscope is more amenable to mass production, relative to a prior design. Both the improved design and the prior design call for a central post that is part of a resonator that partly resembles a cloverleaf or a flower. The prior design is such that the post has to be fabricated as a separate piece, then bonded to the rest of the resonator in the correct position and orientation. The improved design provides for fabrication of the post as an integral part of the resonator and, in so doing, makes it possible to produce a waferful of microgyroscopes, without need to fabricate, position, and attach posts.

  16. Parametric identification of a vibratory system with a clearance

    NASA Technical Reports Server (NTRS)

    Alexander, R. M.; Noah, S. T.; Franck, C. G.

    1993-01-01

    An analytical and experimental investigation of a vibratory system with a clearance was conducted. A finite element model and an equivalent single-degree-of-freedom closed-form solution were used to determine the dynamic parameters and response of an experimental structure interacting with a gap. The closed-form solution is obtained by taking advantage of the piecewise linearity of the system. Results from these solution methods are in agreement with experimental data. The results also suggest that the closed-form solution approximates the response of the experimental structure with accuracy greater than that of the finite element model. The closed-form solution was also used to determine the gap size of the structure. The parameter identification procedure utilized in this study appears to be simple to use and can be readily extended to other types of piecewise-linear multi-degree-of-freedom systems.

  17. Arthropods affecting the human eye.

    PubMed

    Panadero-Fontán, Rosario; Otranto, Domenico

    2015-02-28

    Ocular infestations by arthropods consist in the parasitization of the human eye, either directly (e.g., some insect larvae causing ophthalmomyiasis) or via arthropods feeding on lachrymal/conjunctival secretions (e.g., some eye-seeking insects, which also act as vectors of eye pathogens). In addition, demodicosis and phthiriasis may also cause eye discomfort in humans. Ophthalmomyiasis by larvae of the families Oestridae, Calliphoridae and Sarcophagidae, are frequent causative agents of human ocular infestations. Over the last decades, the extensive use of macrocyclic lactones in cattle has reduced the frequency of infestations by Hypoderma bovis and Hypoderma lineatum (family Oestridae), and consequently, human infestations by these species. A prompt diagnosis of ocular myiasis (e.g., by serological tests) is pivotal for positive prognoses, particularly when the larvae are not detectable during the ophthalmologic examination. Molecular diagnoses may also assist physicians and parasitologists in achieving time-efficient diagnoses of infestations by Oestridae causing myiasis. Finally, due to widespread international travel to exotic destinations, cases of myiasis are increasing in non-endemic areas, therefore requiring physicians to acquire a profound knowledge of the clinical symptoms linked to these infestations to prevent costly, inappropriate treatments or severe complications.

  18. Noninsect Arthropods in Popular Music

    PubMed Central

    Coelho, Joseph R.

    2011-01-01

    The occurrence of noninsect arthropods in popular music was examined in order to explore human attitudes toward these species, especially as compared to insects. Crustaceans were the most commonly referenced taxonomic group in artist names, album titles and cover art, followed by spiders and scorpions. The surprising prevalence of crustaceans may be related to the palatability of many of the species. Spiders and scorpions were primarily used for shock value, as well as totemic qualities of strength and ferocity. Spiders were the most abundant group among song titles, perhaps because of their familiarity to the general public. Three noninsect arthropod album titles were found from the early 1970s, then none appear until 1990. Older albums are difficult to find unless they are quite popular, and the resurgence of albums coincides with the rise of the internet. After 1990, issuance of such albums increased approximately linearly. Giant and chimeric album covers were the most common of themes, indicating the use of these animals to inspire fear and surprise. The lyrics of select songs are presented to illustrate the diversity of sentiments present, from camp spookiness to edibility. PMID:26467627

  19. Floral diversity increases beneficial arthropod richness and decreases variability in arthropod community composition.

    PubMed

    Bennett, Ashley B; Gratton, Claudio

    2013-01-01

    Declines in species diversity resulting from anthropogenic alterations of the environment heighten the need to develop management strategies that conserve species and ecosystem services. This study examined how native plant species and their diversity influence the abundance and richness of beneficial arthropods, a functionally important group that provides ecosystem services such as pollination and natural pest suppression. Beneficial arthropods were sampled in replicated study plots containing native perennials planted in one-, two-, and seven-species mixtures. We found plant diversity had a positive impact on arthropod richness but not on arthropod abundance. An analysis of arthropod community composition revealed that each flower species attracted a different assemblage of beneficial arthropods. In addition, the full seven-species mixture also attracted a distinct arthropod community compared to single-species monocultures. Using a multivariate approach, we determined whether arthropod assemblages in two- and seven-species plots were additive and could be predicted based on assemblages from their component single-species plots. On average, assemblages in diverse plots were nonadditive when compared to assemblages predicted using single-species plots. Arthropod assemblages in two-species plots most closely resembled those of only one of the flower species in the mixture. However, the arthropod assemblages in seven-species plots, although statistically deviating from the expectation of an additive model, more closely resembled predicted communities compared to the assemblages found in two-species plots, suggesting that variability in arthropod community composition decreased as planting diversity increased. Our study demonstrates that careful selection of plants in managed landscapes can augment beneficial arthropod richness and support a more predictable arthropod community, suggesting that planning and design efforts could shape arthropod assemblages in natural

  20. Traumatic insemination in terrestrial arthropods.

    PubMed

    Tatarnic, Nikolai J; Cassis, Gerasimos; Siva-Jothy, Michael T

    2014-01-01

    Traumatic insemination is a bizarre form of mating practiced by some invertebrates in which males use hypodermic genitalia to penetrate their partner's body wall during copulation, frequently bypassing the female genital tract and ejaculating into their blood system. The requirements for traumatic insemination to evolve are stringent, yet surprisingly it has arisen multiple times within invertebrates. In terrestrial arthropods traumatic insemination is most prevalent in the true bug infraorder Cimicomorpha, where it has evolved independently at least three times. Traumatic insemination is thought to occur in the Strepsiptera and has recently been recorded in fruit fly and spider lineages. We review the putative selective pressures that may have led to the evolution of traumatic insemination across these lineages, as well as the pressures that continue to drive divergence in male and female reproductive morphology and behavior. Traumatic insemination mechanisms and attributes are compared across independent lineages.

  1. Effects of invasive plants on arthropods.

    PubMed

    Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

    2014-12-01

    Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to

  2. A flexible genetic toolkit for arthropod neurogenesis

    PubMed Central

    Stollewerk, Angelika

    2016-01-01

    Arthropods show considerable variations in early neurogenesis. This includes the pattern of specification, division and movement of neural precursors and progenitors. In all metazoans with nervous systems, including arthropods, conserved genes regulate neurogenesis, which raises the question of how the various morphological mechanisms have emerged and how the same genetic toolkit might generate different morphological outcomes. Here I address this question by comparing neurogenesis across arthropods and show how variations in the regulation and function of the neural genes might explain this phenomenon and how they might have facilitated the evolution of the diverse morphological mechanisms of neurogenesis. PMID:26598727

  3. Palaeontology: Clearing the Heads of Cambrian Arthropods.

    PubMed

    Strausfeld, Nicholas J

    2015-07-20

    Understanding the identity of segments and the evolution of their appendages is a prime concern of arthropod evolution studies. This has been challenging for long extinct stem-groups. Now, Cambrian fossils offer insights that will help further evolutionary considerations.

  4. Rickettsial pathogens and their arthropod vectors.

    PubMed Central

    Azad, A. F.; Beard, C. B.

    1998-01-01

    Rickettsial diseases, important causes of illness and death worldwide, exist primarily in endemic and enzootic foci that occasionally give rise to sporadic or seasonal outbreaks. Rickettsial pathogens are highly specialized for obligate intracellular survival in both the vertebrate host and the invertebrate vector. While studies often focus primarily on the vertebrate host, the arthropod vector is often more important in the natural maintenance of the pathogen. Consequently, coevolution of rickettsiae with arthropods is responsible for many features of the host-pathogen relationship that are unique among arthropod-borne diseases, including efficient pathogen replication, long-term maintenance of infection, and transstadial and transovarial transmission. This article examines the common features of the host-pathogen relationship and of the arthropod vectors of the typhus and spotted fever group rickettsiae. PMID:9621188

  5. Error Model and Compensation of Bell-Shaped Vibratory Gyro

    PubMed Central

    Su, Zhong; Liu, Ning; Li, Qing

    2015-01-01

    A bell-shaped vibratory angular velocity gyro (BVG), inspired by the Chinese traditional bell, is a type of axisymmetric shell resonator gyroscope. This paper focuses on development of an error model and compensation of the BVG. A dynamic equation is firstly established, based on a study of the BVG working mechanism. This equation is then used to evaluate the relationship between the angular rate output signal and bell-shaped resonator character, analyze the influence of the main error sources and set up an error model for the BVG. The error sources are classified from the error propagation characteristics, and the compensation method is presented based on the error model. Finally, using the error model and compensation method, the BVG is calibrated experimentally including rough compensation, temperature and bias compensation, scale factor compensation and noise filter. The experimentally obtained bias instability is from 20.5°/h to 4.7°/h, the random walk is from 2.8°/h1/2 to 0.7°/h1/2 and the nonlinearity is from 0.2% to 0.03%. Based on the error compensation, it is shown that there is a good linear relationship between the sensing signal and the angular velocity, suggesting that the BVG is a good candidate for the field of low and medium rotational speed measurement. PMID:26393593

  6. Relationships between CSID and vocal fold vibratory function

    NASA Astrophysics Data System (ADS)

    Cooke, Melissa L.

    High correlations have been reported between the acoustic-based Cepstral/Spectral Index of Dysphonia (CSID) and perceptual judgments of dysphonia. This study explores whether CSID provides additional insight and explains more of the variance in HSV-based properties of vocal fold vibratory function than has been reported for other acoustic measures. Using the Analysis of Dysphonia in Speech and Voice (ADSV) program, CSID and its component variables were correlated with HSV-based measures of glottal cycle aperiodicity and glottal area for 20 subjects who underwent phonomicrosurgery. Results indicate CSID is only marginally correlated with glottal cycle aperiodicity in pre- and post-surgical conditions and does not correlate as highly as the cepstral peak prominence alone. Additionally, results reveal higher correlations when examining within-subject change from pre-surgical to post-surgical assessments rather than correlating measures across subjects. Future directions are discussed that aim at improving our understanding of the relationships between acoustic parameters and underlying phonatory function.

  7. Regulation of ecosystem processes by arthropod communities

    SciTech Connect

    Seastedt, T.R.; Crossley, D.A. Jr.

    1983-09-01

    Arthropods or their activities regulate the amounts of forms of mass and nutrients in terrestrial ecosystems. Canopy arthropods have the largest impacts on mobile elements such as potassium, while soil detritivores control mineralization rates of less mobile elements such as nitrogen, phosphorus and calcium. Nominal (base-line) herbivory and detritivory combine to speed nutrient cycling and reduce standing crops of decaying plant materials. 42 references, 1 figure, 3 tables.

  8. Cambrian bivalved arthropod reveals origin of arthrodization.

    PubMed

    Legg, David A; Sutton, Mark D; Edgecombe, Gregory D; Caron, Jean-Bernard

    2012-12-07

    Extant arthropods are diverse and ubiquitous, forming a major constituent of most modern ecosystems. Evidence from early Palaeozoic Konservat Lagerstätten indicates that this has been the case since the Cambrian. Despite this, the details of arthropod origins remain obscure, although most hypotheses regard the first arthropods as benthic predators or scavengers such as the fuxianhuiids or megacheirans ('great-appendage' arthropods). Here, we describe a new arthropod from the Tulip Beds locality of the Burgess Shale Formation (Cambrian, series 3, stage 5) that possesses a weakly sclerotized thorax with filamentous appendages, encased in a bivalved carapace, and a strongly sclerotized, elongate abdomen and telson. A cladistic analysis resolved this taxon as the basal-most member of a paraphyletic grade of nekto-benthic forms with bivalved carapaces. This grade occurs at the base of Arthropoda (panarthropods with arthropodized trunk limbs) and suggests that arthrodization (sclerotization and jointing of the exoskeleton) evolved to facilitate swimming. Predatory and fully benthic habits evolved later in the euarthropod stem-lineage and are plesiomorphically retained in pycnogonids (sea spiders) and euchelicerates (horseshoe crabs and arachnids).

  9. A Shoe Insole Delivering Subsensory Vibratory Noise Improves Balance and Gait in Healthy Elderly People

    PubMed Central

    Lipsitz, Lewis; Lough, Matthew; Niemi, James; Travison, Thomas; Howlett, Harold; Manor, Brad

    2014-01-01

    Objective The objective of this study was to test whether subsensory vibratory noise applied to the sole of the foot using a novel piezo-electric vibratory insole, can significantly improve sensation, enhance balance, and reduce gait variability in elderly people. We also aimed to determine the optimal level of vibratory noise, and whether the therapeutic effect would endure and the user’s sensory threshold would remain constant during the course of a day. Design A randomized single-blind crossover study of three subsensory noise stimulation levels on 3 separate days. Setting Balance and gait laboratory Participants 12 healthy community-dwelling elderly volunteers aged 65 – 90 years who could feel the maximum insole vibration. Intervention A urethane foam insole with the piezo-electric actuators delivering subsensory vibratory noise stimulation to the soles of the feet. Main Outcome Measures Balance, gait, and timed up-and-go tests. Results The vibratory insoles significantly improved performance on the timed up-and-go test, reduced the area of postural sway, and reduced the temporal variability of walking at both 70% and 85% of the sensory threshold and throughout the course of a day. Vibratory sensation thresholds remained relatively stable within and across study days. Conclusions This study provides proof of concept that the application of the principle of stochastic resonance to the foot sole sensory system using a new low voltage piezoelectric technology can improve measures of balance and gait that are associated with falls. Effective vibratory noise amplitudes range from 70% to 85% of the sensory thresholds and can be set once daily. PMID:25450133

  10. Opportunity to Improve Public Perceptions of Arthropods and Arthropod-Related Benefits

    ERIC Educational Resources Information Center

    Harris, Bethany A.; Braman, S. Kristine

    2016-01-01

    The general public may not recognize the value of conserving insects and spiders in home landscapes. We surveyed individuals to assess public perceptions of 10 arthropods--nine common insects and one common spider species--and to determine whether arthropod-related attitudes could be altered. Additionally, we collected data on survey respondent…

  11. Disturbances in Self-Synchronisation of Vibrators in Vibratory Machines

    NASA Astrophysics Data System (ADS)

    Michalczyk, Jerzy; Cieplok, Grzegorz

    2014-03-01

    An influence of elastic support elements arrangements and ratios of elasticity and damping constants in vertical and horizontal direction on self-synchronisation accuracy was investigated in the paper. The obtained results of the other factors influence on disturbances in self-synchronisation of vibrators in vibratory machines are also presented. Especially, influence of a diversification of driving and anti-torque moments, not central direction of the resulting force of the vibrators set , the local flexibility of mounting of vibrators to the machine body and influence of collisions with a feed were described. W pracy zbadano wpływ rozmieszczenia elementów sprężystych zawieszenia i proporcji pomiędzy stałymi sprężystości i tłumienia tych elementów na kierunkach pionowym i poziomym na dokładność samosynchronizacji wibratorów. Przytoczono też rezultaty badań autorów nad wpływem innych przyczyn na zaburzenia samosynchronizacji wibratorów maszyn wibracyjnych. W szczególności określono wpływ na zjawisko samosynchronizacji takich zjawisk jak: zróżnicowanie momentów napędowych i oporowych, niecentralne ukierunkowanie wypadkowej siły wymuszającej zespołu wibratorów, lokalna podatność zamocowania wibratorów do korpusu maszyny i oddziaływanie zderzeń z nadawą

  12. Vibratory sense deficits in patients with symptomatic femoroacetabular impingement

    PubMed Central

    Farkas, G.J.; Shakoor, N.; Cvetanovich, G.L.; Fogg, L.F.; Orías, A.A. Espinoza; Nho, S.J.

    2016-01-01

    Objective: Sensory deficits, measured through vibratory perception threshold (VPT), have been recognized in hip and knee osteoarthritis (OA), but have not been evaluated in femoroacetabular impingement (FAI), thought to be a pre-OA condition. This study aimed to assess VPT in symptomatic FAI pre- and 6-months post-arthroscopy vs. controls. Methods: FAI patients and controls were assessed for VPT at the first metatarsophalangeal joint. Pain was assessed using a visual analog pain scale. FAI participants were evaluated again 6-months after surgery for FAI. Differences between groups and pre- and post- surgery were evaluated with independent and paired sample t-tests, respectively. Secondary analysis was performed using repeated-measures ANOVA to evaluate the effect of pain and time since surgery on VPT pre- and post-operatively. Results: No differences in age and BMI were seen between groups (p>0.05). Reduced VPT (higher value is worse) was evident in the pre- (8.0±3.9V, t=2.81, p=0.009) and post-operative (6.8±2.8V, t=2.34, p=0.027) patients compared to controls (4.7±1.3V). After hip arthroscopy, there was a trend toward improved VPT (t=1.97, p=0.068). Preoperative and 6-months postoperative pain and time since surgery were not found to influence VPT (F-ratio≥0.00, p≥0.427). Conclusion: Sensory deficits were observed in FAI patients both before and 6-months after hip arthroscopy. PMID:26944822

  13. Oscillation control algorithms for resonant sensors with applications to vibratory gyroscopes.

    PubMed

    Park, Sungsu; Tan, Chin-Woo; Kim, Haedong; Hong, Sung Kyung

    2009-01-01

    We present two oscillation control algorithms for resonant sensors such as vibratory gyroscopes. One control algorithm tracks the resonant frequency of the resonator and the other algorithm tunes it to the specified resonant frequency by altering the resonator dynamics. Both algorithms maintain the specified amplitude of oscillations. The stability of each of the control systems is analyzed using the averaging method, and quantitative guidelines are given for selecting the control gains needed to achieve stability. The effects of displacement measurement noise on the accuracy of tracking and estimation of the resonant frequency are also analyzed. The proposed control algorithms are applied to two important problems in a vibratory gyroscope. The first is the leading-following resonator problem in the drive axis of MEMS dual-mass vibratory gyroscope where there is no mechanical linkage between the two proof-masses and the second is the on-line modal frequency matching problem in a general vibratory gyroscope. Simulation results demonstrate that the proposed control algorithms are effective. They ensure the proof-masses to oscillate in an anti-phase manner with the same resonant frequency and oscillation amplitude in a dual-mass gyroscope, and two modal frequencies to match in a general vibratory gyroscope.

  14. Evolving specialization of the arthropod nervous system.

    PubMed

    Jarvis, Erin; Bruce, Heather S; Patel, Nipam H

    2012-06-26

    The diverse array of body plans possessed by arthropods is created by generating variations upon a design of repeated segments formed during development, using a relatively small "toolbox" of conserved patterning genes. These attributes make the arthropod body plan a valuable model for elucidating how changes in development create diversity of form. As increasingly specialized segments and appendages evolved in arthropods, the nervous systems of these animals also evolved to control the function of these structures. Although there is a remarkable degree of conservation in neural development both between individual segments in any given species and between the nervous systems of different arthropod groups, the differences that do exist are informative for inferring general principles about the holistic evolution of body plans. This review describes developmental processes controlling neural segmentation and regionalization, highlighting segmentation mechanisms that create both ectodermal and neural segments, as well as recent studies of the role of Hox genes in generating regional specification within the central nervous system. We argue that this system generates a modular design that allows the nervous system to evolve in concert with the body segments and their associated appendages. This information will be useful in future studies of macroevolutionary changes in arthropod body plans, especially in understanding how these transformations can be made in a way that retains the function of appendages during evolutionary transitions in morphology.

  15. Damage identification in plates using vibratory power estimated from measured accelerations

    NASA Astrophysics Data System (ADS)

    Huh, Young Cheol; Chung, Tae Young; Lee, Jong Won; Kim, Jae Kwan

    2015-02-01

    Vibratory power is defined as the rate of energy transmitted through a cross section of unit width in a vibrating structure. It is known that the vibratory power is a function of the source and travel path. Therefore the spatial distribution of the vibratory power may contain information on the state of a structure. Vibratory power can be estimated experimentally by measuring accelerations. By combining numerical predictions with experimental measurements the location and severity of damage can be identified. This method has been successfully applied to prismatic beam problems. In the present work, the idea is extended to identifying damage in thin plate problems. To identify damage in thin plates by the proposed vibratory power method, the two-dimensional damage index and damage index ratio are newly introduced. The plate is assumed to be of uniform thickness and damaged in the form of a crack simulated as a straight cut of finite length. The vibratory power of the plate is estimated from frequency response functions to random excitations. First, the proposed method is applied numerically and then verified experimentally. Both numerical and experimental results show the present method can identify not only the location of damage but also its direction. The location and direction can be identified by investigating the damage index, the damage index ratio, and local principal axes of the index peak in the vicinity of the damage. The spatial distribution of the damage index, newly introduced in beam problems, can be considered as a scalar field in plate problems. In the neighborhood of the damage, the damage index has the shape of a semi-ellipsoid or a semi-ovoid, and it is found that the major principal axis corresponds to the direction of the crack. It enables us to identify the damage direction correctly without ambiguity.

  16. Vertical stratification in arthropod spatial distribution research.

    PubMed

    Marler, Thomas E

    2013-11-01

    Spatial heterogeneity within individual host trees is often overlooked in surveys of phytophagous arthropod abundance and distribution. The armored scale Aulacaspis yasumatsui is controlled by the predator Rhyzobius lophanthae to a greater degree on leaves at 75-cm height than on leaves at ground level within its host tree Cycas micronesica. The direct influence of elevation on the predator indirectly generates vertical heterogeneity of the scale insect. Arthropod sampling schemes that fail to include all strata within the vertical profile of the host tree species may generate misleading outcomes. Results indicate that sub-meter increments can reveal significant differences in vertical distribution of phytophagous insects, and that inclusion of observations on other organisms that interact with the target arthropod may illuminate determinants of vertical heterogeneity.

  17. Epidemiology of the arthropod-borne encephalitides*

    PubMed Central

    Miles, J. A. R.

    1960-01-01

    Since the recognition that louping-ill, known for well over 100 years as an epizootic disease of sheep in Scotland, was caused by a virus transmitted by arthropods, many other arthropod-borne viruses capable of causing encephalitis in domestic animals or man have been discovered. The author reviews here the knowledge at present available on these viruses, originally termed ”arthropod-borne encephalitides viruses” but now often referred to as ”arbor viruses”. In this discussion of the host and vector relationships of the two broad groups of arbor viruses — the mosquito-borne and the tick-borne—and of the distribution, epidemiology and control of the various diseases they cause, the author includes an outline of the types of investigation likely to provide the most useful information, stressing in this connexion the value of ecological surveys. PMID:14422369

  18. Sophisticated digestive systems in early arthropods.

    PubMed

    Vannier, Jean; Liu, Jianni; Lerosey-Aubril, Rudy; Vinther, Jakob; Daley, Allison C

    2014-05-02

    Understanding the way in which animals diversified and radiated during their early evolutionary history remains one of the most captivating of scientific challenges. Integral to this is the 'Cambrian explosion', which records the rapid emergence of most animal phyla, and for which the triggering and accelerating factors, whether environmental or biological, are still unclear. Here we describe exceptionally well-preserved complex digestive organs in early arthropods from the early Cambrian of China and Greenland with functional similarities to certain modern crustaceans and trace these structures through the early evolutionary lineage of fossil arthropods. These digestive structures are assumed to have allowed for more efficient digestion and metabolism, promoting carnivory and macrophagy in early arthropods via predation or scavenging. This key innovation may have been of critical importance in the radiation and ecological success of Arthropoda, which has been the most diverse and abundant invertebrate phylum since the Cambrian.

  19. Responses of prairie arthropod communities to fire and fertilizer: Balancing plant and arthropod conservation

    USGS Publications Warehouse

    Hartley, M.K.; Rogers, W.E.; Siemann, E.; Grace, J.

    2007-01-01

    Fire is an important tool for limiting woody plant invasions into prairies, but using fire management to maintain grassland plant communities may inadvertently reduce arthropod diversity. To test this, we established twenty-four 100 m2 plots in a tallgrass prairie in Galveston County, Texas, in spring 2000. Plots were assigned a fire (no burn, one time burn [2000], two time burn [2000, 2001]) and fertilization treatment (none, NPK addition) in a full factorial design. Fertilization treatments allowed us to examine the effects of fire at a different level of productivity. We measured plant cover by species and sampled arthropods with sweep nets during the 2001 growing season. Path analysis indicated that fertilization reduced while annual fires increased arthropod diversity via increases and decreases in woody plant abundance, respectively. There was no direct effect of fire on arthropod diversity or abundance. Diptera and Homoptera exhibited particularly strong positive responses to fires. Lepidoptera had a negative response to nutrient enrichment. Overall, the negative effects of fire on the arthropod community were minor in contrast to the strong positive indirect effects of small-scale burning on arthropod diversity if conservation of particular taxa is not a priority. The same fire regime that minimized woody plant invasion also maximized arthropod diversity.

  20. The monitoring system for vibratory disturbance detection in microgravity environment aboard the international space station

    NASA Technical Reports Server (NTRS)

    Laster, Rachel M.

    2004-01-01

    Scientists in the Office of Life and Microgravity Sciences and Applications within the Microgravity Research Division oversee studies in important physical, chemical, and biological processes in microgravity environment. Research is conducted in microgravity environment because of the beneficial results that come about for experiments. When research is done in normal gravity, scientists are limited to results that are affected by the gravity of Earth. Microgravity provides an environment where solid, liquid, and gas can be observed in a natural state of free fall and where many different variables are eliminated. One challenge that NASA faces is that space flight opportunities need to be used effectively and efficiently in order to ensure that some of the most scientifically promising research is conducted. Different vibratory sources are continually active aboard the International Space Station (ISS). Some of the vibratory sources include crew exercise, experiment setup, machinery startup (life support fans, pumps, freezer/compressor, centrifuge), thruster firings, and some unknown events. The Space Acceleration Measurement System (SAMs), which acts as the hardware and carefully positioned aboard the ISS, along with the Microgravity Environment Monitoring System MEMS), which acts as the software and is located here at NASA Glenn, are used to detect these vibratory sources aboard the ISS and recognize them as disturbances. The various vibratory disturbances can sometimes be harmful to the scientists different research projects. Some vibratory disturbances are recognized by the MEMS's database and some are not. Mainly, the unknown events that occur aboard the International Space Station are the ones of major concern. To better aid in the research experiments, the unknown events are identified and verified as unknown events. Features, such as frequency, acceleration level, time and date of recognition of the new patterns are stored in an Excel database. My task is to

  1. Communications

    NASA Technical Reports Server (NTRS)

    Stouffer, Donald D.

    1990-01-01

    Communication in its many forms is a critical component for an effective Space Grant Program. Good communication is needed within individual Space Grant College/Consortia, for example between consortium affiliates and the consortium program office. Effective communication between the several programs, NASA Headquarters, and NASA field centers also is required. Further, communication among the above program elements, industry, local and state government, and the public also are necessary for meeting program objectives.

  2. Communication.

    ERIC Educational Resources Information Center

    Hancock, Alan

    An informal introduction to the study of communication deals with the major topics in the field. It presents basic theories of communication and language, reviews how language takes on meaning, explains the stimulus-response and Piaget theories of learning, and presents major theories dealing with communications and society. These theories include…

  3. Cysteine Proteases from Bloodfeeding Arthropod Ectoparasites

    PubMed Central

    Sojka, Daniel; Francischetti, Ivo M. B.; Calvo, Eric; Kotsyfakis, Michalis

    2012-01-01

    Cysteine proteases have been discovered in various bloodfeeding ectoparasites. Here, we assemble the available information about the function of these peptidases and reveal their role in hematophagy and parasite development. While most of the data shed light on key proteolytic events that play a role in arthropod physiology, we also report on the association of cysteine proteases with arthropod vectorial capacity. With emphasis on ticks, specifically Ixodes ricinus, we finally propose a model about the contribution of cysteine peptidases to blood digestion, and how their concerted action with other tick midgut proteases leads to the absorbance of nutrients by the midgut epithelial cells. PMID:21660665

  4. Microbial control of arthropod-borne disease

    PubMed Central

    Saldaña, Miguel A; Hegde, Shivanand; Hughes, Grant L

    2017-01-01

    Arthropods harbor a diverse array of microbes that profoundly influence many aspects of host biology, including vector competence. Additionally, symbionts can be engineered to produce molecules that inhibit pathogens. Due to their intimate association with the host, microbes have developed strategies that facilitate their transmission, either horizontally or vertically, to conspecifics. These attributes make microbes attractive agents for applied strategies to control arthropod-borne disease. Here we discuss the recent advances in microbial control approaches to reduce the burden of pathogens such as Zika, Dengue and Chikungunya viruses, and Trypanosome and Plasmodium parasites. We also highlight where further investigation is warranted. PMID:28177042

  5. Collective behavior in an early Cambrian arthropod.

    PubMed

    Hou, Xian-Guang; Siveter, Derek J; Aldridge, Richard J; Siveter, David J

    2008-10-10

    Examples that indicate collective behavior in the fossil record are rare. A group association of specimens that belong to a previously unknown arthropod from the Chengjiang Lagerstätte, China, provides evidence that such behavior was present in the early Cambrian (about 525 million years ago), coincident with the earliest extensive diversification of the Metazoa, the so-called Cambrian explosion event. The chainlike form of these specimens is unique for any arthropod, fossil or living, and most likely represents behavior associated with migration.

  6. Arthropods vector grapevine trunk disease pathogens.

    PubMed

    Moyo, P; Allsopp, E; Roets, F; Mostert, L; Halleen, F

    2014-10-01

    Arthropod-mediated dispersal of pathogens is known in many cropping systems but has never been demonstrated for grapevine trunk disease pathogens. Arthropods from vineyards were screened for the presence of pathogens associated with Petri disease and esca using cultural and molecular techniques. The ability of the most abundant pathogen-carrying species to inoculate healthy grapevine vascular tissues was also determined. Millipedes and ants were allowed to associate with a DsRed- Express-transformed Phaeomoniella chlamydospora, after which they were exposed to freshly pruned healthy grapevines under controlled conditions and wounds were monitored for subsequent infection. In addition, the possibility of millipede excreta, commonly found on pruning wounds in the field, to act as inoculum source was determined. A diverse arthropod fauna was associated with declining grapevines and many of these carried trunk disease pathogens. However, spiders, the ant Crematogaster peringueyi, and the millipede Ommattoiulus moreleti were the most abundant pathogen carriers. The ant and millipede species fed on pruning wound sap and effectively transmitted trunk disease pathogens. Millipede excreta contained viable spores of Phaeomoniella chlamydospora and may serve as an inoculum source. Numerous arthropods, including beneficial predators, are potential vectors of grapevine trunk disease pathogens. Our results highlight the need for an integrated approach, including targeted management of ants and millipedes at the time of pruning, to limit the spread of grapevine trunk diseases.

  7. Prevention of arthropod-related disease.

    PubMed

    Elston, Dirk M

    2004-12-01

    Arthropods of medical importance include vespids, ticks, mosquitoes, mites, flies, and fleas. They spread illness as disease vectors, are associated with lethal allergic reactions, and produce potentially deadly toxins. Strategies for prevention of illness include avoidance, vector reduction programs, chemoprophylaxis, and repellents. Strategies must be tailored to regional risks.

  8. Resistance mechanisms against arthropod herbivores in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton plants from the genus Gossypium are grown on more than 30 million hectares worldwide and are a major source of fiber. The plants possess a wide-range of indirect and direct-defense mechanisms against arthropod pests. Direct defense mechanisms include morphological traits such as trichomes and...

  9. Characterizing Vibratory Kinematics in Children and Adults with High-Speed Digital Imaging

    ERIC Educational Resources Information Center

    Patel, Rita; Dubrovskiy, Denis; Döllinger, Michael

    2014-01-01

    Purpose: The aim of this study is to quantify and identify characteristic vibratory motion in typically developing prepubertal children and young adults using high-speed digital imaging. Method: The vibrations of the vocal folds were recorded from 27 children (ages 5-9 years) and 35 adults (ages 21-45 years), with high speed at 4,000 frames per…

  10. Automated Measurement of Vocal Fold Vibratory Asymmetry from High-Speed Videoendoscopy Recordings

    ERIC Educational Resources Information Center

    Mehta, Daryush D.; Deliyski, Dimitar D.; Quatieri, Thomas F.; Hillman, Robert E.

    2011-01-01

    Purpose: In prior work, a manually derived measure of vocal fold vibratory phase asymmetry correlated to varying degrees with visual judgments made from laryngeal high-speed videoendoscopy (HSV) recordings. This investigation extended this work by establishing an automated HSV-based framework to quantify 3 categories of vocal fold vibratory…

  11. Thresholds for detection of constant rotary acceleration during vibratory rotary acceleration.

    PubMed

    Clark, B; Stewart, J D; Phillips, N H

    1980-06-01

    The effects of vibratory angular acceleration (aR) on detection thresholds for constant aR in a dynamic flight simulator are reported in three experiments. Detection thresholds were determined for 10 pilots and four nonpilots using a random, double-staircase procedure while the subjects sat erect in a device which rotated about an earth-vertical axis. Constant aRs were presented for 0.5 and 1.0 s with concurrent, vibratory aR at 1 and 5 Hz, and thresholds with no vibratory aR were established. The thresholds were obtained while the subjects observed a visual reference in the enclosed cockpit in two experiments and in total darkness in a third. The results confirmed earlier experiments showing an inverse relationship between the duration of constant aR and detection threshold and showed that the detection thresholds in darkness were higher than with a visual reference present. Two analyses of variance revealed no significant differences in thresholds across the three vibration conditions. These results indicate that vibratory aRs of fairly high levels can be present in a dynamic flight stimulator without masking the pilot's ability to detect either maneuver or disturbance motions.

  12. Research on the Signal Process of a Bell-Shaped Vibratory Angular Rate Gyro

    PubMed Central

    Su, Zhong; Liu, Ning; Li, Qing; Fu, Mengyin; Liu, Hong; Fan, Junfang

    2014-01-01

    A bell-shaped vibratory angular rate gyro, which is inspired by the Chinese traditional bell, is a kind of axisymmetric shell resonator gyroscope. Its sensitive element is a vibratory-like Chinese traditional bell, using a piezoelectric element on the wall of the vibrator to detect the standing wave's precession to solve the input angular rate. This work mainly studies the circuit system of a bell-shaped vibratory angular rate gyro. It discusses the process of circuit system design, analysis and experiment, in detail, providing the foundation to develop a bell-shaped vibratory angular rate gyro. Since the bell-shaped resonator's curved structure has the characteristics of large noise in the piezoelectric signal and large harmonics, this paper analyzes its working and signal detection method, then gives the whole plan of the circuit system, including the drive module, the detection module and the control loop. It also studies every part of the whole system, gives a detailed design and analysis process and proves part of the circuit system using digital simulation. At the end of the article, the test result of the circuit system shows that it can remove the disadvantages of the curved structure having large noise in the piezoelectric signal and large harmonics and is more effective at solving the input angular rate. PMID:24633451

  13. Can vibratory feedback be used to improve postural stability in persons with transtibial limb loss?

    PubMed

    Rusaw, David; Hagberg, Kerstin; Nolan, Lee; Ramstrand, Nerrolyn

    2012-01-01

    The use of vibration as a feedback modality to convey motion of the body has been shown to improve measures of postural stability in some groups of patients. Because individuals using transtibial prostheses lack sensation distal to the amputation, vibratory feedback could possibly be used to improve their postural stability. The current investigation provided transtibial prosthesis users (n = 24, mean age 48 yr) with vibratory feedback proportional to the signal received from force transducers located under the prosthetic foot. Postural stability was evaluated by measuring center of pressure (CoP) movement, limits of stability, and rhythmic weight shift while participants stood on a force platform capable of rotations in the pitch plane (toes up/toes down). The results showed that the vibratory feedback increased the mediolateral displacement amplitude of CoP in standing balance and reduced the response time to rapid voluntary movements of the center of gravity. The results suggest that the use of vibratory feedback in an experimental setting leads to improvements in fast open-loop mechanisms of postural control in transtibial prosthesis users.

  14. Virus discovery and recent insights into virus diversity in arthropods.

    PubMed

    Junglen, Sandra; Drosten, Christian

    2013-08-01

    Recent studies on virus discovery have focused mainly on mammalian and avian viruses. Arbovirology with its long tradition of ecologically oriented investigation is now catching up, with important novel insights into the diversity of arthropod-associated viruses. Recent discoveries include taxonomically outlying viruses within the families Flaviviridae, Togaviridae, and Bunyaviridae, and even novel virus families within the order Nidovirales. However, the current focusing of studies on blood-feeding arthropods has restricted the range of arthropod hosts analyzed for viruses so far. Future investigations should include species from other arthropod taxa than Ixodita, Culicidae and Phlebotominae in order to shed light on the true diversity of arthropod viruses.

  15. Communicate!

    ERIC Educational Resources Information Center

    Chase, Stuart

    This ten chapter book is designed to provide high school students with an understanding of basic communication processes. The first five chapters include discussions of language development, function, and acquisition in relation to both human and non-human communication. The sixth chapter contains specimen linguistic analyses of speech and…

  16. Trees as templates for tropical litter arthropod diversity.

    PubMed

    Donoso, David A; Johnston, Mary K; Kaspari, Michael

    2010-09-01

    Increased tree species diversity in the tropics is associated with even greater herbivore diversity, but few tests of tree effects on litter arthropod diversity exist. We studied whether tree species influence patchiness in diversity and abundance of three common soil arthropod taxa (ants, gamasid mites, and oribatid mites) in a Panama forest. The tree specialization hypothesis proposes that tree-driven habitat heterogeneity maintains litter arthropod diversity. We tested whether tree species differed in resource quality and quantity of their leaf litter and whether more heterogeneous litter supports more arthropod species. Alternatively, the abundance-extinction hypothesis states that arthropod diversity increases with arthropod abundance, which in turn tracks resource quantity (e.g., litter depth). We found little support for the hypothesis that tropical trees are templates for litter arthropod diversity. Ten tree species differed in litter depth, chemistry, and structural variability. However, the extent of specialization of invertebrates on particular tree taxa was low and the more heterogeneous litter between trees failed to support higher arthropod diversity. Furthermore, arthropod diversity did not track abundance or litter depth. The lack of association between tree species and litter arthropods suggests that factors other than tree species diversity may better explain the high arthropod diversity in tropical forests.

  17. Communication

    NASA Technical Reports Server (NTRS)

    Griner, James

    2010-01-01

    NASA s communication work for the UAS Command and Control area will build upon work currently being conducted under NASA Recovery Act funds. Communication portions of UAS NextGen ConOps, Stateof- the-Art assessment, and Gap Analysis. Preliminary simulations for UAS CNPC link scalability assessment. Surrogate UAS aircraft upgrades. This work will also leverage FY10 in-guide funding for communication link model development. UAS are currently managed through exceptions and are operating using DoD frequencies for line-of-sight (LOS) and satellite-based communications links, low-power LOS links in amateur bands, or unlicensed Instrument/Scientific/Medical (ISM) frequencies. None of these frequency bands are designated for Safety and Regularity of Flight. No radio-frequency (RF) spectrum has been allocated by the International Telecommunications Union (ITU) specifically for UAS command and control links, for either LOS or Beyond LOS (BLOS) communication.

  18. Folsomia candida (Collembola): a "standard" soil arthropod.

    PubMed

    Fountain, Michelle T; Hopkin, Steve P

    2005-01-01

    Folsomia candida Willem 1902, a member of the order Collembola (colloquially called springtails), is a common and widespread arthropod that occurs in soils throughout the world. The species is parthenogenetic and is easy to maintain in the laboratory on a diet of granulated dry yeast. F. candida has been used as a "standard" test organism for more than 40 years for estimating the effects of pesticides and environmental pollutants on nontarget soil arthropods. However, it has also been employed as a model for the investigation of numerous other phenomena such as cold tolerance, quality as a prey item, and effects of microarthropod grazing on pathogenic fungi and mycorrhizae of plant roots. In this comprehensive review, aspects of the life history, ecology, and ecotoxicology of F. candida are covered. We focus on the recent literature, especially studies that have examined the effects of soil pollutants on reproduction in F. candida using the protocol published by the International Standards Organization in 1999.

  19. Arthropods in amber from the Triassic Period

    PubMed Central

    Schmidt, Alexander R.; Jancke, Saskia; Lindquist, Evert E.; Ragazzi, Eugenio; Roghi, Guido; Nascimbene, Paul C.; Schmidt, Kerstin; Wappler, Torsten; Grimaldi, David A.

    2012-01-01

    The occurrence of arthropods in amber exclusively from the Cretaceous and Cenozoic is widely regarded to be a result of the production and preservation of large amounts of tree resin beginning ca. 130 million years (Ma) ago. Abundant 230 million-year-old amber from the Late Triassic (Carnian) of northeastern Italy has previously yielded myriad microorganisms, but we report here that it also preserves arthropods some 100 Ma older than the earliest prior records in amber. The Triassic specimens are a nematoceran fly (Diptera) and two disparate species of mites, Triasacarus fedelei gen. et sp. nov., and Ampezzoa triassica gen. et sp. nov. These mites are the oldest definitive fossils of a group, the Eriophyoidea, which includes the gall mites and comprises at least 3,500 Recent species, 97% of which feed on angiosperms and represents one of the most specialized lineages of phytophagous arthropods. Antiquity of the gall mites in much their extant form was unexpected, particularly with the Triassic species already having many of their present-day features (such as only two pairs of legs); further, it establishes conifer feeding as an ancestral trait. Feeding by the fossil mites may have contributed to the formation of the amber droplets, but we find that the abundance of amber during the Carnian (ca. 230 Ma) is globally anomalous for the pre-Cretaceous and may, alternatively, be related to paleoclimate. Further recovery of arthropods in Carnian-aged amber is promising and will have profound implications for understanding the evolution of terrestrial members of the most diverse phylum of organisms. PMID:22927387

  20. Arthropods in amber from the Triassic Period.

    PubMed

    Schmidt, Alexander R; Jancke, Saskia; Lindquist, Evert E; Ragazzi, Eugenio; Roghi, Guido; Nascimbene, Paul C; Schmidt, Kerstin; Wappler, Torsten; Grimaldi, David A

    2012-09-11

    The occurrence of arthropods in amber exclusively from the Cretaceous and Cenozoic is widely regarded to be a result of the production and preservation of large amounts of tree resin beginning ca. 130 million years (Ma) ago. Abundant 230 million-year-old amber from the Late Triassic (Carnian) of northeastern Italy has previously yielded myriad microorganisms, but we report here that it also preserves arthropods some 100 Ma older than the earliest prior records in amber. The Triassic specimens are a nematoceran fly (Diptera) and two disparate species of mites, Triasacarus fedelei gen. et sp. nov., and Ampezzoa triassica gen. et sp. nov. These mites are the oldest definitive fossils of a group, the Eriophyoidea, which includes the gall mites and comprises at least 3,500 Recent species, 97% of which feed on angiosperms and represents one of the most specialized lineages of phytophagous arthropods. Antiquity of the gall mites in much their extant form was unexpected, particularly with the Triassic species already having many of their present-day features (such as only two pairs of legs); further, it establishes conifer feeding as an ancestral trait. Feeding by the fossil mites may have contributed to the formation of the amber droplets, but we find that the abundance of amber during the Carnian (ca. 230 Ma) is globally anomalous for the pre-Cretaceous and may, alternatively, be related to paleoclimate. Further recovery of arthropods in Carnian-aged amber is promising and will have profound implications for understanding the evolution of terrestrial members of the most diverse phylum of organisms.

  1. Arthropods in amber from the Triassic Period

    NASA Astrophysics Data System (ADS)

    Schmidt, Alexander R.; Jancke, Saskia; Lindquist, Evert E.; Ragazzi, Eugenio; Roghi, Guido; Nascimbene, Paul C.; Schmidt, Kerstin; Wappler, Torsten; Grimaldi, David A.

    2012-09-01

    The occurrence of arthropods in amber exclusively from the Cretaceous and Cenozoic is widely regarded to be a result of the production and preservation of large amounts of tree resin beginning ca. 130 million years (Ma) ago. Abundant 230 million-year-old amber from the Late Triassic (Carnian) of northeastern Italy has previously yielded myriad microorganisms, but we report here that it also preserves arthropods some 100 Ma older than the earliest prior records in amber. The Triassic specimens are a nematoceran fly (Diptera) and two disparate species of mites, Triasacarus fedelei gen. et sp. nov., and Ampezzoa triassica gen. et sp. nov. These mites are the oldest definitive fossils of a group, the Eriophyoidea, which includes the gall mites and comprises at least 3,500 Recent species, 97% of which feed on angiosperms and represents one of the most specialized lineages of phytophagous arthropods. Antiquity of the gall mites in much their extant form was unexpected, particularly with the Triassic species already having many of their present-day features (such as only two pairs of legs); further, it establishes conifer feeding as an ancestral trait. Feeding by the fossil mites may have contributed to the formation of the amber droplets, but we find that the abundance of amber during the Carnian (ca. 230 Ma) is globally anomalous for the pre-Cretaceous and may, alternatively, be related to paleoclimate. Further recovery of arthropods in Carnian-aged amber is promising and will have profound implications for understanding the evolution of terrestrial members of the most diverse phylum of organisms.

  2. Arthropod community organization and development in pear

    NASA Astrophysics Data System (ADS)

    Gut, Larry J.; Liss, W. J.; Westigard, P. H.

    1991-01-01

    Arthropod communities in pear are conceptualized as hierarchically organized systems in which several levels of organization or subsystems can be recognized between the population level and the community as a whole. An individual pear tree is taken to be the community habitat with arthropod subcommunities developing on leaf, fruit, and wood subcommunity habitats. Each subcommunity is composed of trophically organized systems of populations. Each system of populations is comprised of a functional group or guild of phytophagous arthropods that use the habitat primarily for feeding but also for overwintering or egg deposition, and associated groups of specialized predators, parasitoids, and hyperparasitoids. Several species move from one subcommunity to another during the course of community development and thus integrate community subsystems. Community development or change in organization through time is conceptualized as being jointly determined by the development of the habitat and the organization of the species pool. The influence of habitat development on community development within a species pool is emphasized in this research. Seasonal habitat development is expressed as change in the kinds and biomasses of developmental states of wood, leaf, and fruit subcommunity habitats. These changes are accompanied by changes in the kinds, biomasses, and distributions of associated community subsystems.

  3. Effect of vibratory soldier alarm signals on the foraging behavior of subterranean termites (Isoptera: Rhinotermitidae).

    PubMed

    Inta, R; Evans, T A; Lai, J C S

    2009-02-01

    Termite soldiers produce a vibratory alarm signal to warn conspecific workers. This study recorded and characterized the alarm signals of Coptotermes acinaciformis (Froggatt) (Isoptera: Rhinotermitidae) and then investigated the effect of playing these recorded alarm signals on C. acinaciformis feeding activity. Foraging groups of termites were offered paired wooden blocks: either one block, continuously stimulated with a vibratory alarm signal, paired with a nonstimulated block (the alarm treatment), continuously stimulated with a pink noise signal, paired with a nonstimulated block (control for nonspecific vibrations) or two nonstimulated blocks (control for environmental effects), for 4 wk. The amount of wood eaten in the blocks stimulated by the alarm signals was significantly less than the paired nonstimulated blocks, while there seemed to be no preference in the case of the pink noise playback or control for direction. Importantly, the termites seemed not to have adapted to the recorded alarm signal over the 4-wk duration of the experiment, unlike previous studies using nonbiologically derived signals.

  4. Effects of vibratory stimulations on maximal voluntary isometric contraction from delayed onset muscle soreness.

    PubMed

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong; Cho, Byung-Jun; Kim, Jin-Woo; Bo, Kak Hwang

    2013-09-01

    [Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm(2;) frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS.

  5. Effects of Vibratory Stimulations on Maximal Voluntary Isometric Contraction from Delayed Onset Muscle Soreness

    PubMed Central

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong; Cho, Byung-Jun; Kim, Jin-Woo; Bo, Kak Hwang

    2013-01-01

    [Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm2; frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS. PMID:24259922

  6. A controllable vibratory calciner for processing high-temperature superconductors and other ceramic powders

    NASA Astrophysics Data System (ADS)

    Spencer, Nicholas D.; Beeckman, Jean W.; Peders, Thorvald S.; Cameron, Craig P.

    1990-05-01

    A novel vibratory calcination apparatus is described, that enables reactant powders to be heated at or above their sintering temperatures without excessive agglomeration. In addition, the vibration-induced fluidization leads to greatly improved gas-solid contact, which can significantly speed up reactions that are limited by the ingress or egress of gases. Unlike its gas-fluidized counterpart, the vibratory calciner does not lead to excessive loss of fines. Vibration is generated by means of a function generator-amplifier-loudspeaker voice coil system, which allows amplitude, frequency, and time dependence of frequency to be precisely controlled. The system has been used extensively in the laboratory for the calcination of high-temperature superconducting powders, where its use has led to greatly reduced calcination times and a much lower degree of agglomeration in the finished material.

  7. Vibratory Loads Data from a Wind-Tunnel Test of Structurally Tailored Model Helicopter Rotors

    NASA Technical Reports Server (NTRS)

    Yeager, William T., Jr.; Hamouda, M-Nabil H.; Idol, Robert F.; Mirick, Paul H.; Singleton, Jeffrey D.; Wilbur, Matthew L.

    1991-01-01

    An experimental study was conducted in the Langley Transonic Dynamics Tunnel to investigate the use of a Bell Helicopter Textron (BHT) rotor structural tailoring concept, known as rotor nodalization, in conjunction with advanced blade aerodynamics as well as to evaluate rotor blade aerodynamic design methodologies. A 1/5-size, four-bladed bearingless hub, three sets of Mach-scaled model rotor blades were tested in forward flight from transition up to an advance ratio of 0.35. The data presented pertain only to the evaluation of the structural tailoring concept and consist of fixed-system and rotating system vibratory loads. These data will be useful for evaluating the effects of tailoring blade structural properties on fixed-system vibratory loads, as well as validating analyses used in the design of advanced rotor systems.

  8. Mechanical Assessment of the Drep Shield Subject to Vibratory Motion and Dynamic and Static Rock Loading

    SciTech Connect

    R.C. Quittmeyer

    2005-11-16

    The purpose of the drip shield (DS) is to divert water that may seep into emplacement drifts from contacting the waste packages, and to protect the waste packages from impact or static loading from rockfall. The objective of this document is to summarize, into one location, the results of a series of supporting engineering calculations that were developed to study the effect of static and dynamic loads on the mechanical performance of the DS. The potential DS loads are a result of: (1) Potential earthquake vibratory ground motion, and resulting interaction of the DS, waste package and pallet, and drift invert; (2) Dynamic impacts of rockfall resulting from emplacement drift damage as a result of earthquake vibratory motion; and (3) Static load of the caved rock rubble that may come to rest on the DS as a result of vibratory motion or from time-dependent yielding of the rock mass surrounding the emplacement drift. The potential mechanical failure mechanisms that may result from these loads include: (1) Overturning and/or separation of the interlocking DS segments; (2) Loss of structural integrity and stability of the DS, including excessive deformation or buckling; and (3) Localized damage to the top and side-wall plates of the DS. The scope of this document is limited to summarizing results presented in the supporting calculations in the areas of analysis of the potential for DS collapse, and determination of the damaged surface area of the DS plates. New calculations are presented to determine whether or not separation of DSs occur under vibratory motion.

  9. Communications

    ERIC Educational Resources Information Center

    Bailenson, Jeremy; Buzzanell, Patrice; Deetz, Stanley; Tewksbury, David; Thompson, Robert J.; Turow, Joseph; Bichelmeyer, Barbara; Bishop, M. J.; Gayeski, Diane

    2013-01-01

    Scholars representing the field of communications were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Jeremy Bailenson, Patrice Buzzanell, Stanley Deetz, David Tewksbury, Robert J. Thompson, and…

  10. Research on Bell-Shaped Vibratory Angular Rate Gyro's Character of Resonator

    PubMed Central

    Su, Zhong; Fu, Mengyin; Li, Qing; Liu, Ning; Liu, Hong

    2013-01-01

    Bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a new type Coriolis vibratory gyro that was inspired by Chinese traditional clocks. The resonator fuses based on a variable thickness axisymmetric multicurved surface shell. Its characteristics can directly influence the performance of BVG. The BVG structure not only has capabilities of bearing high overload, high impact and, compared with the tuning fork, vibrating beam, shell and a comb structure, but also a higher frequency to overcome the influence of the disturbance of the exterior environment than the same sized hemispherical resonator gyroscope (HRG) and the traditional cylinder vibratory gyroscope. It can be widely applied in high dynamic low precision angular rate measurement occasions. The main work is as follows: the issue mainly analyzes the structure and basic principle, and investigates the bell-shaped resonator's mathematical model. The reasonable structural parameters are obtained from finite element analysis and an intelligent platform. Using the current solid vibration gyro theory analyzes the structural characteristics and principles of BVG. The bell-shaped resonator is simplified as a paraboloid of the revolution mechanical model, which has a fixed closed end and a free opened end. It obtains the natural frequency and vibration modes based on the theory of elasticity. The structural parameters are obtained from the orthogonal method by the research on the structural parameters of the resonator analysis. It obtains the modal analysis, stress analysis and impact analysis with the chosen parameters. Finally, using the turntable experiment verifies the gyro effect of the BVG. PMID:23575033

  11. Damage tolerance based life prediction in gas turbine engine blades under vibratory high cycle fatigue

    SciTech Connect

    Walls, D.P.; deLaneuville, R.E.; Cunningham, S.E.

    1997-01-01

    A novel fracture mechanics approach has been used to predict crack propagation lives in gas turbine engine blades subjected to vibratory high cycle fatigue (HCF). The vibratory loading included both a resonant mode and a nonresonant mode, with one blade subjected to only the nonresonant mode and another blade to both modes. A life prediction algorithm was utilized to predict HCF propagation lives for each case. The life prediction system incorporates a boundary integral element (BIE) derived hybrid stress intensity solution, which accounts for the transition from a surface crack to corner crack to edge crack. It also includes a derivation of threshold crack length from threshold stress intensity factors to give crack size limits for no propagation. The stress intensity solution was calibrated for crack aspect ratios measured directly from the fracture surfaces. The model demonstrates the ability to correlate predicted missions to failure with values deduced from fractographic analysis. This analysis helps to validate the use of fracture mechanics approaches for assessing damage tolerance in gas turbine engine components subjected to combined steady and vibratory stresses.

  12. The temporary threshold shift of vibratory sensation induced by composite-band vibration exposure.

    PubMed

    Nishiyama, K; Taoda, K; Yamashita, H; Watanabe, S

    1996-01-01

    Eight healthy subjects were exposed to three 1/3 octave-band vibrations (63, 200, and 500 Hz) by hand clasping a vibrated handle in a soundproof and thermoregulated room. The vibratory sensation threshold at 125 Hz was measured before and after the vibration exposure at an exposed fingertip. According to a preceding study, we first determined the relationship between the acceleration of the vibration and the temporary threshold shift of vibratory sensation immediately after the vibratory exposure (TTSv,0) induced by 1/3 octave-band vibration. We then measured TTSv after the exposure to a composite vibration composed of two 1/3 octave-band vibrations that might induce an equal magnitude of TTSv,0 on the basis of the above relationship. The TTSv,0 induced by the composite vibration was not larger than the TTSv,0 induced by the component vibrations. This result suggests that the component of the vibration inducing the largest TTSv,0 determines the TTSv,0 by broad-band random vibration.

  13. Teleoperation of steerable flexible needles by combining kinesthetic and vibratory feedback.

    PubMed

    Pacchierotti, Claudio; Abayazid, Momen; Misra, Sarthak; Prattichizzo, Domenico

    2014-01-01

    Needle insertion in soft-tissue is a minimally invasive surgical procedure that demands high accuracy. In this respect, robotic systems with autonomous control algorithms have been exploited as the main tool to achieve high accuracy and reliability. However, for reasons of safety and responsibility, autonomous robotic control is often not desirable. Therefore, it is necessary to focus also on techniques enabling clinicians to directly control the motion of the surgical tools. In this work, we address that challenge and present a novel teleoperated robotic system able to steer flexible needles. The proposed system tracks the position of the needle using an ultrasound imaging system and computes needle's ideal position and orientation to reach a given target. The master haptic interface then provides the clinician with mixed kinesthetic-vibratory navigation cues to guide the needle toward the computed ideal position and orientation. Twenty participants carried out an experiment of teleoperated needle insertion into a soft-tissue phantom, considering four different experimental conditions. Participants were provided with either mixed kinesthetic-vibratory feedback or mixed kinesthetic-visual feedback. Moreover, we considered two different ways of computing ideal position and orientation of the needle: with or without set-points. Vibratory feedback was found more effective than visual feedback in conveying navigation cues, with a mean targeting error of 0.72 mm when using set-points, and of 1.10 mm without set-points.

  14. Exploiting the principle parametric resonance of an electric oscillator for vibratory energy harvesting

    NASA Astrophysics Data System (ADS)

    Caldwell, N. B.; Daqaq, M. F.

    2017-02-01

    Vibratory energy harvesters typically exploit ordinary direct resonances to mechanically amplify environmental inputs before channeling a portion of their energy into an electric load using an electromechanical transduction mechanism. Nonetheless, parametric resonance which has also been recently exploited, but to a lesser extent, holds a key advantage over direct excitations in that, when the level of input excitation exceeds a certain threshold, the amplitude of growth associated with parametric pumping is not limited by the total linear damping present in the system. While all of the previous research studies using parametric resonances for energy harvesting focused on utilizing it as a means of mechanical amplification, this letter demonstrates that vibratory excitations can also be used effectively to induce parametric resonances in the harvesting circuit itself, thereby providing a direct and simple means of electric amplification. A vibratory energy harvester exploiting this phenomenon is proposed in this letter and is shown to produce a maximum of 18 mW root-mean-square power per 1 g of input acceleration.

  15. Research on bell-shaped vibratory angular rate gyro's character of resonator.

    PubMed

    Su, Zhong; Fu, Mengyin; Li, Qing; Liu, Ning; Liu, Hong

    2013-04-10

    Bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a new type Coriolis vibratory gyro that was inspired by Chinese traditional clocks. The resonator fuses based on a variable thickness axisymmetric multicurved surface shell. Its characteristics can directly influence the performance of BVG. The BVG structure not only has capabilities of bearing high overload, high impact and, compared with the tuning fork, vibrating beam, shell and a comb structure, but also a higher frequency to overcome the influence of the disturbance of the exterior environment than the same sized hemispherical resonator gyroscope (HRG) and the traditional cylinder vibratory gyroscope. It can be widely applied in high dynamic low precision angular rate measurement occasions. The main work is as follows: the issue mainly analyzes the structure and basic principle, and investigates the bell-shaped resonator's mathematical model. The reasonable structural parameters are obtained from finite element analysis and an intelligent platform. Using the current solid vibration gyro theory analyzes the structural characteristics and principles of BVG. The bell-shaped resonator is simplified as a paraboloid of the revolution mechanical model, which has a fixed closed end and a free opened end. It obtains the natural frequency and vibration modes based on the theory of elasticity. The structural parameters are obtained from the orthogonal method by the research on the structural parameters of the resonator analysis. It obtains the modal analysis, stress analysis and impact analysis with the chosen parameters. Finally, using the turntable experiment verifies the gyro effect of the BVG.

  16. Gearbox fault diagnosis based on deep random forest fusion of acoustic and vibratory signals

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Sanchez, René-Vinicio; Zurita, Grover; Cerrada, Mariela; Cabrera, Diego; Vásquez, Rafael E.

    2016-08-01

    Fault diagnosis is an effective tool to guarantee safe operations in gearboxes. Acoustic and vibratory measurements in such mechanical devices are all sensitive to the existence of faults. This work addresses the use of a deep random forest fusion (DRFF) technique to improve fault diagnosis performance for gearboxes by using measurements of an acoustic emission (AE) sensor and an accelerometer that are used for monitoring the gearbox condition simultaneously. The statistical parameters of the wavelet packet transform (WPT) are first produced from the AE signal and the vibratory signal, respectively. Two deep Boltzmann machines (DBMs) are then developed for deep representations of the WPT statistical parameters. A random forest is finally suggested to fuse the outputs of the two DBMs as the integrated DRFF model. The proposed DRFF technique is evaluated using gearbox fault diagnosis experiments under different operational conditions, and achieves 97.68% of the classification rate for 11 different condition patterns. Compared to other peer algorithms, the addressed method exhibits the best performance. The results indicate that the deep learning fusion of acoustic and vibratory signals may improve fault diagnosis capabilities for gearboxes.

  17. Optimization of Passive and Active Non-Linear Vibration Mounting Systems Based on Vibratory Power Transmission

    NASA Astrophysics Data System (ADS)

    Royston, T. J.; Singh, R.

    1996-07-01

    While significant non-linear behavior has been observed in many vibration mounting applications, most design studies are typically based on the concept of linear system theory in terms of force or motion transmissibility. In this paper, an improved analytical strategy is presented for the design optimization of complex, active of passive, non-linear mounting systems. This strategy is built upon the computational Galerkin method of weighted residuals, and incorporates order reduction and numerical continuation in an iterative optimization scheme. The overall dynamic characteristics of the mounting system are considered and vibratory power transmission is minimized via adjustment of mount parameters by using both passive and active means. The method is first applied through a computational example case to the optimization of basic passive and active, non-linear isolation configurations. It is found that either active control or intentionally introduced non-linearity can improve the mount's performance; but a combination of both produces the greatest benefit. Next, a novel experimental, active, non-linear isolation system is studied. The effect of non-linearity on vibratory power transmission and active control are assessed via experimental measurements and the enhanced Galerkin method. Results show how harmonic excitation can result in multiharmonic vibratory power transmission. The proposed optimization strategy offers designers some flexibility in utilizing both passive and active means in combination with linear and non-linear components for improved vibration mounts.

  18. ELF Communications System Ecological Monitoring Program: Soil Arthropods and Earthworms.

    DTIC Science & Technology

    1995-04-01

    year of antenna operation. Surface-active Collembola, velvet mites and carabid beetles did not alter their activity patterns following antenna...activity were synchronous in the study sites. Carabid beetle activity, which is highly seasonal and governed mainly by reproductive processes, was not affected by EM fields.

  19. How Did Arthropod Sesquiterpenoids and Ecdysteroids Arise? Comparison of Hormonal Pathway Genes in Noninsect Arthropod Genomes

    PubMed Central

    Qu, Zhe; Kenny, Nathan James; Lam, Hon Ming; Chan, Ting Fung; Chu, Ka Hou; Bendena, William G.; Tobe, Stephen S.; Hui, Jerome Ho Lam

    2015-01-01

    The phylum Arthropoda contains the largest number of described living animal species, with insects and crustaceans dominating the terrestrial and aquatic environments, respectively. Their successful radiations have long been linked to their rigid exoskeleton in conjunction with their specialized endocrine systems. In order to understand how hormones can contribute to the evolution of these animals, here, we have categorized the sesquiterpenoid and ecdysteroid pathway genes in the noninsect arthropod genomes, which are known to play important roles in the regulation of molting and metamorphosis in insects. In our analyses, the majority of gene homologs involved in the biosynthetic, degradative, and signaling pathways of sesquiterpenoids and ecdysteroids can be identified, implying these two hormonal systems were present in the last common ancestor of arthropods. Moreover, we found that the “Broad-Complex” was specifically gained in the Pancrustacea, and the innovation of juvenile hormone (JH) in the insect linage correlates with the gain of the JH epoxidase (CYP15A1/C1) and the key residue changes in the binding domain of JH receptor (“Methoprene-tolerant”). Furthermore, the gain of “Phantom” differentiates chelicerates from the other arthropods in using ponasterone A rather than 20-hydroxyecdysone as molting hormone. This study establishes a comprehensive framework for interpreting the evolution of these vital hormonal pathways in these most successful animals, the arthropods, for the first time. PMID:26112967

  20. A molecular palaeobiological exploration of arthropod terrestrialization

    PubMed Central

    Carton, Robert; Edgecombe, Gregory D.

    2016-01-01

    Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation. Arthropoda (insects, spiders, centipedes and their allies) represent the largest majority of terrestrial biodiversity. Here we implemented a molecular palaeobiological approach, merging molecular and fossil evidence, to elucidate the deepest history of the terrestrial arthropods. We focused on the three independent, Palaeozoic arthropod terrestrialization events (those of Myriapoda, Hexapoda and Arachnida) and showed that a marine route to the colonization of land is the most likely scenario. Molecular clock analyses confirmed an origin for the three terrestrial lineages bracketed between the Cambrian and the Silurian. While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence. An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems. This article is part of the themed issue ‘Dating species divergences using rocks and clocks’. PMID:27325830

  1. A Silurian short-great-appendage arthropod

    PubMed Central

    Siveter, Derek J.; Briggs, Derek E. G.; Siveter, David J.; Sutton, Mark D.; Legg, David; Joomun, Sarah

    2014-01-01

    A new arthropod, Enalikter aphson gen. et sp. nov., is described from the Silurian (Wenlock Series) Herefordshire Lagerstätte of the UK. It belongs to the Megacheira (=short-great-appendage group), which is recognized here, for the first time, in strata younger than mid-Cambrian age. Discovery of this new Silurian taxon allows us to identify a Devonian megacheiran representative, Bundenbachiellus giganteus from the Hunsrück Slate of Germany. The phylogenetic position of megacheirans is controversial: they have been interpreted as stem chelicerates, or stem euarthropods, but when Enalikter and Bundenbachiellus are added to the most comprehensive morphological database available, a stem euarthropod position is supported. Enalikter represents the only fully three-dimensionally preserved stem-group euarthropod, it falls in the sister clade to the crown-group euarthropods, and it provides new insights surrounding the origin and early evolution of the euarthropods. Recognition of Enalikter and Bundenbachiellus as megacheirans indicates that this major arthropod group survived for nearly 100 Myr beyond the mid-Cambrian. PMID:24452026

  2. Visual orientation and navigation in nocturnal arthropods.

    PubMed

    Warrant, Eric; Dacke, Marie

    2010-01-01

    With their highly sensitive visual systems, the arthropods have evolved a remarkable capacity to orient and navigate at night. Whereas some navigate under the open sky, and take full advantage of the celestial cues available there, others navigate in more difficult conditions, such as through the dense understory of a tropical rainforest. Four major classes of orientation are performed by arthropods at night, some of which involve true navigation (i.e. travel to a distant goal that lies beyond the range of direct sensory contact): (1) simple straight-line orientation, typically for escape purposes; (2) nightly short-distance movements relative to a shoreline, typically in the context of feeding; (3) long-distance nocturnal migration at high altitude in the quest to locate favorable feeding or breeding sites, and (4) nocturnal excursions to and from a fixed nest or food site (i.e. homing), a task that in most species involves path integration and/or the learning and recollection of visual landmarks. These four classes of orientation--and their visual basis--are reviewed here, with special emphasis given to the best-understood animal systems that are representative of each.

  3. A molecular palaeobiological exploration of arthropod terrestrialization.

    PubMed

    Lozano-Fernandez, Jesus; Carton, Robert; Tanner, Alastair R; Puttick, Mark N; Blaxter, Mark; Vinther, Jakob; Olesen, Jørgen; Giribet, Gonzalo; Edgecombe, Gregory D; Pisani, Davide

    2016-07-19

    Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation. Arthropoda (insects, spiders, centipedes and their allies) represent the largest majority of terrestrial biodiversity. Here we implemented a molecular palaeobiological approach, merging molecular and fossil evidence, to elucidate the deepest history of the terrestrial arthropods. We focused on the three independent, Palaeozoic arthropod terrestrialization events (those of Myriapoda, Hexapoda and Arachnida) and showed that a marine route to the colonization of land is the most likely scenario. Molecular clock analyses confirmed an origin for the three terrestrial lineages bracketed between the Cambrian and the Silurian. While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence. An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.

  4. Administering and detecting protein marks on arthropods for dispersal research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monitoring arthropod movement is often required to better understand their population dynamics, dispersal patterns, host plant preferences, and other ecological interactions. Arthropods are usually tracked in nature by tagging them with a unique mark and then re-collecting them over time and space t...

  5. Effects of large herbivores on grassland arthropod diversity.

    PubMed

    van Klink, R; van der Plas, F; van Noordwijk, C G E Toos; WallisDeVries, M F; Olff, H

    2015-05-01

    Both arthropods and large grazing herbivores are important components and drivers of biodiversity in grassland ecosystems, but a synthesis of how arthropod diversity is affected by large herbivores has been largely missing. To fill this gap, we conducted a literature search, which yielded 141 studies on this topic of which 24 simultaneously investigated plant and arthropod diversity. Using the data from these 24 studies, we compared the responses of plant and arthropod diversity to an increase in grazing intensity. This quantitative assessment showed no overall significant effect of increasing grazing intensity on plant diversity, while arthropod diversity was generally negatively affected. To understand these negative effects, we explored the mechanisms by which large herbivores affect arthropod communities: direct effects, changes in vegetation structure, changes in plant community composition, changes in soil conditions, and cascading effects within the arthropod interaction web. We identify three main factors determining the effects of large herbivores on arthropod diversity: (i) unintentional predation and increased disturbance, (ii) decreases in total resource abundance for arthropods (biomass) and (iii) changes in plant diversity, vegetation structure and abiotic conditions. In general, heterogeneity in vegetation structure and abiotic conditions increases at intermediate grazing intensity, but declines at both low and high grazing intensity. We conclude that large herbivores can only increase arthropod diversity if they cause an increase in (a)biotic heterogeneity, and then only if this increase is large enough to compensate for the loss of total resource abundance and the increased mortality rate. This is expected to occur only at low herbivore densities or with spatio-temporal variation in herbivore densities. As we demonstrate that arthropod diversity is often more negatively affected by grazing than plant diversity, we strongly recommend considering the

  6. Effects of large herbivores on grassland arthropod diversity

    PubMed Central

    van Klink, R; van der Plas, F; van Noordwijk, C G E (Toos); WallisDeVries, M F; Olff, H

    2015-01-01

    Both arthropods and large grazing herbivores are important components and drivers of biodiversity in grassland ecosystems, but a synthesis of how arthropod diversity is affected by large herbivores has been largely missing. To fill this gap, we conducted a literature search, which yielded 141 studies on this topic of which 24 simultaneously investigated plant and arthropod diversity. Using the data from these 24 studies, we compared the responses of plant and arthropod diversity to an increase in grazing intensity. This quantitative assessment showed no overall significant effect of increasing grazing intensity on plant diversity, while arthropod diversity was generally negatively affected. To understand these negative effects, we explored the mechanisms by which large herbivores affect arthropod communities: direct effects, changes in vegetation structure, changes in plant community composition, changes in soil conditions, and cascading effects within the arthropod interaction web. We identify three main factors determining the effects of large herbivores on arthropod diversity: (i) unintentional predation and increased disturbance, (ii) decreases in total resource abundance for arthropods (biomass) and (iii) changes in plant diversity, vegetation structure and abiotic conditions. In general, heterogeneity in vegetation structure and abiotic conditions increases at intermediate grazing intensity, but declines at both low and high grazing intensity. We conclude that large herbivores can only increase arthropod diversity if they cause an increase in (a)biotic heterogeneity, and then only if this increase is large enough to compensate for the loss of total resource abundance and the increased mortality rate. This is expected to occur only at low herbivore densities or with spatio-temporal variation in herbivore densities. As we demonstrate that arthropod diversity is often more negatively affected by grazing than plant diversity, we strongly recommend considering the

  7. Ecotoxicological Study of Insecticide Effects on Arthropods in Common Bean

    PubMed Central

    de Barros, Emerson Cristi; Ventura, Hudson Vaner; Gontijo, Pablo Costa; Pereira, Renata Ramos; Picanço, Marcelo Coutinho

    2015-01-01

    Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod pests, insecticides can cause environmental damage. We examined the effects of one and two applications of the insecticides chlorfenapyr (0.18 liters a.i. ha-1) and methamidophos (0.45 liters a.i. ha-1), both independently and in combination, on arthropods in plots of common bean. The experiment was repeated for two growing seasons. Principal response curve, richness estimator, and Shannon–Wiener diversity index analyses were performed. The insecticides generally affected the frequency, richness, diversity, and relative abundance of the arthropods. In addition, the arthropods did not experience recovery after the insecticide applications. The results suggest that the insecticide impacts were sufficiently drastic to eliminate many taxa from the studied common bean plots. PMID:25700537

  8. Ecotoxicological study of insecticide effects on arthropods in common bean.

    PubMed

    de Barros, Emerson Cristi; Ventura, Hudson Vaner; Gontijo, Pablo Costa; Pereira, Renata Ramos; Picanço, Marcelo Coutinho

    2015-01-01

    Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod pests, insecticides can cause environmental damage. We examined the effects of one and two applications of the insecticides chlorfenapyr (0.18 liters a.i. ha-1) and methamidophos (0.45 liters a.i. ha-1), both independently and in combination, on arthropods in plots of common bean. The experiment was repeated for two growing seasons. Principal response curve, richness estimator, and Shannon-Wiener diversity index analyses were performed. The insecticides generally affected the frequency, richness, diversity, and relative abundance of the arthropods. In addition, the arthropods did not experience recovery after the insecticide applications. The results suggest that the insecticide impacts were sufficiently drastic to eliminate many taxa from the studied common bean plots.

  9. [Community diversity of soil arthropods in forest-steppe ecotone].

    PubMed

    Zhu, Xin-yu; Gao, Bao-ji; Bi, Hua-ming; Wang, Wen-xun; Yuan, Sheng-liang; Hu, Yun-chuan

    2007-11-01

    An investigation on the community diversity of soil arthropods in the forest-steppe ecotone of north Hebei Province was conducted. A total of 10 420 individuals of soil arthropods were collected, which belonged to 25 groups, 6 classes and 24 orders. Acarina and Collembola were the dominant orders, and there were 8 groups of frequent orders and 15 groups of rare orders. The diversity index (H'), DG index, and evenness of soil arthropod community were relatively higher in forest zone, but lower in meadow-steppe zone. Soil pH had a higher degree of interconnection with the numbers of soil arthropod groups, while soil temperature and moisture content had a higher degree of interconnection with the numbers of soil arthropod individuals.

  10. Vibratory sources as compound stimuli for the octavolateralis systems: Dissection of specific stimulation channels using multiple behavioral approaches

    PubMed Central

    Braun, Christopher B.; Coombs, Sheryl

    2010-01-01

    An underwater vibratory source simultaneously presents acoustic and hydrodynamic disturbances. Because vibratory dipole sources are poor sonic projectors, most researchers have assumed that such sources are of greatest relevance to the lateral line system (LL). Both hydroacoustic principles and empirical studies have shown that vibratory dipole sources are also a potent stimulus to the inner ear of fishes. Responses to vibratory sources in mottled sculpin (Cottus bairdi) were assessed using unconditioned orienting, differential and non-differential-classical conditioning. Orienting responses are dominated by LL inputs and eliminated by LL pharmacological inactivation. Simple conditioning depends on inputs from other systems and was not affected by LL inactivation. Differential conditioning alters behavioral control, and sculpin could be conditioned to ignore substrate borne vibrations and respond only to hydroacoustic stimulation of the ear. The lateral line and inner ear of mottled sculpin do not necessarily exhibit range fractionation, as both systems operate over a similar distance from the animal (within 1.5 body lengths) and respond to many of the same sources. Vibratory dipole sources generate compound stimuli that simultaneously activate multiple octavolateralis systems, and animals make use of the channels differentially under different behavioral tasks. PMID:20384404

  11. Numerical investigation of soil plugging effect inside sleeve of cast-in-place piles driven by vibratory hammers in clays.

    PubMed

    Xiao, Yong Jie; Chen, Fu Quan; Dong, Yi Zhi

    2016-01-01

    During driving sleeve of cast-in-place piles by vibratory hammers, soils were squeezed into sleeve and then soil plugging was formed. The physic-mechanical properties of the soil plug have direct influence on the load transmission between the sleeve wall and soil plug. Nevertheless, the researches on this issue are insufficient. In this study, finite element and infinite element coupling model was introduced, through the commercial code ABAQUS, to simulate the full penetration process of the sleeve driven from the ground surface to the desired depth by applying vibratory hammers. The research results indicated that the cyclic shearing action decreases both in soil shear strength and in granular cementation force when the sleeve is driven by vibratory hammers, which leads to a partially plugged mode of the soil plug inside the sleeve. Accordingly, the penetration resistance of sleeve driven by vibratory hammers is the smallest compared to those by other installation methods. When driving the sleeve, the annular soil arches forming in the soil plug at sleeve end induce a significant rise in the internal shaft resistance. Moreover, the influence of vibration frequencies, sleeve diameters, and soil layer properties on the soil plug was investigated in detail, and at the same time improved formulas were brought forward to describe the soil plug resistance inside vibratory driven sleeve.

  12. Unilateral contact induced blade/casing vibratory interactions in impellers: Analysis for rigid casings

    NASA Astrophysics Data System (ADS)

    Batailly, Alain; Meingast, Markus; Legrand, Mathias

    2015-02-01

    This contribution addresses the vibratory analysis of unilateral-contact induced structural interactions between a bladed impeller and its surrounding rigid casing. Such assemblies can be found in helicopter or small aircraft engines for instance and the interactions of interest shall arise due to the always tighter operating clearances between the rotating and stationary components. The investigation is conducted by extending to cyclically symmetric structures an in-house time-marching based tool dedicated to unilateral contact occurrences in turbomachines. The main components of the considered impeller together with the associated assumptions and modelling principles considered in this work are detailed. Typical dynamical features of cyclically symmetric structures, such as the aliasing effect and frequency clustering are explored in this nonlinear framework by means of thorough frequency-domain analyses and harmonic trackings of the numerically predicted impeller displacements. Additional contact maps highlight the existence of critical rotational velocities at which displacements potentially reach high amplitudes due to the synchronization of the bladed assembly vibratory pattern with the shape of the rigid casing. The proposed numerical investigations are also compared to a simpler and (almost) empirical criterion: it is suggested, based on nonlinear numerical simulations with a linear reduced order model of the impeller and a rigid casing, that this criterion may miss important critical velocities emanating from the unfavorable combination of aliasing and contact-induced higher harmonics in the vibratory response of the impeller. Overall, this work suggests a way to enhance guidelines to improve the design of impellers in the context of nonlinear and nonsmooth dynamics.

  13. Process for forming integral edge seals in porous gas distribution plates utilizing a vibratory means

    NASA Technical Reports Server (NTRS)

    Feigenbaum, Haim (Inventor); Pudick, Sheldon (Inventor)

    1988-01-01

    A process for forming an integral edge seal in a gas distribution plate for use in a fuel cell. A seal layer is formed along an edge of a porous gas distribution plate by impregnating the pores in the layer with a material adapted to provide a seal which is operative dry or when wetted by an electrolyte of a fuel cell. Vibratory energy is supplied to the sealing material during the step of impregnating the pores to provide a more uniform seal throughout the cross section of the plate.

  14. Comparison of energy costs for different control laws of a vibratory robot

    NASA Astrophysics Data System (ADS)

    Golitsyna, Maria

    2017-01-01

    In the study there are introduced several control methods that maximize average velocity of the vibratory robot subject to several constraints. The robot is presented by a rigid box with a pendulum inside it. It can move forwards and backwards and there is a Coulomb friction between the box and the surface. In the paper it is not only shown the difference and advantages of proposed control laws but there is also done a comparison between efforts done by the motor that provides rotation of the pendulum for different control methods.

  15. An examination of the relations between rotor vibratory loads and airframe vibrations

    NASA Technical Reports Server (NTRS)

    Niebanck, C. F.

    1985-01-01

    Harmonic rotor hub loads and airframe interactions in steady flight are reviewed, with regard to the objective of achieving lower airframe vibration by modifying blade root loads. Flight test and wind tunnel data are reviewed, along with sample fuselage response data. Trends which could provide a generalized approach to the above objective are found to be very limited. Recent analytical and corresponding experimental blade tuning modifications are reviewed and compared. Rotor vibratory load modification and substantial vibration changes were achieved over a wide range of rotor operating conditions.

  16. Communications

    NASA Technical Reports Server (NTRS)

    Bonelle, G. J.

    1984-01-01

    Communications in any system is one of the last technologies to be considered, and sometimes it is considered too late to impact the system. This was somewhat the impression on reviewing the NASA budget for two mission scenarios for the space station. However, that budget fortunately was well spent, and the money was spent to get the most benefit per dollar. Another thing that is very often forgotten is that technology is not produced in a vacuum. In fact, in conducting independent research and development (IR&D), the first phase is to define the requirements which must be time phased, becuase very often the conditions will change during the life of the system. From the requirements, a set of architectures that are at least representative of that era are produced. If the exact requirements were not established, at least boundaries are set on the requirements for that architecture. When this is completed, then the technology that is really needed is defined. The major criticism of the work that was presented to the panel is the lack of a firm set of requirements.

  17. Analysis of compensation for a g-sensitivity scale-factor error for a MEMS vibratory gyroscope

    NASA Astrophysics Data System (ADS)

    Park, Byung Su; Han, KyungJun; Lee, SangWoo; Yu, MyeongJong

    2015-11-01

    In this paper, we present recent work on the g-sensitivity error of the MEMS vibratory gyroscope. Generally, the g-sensitivity error has been ignored in the use of commercial MEMS vibratory gyroscopes, but it deserves our attention if we are to achieve tactical grade performance for military applications. First, we mathematically show the reason the g-sensitivity error occurs as an additional scale-factor error during the use of MEMS vibratory gyroscopes. Then, we estimate the g-sensitivity error using FEM simulation and verify it by experiment using a centrifugal machine. Consequently, we propose a compensation model to accommodate the g-sensitivity error of a gyroscope and confirm the theoretical prediction with experimental results.

  18. Investigation on Multi-Physics Simulation-Based Virtual Machining System for Vibratory Finishing of Integrally Bladed Rotors (IBRS)

    NASA Astrophysics Data System (ADS)

    Achiamah-Ampomah, N.; Cheng, Kai

    2016-02-01

    An investigation was carried out to improve the slow surface finishing times of integrally bladed rotors (IBRs) in the aerospace industry. Traditionally they are finished by hand, or more currently by abrasive flow machining. The use of a vibratory finishing technique to improve process times has been suggested; however as a largely empirical process, very few studies have been done to improve and optimize the cycle times, showing that critical and ongoing research is still needed in this area. An extensive review of the literature was carried out, and the findings used to identify the key parameters and model equations which govern the vibratory process. Recommendations were made towards a multi-physics-based simulation model, as well as projections made for the future of vibratory finishing and optimization of surface finishes and cycle times.

  19. Arthropod-borne encephalitides in the Americas*

    PubMed Central

    Monath, T. P.

    1979-01-01

    The arthropod-borne encephalitides are an important cause of equine and human morbidity in the Americas. Between 1975 and 1978, 6970 human cases of arboviral encephalitis were reported in the United States of America; however, this represents only a fraction of the true incidence. St Louis encephalitis (4824 cases), California encephalitis (1035 cases), and western equine encephalitis (WEE, 947 cases) accounted for 98.5% of all reported infections. Approximately 1000-4000 cases of equine encephalitis occur annually in the United States, the majority due to WEE. In tropical America, important outbreaks of Venezuelan, eastern, and western equine encephalitis, and of Rocio encephalitis have occurred. In this article, epidemiological aspects of arboviral encephalitis outbreaks occurring within the past 5 years are reviewed. In addition, summaries of current research activities on the ecology and epidemiology of St Louis, western equine, Venezuelan equine, Rocio, and California encephalitis viruses are presented, and the problem of control of these infections is discussed. PMID:93518

  20. The ecdysis triggering hormone signaling in arthropods

    PubMed Central

    Roller, Ladislav; Žitňanová, Inka; Dai, Li; Šimo, Ladislav; Park, Yoonseong; Satake, Honoo; Tanaka, Yoshiaki; Adams, Michael E.; Žitňan, Dušan

    2010-01-01

    Ecdysis triggering hormones (ETH) from peripheral endocrine Inka cells initiate the ecdysis sequence through action on central neurons expressing ETH receptors (ETHR) in model moth and dipteran species. We used various biochemical, molecular and blast search techniques to detect these signaling molecules in representatives of diverse arthropods. Using peptide isolation from tracheal extracts, cDNA cloning or homology search, we identified ETHs in a variety of hemimetabolous and holometabolous insects. Most insects produce two related ETHs, but only a single active peptide was isolated from the cricket and one peptide is encoded by eth gene of the honeybee, parasitic wasp and aphid. Immunohistochemical staining with antiserum to Manduca PETH revealed Inka cells on tracheal surface of diverse insects. In spite of conserved ETH sequences, comparison of the natural and ETH-induced ecdysis sequence in the honeybee and beetle revealed considerable species-specific differences in pre-ecdysis and ecdysis behaviors. DNA sequences coding for putative ETHR were deduced from available genomes of several hemimetabolous and holometabolous insects. In all examined insects the ethr gene encodes two subtypes of the receptor (ETHR-A and ETHR-B). Phylogenic analysis showed that these receptors fall into a family of closely related GPCRs. Here we report for the first time presence of putative ETHs and ETHRs in genomes of other arthropods, the tick (Arachnida) and water flea (Crustacea). Possible source of ETH in ticks was detected in paired cells located in all pedal segments. Our results provide further evidence of structural and functional conservancy of ETH-ETHR signaling. PMID:19951734

  1. The evolution of the mitochondrial genetic code in arthropods revisited.

    PubMed

    Abascal, Federico; Posada, David; Zardoya, Rafael

    2012-04-01

    A variant of the invertebrate mitochondrial genetic code was previously identified in arthropods (Abascal et al. 2006a, PLoS Biol 4:e127) in which, instead of translating the AGG codon as serine, as in other invertebrates, some arthropods translate AGG as lysine. Here, we revisit the evolution of the genetic code in arthropods taking into account that (1) the number of arthropod mitochondrial genomes sequenced has triplicated since the original findings were published; (2) the phylogeny of arthropods has been recently resolved with confidence for many groups; and (3) sophisticated probabilistic methods can be applied to analyze the evolution of the genetic code in arthropod mitochondria. According to our analyses, evolutionary shifts in the genetic code have been more common than previously inferred, with many taxonomic groups displaying two alternative codes. Ancestral character-state reconstruction using probabilistic methods confirmed that the arthropod ancestor most likely translated AGG as lysine. Point mutations at tRNA-Lys and tRNA-Ser correlated with the meaning of the AGG codon. In addition, we identified three variables (GC content, number of AGG codons, and taxonomic information) that best explain the use of each of the two alternative genetic codes.

  2. Biochemical and evolutionary aspects of arthropod predation on ferns.

    PubMed

    Balick, Michael J; Furth, David G; Cooper-Driver, Gillian

    1978-01-01

    The widely held assumption that very few arthropods feed on ferns was questioned following field observations of arthropod damage on ferns in the state of Veracruz, Mexico. The extent and type of damage was recorded and it was found that in a measured locality, ferns were no less attacked than the angiospermous flora. As chemistry and arthropod host relationships have been shown to be so closely intertwined, plants collected in the field were analysed for both condensed tannins and cyanogenic glycosides, compounds known to be effective deterrents in temperate climates. Although all ferns tested contained tannins these did not appear to inhibit predation. Cyanogenic glycosides were present in only 3% of the fern species analysed, and it is, therefore, unlikely that they play a significant role as defensive compounds in the ferns examined.A literature search revealed a large number of ferns cited as being arthropod hosts. Approximately 420 named species of arthropods have been recorded, the majority of which are from the orders Coleoptera, Hymenoptera, Lepidoptera, and Hemiptera. Both evolutionary primitive (sawflies) and advanced (moths) arthropods are reported to be present on ferns suggesting possible coevolution of arthropods and ferns both before and after the radiation of angiosperms.

  3. Role of arthropod communities in bioenergy crop litter decomposition†.

    PubMed

    Zangerl, Arthur R; Miresmailli, Saber; Nabity, Paul; Lawrance, Allen; Yanahan, Alan; Mitchell, Corey A; Anderson-Teixeira, Kristina J; David, Mark B; Berenbaum, May R; DeLucia, Evan H

    2013-10-01

    The extensive land use conversion expected to occur to meet demands for bioenergy feedstock production will likely have widespread impacts on agroecosystem biodiversity and ecosystem services, including carbon sequestration. Although arthropod detritivores are known to contribute to litter decomposition and thus energy flow and nutrient cycling in many plant communities, their importance in bioenergy feedstock communities has not yet been assessed. We undertook an experimental study quantifying rates of litter mass loss and nutrient cycling in the presence and absence of these organisms in three bioenergy feedstock crops-miscanthus (Miscanthus x giganteus), switchgrass (Panicum virgatum), and a planted prairie community. Overall arthropod abundance and litter decomposition rates were similar in all three communities. Despite effective reduction of arthropods in experimental plots via insecticide application, litter decomposition rates, inorganic nitrogen leaching, and carbon-nitrogen ratios did not differ significantly between control (with arthropods) and treatment (without arthropods) plots in any of the three community types. Our findings suggest that changes in arthropod faunal composition associated with widespread adoption of bioenergy feedstock crops may not be associated with profoundly altered arthropod-mediated litter decomposition and nutrient release.

  4. Diversity of arthropod community in transgenic poplar-cotton ecosystems.

    PubMed

    Zhang, D J; Lu, Z Y; Liu, J X; Li, C L; Yang, M S

    2015-12-02

    Poplar-cotton agro-ecosystems are the main agricultural planting modes of plain cotton fields in China. Here, we performed a systematic survey of the diversity and population of arthropod communities in four different combination of poplar-cotton eco-systems, including I) non-transgenic poplar and non-transgenic cotton fields; II) non-transgenic poplar and transgenic cotton fields [Bacillus thuringiensis (Bt) cotton]; III) Bt transgenic poplar (high insect resistant strain Pb29) and non-transgenic cotton; and IV) transgenic poplar and transgenic cotton fields, over a period of 3 years. Based on the statistical methods used to investigate community ecology, the effects of transgenic ecosystems on the whole structure of the arthropod community, on the structure of arthropods in the nutritive layer, and on the similarity of arthropod communities were evaluated. The main results were as follows: the transgenic poplar-cotton ecosystem has a stronger inhibitory effect on insect pests and has no impact on the structure of the arthropod community, and therefore, maintains the diversity of the arthropod community. The character index of the community indicated that the structure of the arthropod community of the transgenic poplar-cotton ecosystem was better than that of the poplar-cotton ecosystem, and that system IV had the best structure. As for the abundance of nutritional classes, the transgenic poplar-cotton ecosystem was also better than that of the non-transgenic poplar-cotton ecosystem. The cluster analysis and similarity of arthropod communities between the four different transgenic poplar-cotton ecosystems illustrated that the structure of the arthropod community excelled in the small sample of the transgenic poplar-cotton ecosystems.

  5. Structural-acoustic coupling effects on the non-vacuum packaging vibratory cylinder gyroscope.

    PubMed

    Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng; Tao, Yi; Zheng, Yu; Xiao, Dingbang

    2013-12-13

    The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE) model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.

  6. An Overview of A Perturbation Analysis for Uni-directionally Coupled Vibratory Gyroscopes

    NASA Astrophysics Data System (ADS)

    Vu, Huy; Palacios, Antonio; In, Visarath; Longhini, Patrick; Neff, Joseph

    2011-04-01

    The complex behaviours of gyroscope systems have been scientifically researched and thoroughly studied for decades. Most of scientific research involving gyroscopes specifically concentrates on studying the designs and fabrications at the circuitry level. Although gaining a recent popularity with the low cost of MEMS device that offers an attractive approach for gyroscope fabrications, its performance is far from meeting the requirements for an inertial grade guidance system. To improve the performance, our current research is theoretically focusing upon investigating the dynamics of vibratory gyroscopes coupled in a ring configuration. Particularly, a certain topology of arrangements among coupled gyroscopes can be designed and studied to enhance robustness. The main operation depends mostly on an external source for a stable oscillation in the drive axis, while an oscillatory motion in the sense axis, which is used to detect an angular rate of rotation, is enabled through the transfers of energy from the drive via the Coriolis force. With the mathematical model depicted as Duffing oscillators, however, by adding a certain coupling among gyroscopes, a similar behavior to a Duffing oscillator is expected, only with more complicated dynamics at a higher dimension. A number of Perturbation methods have popularly been carried out, to seek for a general asymptotic solution of typical Duffing oscillators. In this work as an overview, the two-time scale Perturbation expansion is asymptotically applied on the uni-directionally coupled vibratory gyroscopes to find an analytical solution which is then compared to the numerical one.

  7. Effect On The Processing Characteristics Of ZnO Varistors Produced Using Vibratory Milling

    NASA Astrophysics Data System (ADS)

    Kelleher, M. C.; Hashmi, M. S. J.

    2011-01-01

    Each manufacturing stage in the production of zinc oxide varistors from powder preparation to the final encapsulated device is important not only for the formation of the varistor component with optimum microstructure and thus electrical characteristics but also for avoiding the introduction of flaws and reduced yield. In this paper the authors describe and discuss the effect of multi-elemental oxide additives having been milled for different durations using a vibratory mill with cylindrical zirconia media on the powder characteristics of the subsequent processing stages. A commercial ZnO varistor formulation was used. The subsequent processing stages that are given particular attention include first spray drying and second milling. The characteristics include agglomerate size, powder density and elemental uniformity of the first spray-dried powders, and particle size, specific surface area, zirconium concentration and pore size of the second milled powders. They were evaluated using laser diffraction, scanning electron microscopic, mercury porosimetry, Brunauer, Emmett and Teller (BET) and inductively coupled plasma (ICP) analysis. Some interesting correlations are observed between the powder properties and vibratory milling durations of the mixed metal oxide additives (MMOA).

  8. Structural-Acoustic Coupling Effects on the Non-Vacuum Packaging Vibratory Cylinder Gyroscope

    PubMed Central

    Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng; Tao, Yi; Zheng, Yu; Xiao, Dingbang

    2013-01-01

    The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE) model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm. PMID:24351631

  9. Background matters: Minor vibratory stimulation during motor skill acquisition selectively reduces off-line memory consolidation.

    PubMed

    Korman, Maria; Herling, Zohar; Levy, Ishay; Egbarieh, Nebal; Engel-Yeger, Batya; Karni, Avi

    2017-04-01

    Although a ubiquitous situation, it is not clear how effective is a learning experience when task-irrelevant, sensory noise occurs in the background. Here, young adults were trained on the finger opposition sequence task, in a well-established training and testing protocol affording measures for online as well as off-line learning. During the training session, one group experienced a minor background vibratory stimulation to the trunk by the means of vibrating cushion, while the second group experienced recorded sound vibrations. A control group was trained with no extra sensory stimulation. Sensory stimulation during training had no effect on the online within-session gains, but dampened the expression of the off-line, consolidation phase, gains in the two sensory stimulation groups. These results suggest that background sensory stimulation can selectively modify off-line, procedural memory consolidation processes, despite well-preserved on-line learning. Classical studies have shown that neural plasticity in sensory systems is modulated by motor input. The current results extend this notion and suggest that some types of task-irrelevant sensory stimulation, concurrent with motor training, may constitute a 'gating' factor - modulating the triggering of long-term procedural memory consolidation processes. Thus, vibratory stimulation may be considered as a behavioral counterpart of pharmacological interventions that do not interfere with short term neural plasticity but block long-term plasticity.

  10. Characterizing vibratory kinematics in children and adults with high-speed digital imaging.

    PubMed

    Patel, Rita; Dubrovskiy, Denis; Döllinger, Michael

    2014-04-01

    PURPOSE The aim of this study is to quantify and identify characteristic vibratory motion in typically developing prepubertal children and young adults using high-speed digital imaging. METHOD The vibrations of the vocal folds were recorded from 27 children (ages 5-9 years) and 35 adults (ages 21-45 years), with high speed at 4,000 frames per second for sustained phonation. Kinematic features of amplitude periodicity, time periodicity, phase asymmetry, spatial symmetry, and glottal gap index were analyzed from the glottal area waveform across mean and standard deviation (i.e., intercycle variability) for each measure. RESULTS Children exhibited lower mean amplitude periodicity compared to men and women and lower time periodicity compared to men. Children and women exhibited greater variability in amplitude periodicity, time periodicity, phase asymmetry, and glottal gap index compared to men. Women had lower mean values of amplitude periodicity and time periodicity compared to men. CONCLUSION Children differed both spatially but more temporally in vocal fold motion, suggesting the need for the development of children-specific kinematic norms. Results suggest more uncontrolled vibratory motion in children, reflecting changes in the vocal fold layered structure and aero-acoustic source mechanisms.

  11. Conjectural bifurcation analysis of the contact-induced vibratory response of an aircraft engine blade

    NASA Astrophysics Data System (ADS)

    Batailly, Alain; Legrand, Mathias; Millecamps, Antoine; Garcin, François

    2015-07-01

    This paper deals with the numerical investigation of the unilateral contact-induced dynamics of a turbomachine blade rotating within a perfectly rigid yet distorted casing. This investigation is motivated by unelucidated vibratory behaviours observed experimentally. The simulations are based on an in-house time-marching strategy incorporating Lagrange multipliers for the unilateral contact treatment, as well as centrifugal stiffening and abradable coating removal. Significant extensions are proposed through the implementation of (1) aerodynamic loading on the blade and (2) post-processing techniques involving the empirical mode decomposition which provides fruitful insights on important transient phenomena. A thorough bifurcation analysis with and without aerodynamic loading highlights the existence of flip bifurcations with period-doubling and period-halving sequences over a broad angular speed range. Numerical simulations with external aerodynamic loading yield quasi-periodic and likely to be chaotic motions that could not be observed under vacuum. The proposed numerical investigations underline the key role of the aerodynamic loading in the blade dynamics and suggest that unexplained experimental vibratory behaviours are related to the vacuum conditions of the experiment.

  12. Analysis of the vibratory excitation of gear systems. II - Tooth error representations, approximations, and application

    NASA Technical Reports Server (NTRS)

    Mark, W. D.

    1979-01-01

    The second part of a theory for predicting the vibratory excitation of gear systems from fundamental descriptions of gear tooth elastic properties and deviations of tooth faces from perfect involute surfaces is presented. The first part of the theory provides expressions for the Fourier-series coefficients of the vibratory excitation, and this paper gives expressions for these Fourier-series coefficients in terms of easily interpreted gear tooth metrics that are readily evaluated from tooth-face measurements. Results are given for rectangular tooth-face contact regions using two-dimensional Legendre polynomial expansions of local tooth-pair stiffnesses and stiffness-weighted deviations of tooth faces from perfect involute surfaces. A rigorous transfer function approach is developed that permits separation of the effects of gear tooth errors and gear design parameters; the theory is applicable to helical and spur gears and is illustrated with measurements of tooth-spacing errors and tooth profiles obtained from a pair of spur gears.

  13. Insecticide-induced hormesis and arthropod pest management.

    PubMed

    Guedes, Raul Narciso C; Cutler, G Christopher

    2014-05-01

    Ecological backlashes such as insecticide resistance, resurgence and secondary pest outbreaks are frequent problems associated with insecticide use against arthropod pest species. The last two have been particularly important in sparking interest in the phenomenon of insecticide-induced hormesis within entomology and acarology. Hormesis describes a biphasic dose-response relationship that is characterized by a reversal of response between low and high doses of a stressor (e.g. insecticides). Although the concept of insecticide-induced hormesis often does not receive sufficient attention, or has been subject to semantic confusion, it has been reported in many arthropod pest species and natural enemies, and has been linked to pest outbreaks and potential problems with insecticide resistance. The study of hormesis remains largely neglected in entomology and acarology. Here, we examined the concept of insecticide-induced hormesis in arthropods, its functional basis and potential fitness consequences, and its importance in arthropod pest management and other areas.

  14. Arthropod surveillance programs: Basic components, strategies, and analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective entomological surveillance planning stresses a careful consideration of methodology, trapping technologies, and analysis techniques. Herein, the basic principles and technological components of arthropod surveillance plans are described, as promoted in the symposium “Advancements in arthro...

  15. Nuisance arthropods, nonhost odors, and vertebrate chemical aposematism

    NASA Astrophysics Data System (ADS)

    Weldon, Paul J.

    2010-05-01

    Mosquitoes, ticks, and other ectoparasitic arthropods use chemoreception to avoid vertebrates that are known or presumed to be dangerous or otherwise unprofitable hosts. Nonhosts may belong to a species that is regularly unaccepted or one that includes both accepted and unaccepted individuals. A diverse array of qualities including immunocompetence, vigilant grooming behavior, mechanical inaccessibility, and toxicity have been proposed as the features that render vertebrate chemical emitters unsuitable as hosts for arthropods. In addition to advantages accrued by ectoparasitic arthropods that avoid nonhosts, vertebrates that are not accepted as hosts benefit by evading injurious ectoparasites and the infectious agents they transmit. The conferral of advantages to both chemical receivers (ectoparasitic arthropods) and emitters (unpreferred vertebrates) in these interactions renders nonhost odors aposematic. Chemical aposematism involving ectoparasites selects for vertebrates that emit distinctive odors. In addition, chemical mimicry, where vulnerable organisms benefit when misidentified as nonhosts, may be accommodated by duped ectoparasites.

  16. Ecological mechanisms underlying arthropod species diversity in grasslands.

    PubMed

    Joern, Anthony; Laws, Angela N

    2013-01-01

    Arthropods are an important component of grassland systems, contributing significantly to biodiversity and ecosystem structure and function. Climate, fire, and grazing by large herbivores are important drivers in grasslands worldwide. Arthropod responses to these drivers are highly variable and clear patterns are difficult to find, but responses are largely indirect with respect to changes in resources, species interactions, habitat structure, and habitat heterogeneity resulting from interactions among fire, grazing, and climate. Here, we review these ecological mechanisms influencing grassland arthropod diversity. We summarize hypotheses describing species diversity at local and regional scales and then discuss specific factors that may affect arthropod diversity in grassland systems. These factors include direct and indirect effects of grazing, fire, and climate, species interactions, above- and belowground interactions, and landscape-level effects.

  17. Administering and Detecting Protein Marks on Arthropods for Dispersal Research.

    PubMed

    Hagler, James R; Machtley, Scott A

    2016-01-28

    Monitoring arthropod movement is often required to better understand associated population dynamics, dispersal patterns, host plant preferences, and other ecological interactions. Arthropods are usually tracked in nature by tagging them with a unique mark and then re-collecting them over time and space to determine their dispersal capabilities. In addition to actual physical tags, such as colored dust or paint, various types of proteins have proven very effective for marking arthropods for ecological research. Proteins can be administered internally and/or externally. The proteins can then be detected on recaptured arthropods with a protein-specific enzyme-linked immunosorbent assay (ELISA). Here we describe protocols for externally and internally tagging arthropods with protein. Two simple experimental examples are demonstrated: (1) an internal protein mark introduced to an insect by providing a protein-enriched diet and (2) an external protein mark topically applied to an insect using a medical nebulizer. We then relate a step-by-step guide of the sandwich and indirect ELISA methods used to detect protein marks on the insects. In this demonstration, various aspects of the acquisition and detection of protein markers on arthropods for mark-release-recapture, mark-capture, and self-mark-capture types of research are discussed, along with the various ways that the immunomarking procedure has been adapted to suit a wide variety of research objectives.

  18. The incidence of bacterial endosymbionts in terrestrial arthropods.

    PubMed

    Weinert, Lucy A; Araujo-Jnr, Eli V; Ahmed, Muhammad Z; Welch, John J

    2015-05-22

    Intracellular endosymbiotic bacteria are found in many terrestrial arthropods and have a profound influence on host biology. A basic question about these symbionts is why they infect the hosts that they do, but estimating symbiont incidence (the proportion of potential host species that are actually infected) is complicated by dynamic or low prevalence infections. We develop a maximum-likelihood approach to estimating incidence, and testing hypotheses about its variation. We apply our method to a database of screens for bacterial symbionts, containing more than 3600 distinct arthropod species and more than 150 000 individual arthropods. After accounting for sampling bias, we estimate that 52% (CIs: 48-57) of arthropod species are infected with Wolbachia, 24% (CIs: 20-42) with Rickettsia and 13% (CIs: 13-55) with Cardinium. We then show that these differences stem from the significantly reduced incidence of Rickettsia and Cardinium in most hexapod orders, which might be explained by evolutionary differences in the arthropod immune response. Finally, we test the prediction that symbiont incidence should be higher in speciose host clades. But while some groups do show a trend for more infection in species-rich families, the correlations are generally weak and inconsistent. These results argue against a major role for parasitic symbionts in driving arthropod diversification.

  19. Hox genes and the phylogeny of the arthropods.

    PubMed

    Cook, C E; Smith, M L; Telford, M J; Bastianello, A; Akam, M

    2001-05-15

    The arthropods are the most speciose, and among the most morphologically diverse, of the animal phyla. Their evolution has been the subject of intense research for well over a century, yet the relationships among the four extant arthropod subphyla - chelicerates, crustaceans, hexapods, and myriapods - are still not fully resolved. Morphological taxonomies have often placed hexapods and myriapods together (the Atelocerata) [1, 2], but recent molecular studies have generally supported a hexapod/crustacean clade [2-9]. A cluster of regulatory genes, the Hox genes, control segment identity in arthropods, and comparisons of the sequences and functions of Hox genes can reveal evolutionary relationships [10]. We used Hox gene sequences from a range of arthropod taxa, including new data from a basal hexapod and a myriapod, to estimate a phylogeny of the arthropods. Our data support the hypothesis that insects and crustaceans form a single clade within the arthropods to the exclusion of myriapods. They also suggest that myriapods are more closely allied to the chelicerates than to this insect/crustacean clade.

  20. The incidence of bacterial endosymbionts in terrestrial arthropods

    PubMed Central

    Weinert, Lucy A.; Araujo-Jnr, Eli V.; Ahmed, Muhammad Z.; Welch, John J.

    2015-01-01

    Intracellular endosymbiotic bacteria are found in many terrestrial arthropods and have a profound influence on host biology. A basic question about these symbionts is why they infect the hosts that they do, but estimating symbiont incidence (the proportion of potential host species that are actually infected) is complicated by dynamic or low prevalence infections. We develop a maximum-likelihood approach to estimating incidence, and testing hypotheses about its variation. We apply our method to a database of screens for bacterial symbionts, containing more than 3600 distinct arthropod species and more than 150 000 individual arthropods. After accounting for sampling bias, we estimate that 52% (CIs: 48–57) of arthropod species are infected with Wolbachia, 24% (CIs: 20–42) with Rickettsia and 13% (CIs: 13–55) with Cardinium. We then show that these differences stem from the significantly reduced incidence of Rickettsia and Cardinium in most hexapod orders, which might be explained by evolutionary differences in the arthropod immune response. Finally, we test the prediction that symbiont incidence should be higher in speciose host clades. But while some groups do show a trend for more infection in species-rich families, the correlations are generally weak and inconsistent. These results argue against a major role for parasitic symbionts in driving arthropod diversification. PMID:25904667

  1. An invasive plant-fungal mutualism reduces arthropod diversity.

    PubMed

    Rudgers, Jennifer A; Clay, Keith

    2008-08-01

    Ecological theory holds that competition and predation are the most important biotic forces affecting the composition of communities. Here, we expand this framework by demonstrating that mutualism can fundamentally alter community and food web structure. In large, replicated field plots, we manipulated the mutualism between a dominant plant (Lolium arundinaceum) and symbiotic fungal endophyte (Neotyphodium coenophialum). The presence of the mutualism reduced arthropod abundance up to 70%, reduced arthropod diversity nearly 20%, shifted arthropod species composition relative to endophyte-free plots and suppressed the biomass and richness of other plant species in the community. Herbivorous arthropods were more strongly affected than carnivores, and for both herbivores and carnivores, effects of the mutualism appeared to propagate indirectly via organisms occurring more basally in the food web. The influence of the mutualism was as great or greater than previously documented effects of competition and predation on arthropod communities. Our work demonstrates that a keystone mutualism can significantly reduce arthropod biodiversity at a broad community scale.

  2. Vaccines against blood-sucking arthropods.

    PubMed

    Opdebeeck, J P

    1994-08-01

    This paper provides selected personal insights on the development of vaccines against blood-sucking arthropods, with particular emphasis on vaccines against ticks. The emergence of novel or concealed antigens of haematophagous ectoparasites as candidate vaccine antigens is reviewed and the effect of feeding by the parasite on the expression of protective antigens is considered. The distribution of protective antigens through life cycle stages, the stage of the life cycle targeted by protective responses, and the nature of these responses, are commented on briefly. Concealed antigens of the gut, including the peritrophic membrane, and other internal organs, are evaluated for the role they play in induction of immunity artificially. Some of the work carried out to purify and characterise protective antigens of tick guts is described. A commentary is developed on vaccines that combine both "concealed" and "exposed" antigens. Some of the problems associated with the infestation and challenge of vaccinated hosts in the field are identified and the delivery of parasite antigens as vaccines that are both protective and "user-friendly" is emphasised as a major problem to be solved.

  3. Microspectrophotometry of Arthropod Visual Screening Pigments

    PubMed Central

    Strother, G. K.; Casella, A. J.

    1972-01-01

    Absorption spectra of visual screening pigments obtained in vitro with a microspectrophotometer using frozen sections are given for the insects Musca domestica, Phormia regina, Libellula luctuosa, Apis mellifera (worker honeybee only), Drosophila melanogaster (wild type only) and the arachnids Lycosa baltimoriana and Lycosa miami. The spectral range covered is 260–700 nm for Lycosa and Drosophila and 310–700 nm for the remainder of the arthropods. A complete description of the instrumentation is given. For the flies, Phormia and Musca, light absorption by the yellow and red pigments is high from 310 to about 610 nm. This implies that for these insects there should be no wavelength shift in electroretinogram (ERG) results due to light leakage among neighboring ommatidia for this wavelength range. The same comment applies to Calliphora erythrocephala, which is known to have similar screening pigments. For some of the insects studied a close correspondence is noted between screening pigment absorption spectra and spectral sensitivity curves for individual photoreceptors, available in the literature. In some cases the screening pigment absorption spectra can be related to chemical extraction results, with the general observation that some of the in vitro absorption peaks are shifted to the red. The Lycosa, Apis, and Libellula dark red pigments absorb strongly over a wide spectral range and therefore prevent chemical identification. PMID:4623852

  4. The nature of alarm communication in Constrictotermes cyphergaster (Blattodea: Termitoidea: Termitidae): the integration of chemical and vibroacoustic signals

    PubMed Central

    Cristaldo, Paulo F.; Jandák, Vojtĕch; Kutalová, Kateřina; Rodrigues, Vinícius B.; Brothánek, Marek; Jiříček, Ondřej; DeSouza, Og; Šobotník, Jan

    2015-01-01

    ABSTRACT Alarm signalling is of paramount importance to communication in all social insects. In termites, vibroacoustic and chemical alarm signalling are bound to operate synergistically but have never been studied simultaneously in a single species. Here, we inspected the functional significance of both communication channels in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae), confirming the hypothesis that these are not exclusive, but rather complementary processes. In natural situations, the alarm predominantly attracts soldiers, which actively search for the source of a disturbance. Laboratory testing revealed that the frontal gland of soldiers produces a rich mixture of terpenoid compounds including an alarm pheromone. Extensive testing led to identification of the alarm pheromone being composed of abundant monoterpene hydrocarbons (1S)-α-pinene and myrcene, along with a minor component, (E)-β-ocimene. The vibratory alarm signalling consists of vibratory movements evidenced as bursts; a series of beats produced predominantly by soldiers. Exposing termite groups to various mixtures containing the alarm pheromone (crushed soldier heads, frontal gland extracts, mixture of all monoterpenes, and the alarm pheromone mixture made of standards) resulted in significantly higher activity in the tested groups and also increased intensity of the vibratory alarm communication, with the responses clearly dose-dependent. Lower doses of the pheromone provoked higher numbers of vibratory signals compared to higher doses. Higher doses induced long-term running of all termites without stops necessary to perform vibratory behaviour. Surprisingly, even crushed worker heads led to low (but significant) increases in the alarm responses, suggesting that other unknown compound in the worker's head is perceived and answered by termites. Our results demonstrate the existence of different alarm levels in termites, with lower levels being communicated through vibratory

  5. The nature of alarm communication in Constrictotermes cyphergaster (Blattodea: Termitoidea: Termitidae): the integration of chemical and vibroacoustic signals.

    PubMed

    Cristaldo, Paulo F; Jandák, Vojtĕch; Kutalová, Kateřina; Rodrigues, Vinícius B; Brothánek, Marek; Jiříček, Ondřej; DeSouza, Og; Šobotník, Jan

    2015-11-04

    Alarm signalling is of paramount importance to communication in all social insects. In termites, vibroacoustic and chemical alarm signalling are bound to operate synergistically but have never been studied simultaneously in a single species. Here, we inspected the functional significance of both communication channels in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae), confirming the hypothesis that these are not exclusive, but rather complementary processes. In natural situations, the alarm predominantly attracts soldiers, which actively search for the source of a disturbance. Laboratory testing revealed that the frontal gland of soldiers produces a rich mixture of terpenoid compounds including an alarm pheromone. Extensive testing led to identification of the alarm pheromone being composed of abundant monoterpene hydrocarbons (1S)-α-pinene and myrcene, along with a minor component, (E)-β-ocimene. The vibratory alarm signalling consists of vibratory movements evidenced as bursts; a series of beats produced predominantly by soldiers. Exposing termite groups to various mixtures containing the alarm pheromone (crushed soldier heads, frontal gland extracts, mixture of all monoterpenes, and the alarm pheromone mixture made of standards) resulted in significantly higher activity in the tested groups and also increased intensity of the vibratory alarm communication, with the responses clearly dose-dependent. Lower doses of the pheromone provoked higher numbers of vibratory signals compared to higher doses. Higher doses induced long-term running of all termites without stops necessary to perform vibratory behaviour. Surprisingly, even crushed worker heads led to low (but significant) increases in the alarm responses, suggesting that other unknown compound in the worker's head is perceived and answered by termites. Our results demonstrate the existence of different alarm levels in termites, with lower levels being communicated through vibratory signals, and

  6. Quantification of the extent of non-proportional viscous damping in discrete vibratory systems

    NASA Astrophysics Data System (ADS)

    Praterjr, G.; Singh, R.

    1986-01-01

    The primary objective of this paper is to present several numerical indices developed to determine quantitatively the extent of non-proportional damping present within a discrete vibratory system. A total of five distinct indices are considered. Two of these are based on the complex modes of a generally damped system, and three are based on the configuration of the system damping matrix after transformation into real normal coordinates. Each index has been normalized so that it assumes values between zero (proportional damping case) and one. Application of the indices is illustrated through a four degree of freedom system example problems. As part of this exercise, an effort is made to relate the magnitudes of the indices to the frequency response errors induced by two proportional damping approximations often found in the literature.

  7. Understanding the role of nonlinearities in the transduction of vibratory energy harvesters

    NASA Astrophysics Data System (ADS)

    Masana, Ravindra Shiva Charan

    The last two decades have witnessed several advances in micro-fabrication technologies and electronics, leading to the development of small, low-power devices for wireless sensing, data transmission, actuation, and medical implants. Unfortunately, the actual implementation of such devices in their respective environment has been hindered by the lack of scalable energy sources that are necessary to power and maintain them. Batteries, which remain the most commonly used power source, have not kept pace with the demands of these devices, especially in terms of energy density. In light of this challenge, the concept of vibratory energy harvesting has flourished in recent years as a possible alternative to power and maintain low-power electronics. While linear vibratory energy harvesters have received the majority of the literature's attention, a significant body of the current research activity is focused on the concept of purposeful inclusion of nonlinearities for broadband transduction. When compared to their linear resonant counterparts, nonlinear energy harvesters have a wider steady-state frequency bandwidth, leading to the common belief that they can be utilized to improve performance especially in random and non-stationary vibratory environments. This dissertation aims to critically investigate this belief by drawing a clearer picture of the role of nonlinearities in the transduction of energy harvesters and by defining the conditions under which nonlinearities can be used to enhance performance. To achieve this goal, the Thesis is divided into three parts. The first part investigates the performance of mono- and bi-stable energy harvesters under harmonic excitations and carries a detailed analysis of their relative performance. The second part investigates their response to broadband and narrowband random excitations and again analyzes their relative behavior. The third part exploits the super-harmonic resonance bands of bi-stable energy harvesters for the

  8. Effect of residual stress on modal patterns of MEMS vibratory gyroscope

    NASA Astrophysics Data System (ADS)

    Dutta, Shankar; Panchal, Abha; Kumar, Manoj; Pal, Ramjay; Bhan, R. K.

    2016-04-01

    Deep boron diffusion often induces residual stress in bulk micromachined MEMS structures, which may affect the MEMS devices operation. In this study, we studied the modal patterns of MEMS vibratory gyroscope under the residual stress (100 - 1000 MPa). Modal patterns and modal frequencies of the gyro are found to be dependent on the residual stress values. Without any residual stress, the modal frequencies drive and sense modeswere found to be 20.06 kHz and 20.36 kHz respectively. In presence of 450 MPa residual stress, the modal frequencies of the drive and sense modes were changed to 42.75 kHz and 43.07 kHz respectively.

  9. Accuracy of micro powder dosing via a vibratory sieve-chute system.

    PubMed

    Besenhard, M O; Faulhammer, E; Fathollahi, S; Reif, G; Calzolari, V; Biserni, S; Ferrari, A; Lawrence, S M; Llusa, M; Khinast, J G

    2015-08-01

    This paper describes a powder dosing system with a vibratory sieve mounted on a chute that doses particles into a capsule. Vertical vibration occurred with a broad range of frequencies and amplitudes. During dosing events, the fill weight was accurately recorded via a capacitance sensor, covering the capsules and making it possible to analyze filling characteristics, that is, the fill rates and their robustness. The range of frequencies and amplitudes was screened for settings that facilitated reasonable (no blocking, no spilling) fill rates for three lactose powders. The filling characteristics were studied within this operating space. The results reveal similar operating spaces for all investigated powders. The fill rate robustness varied distinctly in the operating space, which is of prime importance for selecting the settings for continuous feeding applications. In addition, we present accurate dosing studies utilizing the knowledge about the filling characteristics of each powder.

  10. A novel oscillation control for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation technique

    NASA Astrophysics Data System (ADS)

    Ma, Wei; Lin, Yiyu; Liu, Siqi; Zheng, Xudong; Jin, Zhonghe

    2017-02-01

    This paper reports a novel oscillation control algorithm for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation (MEAM) technique, which enhances the robustness against the frequency variation of the driving mode, compared to the conventional EAM (CEAM) scheme. In this approach, the carrier voltage exerted on the proof mass is frequency-modulated by the drive resonant frequency. Accordingly, the pick-up signal from the interface circuit involves a constant-frequency component that contains the amplitude and phase information of the vibration displacement. In other words, this informational detection signal is independent of the mechanical resonant frequency, which varies due to different batches, imprecise micro-fabrication and changing environmental temperature. In this paper, the automatic gain control loop together with the phase-locked loop are simultaneously analyzed using the averaging method and Routh-Hurwitz criterion, deriving the stability condition and the parameter optimization rules of the transient response. Then, a simulation model based on the real system is set up to evaluate the control algorithm. Further, the proposed MEAM method is tested using a field-programmable-gate-array based digital platform on a capacitive vibratory gyroscope. By optimizing the control parameters, the transient response of the drive amplitude reveals a settling time of 45.2 ms without overshoot, according well with the theoretical prediction and simulation results. The first measurement results show that the amplitude variance of the drive displacement is 12 ppm in an hour while the phase standard deviation is as low as 0.0004°. The mode-split gyroscope operating under atmospheric pressure demonstrates an outstanding performance. By virtue of the proposed MEAM method, the bias instability and angle random walk are measured to be 0.9° h-1 (improved by 2.4 times compared to the CEAM method) and 0.068° (√h)-1 (improved by 1.4 times

  11. An Intensified Vibratory Milling Process for Enhancing the Breakage Kinetics during the Preparation of Drug Nanosuspensions.

    PubMed

    Li, Meng; Zhang, Lu; Davé, Rajesh N; Bilgili, Ecevit

    2016-04-01

    As a drug-sparing approach in early development, vibratory milling has been used for the preparation of nanosuspensions of poorly water-soluble drugs. The aim of this study was to intensify this process through a systematic increase in vibration intensity and bead loading with the optimal bead size for faster production. Griseofulvin, a poorly water-soluble drug, was wet-milled using yttrium-stabilized zirconia beads with sizes ranging from 50 to 1500 μm at low power density (0.87 W/g). Then, this process was intensified with the optimal bead size by sequentially increasing vibration intensity and bead loading. Additional experiments with several bead sizes were performed at high power density (16 W/g), and the results were compared to those from wet stirred media milling. Laser diffraction, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and dissolution tests were used for characterization. Results for the low power density indicated 800 μm as the optimal bead size which led to a median size of 545 nm with more than 10% of the drug particles greater than 1.8 μm albeit the fastest breakage. An increase in either vibration intensity or bead loading resulted in faster breakage. The most intensified process led to 90% of the particles being smaller than 300 nm. At the high power intensity, 400 μm beads were optimal, which enhanced griseofulvin dissolution significantly and signified the importance of bead size in view of the power density. Only the optimally intensified vibratory milling led to a comparable nanosuspension to that prepared by the stirred media milling.

  12. Arthropod community structure on strip-mined lands in Ohio

    SciTech Connect

    Urbanek, R.P.

    1982-01-01

    During 1978-79, biomass, density, diversity, and taxonomic composition of above-ground, non-acarine arthropods were studied on newly reclaimed areas planted to grass-legumes (1-4 years after reclamation), older mined lands planted to crown vetch (Coronilla varia L.) and unmined old field habitat in Harrison County, Ohio. The reclaimed areas were rapidly colonized and productive. In the herbaceous layer, newly reclaimed areas had highest annual arthropod densities (1062.5 individuals/m/sup 2/) and biomass (553.6 mg/m/sup 2/). Larvae of alfalfa weevil (Hypera postica Gyllenhal) were major contributors to arthropod density in the herbaceous layer during spring 1978, accounting for 47.4% and 18.8% of individuals on the areas examined 1 and 3 years after reclamation, respectively. During September, grasshoppers (Acrididae) accounted for up to 70% of arthropod biomass in the herbaceous layer on newly reclaimed areas. A significant decline in arthropod biomass from 1 to 2 years after reclamation was due to a large decrease in weevil and spittlebug (Philaenus spumarius L.) populations, associated with a decline in yellow sweet clover (Melilotus officinalis (L.) Lam.) and red clover (Trifolium pratense L.). The crown vetch area supported low numbers and biomass of arthropods in the herbaceous layer but moderate to high numbers and biomass in the litter layer. Nematoceran larvae (Cecidomyiidae, Chironomidae) were abundant during May on the area examined 2 years after reclamation and comprised 73.5% of litter arthropod individuals. The unmined old field was generally richer (48.0% more morphotypes, 32.2% more families per sampling period) than the mined sites. On newly reclaimed areas richness in the herbaceous layer was positively related to biomass of clovers.

  13. Exoskeletons and economics: indoor arthropod diversity increases in affluent neighbourhoods

    PubMed Central

    Bertone, Matthew A.; Bayless, Keith M.; Dunn, Robert R.; Trautwein, Michelle D.

    2016-01-01

    In urban ecosystems, socioeconomics contribute to patterns of biodiversity. The ‘luxury effect’, in which wealthier neighbourhoods are more biologically diverse, has been observed for plants, birds, bats and lizards. Here, we used data from a survey of indoor arthropod diversity (defined throughout as family-level richness) from 50 urban houses and found that house size, surrounding vegetation, as well as mean neighbourhood income best predict the number of kinds of arthropods found indoors. Our finding, that homes in wealthier neighbourhoods host higher indoor arthropod diversity (consisting of primarily non-pest species), shows that the luxury effect can extend to the indoor environment. The effect of mean neighbourhood income on indoor arthropod diversity was particularly strong for individual houses that lacked high surrounding vegetation ground cover, suggesting that neighbourhood dynamics can compensate for local choices of homeowners. Our work suggests that the management of neighbourhoods and cities can have effects on biodiversity that can extend from trees and birds all the way to the arthropod life in bedrooms and basements. PMID:27484644

  14. Skimming the surface with Burgess Shale arthropod locomotion.

    PubMed

    Minter, Nicholas J; Mángano, M Gabriela; Caron, Jean-Bernard

    2012-04-22

    The first arthropod trackways are described from the Middle Cambrian Burgess Shale Formation of Canada. Trace fossils, including trackways, provide a rich source of biological and ecological information, including direct evidence of behaviour not commonly available from body fossils alone. The discovery of large arthropod trackways is unique for Burgess Shale-type deposits. Trackway dimensions and the requisite number of limbs are matched with the body plan of a tegopeltid arthropod. Tegopelte, one of the rarest Burgess Shale animals, is over twice the size of all other benthic arthropods known from this locality, and only its sister taxon, Saperion, from the Lower Cambrian Chengjiang biota of China, approaches a similar size. Biomechanical trackway analysis demonstrates that tegopeltids were capable of rapidly skimming across the seafloor and, in conjunction with the identification of gut diverticulae in Tegopelte, supports previous hypotheses on the locomotory capabilities and carnivorous mode of life of such arthropods. The trackways occur in the oldest part (Kicking Horse Shale Member) of the Burgess Shale Formation, which is also known for its scarce assemblage of soft-bodied organisms, and indicate at least intermittent oxygenated bottom waters and low sedimentation rates.

  15. The non-target impact of spinosyns on beneficial arthropods.

    PubMed

    Biondi, Antonio; Mommaerts, Veerle; Smagghe, Guy; Viñuela, Elisa; Zappalà, Lucia; Desneux, Nicolas

    2012-12-01

    Spinosyn-based products, mostly spinosad, have been widely recommended by extension specialists and agribusiness companies; consequently, they have been used to control various pests in many different cropping systems. Following the worldwide adoption of spinosad-based products for integrated and organic farming, an increasing number of ecotoxicological studies have been published in the past 10 years. These studies are primarily related to the risk assessment of spinosad towards beneficial arthropods. This review takes into account recent data with the aim of (i) highlighting potentially adverse effects of spinosyns on beneficial arthropods (and hence on ecosystem services that they provide in agroecosystems), (ii) clarifying the range of methods used to address spinosyn side effects on biocontrol agents and pollinators in order to provide new insights for the development of more accurate bioassays, (iii) identifying pitfalls when analysing laboratory results to assess field risks and (iv) gaining increasing knowledge on side effects when using spinosad for integrated pest management (IPM) programmes and organic farming. For the first time, a thorough review of possible risks of spinosad and novel spinosyns (such as spinetoram) to beneficial arthropods (notably natural enemies and pollinators) is provided. The acute lethal effect and multiple sublethal effects have been identified in almost all arthropod groups studied. This review will help to optimise the future use of spinosad and new spinosyns in IPM programmes and for organic farming, notably by preventing the possible side effects of spinosyns on beneficial arthropods.

  16. Arthropod abundance and diversity in transgenic Bt soybean.

    PubMed

    Yu, Huilin; Li, Yunhe; Li, Xiangju; Wu, Kongming

    2014-08-01

    Before the commercialization of any insect-resistant genetically modified crop, it must be subjected to a rigorous premarket risk assessment. Here, possible effects of growing of transgenic Cry1Ac soybean on arthropod communities under field conditions were assessed for 2 yr and quantified in terms of arthropod community indices including the Shannon-Weaver diversity index, richness index, and dominance index. Our results showed no significant differences of diversity, richness, or dominant indices for Bt soybean compared with the recipient cultivar, conventional soybean, or sprayed conventional soybean. Conventional soybean treatment with insecticide had an adverse effect on the arthropod community after spraying, but arthropod community diversity recovered quickly. Bt soybean had no negative effect on the dominant distribution of subcommunities, including sucking pests, other pests, predators, parasitoids, and others except for lepidopteran pests. The dominance distribution of lepidopteran pests decreased significantly in Bt soybean because of the significant decrease in the numbers of Spodoptera litura (F.) and Ascotis selenaria Schiffermüller et Denis compared with the recipient cultivar. Our results showed that there were no negative effects of Cry1Ac soybean on the arthropod community in soybean field plots in the short term.

  17. Exoskeletons and economics: indoor arthropod diversity increases in affluent neighbourhoods.

    PubMed

    Leong, Misha; Bertone, Matthew A; Bayless, Keith M; Dunn, Robert R; Trautwein, Michelle D

    2016-08-01

    In urban ecosystems, socioeconomics contribute to patterns of biodiversity. The 'luxury effect', in which wealthier neighbourhoods are more biologically diverse, has been observed for plants, birds, bats and lizards. Here, we used data from a survey of indoor arthropod diversity (defined throughout as family-level richness) from 50 urban houses and found that house size, surrounding vegetation, as well as mean neighbourhood income best predict the number of kinds of arthropods found indoors. Our finding, that homes in wealthier neighbourhoods host higher indoor arthropod diversity (consisting of primarily non-pest species), shows that the luxury effect can extend to the indoor environment. The effect of mean neighbourhood income on indoor arthropod diversity was particularly strong for individual houses that lacked high surrounding vegetation ground cover, suggesting that neighbourhood dynamics can compensate for local choices of homeowners. Our work suggests that the management of neighbourhoods and cities can have effects on biodiversity that can extend from trees and birds all the way to the arthropod life in bedrooms and basements.

  18. Sampling of Stochastic Input Parameters for Rockfall Calculations and for Structural Response Calculations Under Vibratory Ground Motion

    SciTech Connect

    M. Gross

    2004-09-01

    The purpose of this scientific analysis is to define the sampled values of stochastic (random) input parameters for (1) rockfall calculations in the lithophysal and nonlithophysal zones under vibratory ground motions, and (2) structural response calculations for the drip shield and waste package under vibratory ground motions. This analysis supplies: (1) Sampled values of ground motion time history and synthetic fracture pattern for analysis of rockfall in emplacement drifts in nonlithophysal rock (Section 6.3 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (2) Sampled values of ground motion time history and rock mechanical properties category for analysis of rockfall in emplacement drifts in lithophysal rock (Section 6.4 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (3) Sampled values of ground motion time history and metal to metal and metal to rock friction coefficient for analysis of waste package and drip shield damage to vibratory motion in ''Structural Calculations of Waste Package Exposed to Vibratory Ground Motion'' (BSC 2004 [DIRS 167083]) and in ''Structural Calculations of Drip Shield Exposed to Vibratory Ground Motion'' (BSC 2003 [DIRS 163425]). The sampled values are indices representing the number of ground motion time histories, number of fracture patterns and rock mass properties categories. These indices are translated into actual values within the respective analysis and model reports or calculations. This report identifies the uncertain parameters and documents the sampled values for these parameters. The sampled values are determined by GoldSim V6.04.007 [DIRS 151202] calculations using appropriate distribution types and parameter ranges. No software development or model development was required for these calculations. The calculation of the sampled values allows parameter uncertainty to be incorporated into the rockfall and structural response calculations that support development of the seismic scenario for the

  19. Modulatory Communication Signal Performance Is Associated with a Distinct Neurogenomic State in Honey Bees

    PubMed Central

    Schneider, Stanley S.; Southey, Bruce R.; Rodriguez-Zas, Sandra; Robinson, Gene E.

    2009-01-01

    Studies of animal communication systems have revealed that the perception of a salient signal can cause large-scale changes in brain gene expression, but little is known about how communication affects the neurogenomic state of the sender. We explored this issue by studying honey bees that produce a vibratory modulatory signal. We chose this system because it represents an extreme case of animal communication; some bees perform this behavior intensively, effectively acting as communication specialists. We show large differences in patterns of brain gene expression between individuals producing vibratory signal as compared with carefully matched non-senders. Some of the differentially regulated genes have previously been implicated in the performance of other motor activities, including courtship behavior in Drosophila melanogaster and Parkinson's Disease in humans. Our results demonstrate for the first time a neurogenomic brain state associated with sending a communication signal and provide suggestive glimpses of molecular roots for motor control. PMID:19693278

  20. Inbreeding and the evolution of sociality in arthropods.

    PubMed

    Tabadkani, Seyed Mohammad; Nozari, Jamasb; Lihoreau, Mathieu

    2012-10-01

    Animals have evolved strategies to optimally balance costs and benefits of inbreeding. In social species, these adaptations can have a considerable impact on the structure, the organization, and the functioning of groups. Here, we consider how selection for inbreeding avoidance fashions the social behavior of arthropods, a phylum exhibiting an unparalleled richness of social lifestyles. We first examine life histories and parental investment patterns determining whether individuals should actively avoid or prefer inbreeding. Next, we illustrate the diversity of inbreeding avoidance mechanisms in arthropods, from the dispersal of individuals to the rejection of kin during mate choice and the production of unisexual broods by females. Then, we address the particular case of haplodiploid insects. Finally, we discuss how inbreeding may drive and shape the evolution of arthropods societies along two theoretical pathways.

  1. Arthropod evolution and development: recent insights from chelicerates and myriapods.

    PubMed

    Leite, Daniel J; McGregor, Alistair P

    2016-08-01

    Research on arthropod genetics and development has added much to our understanding of animal evolution. While this work has mainly focused on insects, a growing body of research on the less studied myriapods and chelicerates is providing important new insights into arthropod genomics and development. Multiple chelicerate lineages have a high incidence of gene duplication, which is suggestive of large-scale and even whole genome duplications. Furthermore, the duplication and divergence of genes is associated with the evolution of appendage morphology and other phenotypes in chelicerates and myriapods. Recent studies of these arthropods have also helped to understand the evolution and development of segmented bodies. Further research on chelicerate and myriapod models as well as species from other orders of these subphyla has great potential to expand our understanding of the evolution of animal genomes and development.

  2. Inbreeding and the evolution of sociality in arthropods

    NASA Astrophysics Data System (ADS)

    Tabadkani, Seyed Mohammad; Nozari, Jamasb; Lihoreau, Mathieu

    2012-10-01

    Animals have evolved strategies to optimally balance costs and benefits of inbreeding. In social species, these adaptations can have a considerable impact on the structure, the organization, and the functioning of groups. Here, we consider how selection for inbreeding avoidance fashions the social behavior of arthropods, a phylum exhibiting an unparalleled richness of social lifestyles. We first examine life histories and parental investment patterns determining whether individuals should actively avoid or prefer inbreeding. Next, we illustrate the diversity of inbreeding avoidance mechanisms in arthropods, from the dispersal of individuals to the rejection of kin during mate choice and the production of unisexual broods by females. Then, we address the particular case of haplodiploid insects. Finally, we discuss how inbreeding may drive and shape the evolution of arthropods societies along two theoretical pathways.

  3. Arthropods and their products as aphrodisiacs--review of literature.

    PubMed

    Pajovic, B; Radosavljevic, M; Radunovic, M; Radojevic, N; Bjelogrlic, B

    2012-04-01

    After a short review of impotence, the definitions of erectants and aphrodisiacs are presented. The Authors propose division of arthropods according to the places of effect. The description of particular arthropods with their pictures and nomenclature, is followed by certain or probable mechanisms of achieving the aphrodisiac and sometimes toxic effect, that were available in the literature since 1929 till nowadays. We mention the most usual locations, mainly in Asia, where they are found and consumed, but also, we describe the manner of preparing and intake. The review includes the following arthropods: lobster, Arizona bark scorpion, deathstalker, banana spider, Mediterranean black widow, Burmeister's triatoma, giant water bug, diving-beetle, Korean bug, diaclina, flannel moth, Spanish fly, migratory locust, red wood ant and honeybee.

  4. Plant species loss decreases arthropod diversity and shifts trophic structure.

    PubMed

    Haddad, Nick M; Crutsinger, Gregory M; Gross, Kevin; Haarstad, John; Knops, Johannes M H; Tilman, David

    2009-10-01

    Plant diversity is predicted to be positively linked to the diversity of herbivores and predators in a foodweb. Yet, the relationship between plant and animal diversity is explained by a variety of competing hypotheses, with mixed empirical results for each hypothesis. We sampled arthropods for over a decade in an experiment that manipulated the number of grassland plant species. We found that herbivore and predator species richness were strongly, positively related to plant species richness, and that these relationships were caused by different mechanisms at herbivore and predator trophic levels. Even more dramatic was the threefold increase, from low- to high-plant species richness, in abundances of predatory and parasitoid arthropods relative to their herbivorous prey. Our results demonstrate that, over the long term, the loss of plant species propagates through food webs, greatly decreasing arthropod species richness, shifting a predator-dominated trophic structure to being herbivore dominated, and likely impacting ecosystem functioning and services.

  5. Predator localization by sensory hairs in free-swimming arthropods

    NASA Astrophysics Data System (ADS)

    Takagi, Daisuke; Hartline, Daniel K.

    2016-11-01

    Free-swimming arthropods such as copepods rely on minute deflections of cuticular hairs (or "setae") for local flow sensing that is needed to detect food and escape from predators. We present a simple hydrodynamic model to analyze how the location, speed, and size of an approaching distant predator can be inferred from local flow deformation alone. The model informs suitable strategies of escape from an imminent predatory attack. The sensory capabilities of aquatic arthropods could inspire the design of flow sensors in technological applications.

  6. Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load

    SciTech Connect

    Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.

    1988-11-01

    Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of /sup 3/H/sub 2/O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the /sup 3/H/sub 2/O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc.

  7. Characterizing the Effective Bandwidth of Nonlinear Vibratory Energy Harvesters Possessing Multiple Stable Equilibria

    NASA Astrophysics Data System (ADS)

    Panyam Mohan Ram, Meghashyam

    In the last few years, advances in micro-fabrication technologies have lead to the development of low-power electronic devices spanning critical fields related to sensing, data transmission, and medical implants. Unfortunately, effective utilization of these devices is currently hindered by their reliance on batteries. In many of these applications, batteries may not be a viable choice as they have a fixed storage capacity and need to be constantly replaced or recharged. In light of such challenges, several novel concepts for micro-power generation have been recently introduced to harness, otherwise, wasted ambient energy from the environment and maintain these low-power devices. Vibratory energy harvesting is one such concept which has received significant attention in recent years. While linear vibratory energy harvesters have been well studied in the literature and their performance metrics have been established, recent research has focused on deliberate introduction of stiffness nonlinearities into the design of these devices. It has been shown that, nonlinear energy harvesters have a wider steady-state frequency bandwidth as compared to their linear counterparts, leading to the premise that they can used to improve performance, and decrease sensitivity to variations in the design and excitation parameters. This dissertation aims to investigate this premise by developing an analytical framework to study the influence of stiffness nonlinearities on the performance and effective bandwidth of nonlinear vibratory energy harvesters. To achieve this goal, the dissertation is divided into three parts. The first part investigates the performance of bi-stable energy harvesters possessing a symmetric quartic potential energy function under harmonic excitations and carries out a detailed analysis to define their effective frequency bandwidth. The second part investigates the relative performance of mono- and bi-stable energy harvesters under optimal electric loading

  8. Investigating acoustic correlates of human vocal fold vibratory phase asymmetry through modeling and laryngeal high-speed videoendoscopya

    PubMed Central

    Mehta, Daryush D.; Zañartu, Matías; Quatieri, Thomas F.; Deliyski, Dimitar D.; Hillman, Robert E.

    2011-01-01

    Vocal fold vibratory asymmetry is often associated with inefficient sound production through its impact on source spectral tilt. This association is investigated in both a computational voice production model and a group of 47 human subjects. The model provides indirect control over the degree of left–right phase asymmetry within a nonlinear source–filter framework, and high-speed videoendoscopy provides in vivo measures of vocal fold vibratory asymmetry. Source spectral tilt measures are estimated from the inverse-filtered spectrum of the simulated and recorded radiated acoustic pressure. As expected, model simulations indicate that increasing left–right phase asymmetry induces steeper spectral tilt. Subject data, however, reveal that none of the vibratory asymmetry measures correlates with spectral tilt measures. Probing further into physiological correlates of spectral tilt that might be affected by asymmetry, the glottal area waveform is parameterized to obtain measures of the open phase (open/plateau quotient) and closing phase (speed/closing quotient). Subjects’ left–right phase asymmetry exhibits low, but statistically significant, correlations with speed quotient (r = 0.45) and closing quotient (r = −0.39). Results call for future studies into the effect of asymmetric vocal fold vibration on glottal airflow and the associated impact on voice source spectral properties and vocal efficiency. PMID:22225054

  9. Identification and experimental validation of damping ratios of different human body segments through anthropometric vibratory model in standing posture.

    PubMed

    Gupta, T C

    2007-08-01

    A 15 degrees of freedom lumped parameter vibratory model of human body is developed, for vertical mode vibrations, using anthropometric data of the 50th percentile US male. The mass and stiffness of various segments are determined from the elastic modulii of bones and tissues and from the anthropometric data available, assuming the shape of all the segments is ellipsoidal. The damping ratio of each segment is estimated on the basis of the physical structure of the body in a particular posture. Damping constants of various segments are calculated from these damping ratios. The human body is modeled as a linear spring-mass-damper system. The optimal values of the damping ratios of the body segments are estimated, for the 15 degrees of freedom model of the 50th percentile US male, by comparing the response of the model with the experimental response. Formulating a similar vibratory model of the 50th percentile Indian male and comparing the frequency response of the model with the experimental response of the same group of subjects validate the modeling procedure. A range of damping ratios has been considered to develop a vibratory model, which can predict the vertical harmonic response of the human body.

  10. 40 CFR 180.1124 - Arthropod pheromones; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Arthropod pheromones; exemption from... FOOD Exemptions From Tolerances § 180.1124 Arthropod pheromones; exemption from the requirement of a tolerance. Arthropod pheromones, as described in § 152.25(b) of this chapter, when used in retrievably...

  11. 40 CFR 180.1124 - Arthropod pheromones; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Arthropod pheromones; exemption from... FOOD Exemptions From Tolerances § 180.1124 Arthropod pheromones; exemption from the requirement of a tolerance. Arthropod pheromones, as described in § 152.25(b) of this chapter, when used in retrievably...

  12. An Approach to Mark Arthropods for Mark Capture Type Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of studies were conducted to validate methods for marking a wide variety of arthropods with inexpensive proteins for mark-capture dispersal research. The markers tested included egg albumin protein in chicken egg whites and casein protein in bovine milk. The first study qualified the effec...

  13. Diet-consumer nitrogen isotope fractionation for prolonged fasting arthropods.

    PubMed

    Mizota, Chitoshi; Yamanaka, Toshiro

    2011-12-01

    Nitrogen acquisition for cellular metabolism during diapause is a primary concern for herbivorous arthropods. Analyses of naturally occurring stable isotopes of nitrogen help elucidate the mechanism. Relevant articles have cited (58 times up to mid-June 2011) anomalously elevated δ(15)N (per mil deviation of (15)N/(14)N, relative to atmospheric nitrogen=0 ‰) values (diet-consumer nitrogen isotope fractionation; up to 12 ‰) for a prolonged fasting raspberry beetle (Byturus tomentosus Degeer (Coleoptera: Byturidae)), which feeds on red raspberries (Rubus idaeus: δ(15)N= ~ +2 ‰). Biologists have hypothesised that extensive recycling of amino acid nitrogen is responsible for the prolonged fasting. Since this hypothesis was proposed in 1995, scientists have integrated biochemical and molecular knowledge to support the mechanism of prolonged diapausing of animals. To test the validity of the recycling hypothesis, we analysed tissue nitrogen isotope ratios for four Japanese arthropods: the shield bug Parastrachia japonensis Scott (Hemiptera: Cydnidae), the burrower bug Canthophorus niveimarginatus Scott (Hemiptera: Cydnidae), leaf beetle Gastrophysa atrocyanea Motschulsky (Coleoptera: Chrysomelidae) and the Japanese oak silkworm Antheraea yamamai (Lepidoptera: Saturniidae), all of which fast for more than 6 months as part of their life-history strategy. Resulting diet-consumer nitrogen isotope discrimination during fasting ranged from 0 to 7‰, as in many commonly known terrestrial arthropods. We conclude that prolonged fasting of arthropods does not always result in anomalous diet-consumer nitrogen isotope fractionation, since the recycling process is closed or nearly closed with respect to nitrogen isotopes.

  14. Effects of a Major Tree Invader on Urban Woodland Arthropods.

    PubMed

    Buchholz, Sascha; Tietze, Hedwig; Kowarik, Ingo; Schirmel, Jens

    2015-01-01

    Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia), which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera); 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity.

  15. Arthropod Surveillance Programs: Basic Components, Strategies, and Analysis.

    PubMed

    Cohnstaedt, Lee W; Rochon, Kateryn; Duehl, Adrian J; Anderson, John F; Barrera, Roberto; Su, Nan-Yao; Gerry, Alec C; Obenauer, Peter J; Campbell, James F; Lysyk, Tim J; Allan, Sandra A

    2012-03-01

    Effective entomological surveillance planning stresses a careful consideration of methodology, trapping technologies, and analysis techniques. Herein, the basic principles and technological components of arthropod surveillance plans are described, as promoted in the symposium "Advancements in arthropod monitoring technology, techniques, and analysis" presented at the 58th annual meeting of the Entomological Society of America in San Diego, CA. Interdisciplinary examples of arthropod monitoring for urban, medical, and veterinary applications are reviewed. Arthropod surveillance consists of the three components: 1) sampling method, 2) trap technology, and 3) analysis technique. A sampling method consists of selecting the best device or collection technique for a specific location and sampling at the proper spatial distribution, optimal duration, and frequency to achieve the surveillance objective. Optimized sampling methods are discussed for several mosquito species (Diptera: Culicidae) and ticks (Acari: Ixodidae). The advantages and limitations of novel terrestrial and aerial insect traps, artificial pheromones and kairomones are presented for the capture of red flour beetle (Coleoptera: Tenebrionidae), small hive beetle (Coleoptera: Nitidulidae), bed bugs (Hemiptera: Cimicidae), and Culicoides (Diptera: Ceratopogonidae) respectively. After sampling, extrapolating real world population numbers from trap capture data are possible with the appropriate analysis techniques. Examples of this extrapolation and action thresholds are given for termites (Isoptera: Rhinotermitidae) and red flour beetles.

  16. Extreme Arthropods: Exploring Evolutionary Adaptations to Polar and Temperate Deserts

    ERIC Educational Resources Information Center

    Sandro, Luke; Constible, Juanita M.; Lee, Richard E., Jr.

    2007-01-01

    In this activity, Namib and Antarctic arthropods are used to illustrate several important biological principles. Among these are the key ideas that form follows function and that the environment drives evolution. In addition, students will discover that the climates of the Namib Desert and the Antarctic Peninsula are similar in several ways, and…

  17. Effects of a Major Tree Invader on Urban Woodland Arthropods

    PubMed Central

    2015-01-01

    Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia), which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera); 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity. PMID:26359665

  18. Evolution of the salivary apyrases of blood-feeding arthropods.

    PubMed

    Hughes, Austin L

    2013-09-15

    Phylogenetic analyses of three families of arthropod apyrases were used to reconstruct the evolutionary relationships of salivary-expressed apyrases, which have an anti-coagulant function in blood-feeding arthropods. Members of the 5'nucleotidase family were recruited for salivary expression in blood-feeding species at least five separate times in the history of arthropods, while members of the Cimex-type apyrase family have been recruited at least twice. In spite of these independent events of recruitment for salivary function, neither of these families showed evidence of convergent amino acid sequence evolution in salivary-expressed members. On the contrary, in the 5'-nucleotide family, salivary-expressed proteins conserved ancestral amino acid residues to a significantly greater extent than related proteins without salivary function, implying parallel evolution by conservation of ancestral characters. This unusual pattern of sequence evolution suggests the hypothesis that purifying selection favoring conservation of ancestral residues is particularly strong in salivary-expressed members of the 5'-nucleotidase family of arthropods because of constraints arising from expression within the vertebrate host.

  19. Sampling epigeal arthropods: A permanent, sheltered, closeable pitfall trapping station

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epigeal arthropods constitute the bulk of herbivore, predator, and decomposer species in soil and litter ecosystems. Being small and difficult to observe within these sometimes densely vegetated habitats, they are inherently difficult to sample quantitatively. Further, most methods have inherent tax...

  20. Genome-scale evidence of the nematode-arthropod clade

    PubMed Central

    Dopazo, Hernán; Dopazo, Joaquín

    2005-01-01

    Background The issue of whether coelomates form a single clade, the Coelomata, or whether all animals that moult an exoskeleton (such as the coelomate arthropods and the pseudocoelomate nematodes) form a distinct clade, the Ecdysozoa, is the most puzzling issue in animal systematics and a major open-ended subject in evolutionary biology. Previous single-gene and genome-scale analyses designed to resolve the issue have produced contradictory results. Here we present the first genome-scale phylogenetic evidence that strongly supports the Ecdysozoa hypothesis. Results Through the most extensive phylogenetic analysis carried out to date, the complete genomes of 11 eukaryotic species have been analyzed in order to find homologous sequences derived from 18 human chromosomes. Phylogenetic analysis of datasets showing an increased adjustment to equal evolutionary rates between nematode and arthropod sequences produced a gradual change from support for Coelomata to support for Ecdysozoa. Transition between topologies occurred when fast-evolving sequences of Caenorhabditis elegans were removed. When chordate, nematode and arthropod sequences were constrained to fit equal evolutionary rates, the Ecdysozoa topology was statistically accepted whereas Coelomata was rejected. Conclusions The reliability of a monophyletic group clustering arthropods and nematodes was unequivocally accepted in datasets where traces of the long-branch attraction effect were removed. This is the first phylogenomic evidence to strongly support the 'moulting clade' hypothesis. PMID:15892869

  1. Horizontal Gene Transfer Contributes to the Evolution of Arthropod Herbivory.

    PubMed

    Wybouw, Nicky; Pauchet, Yannick; Heckel, David G; Van Leeuwen, Thomas

    2016-06-27

    Within animals, evolutionary transition toward herbivory is severely limited by the hostile characteristics of plants. Arthropods have nonetheless counteracted many nutritional and defensive barriers imposed by plants and are currently considered as the most successful animal herbivores in terrestrial ecosystems. We gather a body of evidence showing that genomes of various plant feeding insects and mites possess genes whose presence can only be explained by horizontal gene transfer (HGT). HGT is the asexual transmission of genetic information between reproductively isolated species. Although HGT is known to have great adaptive significance in prokaryotes, its impact on eukaryotic evolution remains obscure. Here, we show that laterally transferred genes into arthropods underpin many adaptations to phytophagy, including efficient assimilation and detoxification of plant produced metabolites. Horizontally acquired genes and the traits they encode often functionally diversify within arthropod recipients, enabling the colonization of more host plant species and organs. We demonstrate that HGT can drive metazoan evolution by uncovering its prominent role in the adaptations of arthropods to exploit plants.

  2. [Arthropods as a cause of leisure sickness: ectoparasites].

    PubMed

    Kekker, Thecla A M

    2014-01-01

    Ectoparasites are a type of arthropod parasites that live on the body surface of their host. Many ectoparasitic infestations are associated with travel and leisure. Recognition of the specific symptoms of ectoparasitic infestations is important because of the hygienic and therapeutic consequences.

  3. Successive gain of insulator proteins in arthropod evolution.

    PubMed

    Heger, Peter; George, Rebecca; Wiehe, Thomas

    2013-10-01

    Alteration of regulatory DNA elements or their binding proteins may have drastic consequences for morphological evolution. Chromatin insulators are one example of such proteins and play a fundamental role in organizing gene expression. While a single insulator protein, CTCF (CCCTC-binding factor), is known in vertebrates, Drosophila melanogaster utilizes six additional factors. We studied the evolution of these proteins and show here that-in contrast to the bilaterian-wide distribution of CTCF-all other D. melanogaster insulators are restricted to arthropods. The full set is present exclusively in the genus Drosophila whereas only two insulators, Su(Hw) and CTCF, existed at the base of the arthropod clade and all additional factors have been acquired successively at later stages. Secondary loss of factors in some lineages further led to the presence of different insulator subsets in arthropods. Thus, the evolution of insulator proteins within arthropods is an ongoing and dynamic process that reshapes and supplements the ancient CTCF-based system common to bilaterians. Expansion of insulator systems may therefore be a general strategy to increase an organism's gene regulatory repertoire and its potential for morphological plasticity.

  4. Book Review: Bioassays with Arthropods: 2nd Edition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technical book "Bioassays with Arthropods: 2nd Edition" (2007. Jacqueline L. Robertson, Robert M. Russell, Haiganoush K, Preisler and N. E. Nevin, Eds. CRC Press, Boca Raton, FL, 224 pp.) was reviewed for the scientific readership of the peer-reviewed publication Journal of Economic Entomology. ...

  5. Arthropod Surveillance Programs: Basic Components, Strategies, and Analysis

    PubMed Central

    Rochon, Kateryn; Duehl, Adrian J.; Anderson, John F.; Barrera, Roberto; Su, Nan-Yao; Gerry, Alec C.; Obenauer, Peter J.; Campbell, James F.; Lysyk, Tim J.; Allan, Sandra A.

    2015-01-01

    Effective entomological surveillance planning stresses a careful consideration of methodology, trapping technologies, and analysis techniques. Herein, the basic principles and technological components of arthropod surveillance plans are described, as promoted in the symposium “Advancements in arthropod monitoring technology, techniques, and analysis” presented at the 58th annual meeting of the Entomological Society of America in San Diego, CA. Interdisciplinary examples of arthropod monitoring for urban, medical, and veterinary applications are reviewed. Arthropod surveillance consists of the three components: 1) sampling method, 2) trap technology, and 3) analysis technique. A sampling method consists of selecting the best device or collection technique for a specific location and sampling at the proper spatial distribution, optimal duration, and frequency to achieve the surveillance objective. Optimized sampling methods are discussed for several mosquito species (Diptera: Culicidae) and ticks (Acari: Ixodidae). The advantages and limitations of novel terrestrial and aerial insect traps, artificial pheromones and kairomones are presented for the capture of red flour beetle (Coleoptera: Tenebrionidae), small hive beetle (Coleoptera: Nitidulidae), bed bugs (Hemiptera: Cimicidae), and Culicoides (Diptera: Ceratopogonidae) respectively. After sampling, extrapolating real world population numbers from trap capture data are possible with the appropriate analysis techniques. Examples of this extrapolation and action thresholds are given for termites (Isoptera: Rhinotermitidae) and red flour beetles. PMID:26543242

  6. Bioactivity of cedarwood oil and cedrol against arthropod pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heartwood samples from Juniperus virginiana, were extracted with liquid carbon dioxide and the bioactivity of carbon dioxide-derived cedarwood oil (CWO) towards several species of arthropods was investigated. Repellency or toxicity was tested for ants, ticks, and cockroaches. Ants in an outdoor bi...

  7. Evaluation of insecticides on cotton fleahopper and beneficial arthropod populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was initiated in 2009 concurrently with a cotton fleahopper insecticide efficacy trial to determine which products were the most and least detrimental to arthropod natural enemies. Insecticides evaluated included Bidrin 8E, Bidrin XP, Centric 40WG, Discipline 2EC, Intruder 70WP, Orthe...

  8. Fossils and the Evolution of the Arthropod Brain.

    PubMed

    Strausfeld, Nicholas J; Ma, Xiaoya; Edgecombe, Gregory D

    2016-10-24

    The discovery of fossilized brains and ventral nerve cords in lower and mid-Cambrian arthropods has led to crucial insights about the evolution of their central nervous system, the segmental identity of head appendages and the early evolution of eyes and their underlying visual systems. Fundamental ground patterns of lower Cambrian arthropod brains and nervous systems correspond to the ground patterns of brains and nervous systems belonging to three of four major extant panarthropod lineages. These findings demonstrate the evolutionary stability of early neural arrangements over an immense time span. Here, we put these fossil discoveries in the context of evidence from cladistics, as well as developmental and comparative neuroanatomy, which together suggest that despite many evolved modifications of neuropil centers within arthropod brains and ganglia, highly conserved arrangements have been retained. Recent phylogenies of the arthropods, based on fossil and molecular evidence, and estimates of divergence dates, suggest that neural ground patterns characterizing onychophorans, chelicerates and mandibulates are likely to have diverged between the terminal Ediacaran and earliest Cambrian, heralding the exuberant diversification of body forms that account for the Cambrian Explosion.

  9. Horizontal Gene Transfer Contributes to the Evolution of Arthropod Herbivory

    PubMed Central

    Wybouw, Nicky; Pauchet, Yannick; Heckel, David G.; Van Leeuwen, Thomas

    2016-01-01

    Within animals, evolutionary transition toward herbivory is severely limited by the hostile characteristics of plants. Arthropods have nonetheless counteracted many nutritional and defensive barriers imposed by plants and are currently considered as the most successful animal herbivores in terrestrial ecosystems. We gather a body of evidence showing that genomes of various plant feeding insects and mites possess genes whose presence can only be explained by horizontal gene transfer (HGT). HGT is the asexual transmission of genetic information between reproductively isolated species. Although HGT is known to have great adaptive significance in prokaryotes, its impact on eukaryotic evolution remains obscure. Here, we show that laterally transferred genes into arthropods underpin many adaptations to phytophagy, including efficient assimilation and detoxification of plant produced metabolites. Horizontally acquired genes and the traits they encode often functionally diversify within arthropod recipients, enabling the colonization of more host plant species and organs. We demonstrate that HGT can drive metazoan evolution by uncovering its prominent role in the adaptations of arthropods to exploit plants. PMID:27307274

  10. Two Novel Measurements for the Drive-Mode Resonant Frequency of a Micromachined Vibratory Gyroscope

    PubMed Central

    Wang, Ancheng; Hu, Xiaoping; Luo, Bing; Jiang, Mingming; He, Xiaofeng; Tang, Kanghua

    2013-01-01

    To investigate the drive-mode resonance frequency of a micromachined vibratory gyroscope (MVG), one needs to measure it accurately and efficiently. The conventional approach to measure the resonant frequency is by performing a sweep frequency test and spectrum analysis. The method is time-consuming and inconvenient because of the requirements of many test points, a lot of data storage and off-line analyses. In this paper, we propose two novel measurement methods, the search method and track method, respectively. The former is based on the magnitude-frequency characteristics of the drive mode, utilizing a one-dimensional search technique. The latter is based on the phase-frequency characteristics, applying a feedback control loop. Their performances in precision, noise resistivity and efficiency are analyzed through detailed simulations. A test system is implemented based on a field programmable gate array (FPGA) and experiments are carried out. By comparing with the common approach, feasibility and superiorities of the proposed methods are validated. In particular, significant efficiency improvements are achieved whereby the conventional frequency method consumes nearly 5,000 s to finish a measurement, while only 5 s is needed for the track method and 1 s for the search method. PMID:24256977

  11. Modeling and analysis of mechanical Quality factor of the resonator for cylinder vibratory gyroscope

    NASA Astrophysics Data System (ADS)

    Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng

    2017-01-01

    Mechanical Quality factor( Q factor) of the resonator is an important parameter for the cylinder vibratory gyroscope(CVG). Traditional analytical methods mainly focus on a partial energy loss during the vibration process of the CVG resonator, thus are not accurate for the mechanical Q factor prediction. Therefore an integrated model including air damping loss, surface defect loss, support loss, thermoelastic damping loss and internal friction loss is proposed to obtain the mechanical Q factor of the CVG resonator. Based on structural dynamics and energy dissipation analysis, the contribution of each energy loss to the total mechanical Q factor is quantificationally analyzed. For the resonator with radius ranging from 10 mm to 20 mm, its mechanical Q factor is mainly related to the support loss, thermoelastic damping loss and internal friction loss, which are fundamentally determined by the geometric sizes and material properties of the resonator. In addition, resonators made of alloy 3J53 (Ni42CrTiAl), with different sizes, were experimentally fabricated to test the mechanical Q factor. The theoretical model is well verified by the experimental data, thus provides an effective theoretical method to design and predict the mechanical Q factor of the CVG resonator.

  12. Programmable Mechanobioreactor for Exploration of the Effects of Periodic Vibratory Stimulus on Mesenchymal Stem Cell Differentiation

    PubMed Central

    Cashion, Avery T.; Caballero, Montserrat; Halevi, Alexandra; Pappa, Andrew; Dennis, Robert G.

    2014-01-01

    Abstract A programmable bioreactor using a voice-coil actuator was developed to enable research on the effects of periodic vibratory stimulus on human and porcine mesenchymal stem cells (MSCs). We hypothesized that low frequency vibrations would result in a cartilage phenotype and higher frequency vibrations would result in a bone phenotype. The mechanical stimulation protocol is adjusted from a computer external to the incubator via a USB cable. Once programmed, the embedded microprocessor and sensor system on the bioreactor execute the protocol independent of the computer. In each test, a sinusoidal stimulus was applied to a culture plate in 1-min intervals with a 15-min rest following each, for a total of 15 h per day for 10 days. Frequencies of 1 and 100 Hz were applied to cultures of both human and porcine umbilical cord–derived MSCs. Chondrogenesis was determined by Alcian blue staining for glycosaminoglycans and an increased differentiation index (ratio of mRNA for collagen II and collagen I). Osteogenic differentiation was indicated with Alizarin red for calcium staining and increased bone morphogenetic protein 2 mRNA. One-hertz stimulation resulted in a cartilage phenotype for both human and porcine MSCs, while 100-Hz stimulation resulted in a bone phenotype. PMID:24570842

  13. Development of a lateral velocity-controlled MEMS vibratory gyroscope and its performance test

    NASA Astrophysics Data System (ADS)

    Sung, Woon-Tahk; Sung, Sangkyung; Lee, June-Young; Kang, Taesam; Lee, Young Jae; Lee, Jang Gyu

    2008-05-01

    The objective of this paper is to present a velocity-controlled vibratory MEMS gyroscope that achieves consistent output characteristics in the lateral driving dynamics of the system. Through a systematic automatic gain control loop design process, the driving mode dynamics of the gyroscope is first transformed to take account of the velocity envelope; a reference tracking integral control is then employed. For stabilized loop construction, a mathematical development and stability analysis of the feedback loop is presented, which is followed by numerical simulation using practical sensor parameters. The mechanical structure was fabricated using the conventional deep reactive ion etching process and the anodic wafer bonding method. Vacuum-packaged devices were used for the resonant gyroscope operation. An essential fabrication process for realizing the electrical connection through a thick glass substrate was possible by applying a sandblasting process and spin coating process of conductive epoxy. Finally, loop simulation and experimental results verified that the amplitude-controlled property in the driving loop is preserved under the system parameter variation which resulted in enhanced gyroscope output performance in comparison with other driving schemes.

  14. Nonlinear stochastic controllers for power-flow-constrained vibratory energy harvesters

    NASA Astrophysics Data System (ADS)

    Cassidy, Ian L.; Scruggs, Jeffrey T.

    2013-06-01

    This study addresses the formulation of nonlinear feedback controllers for stochastically excited vibratory energy harvesters. Maximizing the average power generated from such systems requires the transducer current to be regulated using a bi-directional power electronic converter. There are many applications where the implementation of these types of converters is infeasible, due to the higher parasitic losses they must sustain. If instead the transducer current is regulated using a converter capable of single-directional power-flow, then these parasitic losses can be reduced significantly. However, the constraint on the power-flow directionality restricts the domain of feasible feedback laws. The only feasible linear feedback law imposes a static relationship between current and voltage, i.e., a static admittance. In stochastic response, the power generation performance can be enhanced significantly beyond that of the optimal static admittance, using nonlinear feedback. In this paper, a general approach to nonlinear control synthesis for power-flow-constrained energy harvesters is presented, which is analytically guaranteed to outperform the optimal static admittance in stationary stochastic response. Simulation results are presented for a single-degree-of-freedom resonant oscillator with an electromagnetic transducer, as well as for a piezoelectric bimorph cantilever beam.

  15. Electrophysiological responses to vibratory stimulation in the brainstem of the tadpole

    NASA Astrophysics Data System (ADS)

    Simmons, Andrea M.; Two, Aimee; Horowitz, Seth S.

    2005-04-01

    Maturation of saccular responses to vibratory stimuli in 3 axes was measured in the Rana catesbeiana tadpole across metamorphic development. The animal was suspended in a water-filled circular aluminum dish attached to a shaker table system consisting of 5 vibration exciters producing sinusoidal, translational movements in the x, y, and z planes. Multi-unit responses were recorded from the medulla with tungsten or platinum-iridium microelectrodes. Recording sites were electrolytically marked to verify electrode placement. Data were collected from 16 animals in late larval stages, before onset of metamorphic climax. Most recording sites were sensitive to vibrations in the z (vertical) direction, indicating a saccular origin of the response. Vibration frequencies of 40 Hz or below produced the strongest activity, with thresholds below a displacement of 10 nm. Secondary sensitivity was sometimes observed to either x (body-longitudinal) or y (body-lateral) directions of movement. Although some sites produced strong phase-locked activity to the stimulation, others showed more diverse temporal patterns of response. Active recording sites were found in the medial vestibular nucleus, lateral vestibular nucleus, reticular gray, and dorsal superior olivary nucleus. These data suggest that tadpole saccule is functional early in larval development, with sensitivity similar to that observed in adult bullfrogs.

  16. Leaf litter arthropod responses to tropical forest restoration.

    PubMed

    Cole, Rebecca J; Holl, Karen D; Zahawi, Rakan A; Wickey, Philipp; Townsend, Alan R

    2016-08-01

    Soil and litter arthropods represent a large proportion of tropical biodiversity and perform important ecosystem functions, but little is known about the efficacy of different tropical forest restoration strategies in facilitating their recovery in degraded habitats. We sampled arthropods in four 7- to 8-year-old restoration treatments and in nearby reference forests. Sampling was conducted during the wet and dry seasons using extractions from litter and pitfall samples. Restoration treatments were replicated in 50 × 50-m plots in four former pasture sites in southern Costa Rica: plantation - trees planted throughout the plot; applied nucleation/islands - trees planted in patches of different sizes; and natural regeneration - no tree planting. Arthropod abundance, measures of richness and diversity, and a number of functional groups were greater in the island treatment than in natural regeneration or plantation treatments and, in many cases, were similar to reference forest. Litter and pitfall morphospecies and functional group composition in all three restoration treatments were significantly different than reference sites, but island and plantation treatments showed more recovery than natural regeneration. Abundance and functional group diversity showed a much greater degree of recovery than community composition. Synthesis and applications: The less resource-intensive restoration strategy of planting tree islands was more effective than tree plantations in restoring arthropod abundance, richness, and functional diversity. None of the restoration strategies, however, resulted in similar community composition as reference forest after 8 years of recovery, highlighting the slow rate of recovery of arthropod communities after disturbance, and underscoring the importance of conservation of remnant forests in fragmented landscapes.

  17. Influence of crop management practices on bean foliage arthropods.

    PubMed

    Pereira, J L; Picanço, M C; Pereira, E J G; Silva, A A; Jakelaitis, A; Pereira, R R; Xavier, V M

    2010-12-01

    Crop management practices can affect the population of phytophagous pest species and beneficial arthropods with consequences for integrated pest management. In this study, we determined the effect of no-tillage and crop residue management on the arthropod community associated with the canopy of common beans (Phaseolus vulgaris L.). Abundance and species composition of herbivorous, detritivorous, predaceous and parasitoid arthropods were recorded during the growing seasons of 2003 and 2004 in Coimbra County, Minas Gerais State, Brazil. Arthropod diversity and guild composition were similar among crop management systems, but their abundance was higher under no-tillage relative to conventional cultivation and where residues from the preceding crop were maintained in the field. Thirty-four arthropod species were recorded, and those most representative of the impact of the crop management practices were Hypogastrura springtails, Empoasca kraemeri and Circulifer leafhoppers, and Solenopsis ants. The infestation levels of major insect-pests, especially leafhoppers (Hemiptera: Cicadellidae), was on average seven-fold lower under no-tillage with retention of crop residues relative to the conventional system with removal of residues, whereas the abundance of predatory ants (Hymenoptera: Formicidae) and springtails (Collembola: Hypogastruridae) were, respectively, about seven- and 15-fold higher in that treatment. Importantly, a significant trophic interaction among crop residues, detritivores, predators and herbivores was observed. Plots managed with no-tillage and retention of crop residues had the highest bean yield, while those with conventional cultivation and removal of the crop residues yielded significantly less beans. This research shows that cropping systems that include zero tillage and crop residue retention can reduce infestation by foliar insect-pests and increase abundance of predators and detritivores, thus having direct consequences for insect pest management.

  18. [Exposure degree of important non-target arthropods to Cry2Aa in Bt rice fields].

    PubMed

    Zhang, Qing-Ling; Li, Yun-He; Hua, Hong-Xia; Yang, Chang-Ju; Wu, Hong-Jin; Peng, Yu-Fa

    2013-06-01

    Based on the principle of "risk = hazard x exposure", the selected representative nontarget organisms in the assessment of the potential effects of insect-resistant genetically modified (GM) crops on non-target arthropods in laboratory are generally the arthropod species highly exposed to the insecticidal proteins expressed by the GM crops in farmland ecosystem. In order to understand the exposure degree of the important arthropod species to Cry proteins in Bt rice fields, and to select the appropriate non-target arthropods in the risk assessment of insect-resistant GM crops, the enzyme-linked immunosorbent assay (ELISA) was conducted to measure the Cry2Aa protein concentration in the arthropods collected from the cry2Aa rice fields at different rice growth stages. The results showed that there was a significant difference in the Cry2Aa content protein concentration in different arthropod species. Some species did not contain Cry2Aa protein, while some species contained larger amounts of Cry2Aa protein. Relative to the arthropods colleted after rice anthesis, the arthropods colleted in rice anthesis contained relative higher concentrations of Cry2Aa protein, especially for the predacious arthropods. No Cry proteins were detected in parasitic arthropods. This study provided references for the laboratory assessment of the effects of GM rice on nontarget arthropods.

  19. [Responses of ground arthropod functional groups to the enclosure of grazing grassland in desert steppe].

    PubMed

    Liu, Ren-tao; Li, Xue-bin; Xin, Ming; Ma, Lin; Liu, Kai

    2011-08-01

    With the support of the National Resources Monitoring Station in Yanchi County of Ningxia, an investigation was conducted on the ground arthropods, vegetations, and soil properties in the enclosed and un-enclosed grazing grassland in desert steppe. In the meantime, the functional groups of ground arthropods were classified according to their feeding habits. The ground arthropods in the desert steppe could be classified into four functional groups, i.e., predatory, phytophagous, saprophagous, and omnivorous, among which, predatory and phytophagous groups were dominant in quantity, and phytophagous and saprophagous groups were predominant in biomass, implying that the ground arthropod in desert steppe was mainly characterized by phytophagous arthropods. Enclosure increased the individual and group number of predatory, phytophagous, and omnivorous arthropods as well as the biomass of predatory and omnivorous arthropods, and enhanced the biodiversity of predatory and phytophagous arthropods, which was closely correlated with the vegetation recovery and soil environment improvement, and demonstrated that the enclosure of grazing grassland increased the diversity and complexity of ground arthropod functional groups in desert steppe. Nevertheless, the individual number and biomass of saprophagous arthropods decreased after the enclosure, reflecting the dependence of these arthropods on grazing grassland.

  20. Arthropod food webs become increasingly lipid-limited at higher trophic levels.

    PubMed

    Wilder, Shawn M; Norris, Michael; Lee, Raymond W; Raubenheimer, David; Simpson, Stephen J

    2013-07-01

    Understanding why food chains are relatively short in length has been an area of research and debate for decades. We tested if progressive changes in the nutritional content of arthropods with trophic position limit the availability of a key nutrient, lipid, for carnivores. Arthropods at higher trophic levels had progressively less lipid and more protein in their bodies compared with arthropods at lower trophic levels. The nutrients present in arthropod bodies were directly related to the nutrients that predators extracted when feeding on those arthropods. As a consequence, nutrient assimilation shifted from lipid-biased to protein-biased as arthropods ascended trophic levels from herbivores to secondary carnivores. Successive changes in the nutritional consequences of predation may ultimately set an upper limit on the number of trophic levels in arthropod communities. Further work is needed to examine the influence of lipid and other nutrients on food web traits in a range of ecosystems.

  1. Relative performance of a vibratory energy harvester in mono- and bi-stable potentials

    NASA Astrophysics Data System (ADS)

    Masana, Ravindra; Daqaq, Mohammed F.

    2011-11-01

    Motivated by the need for broadband vibratory energy harvesting, many research studies have recently proposed energy harvesters with nonlinear characteristics. Based on the shape of their potential function, such devices are classified as either mono- or bi-stable energy harvesters. This paper aims to investigate the relative performance of these two classes under similar excitations and electric loading conditions. To achieve this goal, an energy harvester consisting of a clamped-clamped piezoelectric beam bi-morph is considered. The shape of the harvester's potential function is altered by applying a static compressive axial load at one end of the beam. This permits operation in the mono-stable (pre-buckling) and bi-stable (post-buckling) configurations. For the purpose of performance comparison, the axial load is used to tune the harvester's oscillation frequencies around the static equilibria such that they have equal values in the mono- and bi-stable configurations. The harvester is subjected to harmonic base excitations of different magnitudes and a slowly varying frequency spanning a wide band around the tuned oscillation frequency. The output voltage measured across a purely resistive load is compared over the frequency range considered. Two cases are discussed; the first compares the performance when the bi-stable harvester has deep potential wells, while the second treats a bi-stable harvester with shallow wells. Both numerical and experimental results demonstrate the essential role that the potential shape plays in conjunction with the base acceleration to determine whether the bi-stable harvester can outperform the mono-stable one and for what range of frequencies. Results also illustrate that, for a bi-stable harvester with shallow potential wells, super-harmonic resonances can activate the inter-well dynamics even for a small base acceleration, thereby producing large voltages in the low frequency range.

  2. Two-time-scale analysis of a ring of coupled vibratory gyroscopes.

    PubMed

    Vu, Huy; Palacios, Antonio; In, Visarath; Longhini, Patrick; Neff, Joseph D

    2010-03-01

    A coupling inertial navigation sensor (INS) system may proven to be beneficial for performance improvement, especially when the manufacturing yield is very low for meeting the specification requirement of various applications. For instance, navigation grade sensors using the current fabrication process would yield one in every few hundreds which would meet the specification requirement after careful selection process and testing. We propose to couple these sensors by putting together the "low grade" sensors in a small array of particular coupling topology to explore their stability properties of known parameter variations produced during the fabrication process. By coupling them in a particular way one may improve the system stability to effect the performance of the INS. Thus in this work we present a coupled inertial navigation sensor (CINS) system consisting of a ring of vibratory gyroscopes coupled through the driving axis of each individual gyroscope. Numerical simulations show that under certain conditions, which depend mainly on the coupling strength, the dynamics of the individual gyroscopes will synchronize with one another. The same simulations also show an optimal network size at which the effects of noise can be minimized, thus yielding a reduction in the phase drift. We quantify the reduction in the phase drift and perform an asymptotic analysis of the motion equations to determine the conditions for the existence of the synchronized state. The analysis yields an analytical expression for a critical coupling strength at which different nonzero mean oscillations merge in a pitchfork bifurcation; passed this critical coupling the synchronized state becomes locally asymptotically stable. The Liapunov-Schmidt (LS) reduction is then applied to determine the stability properties of the synchronized solution and to further show that the pitchfork bifurcation can be subcritical or supercritical, depending on the coefficient of the nonlinear terms in the

  3. Effect of axial force on the performance of micromachined vibratory rate gyroscopes.

    PubMed

    Hou, Zhanqiang; Xiao, Dingbang; Wu, Xuezhong; Dong, Peitao; Chen, Zhihua; Niu, Zhengyi; Zhang, Xu

    2011-01-01

    It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F) beam and the other one was suspended with a clamped-clamped (C-C) beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF) due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

  4. Personal Protection Measures Against Mosquitoes, Ticks, and Other Arthropods.

    PubMed

    Alpern, Jonathan D; Dunlop, Stephen J; Dolan, Benjamin J; Stauffer, William M; Boulware, David R

    2016-03-01

    Arthropod-associated diseases are a major cause of morbidity among travelers. Obtaining a detailed travel itinerary and understanding traveler-specific and destination-specific risk factors can help mitigate the risk of vector-borne diseases. DEET, picaridin, PMD, and IR3535 are insect repellents that offer sufficient protection against arthropod bites. IR3535 does not provide adequate protection against Anopheles mosquitoes, and should be avoided in malaria-endemic regions. General protective measures, such as bite avoidance, protective clothing, insecticide-treated bed nets, and insecticide-treated clothing, should be recommended, especially in malaria-endemic areas. Spatial repellents may prevent nuisance biting, but have not been shown to prevent against vector-borne disease.

  5. Pathogen-mediated manipulation of arthropod microbiota to promote infection

    PubMed Central

    Abraham, Nabil M.; Liu, Lei; Jutras, Brandon Lyon; Yadav, Akhilesh K.; Narasimhan, Sukanya; Gopalakrishnan, Vissagan; Ansari, Juliana M.; Jefferson, Kimberly K.; Cava, Felipe; Jacobs-Wagner, Christine; Fikrig, Erol

    2017-01-01

    Arthropods transmit diverse infectious agents; however, the ways microbes influence their vector to enhance colonization are poorly understood. Ixodes scapularis ticks harbor numerous human pathogens, including Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis. We now demonstrate that A. phagocytophilum modifies the I. scapularis microbiota to more efficiently infect the tick. A. phagocytophilum induces ticks to express Ixodes scapularis antifreeze glycoprotein (iafgp), which encodes a protein with several properties, including the ability to alter bacterial biofilm formation. IAFGP thereby perturbs the tick gut microbiota, which influences the integrity of the peritrophic matrix and gut barrier—critical obstacles for Anaplasma colonization. Mechanistically, IAFGP binds the terminal d-alanine residue of the pentapeptide chain of bacterial peptidoglycan, resulting in altered permeability and the capacity of bacteria to form biofilms. These data elucidate the molecular mechanisms by which a human pathogen appropriates an arthropod antibacterial protein to alter the gut microbiota and more effectively colonize the vector. PMID:28096373

  6. Survey of the arthropods on jojoba (Simmondsia chinensis)

    SciTech Connect

    Pinto, J.D.; Frommer, S.I.

    1980-02-01

    Simmondsia chinensis (jojoba), a plant native to southwestern North America, has become of economic interest due to the various industrial uses of the unique liquid wax found in its seeds. In a survey of arthropods associated with sylvatic jojoba in California and Arizona, we collected 106 species of insects and mites. Of these, 50 are phytophagous, 29 are parasitic, and 18 are predaceous. Most of the phytophagous species are also known to feed on plants other than jojoba; several of these are notorious generalists. The bionomics of the 4 commonest phytophagous species, Asphondylia n. sp. (Cecidomyiidae), Epinotia kasloana (Olethreutidae), Periploca n. sp. (Walshiidae), and Incisitermes fruticavus (Kalotermitidae) are summarized briefly. None of the phytophagous species were observed to cause extensive damage to sylvatic jojoba. The numerous parasitic and predaceous arthropods probably account for the natural control of many of them. These relationships should be kept in mind when planning future commercial plantations of jojoba.

  7. Arthropod-borne diseases associated with political and social disorder.

    PubMed

    Brouqui, Philippe

    2011-01-01

    The living conditions and the crowded situations of the homeless, war refugees, or victims of a natural disaster provide ideal conditions for the spread of lice, fleas, ticks, flies and mites. The consequence of arthropod infestation in these situations is underestimated. Along with louse-borne infections such as typhus, trench fever, and relapsing fever, the relationship between Acinetobacter spp.-infected lice and bacteremia in the homeless is not clear. Murine typhus, tungiasis, and myiasis are likely underestimated, and there has been a reemergence of bed bugs. Attempted eradication of the body louse, despite specific measures, has been disappointing, and infections with Bartonella quintana continue to be reported. The efficacy of ivermectin in eradicating the human body louse, although the effect is not sustained, might provide new therapeutic approaches. Arthropod-borne diseases continue to emerge within the deprived population. Public health programs should be engaged rapidly to control these pests and reduce the incidence of these transmissible diseases.

  8. Passive aerial dispersal of insects and other arthropods

    NASA Astrophysics Data System (ADS)

    Miller, Laura

    2016-11-01

    One of the defining features of the aerial dispersal of tiny organisms is the ability to overcome negative buoyancy. This can be accomplished by dispersing in the right wind conditions (e.g. an updraft) or by active flight or active release. Once in the air, draggy structures, such as the draglines of spiders or bristled wings of tiny insects, can reduce the settling velocity and extend the time of transport. Purely passive mechanisms allow spiders and other arthropods to drift on strands of silk to heights of 14,000 m and distances of hundreds of miles. Similarly, tiny insects like thrips and parasitoid wasps can travel distances of thousands to tens of thousands of meters, possibly using a combination of periods of active and passive flight. In this presentation, we used the immersed boundary method to quantify settling velocities and transport dynamics of parachuting insects and other arthropods within a quiescent fluid, a uniform updraft, and eddies.

  9. Diversity of plant evolutionary lineages promotes arthropod diversity.

    PubMed

    Dinnage, Russell; Cadotte, Marc W; Haddad, Nick M; Crutsinger, Gregory M; Tilman, David

    2012-11-01

    Large-scale habitat destruction and climate change result in the non-random loss of evolutionary lineages, reducing the amount of evolutionary history represented in ecological communities. Yet, we have limited understanding of the consequences of evolutionary history on the structure of food webs and the services provided by biological communities. Drawing on 11 years of data from a long-term plant diversity experiment, we show that evolutionary history of plant communities - measured as phylogenetic diversity - strongly predicts diversity and abundance of herbivorous and predatory arthropods. Effects of plant species richness on arthropods become stronger when phylogenetic diversity is high. Plant phylogenetic diversity explains predator and parasitoid richness as strongly as it does herbivore richness. Our findings indicate that accounting for evolutionary relationships is critical to understanding the severity of species loss for food webs and ecosystems, and for developing conservation and restoration policies.

  10. The relationships between residual stress relaxation and texture development in AZ31 Mg alloys via the vibratory stress relief technique

    SciTech Connect

    Wang, Jia-Siang; Hsieh, Chih-Chun; Lai, Hsuan-Han; Kuo, Che-Wei; Wu, Paxon Ti-Yuan; Wu, Weite

    2015-01-15

    A systematic study of residual stress relaxation and the texture evolution of cold-rolled AZ31 Mg alloys using the vibratory stress relief technique with a simple cantilever beam vibration system was performed using a high-resolution X-ray diffractometer and a portable X-ray residual stress analyzer. The effects of vibrational stress excitation on the surface residual stress distribution and on the texture of pole figures (0002) occurring during the vibratory stress relief were examined. Compared with the effects corresponding to the same alloy under non-vibration condition, it can be observed that the uniform surface residual stress distribution and relaxation of the compressive residual stress in the stress concentration zone were observed rather than all of the residual stresses being eliminated. Furthermore, with an increase in the vibrational aging time, the compressive residual stress, texture density, and (0002) preferred orientation increased first and then decreased. It should be underlined that the vibratory stress relief process for the vibrational aging time of more than 10 min is able to weaken the strong basal textures of AZ31 Mg alloys, which is valuable for enhancement of their formability and is responsible for an almost perfect 3D-Debye–Scherrer ring. - Highlights: • 3D-Debye ring about VSR technique is not discussed in the existing literature. • A newly developed VSR method is suitable for small or thin workpieces. • The cosα method accurately and effectively determines the residual stresses. • The VSR technique is valuable for enhancement of their formability. • The texture and preferred orientation change with the vibrational aging time.

  11. Static-transmission-error vibratory-excitation contributions from plastically deformed gear teeth caused by tooth bending-fatigue damage

    NASA Astrophysics Data System (ADS)

    Mark, W. D.; Reagor, C. P.

    2007-02-01

    To assess gear health and detect gear-tooth damage, the vibratory response from meshing gear-pair excitations is commonly monitored by accelerometers. In an earlier paper, strong evidence was presented suggesting that, in the case of tooth bending-fatigue damage, the principal source of detectable damage is whole-tooth plastic deformation; i.e. yielding, rather than changes in tooth stiffness caused by tooth-root cracks. Such plastic deformations are geometric deviation contributions to the "static-transmission-error" (STE) vibratory excitation caused by meshing gear pairs. The STE contributions caused by two likely occurring forms of such plastic deformations on a single tooth are derived, and displayed in the time domain as a function of involute "roll distance." Example calculations are provided for transverse contact ratios of Qt=1.4 and 1.8, for spur gears and for helical-gear axial contact ratios ranging from Qa=1.2 to Qa=3.6. Low-pass- and band-pass-filtered versions of these same STE contributions also are computed and displayed in the time domain. Several calculations, consisting of superposition of the computed STE tooth-meshing fundamental harmonic contribution and the band-pass STE contribution caused by a plastically deformed tooth, exhibit the amplitude and frequency or phase modulation character commonly observed in accelerometer-response waveforms caused by damaged teeth. General formulas are provided that enable computation of these STE vibratory-excitation contributions for any form of plastic deformation on any number of teeth for spur and helical gears with any contact ratios.

  12. Arthropod succession on exposed rabbit carrion in Alexandria, Egypt.

    PubMed

    Tantawi, T I; eL-Kady, E M; Greenberg, B; el-Ghaffar, H A

    1996-07-01

    In 1988 and 1989, seasonal field studies on exposed rabbit carcasses were conducted in Alexandria, Egypt, to describe the decomposition process and arthropod succession patterns. Four decomposition stages were recognized: fresh, bloated, decay, and dry. Carcasses in summer and spring decayed at a much faster rate than those in fall and winter. The bloated stage in summer lasted longer than in spring because of the difference in breeding biology of the primary flies infesting carcasses in these seasons. Dipterous larvae of the family Calliphoridae, and to a lesser extent of the families Sarcophagidae and Muscidae, were responsible for the process of carrion degradation. Carrion-arthropod communities in cooler seasons were distinguished from those in warmer seasons by the presence of certain dipterous (muscids and fanniids) and coleopterous larvae, and by adults of small flies such as sphaerocerids and scatopsids. The presence of adult psychodids, sciarids, and phorids was unique to the winter carrion-arthropod community. Eleven species of carrion-breeding Diptera were found to coexist in the study site. The coexistence of the 2 calliphorids Chrysomya albiceps (Wiedemann) and Lucilia sericata (Meigen) in carrion in fall and spring is a new record for the Palaearctic Region. In spring, 3rd instars of C. albiceps were observed preying on the pupae of their own species. Although the carcasses were of equal size and simultaneously exposed, there was considerable variation in the rate of decay among fall carcasses only, which was attributed to unknown reasons at the beginning of the experiment and to heavy rains later on. This affected oviposition and the feeding period of maggots. Approximately 100 arthropod species were recovered on carcasses throughout the study. Diptera was the predominant group, whereas Coleoptera ranked 2nd. Carcasses in cooler seasons were richer in species than in warmer seasons.

  13. Cyberdiversity: Improving the Informatic Value of Diverse Tropical Arthropod Inventories

    PubMed Central

    Miller, Jeremy A.; Miller, Joshua H.; Pham, Dinh-Sac; Beentjes, Kevin K.

    2014-01-01

    In an era of biodiversity crisis, arthropods have great potential to inform conservation assessment and test hypotheses about community assembly. This is because their relatively narrow geographic distributions and high diversity offer high-resolution data on landscape-scale patterns of biodiversity. However, a major impediment to the more widespread application of arthropod data to a range of scientific and policy questions is the poor state of modern arthropod taxonomy, especially in the tropics. Inventories of spiders and other megadiverse arthropods from tropical forests are dominated by undescribed species. Such studies typically organize their data using morphospecies codes, which make it difficult for data from independent inventories to be compared and combined. To combat this shortcoming, we offer cyberdiversity, an online community-based approach for reconciling results of independent inventory studies where current taxonomic knowledge is incomplete. Participating scientists can upload images and DNA barcode sequences to dedicated databases and submit occurrence data and links to a web site (www.digitalSpiders.org). Taxonomic determinations can be shared with a crowdsourcing comments feature, and researchers can discover specimens of interest available for loan and request aliquots of genomic DNA extract. To demonstrate the value of the cyberdiversity framework, we reconcile data from three rapid structured inventories of spiders conducted in Vietnam with an independent inventory (Doi Inthanon, Thailand) using online image libraries. Species richness and inventory completeness were assessed using non-parametric estimators. Community similarity was evaluated using a novel index based on the Jaccard replacing observed with estimated values to correct for unobserved species. We use a distance-decay framework to demonstrate a rudimentary model of landscape-scale changes in community composition that will become increasingly informative as additional

  14. Arthropod bites, stings, and infestations: their prevention and treatment.

    PubMed

    Honig, P J

    1986-06-01

    Readily available information as to the management of arthropod bites, stings, and infestations is important to have but often difficult to find. This article brings such information together in one reference for use by the practicing pediatrician, dermatologist, and family practitioner. Preventive measures are stressed and therapy is outlined for each entity; the rationale for many of the interventions is discussed. It is not the intent of this paper to cover each subject comprehensively.

  15. Cyberdiversity: improving the informatic value of diverse tropical arthropod inventories.

    PubMed

    Miller, Jeremy A; Miller, Joshua H; Pham, Dinh-Sac; Beentjes, Kevin K

    2014-01-01

    In an era of biodiversity crisis, arthropods have great potential to inform conservation assessment and test hypotheses about community assembly. This is because their relatively narrow geographic distributions and high diversity offer high-resolution data on landscape-scale patterns of biodiversity. However, a major impediment to the more widespread application of arthropod data to a range of scientific and policy questions is the poor state of modern arthropod taxonomy, especially in the tropics. Inventories of spiders and other megadiverse arthropods from tropical forests are dominated by undescribed species. Such studies typically organize their data using morphospecies codes, which make it difficult for data from independent inventories to be compared and combined. To combat this shortcoming, we offer cyberdiversity, an online community-based approach for reconciling results of independent inventory studies where current taxonomic knowledge is incomplete. Participating scientists can upload images and DNA barcode sequences to dedicated databases and submit occurrence data and links to a web site (www.digitalSpiders.org). Taxonomic determinations can be shared with a crowdsourcing comments feature, and researchers can discover specimens of interest available for loan and request aliquots of genomic DNA extract. To demonstrate the value of the cyberdiversity framework, we reconcile data from three rapid structured inventories of spiders conducted in Vietnam with an independent inventory (Doi Inthanon, Thailand) using online image libraries. Species richness and inventory completeness were assessed using non-parametric estimators. Community similarity was evaluated using a novel index based on the Jaccard replacing observed with estimated values to correct for unobserved species. We use a distance-decay framework to demonstrate a rudimentary model of landscape-scale changes in community composition that will become increasingly informative as additional

  16. A phylogenomic approach to resolve the arthropod tree of life.

    PubMed

    Meusemann, Karen; von Reumont, Björn M; Simon, Sabrina; Roeding, Falko; Strauss, Sascha; Kück, Patrick; Ebersberger, Ingo; Walzl, Manfred; Pass, Günther; Breuers, Sebastian; Achter, Viktor; von Haeseler, Arndt; Burmester, Thorsten; Hadrys, Heike; Wägele, J Wolfgang; Misof, Bernhard

    2010-11-01

    Arthropods were the first animals to conquer land and air. They encompass more than three quarters of all described living species. This extraordinary evolutionary success is based on an astoundingly wide array of highly adaptive body organizations. A lack of robustly resolved phylogenetic relationships, however, currently impedes the reliable reconstruction of the underlying evolutionary processes. Here, we show that phylogenomic data can substantially advance our understanding of arthropod evolution and resolve several conflicts among existing hypotheses. We assembled a data set of 233 taxa and 775 genes from which an optimally informative data set of 117 taxa and 129 genes was finally selected using new heuristics and compared with the unreduced data set. We included novel expressed sequence tag (EST) data for 11 species and all published phylogenomic data augmented by recently published EST data on taxonomically important arthropod taxa. This thorough sampling reduces the chance of obtaining spurious results due to stochastic effects of undersampling taxa and genes. Orthology prediction of genes, alignment masking tools, and selection of most informative genes due to a balanced taxa-gene ratio using new heuristics were established. Our optimized data set robustly resolves major arthropod relationships. We received strong support for a sister group relationship of onychophorans and euarthropods and strong support for a close association of tardigrades and cycloneuralia. Within pancrustaceans, our analyses yielded paraphyletic crustaceans and monophyletic hexapods and robustly resolved monophyletic endopterygote insects. However, our analyses also showed for few deep splits that were recently thought to be resolved, for example, the position of myriapods, a remarkable sensitivity to methods of analyses.

  17. Impacts of Rotation Schemes on Ground-Dwelling Beneficial Arthropods.

    PubMed

    Dunbar, Mike W; Gassmann, Aaron J; O'Neal, Matthew E

    2016-10-01

    Crop rotation alters agroecosystem diversity temporally, and increasing the number of crops in rotation schemes can increase crop yields and reduce reliance on pesticides. We hypothesized that increasing the number of crops in annual rotation schemes would positively affect ground-dwelling beneficial arthropod communities. During 2012 and 2013, pitfall traps were used to measure activity-density and diversity of ground-dwelling communities within three previously established, long-term crop rotation studies located in Wisconsin and Illinois. Rotation schemes sampled included continuous corn, a 2-yr annual rotation of corn and soybean, and a 3-yr annual rotation of corn, soybean, and wheat. Insects captured were identified to family, and non-insect arthropods were identified to class, order, or family, depending upon the taxa. Beneficial arthropods captured included natural enemies, granivores, and detritivores. The beneficial community from continuous corn plots was significantly more diverse compared with the community in the 2-yr rotation, whereas the community in the 3-yr rotation did not differ from either rotation scheme. The activity-density of the total community and any individual taxa did not differ among rotation schemes in either corn or soybean. Crop species within all three rotation schemes were annual crops, and are associated with agricultural practices that make infield habitat subject to anthropogenic disturbances and temporally unstable. Habitat instability and disturbance can limit the effectiveness and retention of beneficial arthropods, including natural enemies, granivores, and detritivores. Increasing non-crop and perennial species within landscapes in conjunction with more diverse rotation schemes may increase the effect of biological control of pests by natural enemies.

  18. Evidence for a clade of nematodes, arthropods and other moulting animals.

    PubMed

    Aguinaldo, A M; Turbeville, J M; Linford, L S; Rivera, M C; Garey, J R; Raff, R A; Lake, J A

    1997-05-29

    The arthropods constitute the most diverse animal group, but, despite their rich fossil record and a century of study, their phylogenetic relationships remain unclear. Taxa previously proposed to be sister groups to the arthropods include Annelida, Onychophora, Tardigrada and others, but hypotheses of phylogenetic relationships have been conflicting. For example, onychophorans, like arthropods, moult periodically, have an arthropod arrangement of haemocoel, and have been related to arthropods in morphological and mitochondrial DNA sequence analyses. Like annelids, they possess segmental nephridia and muscles that are a combination of smooth and obliquely striated fibres. Our phylogenetic analysis of 18S ribosomal DNA sequences indicates a close relationship between arthropods, nematodes and all other moulting phyla. The results suggest that ecdysis (moulting) arose once and support the idea of a new clade, Ecdysozoa, containing moulting animals: arthropods, tardigrades, onychophorans, nematodes, nematomorphs, kinorhynchs and priapulids. No support is found for a clade of segmented animals, the Articulata, uniting annelids with arthropods. The hypothesis that nematodes are related to arthropods has important implications for developmental genetic studies using as model systems the nematode Caenorhabditis elegans and the arthropod Drosophila melanogaster, which are generally held to be phylogenetically distant from each other.

  19. Experimental Investigation of Vibratory Stresses in a Concentric-Ring Direct-Air-Cycle Nuclear Fuel Element

    NASA Technical Reports Server (NTRS)

    Chiarito, Patrick T.

    1957-01-01

    Preliminary tests made by the General Electric Company indicated that aerodynamic loads might cause large enough distortions in the thin sheet-metal rings of a nuclear fuel element to result in structural failure. The magnitude of the distortions in a test fuel element was determined from strains measured with airflow conditions simulating those expected during engine operation. The measured vibratory strains were low enough to indicate the improbability of failure by fatigue. A conservative estimate of the radial deflection that accompanied peak strains in the outer ring was +0.0006 inch.

  20. Mechanisms of arthropod transmission of plant and animal viruses.

    PubMed

    Gray, S M; Banerjee, N

    1999-03-01

    A majority of the plant-infecting viruses and many of the animal-infecting viruses are dependent upon arthropod vectors for transmission between hosts and/or as alternative hosts. The viruses have evolved specific associations with their vectors, and we are beginning to understand the underlying mechanisms that regulate the virus transmission process. A majority of plant viruses are carried on the cuticle lining of a vector's mouthparts or foregut. This initially appeared to be simple mechanical contamination, but it is now known to be a biologically complex interaction between specific virus proteins and as yet unidentified vector cuticle-associated compounds. Numerous other plant viruses and the majority of animal viruses are carried within the body of the vector. These viruses have evolved specific mechanisms to enable them to be transported through multiple tissues and to evade vector defenses. In response, vector species have evolved so that not all individuals within a species are susceptible to virus infection or can serve as a competent vector. Not only are the virus components of the transmission process being identified, but also the genetic and physiological components of the vectors which determine their ability to be used successfully by the virus are being elucidated. The mechanisms of arthropod-virus associations are many and complex, but common themes are beginning to emerge which may allow the development of novel strategies to ultimately control epidemics caused by arthropod-borne viruses.

  1. Preliminary observations of arthropods associated with buried carrion on Oahu.

    PubMed

    Rysavy, Noel M; Goff, M Lee

    2015-03-01

    Several studies in Hawaii have focused on arthropod succession and decomposition patterns of surface remains, but the current research presents the first study to focus on shallow burials in this context. Three domestic pig carcasses (Sus scrofa L.) were buried at the depths of 20-40 cm in silty clay loam soil on an exposed ridge on the leeward side of the volcanically formed Koolau Mountain Range. One carcass was exhumed after 3 weeks, another after 6 weeks, and the last carcass was exhumed after 9 weeks. An inventory of arthropod taxa present on the carrion and in the surrounding soil and observations pertaining to decomposition were recorded at each exhumation. The longer the carrion was buried, the greater the diversity of arthropod species that were recovered from the remains. Biomass loss was calculated to be 49% at the 3-week interval, 56% at the 6-week interval, and 59% at the 9-week interval.

  2. Evolution, Discovery, and Interpretations of Arthropod Mushroom Bodies

    PubMed Central

    Strausfeld, Nicholas J.; Hansen, Lars; Li, Yongsheng; Gomez, Robert S.; Ito, Kei

    1998-01-01

    Mushroom bodies are prominent neuropils found in annelids and in all arthropod groups except crustaceans. First explicitly identified in 1850, the mushroom bodies differ in size and complexity between taxa, as well as between different castes of a single species of social insect. These differences led some early biologists to suggest that the mushroom bodies endow an arthropod with intelligence or the ability to execute voluntary actions, as opposed to innate behaviors. Recent physiological studies and mutant analyses have led to divergent interpretations. One interpretation is that the mushroom bodies conditionally relay to higher protocerebral centers information about sensory stimuli and the context in which they occur. Another interpretation is that they play a central role in learning and memory. Anatomical studies suggest that arthropod mushroom bodies are predominately associated with olfactory pathways except in phylogenetically basal insects. The prominent olfactory input to the mushroom body calyces in more recent insect orders is an acquired character. An overview of the history of research on the mushroom bodies, as well as comparative and evolutionary considerations, provides a conceptual framework for discussing the roles of these neuropils. PMID:10454370

  3. Mechanisms of Arthropod Transmission of Plant and Animal Viruses

    PubMed Central

    Gray, Stewart M.; Banerjee, Nanditta

    1999-01-01

    A majority of the plant-infecting viruses and many of the animal-infecting viruses are dependent upon arthropod vectors for transmission between hosts and/or as alternative hosts. The viruses have evolved specific associations with their vectors, and we are beginning to understand the underlying mechanisms that regulate the virus transmission process. A majority of plant viruses are carried on the cuticle lining of a vector’s mouthparts or foregut. This initially appeared to be simple mechanical contamination, but it is now known to be a biologically complex interaction between specific virus proteins and as yet unidentified vector cuticle-associated compounds. Numerous other plant viruses and the majority of animal viruses are carried within the body of the vector. These viruses have evolved specific mechanisms to enable them to be transported through multiple tissues and to evade vector defenses. In response, vector species have evolved so that not all individuals within a species are susceptible to virus infection or can serve as a competent vector. Not only are the virus components of the transmission process being identified, but also the genetic and physiological components of the vectors which determine their ability to be used successfully by the virus are being elucidated. The mechanisms of arthropod-virus associations are many and complex, but common themes are beginning to emerge which may allow the development of novel strategies to ultimately control epidemics caused by arthropod-borne viruses. PMID:10066833

  4. Digital cameras with designs inspired by the arthropod eye.

    PubMed

    Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Xiao, Jianliang; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B; Huang, Yonggang; Rogers, John A

    2013-05-02

    In arthropods, evolution has created a remarkably sophisticated class of imaging systems, with a wide-angle field of view, low aberrations, high acuity to motion and an infinite depth of field. A challenge in building digital cameras with the hemispherical, compound apposition layouts of arthropod eyes is that essential design requirements cannot be met with existing planar sensor technologies or conventional optics. Here we present materials, mechanics and integration schemes that afford scalable pathways to working, arthropod-inspired cameras with nearly full hemispherical shapes (about 160 degrees). Their surfaces are densely populated by imaging elements (artificial ommatidia), which are comparable in number (180) to those of the eyes of fire ants (Solenopsis fugax) and bark beetles (Hylastes nigrinus). The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors into integrated sheets that can be elastically transformed from the planar geometries in which they are fabricated to hemispherical shapes for integration into apposition cameras. Our imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

  5. Structural Diversity of Self-Assembled Iridescent Arthropod Biophotonic Nanostructures

    NASA Astrophysics Data System (ADS)

    Saranathan, Vinod Kumar; Prum, Richard O.

    2015-03-01

    Many organisms, especially arthropods, produce vivid interference colors using diverse mesoscopic (100-350 nm) integumentary biophotonic nanostructures that are increasingly being investigated for technological applications. Despite a century of interest, we lack precise structural knowledge of many biophotonic nanostructures and mechanisms controlling their development, when such knowledge can open novel biomimetic routes to facilely self-assemble tunable, multi-functional materials. Here, we use synchrotron small angle X-ray scattering and electron microscopy to characterize the photonic nanostructure of 140 iridescent integumentary scales and setae from 127 species of terrestrial arthropods in 85 genera from 5 orders. We report a rich nanostructural diversity, including triply-periodic bicontinuous networks, close-packed spheres, inverse columnar, perforated lamellar, and disordered sponge-like morphologies, commonly observed as stable phases of amphiphilic surfactants, block copolymer, and lyotropic lipid-water systems. Diverse arthropod lineages appear to have independently evolved to utilize the self-assembly of infolding bilayer membranes to develop biophotonic nanostructures that span the phase-space of amphiphilic morphologies, but at optical length scales.

  6. Genetic diversity in aspen and its relation to arthropod abundance.

    PubMed

    Zhang, Chunxia; Vornam, Barbara; Volmer, Katharina; Prinz, Kathleen; Kleemann, Frauke; Köhler, Lars; Polle, Andrea; Finkeldey, Reiner

    2014-01-01

    The ecological consequences of biodiversity have become a prominent public issue. Little is known on the effect of genetic diversity on ecosystem services. Here, a diversity experiment was established with European and North American aspen (Populus tremula, P. tremuloides) planted in plots representing either a single deme only or combinations of two, four and eight demes. The goals of this study were to explore the complex inter- and intraspecific genetic diversity of aspen and to then relate three measures for diversity (deme diversity, genetic diversity determined as Shannon index or as expected heterozygosity) to arthropod abundance. Microsatellite and AFLP markers were used to analyze the genetic variation patterns within and between the aspen demes and deme mixtures. Large differences were observed regarding the genetic diversity within demes. An analysis of molecular variance revealed that most of the total genetic diversity was found within demes, but the genetic differentiation among demes was also high. The complex patterns of genetic diversity and differentiation resulted in large differences of the genetic variation within plots. The average diversity increased from plots with only one deme to plots with two, four, and eight demes, respectively and separated plots with and without American aspen. To test whether intra- and interspecific diversity impacts on ecosystem services, arthropod abundance was determined. Increasing genetic diversity of aspen was related to increasing abundance of arthropods. However, the relationship was mainly driven by the presence of American aspen suggesting that species identity overrode the effect of intraspecific variation of European aspen.

  7. Microbial control of arthropod pests of tropical tree fruits.

    PubMed

    Dolinski, Claudia; Lacey, Lawrence A

    2007-01-01

    A multitude of insects and mites attack fruit crops throughout the tropics. The traditional method for controlling most of these pests is the application of chemical pesticides. Growing concern on the negative environmental effects has encouraged the development of alternatives. Inundatively and inoculatively applied microbial control agents (virus, bacteria, fungi, and entomopathogenic nematodes) have been developed as alternative control methods of a wide variety of arthropods including tropical fruit pests. The majority of the research and applications in tropical fruit agroecosystems has been conducted in citrus, banana, coconut, and mango. Successful microbial control initiatives of citrus pests and mites have been reported. Microbial control of arthropod pests of banana includes banana weevil, Cosmopolites sordidus Germar (Coleoptera: Curculionidae) (with EPNs and fungi) among others Oryctes rhinoceros (L.) is one of the most important pests of coconut and one of the most successful uses of non-occluded virus for classical biological control. Key pests of mango that have been controlled with microbial control agents include fruit flies (Diptera: Tephritidae) (with EPNs and fungi), and other pests. Also successful is the microbial control of arthropod pests of guava, papaya and pineapple. The challenge towards a broader application of entomopathogens is the development of successful combinations of entomopathogens, predators, and parasitoids along with other interventions to produce effective and sustainable pest management.

  8. A study on the contribution of body vibrations to the vibratory sensation induced by high-level, complex low-frequency noise.

    PubMed

    Takahashi, Yukio

    2011-01-01

    To investigate the contribution of body vibrations to the vibratory sensation induced by high-level, complex low-frequency noise, we conducted two experiments. In Experiment 1, eight male subjects were exposed to seven types of low-frequency noise stimuli: two pure tones [a 31.5-Hz, 100-dB(SPL) tone and a 50-Hz, 100-dB(SPL) tone] and five complex noises composed of the pure tones. For the complex noise stimuli, the sound pressure level of one tonal component was 100 dB(SPL) and that of another one was either 90, 95, or 100 dB(SPL). Vibration induced on the body surface was measured at five locations, and the correlation with the subjective rating of the vibratory sensation at each site of measurement was examined. In Experiment 2, the correlation between the body surface vibration and the vibratory sensation was similarly examined using seven types of noise stimuli composed of a 25-Hz tone and a 50-Hz tone. In both the experiments, we found that at the chest and the abdomen, the rating of the vibratory sensation was in close correlation with the vibration acceleration level (VAL) of the body surface vibration measured at each corresponding location. This was consistent with our previous results and suggested that at the trunk of the body (the chest and the abdomen), the mechanoreception of body vibrations plays an important role in the experience of the vibratory sensation in persons exposed to high-level low-frequency noise. At the head, however, no close correlation was found between the rating of the vibratory sensation and the VAL of body surface vibration. This suggested that at the head, the perceptual mechanisms of vibration induced by high-level low-frequency noise were different from those in the trunk of the body.

  9. Bioinformatic prediction of arthropod/nematode-like peptides in non-arthropod, non-nematode members of the Ecdysozoa.

    PubMed

    Christie, Andrew E; Nolan, Daniel H; Garcia, Zachery A; McCoole, Matthew D; Harmon, Sarah M; Congdon-Jones, Benjamin; Ohno, Paul; Hartline, Niko; Congdon, Clare Bates; Baer, Kevin N; Lenz, Petra H

    2011-02-01

    The Onychophora, Priapulida and Tardigrada, along with the Arthropoda, Nematoda and several other small phyla, form the superphylum Ecdysozoa. Numerous peptidomic studies have been undertaken for both the arthropods and nematodes, resulting in the identification of many peptides from each group. In contrast, little is known about the peptides used as paracrines/hormones by species from the other ecdysozoan taxa. Here, transcriptome mining and bioinformatic peptide prediction were used to identify peptides in members of the Onychophora, Priapulida and Tardigrada, the only non-arthropod, non-nematode members of the Ecdysozoa for which there are publicly accessible expressed sequence tags (ESTs). The extant ESTs for each phylum were queried using 106 arthropod/nematode peptide precursors. Transcripts encoding calcitonin-like diuretic hormone and pigment-dispersing hormone (PDH) were identified for the onychophoran Peripatopsis sedgwicki, with transcripts encoding C-type allatostatin (C-AST) and FMRFamide-like peptide identified for the priapulid Priapulus caudatus. For the Tardigrada, transcripts encoding members of the A-type allatostatin, C-AST, insect kinin, orcokinin, PDH and tachykinin-related peptide families were identified, all but one from Hypsibius dujardini (the exception being a Milnesium tardigradum orcokinin-encoding transcript). The proteins deduced from these ESTs resulted in the prediction of 48 novel peptides, six onychophoran, eight priapulid and 34 tardigrade, which are the first described from these phyla.

  10. The i5K Initiative: advancing arthropod genomics for knowledge, human health, agriculture, and the environment.

    PubMed

    2013-01-01

    Insects and their arthropod relatives including mites, spiders, and crustaceans play major roles in the world's terrestrial, aquatic, and marine ecosystems. Arthropods compete with humans for food and transmit devastating diseases. They also comprise the most diverse and successful branch of metazoan evolution, with millions of extant species. Here, we describe an international effort to guide arthropod genomic efforts, from species prioritization to methodology and informatics. The 5000 arthropod genomes initiative (i5K) community met formally in 2012 to discuss a roadmap for sequencing and analyzing 5000 high-priority arthropods and is continuing this effort via pilot projects, the development of standard operating procedures, and training of students and career scientists. With university, governmental, and industry support, the i5K Consortium aspires to deliver sequences and analytical tools for each of the arthropod branches and each of the species having beneficial and negative effects on humankind.

  11. The i5K Initiative: Advancing Arthropod Genomics for Knowledge, Human Health, Agriculture, and the Environment

    PubMed Central

    2013-01-01

    Insects and their arthropod relatives including mites, spiders, and crustaceans play major roles in the world’s terrestrial, aquatic, and marine ecosystems. Arthropods compete with humans for food and transmit devastating diseases. They also comprise the most diverse and successful branch of metazoan evolution, with millions of extant species. Here, we describe an international effort to guide arthropod genomic efforts, from species prioritization to methodology and informatics. The 5000 arthropod genomes initiative (i5K) community met formally in 2012 to discuss a roadmap for sequencing and analyzing 5000 high-priority arthropods and is continuing this effort via pilot projects, the development of standard operating procedures, and training of students and career scientists. With university, governmental, and industry support, the i5K Consortium aspires to deliver sequences and analytical tools for each of the arthropod branches and each of the species having beneficial and negative effects on humankind. PMID:23940263

  12. The diversity of arthropods in homes across the United States as determined by environmental DNA analyses.

    PubMed

    Madden, Anne A; Barberán, Albert; Bertone, Matthew A; Menninger, Holly L; Dunn, Robert R; Fierer, Noah

    2016-12-01

    We spend most of our lives inside homes, surrounded by arthropods that impact our property as pests and our health as disease vectors and producers of sensitizing allergens. Despite their relevance to human health and well-being, we know relatively little about the arthropods that exist in our homes and the factors structuring their diversity. As previous work has been limited in scale by the costs and time associated with collecting arthropods and the subsequent morphological identification, we used a DNA-based method for investigating the arthropod diversity in homes via high-throughput marker gene sequencing of home dust. Settled dust samples were collected by citizen scientists from both inside and outside more than 700 homes across the United States, yielding the first continental-scale estimates of arthropod diversity associated with our residences. We were able to document food webs and previously unknown geographic distributions of diverse arthropods - from allergen producers to invasive species and nuisance pests. Home characteristics, including the presence of basements, home occupants and surrounding land use, were more useful than climate parameters in predicting arthropod diversity in homes. These noninvasive, scalable tools and resultant findings not only provide the first continental-scale maps of household arthropod diversity, but our analyses also provide valuable baseline information on arthropod allergen exposures and the distributions of invasive pests inside homes.

  13. Ectomycota Associated with Arthropods from Bat Hibernacula in Eastern Canada, with Particular Reference to Pseudogymnoascus destructans

    PubMed Central

    Vanderwolf, Karen J.; Malloch, David; McAlpine, Donald F.

    2016-01-01

    The introduction of Pseudogymnoascus destructans (Pd) to North America, agent of white-nose syndrome in hibernating bats, has increased interest in fungi from underground habitats. While bats are assumed to be the main vector transmitting Pd cave-to-cave, the role of other fauna is unexplored. We documented the fungi associated with over-wintering arthropods in Pd-positive hibernacula, including sites where bats had been recently extirpated or near-extirpated, to determine if arthropods carried Pd, and to compare fungal assemblages on arthropods to bats. We isolated 87 fungal taxa in 64 genera from arthropods. Viable Pd was cultured from 15.3% of arthropods, most frequently from harvestmen (Nelima elegans). Fungal assemblages on arthropods were similar to those on bats. The different fungal assemblages documented among arthropods may be due to divergent patterns of movement, aggregation, feeding, or other factors. While it is unlikely that arthropods play a major role in the transmission dynamics of Pd, we demonstrate that arthropods may carry viable Pd spores and therefore have the potential to transport Pd, either naturally or anthropogenically, within or among hibernacula. This underlines the need for those entering hibernacula to observe decontamination procedures and for such procedures to evolve as our understanding of potential mechanisms of Pd dispersal improve. PMID:27110827

  14. Arthropods of the great indoors: characterizing diversity inside urban and suburban homes

    PubMed Central

    Leong, Misha; Bayless, Keith M.; Malow, Tara L.F.; Dunn, Robert R.; Trautwein, Michelle D.

    2016-01-01

    Although humans and arthropods have been living and evolving together for all of our history, we know very little about the arthropods we share our homes with apart from major pest groups. Here we surveyed, for the first time, the complete arthropod fauna of the indoor biome in 50 houses (located in and around Raleigh, North Carolina, USA). We discovered high diversity, with a conservative estimate range of 32–211 morphospecies, and 24–128 distinct arthropod families per house. The majority of this indoor diversity (73%) was made up of true flies (Diptera), spiders (Araneae), beetles (Coleoptera), and wasps and kin (Hymenoptera, especially ants: Formicidae). Much of the arthropod diversity within houses did not consist of synanthropic species, but instead included arthropods that were filtered from the surrounding landscape. As such, common pest species were found less frequently than benign species. Some of the most frequently found arthropods in houses, such as gall midges (Cecidomyiidae) and book lice (Liposcelididae), are unfamiliar to the general public despite their ubiquity. These findings present a new understanding of the diversity, prevalence, and distribution of the arthropods in our daily lives. Considering their impact as household pests, disease vectors, generators of allergens, and facilitators of the indoor microbiome, advancing our knowledge of the ecology and evolution of arthropods in homes has major economic and human health implications. PMID:26819844

  15. [Relationships between island characteristics and arthropod diversity in Thousand-Island Lake].

    PubMed

    Ren, Li-jun; Xu, Zhi-hong; Lu, Jian-bo; Zhao, Gai; Zhang, Qun

    2009-09-01

    In April, May, August, and October 2006, grid-based sampling method was adopted to investigate the diversity and abundance of arthropods on 50 islands in the Thousand-island Lake, with the effects of island area, island altitude, island shape, inter-island distance, and island-mainland distance on arthropod species richness analyzed. With the increase of island area, the richness of total arthropod species and that of the arthropod species with high- and low- dispersal ability all increased, and the relationships between island area and arthropod species richness corresponded to the classical island biogeography model. The island area, island altitude, and island shape had comprehensive effects on the arthropod species richness, while inter-island distance and island-mainland distance had less effects. The richness of total arthropod species had a significant positive correlation with island altitude and island shape, that of the arthropod species with high- dispersal ability was significantly positively correlated with island area and island altitude, while no significant relationship was observed between the richness of arthropod species with low-dispersal ability and the island characteristics.

  16. Geographic patterns of ground-dwelling arthropods across an ecoregional transition in the north American Southwest

    USGS Publications Warehouse

    Lightfoot, D.C.; Brantley, S.L.; Allen, C.D.

    2008-01-01

    We examined the biogeographic patterns of ground-dwelling arthropod communities across a heterogeneous semiarid region of the Southern Rio Grande Rift Valley of New Mexico. Our 3 sites included portions of 5 ecoregions, with the middle site a transition area where all ecoregions converged. We addressed the following 3 questions: (1) Do the species assemblage patterns for ground arthropods across habitats and sites conform to recognized ecoregions? (2) Are arthropod assemblages in distinct vegetation-defined habitats within an ecoregion more similar to each other or to assemblages in similar vegetation-defined habitats in other ecoregions? (3) Is there a detectable edge effect with increased arthropod diversity in the area of converging ecoregions? We encountered 442 target arthropod species from pitfall traps operating continuously for 7 years over a series of different habitats at each of the 3 sites. We examined geographic distributions of spider and cricket/grasshopper species in detail, and they showed affinities for different ecoregions, respectively. Each habitat within a study site supported a unique overall arthropod assemblage; nevertheless, different habitats at the same site were more similar to each other than they were to similar habitats at other sites. Overall arthropod species richness was greatest in the area where all 5 ecoregions converged. Arthropod species and their geographic distributions are poorly known relative to vascular plants and vertebrate animals. Findings from this research indicate that ecoregional classification is a useful tool for understanding biogeographic patterns among arthropods.

  17. Arthropods of the great indoors: characterizing diversity inside urban and suburban homes.

    PubMed

    Bertone, Matthew A; Leong, Misha; Bayless, Keith M; Malow, Tara L F; Dunn, Robert R; Trautwein, Michelle D

    2016-01-01

    Although humans and arthropods have been living and evolving together for all of our history, we know very little about the arthropods we share our homes with apart from major pest groups. Here we surveyed, for the first time, the complete arthropod fauna of the indoor biome in 50 houses (located in and around Raleigh, North Carolina, USA). We discovered high diversity, with a conservative estimate range of 32-211 morphospecies, and 24-128 distinct arthropod families per house. The majority of this indoor diversity (73%) was made up of true flies (Diptera), spiders (Araneae), beetles (Coleoptera), and wasps and kin (Hymenoptera, especially ants: Formicidae). Much of the arthropod diversity within houses did not consist of synanthropic species, but instead included arthropods that were filtered from the surrounding landscape. As such, common pest species were found less frequently than benign species. Some of the most frequently found arthropods in houses, such as gall midges (Cecidomyiidae) and book lice (Liposcelididae), are unfamiliar to the general public despite their ubiquity. These findings present a new understanding of the diversity, prevalence, and distribution of the arthropods in our daily lives. Considering their impact as household pests, disease vectors, generators of allergens, and facilitators of the indoor microbiome, advancing our knowledge of the ecology and evolution of arthropods in homes has major economic and human health implications.

  18. Arthropod phylogeny revisited, with a focus on crustacean relationships.

    PubMed

    Koenemann, Stefan; Jenner, Ronald A; Hoenemann, Mario; Stemme, Torben; von Reumont, Björn M

    2010-01-01

    Higher-level arthropod phylogenetics is an intensely active field of research, not least as a result of the hegemony of molecular data. However, not all areas of arthropod phylogenetics have so far received equal attention. The application of molecular data to infer a comprehensive phylogeny of Crustacea is still in its infancy, and several emerging results are conspicuously at odds with morphology-based studies. In this study, we present a series of molecular phylogenetic analyses of 88 arthropods, including 57 crustaceans, representing all the major lineages, with Onychophora and Tardigrada as outgroups. Our analyses are based on published and new sequences for two mitochondrial markers, 16S rDNA and cytochrome c oxidase subunit I (COI), and the nuclear ribosomal gene 18S rDNA. We designed our phylogenetic analyses to assess the effects of different strategies of sequence alignment, alignment masking, nucleotide coding, and model settings. Our comparisons show that alignment optimization of ribosomal markers based on secondary structure information can have a radical impact on phylogenetic reconstruction. Trees based on optimized alignments recover monophyletic Arthropoda (excluding Onychophora), Pancrustacea, Malacostraca, Insecta, Myriapoda and Chelicerata, while Maxillopoda and Hexapoda emerge as paraphyletic groups. Our results are unable to resolve the highest-level relationships within Arthropoda, and none of our trees supports the monophyly of Myriochelata or Mandibulata. We discuss our results in the context of both the methodological variations between different analyses, and of recently proposed phylogenetic hypotheses. This article offers a preliminary attempt to incorporate the large diversity of crustaceans into a single molecular phylogenetic analysis, assessing the robustness of phylogenetic relationships under varying analysis parameters. It throws into sharp relief the relative strengths and shortcomings of the combined molecular data for

  19. Waptia and the Diversification of Brood Care in Early Arthropods.

    PubMed

    Caron, Jean-Bernard; Vannier, Jean

    2016-01-11

    Brood care, including the carrying of eggs or juveniles, is a form of parental care, which, like other parental traits [1], enhances offspring fitness with variable costs and benefits to the parents [2]. Attempts to understand why and how parental care evolved independently in numerous animal groups often emphasize the role of environmental pressures such as predation, ephemeral resources, and, more generally, the harshness of environment. The fossil record can, in principle, provide minimum age constraints on the evolution of life-history traits, including brood care and key information on the reproductive strategies of extinct organisms. New, exceptionally preserved specimens of the weakly sclerotized arthropod Waptia fieldensis from the middle Cambrian (ca. 508 million years ago) Burgess Shale, Canada, provide the oldest example of in situ eggs with preserved embryos in the fossil record. The relatively small clutch size, up to 24 eggs, and the relatively large diameter of individual eggs, some over 2 mm, contrast with the high number of small eggs-found without preserved embryos-in the bivalved bradoriid arthropod Kunmingella douvillei from the Chengjiang biota (ca. 515 million years ago). The presence of these two different parental strategies suggests a rapid evolution of a variety of modern-type life-history traits, including extended investment in offspring survivorship, soon after the Cambrian emergence of animals. Together with previously described brooded eggs in ostracods from the Upper Ordovician (ca. 450 million years ago), these new findings suggest that the presence of a bivalved carapace played a key role in the early evolution of parental care in arthropods.

  20. Impacts of major predators on tropical agroforest arthropods: comparisons within and across taxa.

    PubMed

    Philpott, Stacy M; Greenberg, Russell; Bichier, Peter; Perfecto, Ivette

    2004-06-01

    In food web studies, taxonomically unrelated predators are often grouped into trophic levels regardless of their relative importance on prey assemblages, multiple predator effects, or interactions such as omnivory. Ants and birds are important predators likely to differentially shape arthropod assemblages, but no studies have compared their effects on a shared prey base. In two separate studies, we excluded birds and ants from branches of a canopy tree ( Inga micheliana) in a coffee farm in Mexico for 2 months in the dry and wet seasons of 2002. We investigated changes in arthropod densities with and without predation pressure from (1) birds and (2) ant assemblages dominated by one of two ant species ( Azteca instabilis and Camponotus senex). We first analyzed individual effects of each predator (birds, Azteca instabilis, and C. senex) then used a per day effect metric to compare differences in effects across (birds vs ants) and within predator taxa (the two ant species). Individually, birds reduced densities of total and large arthropods and some arthropod orders (e.g., spiders, beetles, roaches) in both seasons. Azteca instabilis did not significantly affect arthropods (total, small, large or specific orders). Camponotus senex, however, tended to remove arthropods (total, small), especially in the dry season, and affected arthropod densities of some orders both positively and negatively. Predators greatly differed in their effects on Inga arthropods (for all, small, large, and individual orders of arthropods) both in sign (+/-) and magnitudes of effects. Birds had stronger negative effects on arthropods than ants and the two dominant ant species had stronger effects on arthropods in different seasons. Our results show that aggregating taxonomically related and unrelated predators into trophic levels without prior experimental data quantifying the sign and strengths of effects may lead to a misrepresentation of food web interactions.

  1. Interactions among predators and the cascading effects of vertebrate insectivores on arthropod communities and plants.

    PubMed

    Mooney, Kailen A; Gruner, Daniel S; Barber, Nicholas A; Van Bael, Sunshine A; Philpott, Stacy M; Greenberg, Russell

    2010-04-20

    Theory on trophic interactions predicts that predators increase plant biomass by feeding on herbivores, an indirect interaction called a trophic cascade. Theory also predicts that predators feeding on predators, or intraguild predation, will weaken trophic cascades. Although past syntheses have confirmed cascading effects of terrestrial arthropod predators, we lack a comprehensive analysis for vertebrate insectivores-which by virtue of their body size and feeding habits are often top predators in these systems-and of how intraguild predation mediates trophic cascade strength. We report here on a meta-analysis of 113 experiments documenting the effects of insectivorous birds, bats, or lizards on predaceous arthropods, herbivorous arthropods, and plants. Although vertebrate insectivores fed as intraguild predators, strongly reducing predaceous arthropods (38%), they nevertheless suppressed herbivores (39%), indirectly reduced plant damage (40%), and increased plant biomass (14%). Furthermore, effects of vertebrate insectivores on predatory and herbivorous arthropods were positively correlated. Effects were strongest on arthropods and plants in communities with abundant predaceous arthropods and strong intraguild predation, but weak in communities depauperate in arthropod predators and intraguild predation. The naturally occurring ratio of arthropod predators relative to herbivores varied tremendously among the studied communities, and the skew to predators increased with site primary productivity and in trees relative to shrubs. Although intraguild predation among arthropod predators has been shown to weaken herbivore suppression, we find this paradigm does not extend to vertebrate insectivores in these communities. Instead, vertebrate intraguild preda-tion is associated with strengthened trophic cascades, and insectivores function as dominant predators in terrestrial plant-arthropod communities.

  2. High-performance micromachined vibratory rate- and rate-integrating gyroscopes

    NASA Astrophysics Data System (ADS)

    Cho, Jae Yoong

    The performance of vibratory micromachined gyroscopes has been continuously improving for the past two decades. However, to further improve performance of the MEMS gyroscope in harsh environment, it is necessary for gyros to reduce the sensitivity to environmental parameters, including vibration and temperature change. In addition, conventional rate-mode MEMS gyroscopes have limitation in performance due to tradeoff between resolution, bandwidth, and full-scale range. In this research, we aim to reduce vibration sensitivity by developing gyros that operate in the balanced mode. The balanced mode creates zero net momentum and reduces energy loss through an anchor. The gyro can differentially cancel measurement errors from external vibration along both sensor axes. The vibration sensitivity of the balanced-mode gyroscope including structural imbalance from microfabrication reduces as the absolute difference between in-phase parasitic mode and operating mode frequencies increases. The parasitic sensing mode frequency is designed larger than the operating mode frequency to achieve both improved vibration insensitivity and shock resistivity. A single anchor is used in order to minimize thermoresidual stress change. We developed two gyroscope based on these design principles. The Balanced Oscillating Gyro (BOG) is a quad-mass tuning-fork rate gyroscope. The relationship between gyro design and modal characteristics is studied extensively using finite element method (FEM). The gyro is fabricated using the planar Si-on-glass (SOG) process with a device thickness of 100microm. The BOG is evaluated using the first-generation analog interface circuitry. Under a frequency mismatch of 5Hz between driving and sense modes, the angle random walk (ARW) is measured to be 0.44°/sec/✓Hz. The performance is limited by quadrature error and low-frequency noise in the circuit. The Cylindrical Rate-Integrating Gyroscope (CING) operates in whole-angle mode. The gyro is completely

  3. A palaeontological solution to the arthropod head problem.

    PubMed

    Budd, Graham E

    2002-05-16

    The composition of the arthropod head has been one of the most controversial topics in zoology, with a large number of theories being proposed to account for it over the last century. Although fossils have been recognized as being of potential importance in resolving the issue, a lack of consensus over their systematics has obscured their contribution. Here, I show that a group of previously problematic Cambrian arthropods from the Burgess Shale and Chengjiang faunas form a clade close to crown-group euarthropods, the group containing myriapods, chelicerates, insects and crustaceans. They are characterized by modified or even absent endopods, and two pre-oral appendages. Comparison with reconstructions of the crown-group euarthropod ground plan and recent investigations into onychophorans demonstrates that these two appendages are the first antenna (of extant crustaceans) and a more anterior appendage associated with an ocular segment. The latter appendage has been reduced in all crown-group euarthropods. Its most likely relic is as a component of the labrum. These fossils thus tie together results from disparate living groups (onychophorans and euarthropods).

  4. Arthropods as a source of new RNA viruses.

    PubMed

    Bichaud, L; de Lamballerie, X; Alkan, C; Izri, A; Gould, E A; Charrel, R N

    2014-12-01

    The discovery and development of methods for isolation, characterisation and taxonomy of viruses represents an important milestone in the study, treatment and control of virus diseases during the 20th century. Indeed, by the late-1950s, it was becoming common belief that most human and veterinary pathogenic viruses had been discovered. However, at that time, knowledge of the impact of improved commercial transportation, urbanisation and deforestation, on disease emergence, was in its infancy. From the late 1960s onwards viruses, such as hepatitis virus (A, B and C) hantavirus, HIV, Marburg virus, Ebola virus and many others began to emerge and it became apparent that the world was changing, at least in terms of virus epidemiology, largely due to the influence of anthropological activities. Subsequently, with the improvement of molecular biotechnologies, for amplification of viral RNA, genome sequencing and proteomic analysis the arsenal of available tools for virus discovery and genetic characterization opened up new and exciting possibilities for virological discovery. Many recently identified but "unclassified" viruses are now being allocated to existing genera or families based on whole genome sequencing, bioinformatic and phylogenetic analysis. New species, genera and families are also being created following the guidelines of the International Committee for the Taxonomy of Viruses. Many of these newly discovered viruses are vectored by arthropods (arboviruses) and possess an RNA genome. This brief review will focus largely on the discovery of new arthropod-borne viruses.

  5. Technique for Studying Arthropod and Microbial Communities within Tree Tissues

    PubMed Central

    Aflitto, Nicholas C; Hofstetter, Richard W; McGuire, Reagan; Dunn, David D; Potter, Kristen A

    2014-01-01

    Phloem tissues of pine are habitats for many thousands of organisms. Arthropods and microbes use phloem and cambium tissues to seek mates, lay eggs, rear young, feed, or hide from natural enemies or harsh environmental conditions outside of the tree. Organisms that persist within the phloem habitat are difficult to observe given their location under bark. We provide a technique to preserve intact phloem and prepare it for experimentation with invertebrates and microorganisms. The apparatus is called a ‘phloem sandwich’ and allows for the introduction and observation of arthropods, microbes, and other organisms. This technique has resulted in a better understanding of the feeding behaviors, life-history traits, reproduction, development, and interactions of organisms within tree phloem. The strengths of this technique include the use of inexpensive materials, variability in sandwich size, flexibility to re-open the sandwich or introduce multiple organisms through drilled holes, and the preservation and maintenance of phloem integrity. The phloem sandwich is an excellent educational tool for scientific discovery in both K-12 science courses and university research laboratories. PMID:25489987

  6. Early History of Arthropod and Vascular Plant Associations

    NASA Astrophysics Data System (ADS)

    Labandeira, Conrad C.

    Although research on modern plant-arthropod associations is one of the cornerstones of biodiversity studies, very little of that interest has percolated down to the fossil record. Much of this neglect is attributable to dismissal of Paleozoic plant-arthropod interactions as being dominated by detritivory, with substantive herbivory not emerging until the Mesozoic. Recent examination of associations from some of the earliest terrestrial communities indicates that herbivory probably extends to the Early Devonian, in the form of spore feeding and piercing-and-sucking. External feeding on pinnule margins and the intimate and intricate association of galling are documented from the Middle and Late Pennsylvanian, respectively. During the Early Permian, the range of external foliage feeding extended to hole feeding and skeletonization and was characterized by the preferential targeting of certain seed plants. At the close of the Paleozoic, surface fluid feeding was established, but there is inconclusive evidence for mutualistic relationships between insect pollinivores and seed plants. These data are gleaned from the largely separate trace-fossil records of gut contents, coprolites, and plant damage and the body-fossil records of plant reproductive and vegetative structures, insect mouthparts, and ovipositors. While these discoveries accentuate the potential for identifying particular associations, the greatest theoretical demand is to establish the spectrum and level of intensity for the emergence of insect herbivory in a range of environments during the Pennsylvanian and Permian.

  7. The Arthropod-borne Animal Diseases Unit: research program update and status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To accomplish the continuing research mission of the Arthropod Borne Animal Diseases Unit (ABADRU) in solving major endemic, emerging, and exotic arthropod-borne disease problems in livestock, the Unit has completed the move to Manhattan, KS. The ABADRU is one of five units at the Center for Grain a...

  8. Application of a Computerized General Purpose Information Management System (SELGEM) to Medically Important Arthropods (Diptera: Culcidae).

    DTIC Science & Technology

    1980-06-01

    COMPUTERIZED GENERAL PURPOSE INFORMATION MANAGEMENT SYSTEM (SELGE.M) TO KEDICALLY IMPORTANT ARTHROPODS (DIPTERA: CULICIDAE) Annual Report Terry L. Erwin June...GENERAL PURPOSE INFORMATION MANAGEMENT SYSTEM Annual--1 September 1979- (SEIGEM) TO MEDICALLY ThWORTANT ARTHROPODS 30 May 1980 (DIPTERA: CULICIDAE) 6

  9. "Bugs on Bugs": An Inquiry-Based, Collaborative Activity to Learn Arthropod & Microbial Biodiversity

    ERIC Educational Resources Information Center

    Lampert, Evan C.; Morgan, Jeanelle M.

    2015-01-01

    Diverse communities of arthropods and microbes provide humans with essential ecosystem goods and services. Arthropods are the most diverse and abundant macroscopic animals on the planet, and many remain to be discovered. Much less is known about microbial diversity, despite their importance as free-living species and as symbionts. We created…

  10. The i5K Initiative: Advancing arthropod genomics for knowledge, human health, agriculture, and the environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insects and their arthropod relatives including mites, spiders, and crustaceans, play major roles in the world’s terrestrial, aquatic, and marine ecosystems. Arthropods compete with humans for food and transmit devastating diseases. They also comprise the most diverse and successful branch of metazo...

  11. Life tables as tools of evaluation and quality control for arthropod mass production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Life tables, as a basic concept, are descriptions of survival potential at various ages or stages. Understanding critical life stages of arthropod development and their influence on the population structure is of great importance for arthropod rearing systems. Another important advantage of a life t...

  12. [Community structure and diversity of soil arthropods in naturally restored sandy grasslands after grazing].

    PubMed

    Liu, Ren-tao; Zhao, Ha-lin; Zhao, Xue-yong

    2010-11-01

    Taking the Naiman Desertification Research Station under Chinese Academy of Sciences as a base, an investigation was conducted on the community structure of soil arthropods in the naturally restored sandy grasslands after different intensity grazing disturbance, with the effects of vegetation and soil on this community structure approached. In the non-grazing grassland, soil arthropods were rich in species and more in individuals, and had the highest diversity. In the restored grassland after light grazing, soil arthropods had the lowest evenness and diversity. In the restored grassland after moderate grazing, the individuals of soil arthropods were lesser but the major groups were more, and the evenness and diversity were higher. In the restored grassland after heavy grazing, the individuals of soil arthropods were more but the major groups were lesser, and the diversity was higher. Plant individuals' number, vegetation height and coverage, and soil alkalinity were the main factors affecting the soil arthropod community in naturally restored grasslands after different intensity grazing disturbance. It was implied that after 12-year exclosure of grassland, soil arthropod community could be recovered to some degree, while grazing disturbance had long-term negative effects on the arthropod community.

  13. Taxonomic and functional composition of arthropod assemblages across contrasting Amazonian forests.

    PubMed

    Lamarre, Greg P A; Hérault, Bruno; Fine, Paul V A; Vedel, Vincent; Lupoli, Roland; Mesones, Italo; Baraloto, Christopher

    2016-01-01

    Arthropods represent most of global biodiversity, with the highest diversity found in tropical rain forests. Nevertheless, we have a very incomplete understanding of how tropical arthropod communities are assembled. We conducted a comprehensive mass sampling of arthropod communities within three major habitat types of lowland Amazonian rain forest, including terra firme clay, white-sand and seasonally flooded forests in Peru and French Guiana. We examined how taxonomic and functional composition (at the family level) differed across these habitat types in the two regions. The overall arthropod community composition exhibited strong turnover among habitats and between regions. In particular, seasonally flooded forest habitats of both regions comprised unique assemblages. Overall, 17·7% (26 of 147) of arthropod families showed significant preferences for a particular habitat type. We present a first reproducible arthropod functional classification among the 147 taxa based on similarity among 21 functional traits describing feeding source, major mouthparts and microhabitats inhabited by each taxon. We identified seven distinct functional groups whose relative abundance contrasted strongly across the three habitats, with sap and leaf feeders showing higher abundances in terra firme clay forest. Our novel arthropod functional classification provides an important complement to link these contrasting patterns of composition to differences in forest functioning across geographical and environmental gradients. This study underlines that both environment and biogeographical processes are responsible for driving arthropod taxonomic composition while environmental filtering is the main driver of the variance in functional composition.

  14. Arthropods in no-tillage soybean agroecosystems: Community composition and ecosystem interactions

    NASA Astrophysics Data System (ADS)

    House, Garfield J.; Stinner, Benjamin R.

    1983-01-01

    Sampling data are provided and concepts discussed regarding soil and foliage arthropod communities in conventional and no-tillage soybean agroecosystems Soil arthropod communities from the two cropping systems were also compared with that from an adjacent old field. Biweekly arthropod samples were collected from conventional, no-tillage, and old-field systems Soil arthropods were sampled by quadrat and pitfall trap methods, foliage arthropods were collected by sweep net Quadrat sampling revealed that ground beetle number, species diversity, and biomass were significantly higher ( P<0.05) in no-tillage than in conventional tillage systems. Pitfall trap data indicated higher densities and species diversity for most major soil macro-arthropod guilds Foliage arthropod guilds from no-tillage treatments showed higher species diversity throughout the growing season than those of conventional tillage, possibly because of greater structural diversity provided by weeds and litter in notillage systems No-tillage systems supported a larger and more diverse arthropod community than conventionally grown soybeans, suggesting a need for pest management strategies that simultaneously consider many variables. Both foliar grazing and leaf nitrogen content were higher in conventional than in no-tillage systems, indicating a possible causal connection between soil tillage and insect herbivory rates

  15. Arthropods from the Eocene Eckfelder Maar (Eifel, Germany) as a source for paleoecological information

    NASA Astrophysics Data System (ADS)

    Lutz, H.

    The arthropod-thanatocoenosis from the Middle-Eocene sediments of the Eckfelder Maar (Eifel, Germany) is characterized by a striking contrast between a highly diversified assemblage of terrestrial species on one hand and very few aquatic species on the other, hand. This most likely does not result from taphonomic biassing, but reflects a poor aquatic arthropod-community.

  16. Arthropods associated with fungal galls: do large galls support more abundant and diverse inhabitants?

    NASA Astrophysics Data System (ADS)

    Funamoto, Daichi; Sugiura, Shinji

    2017-02-01

    Fungus-induced galls can attract spore-feeding arthropods as well as gall-feeding ones, resulting in diverse communities. Do large fungal galls support more abundant and diverse arthropod communities than small fungal galls? To address this question, we investigated the structure of the arthropod community associated with bud galls induced by the fungus Melanopsichium onumae on the tree species Cinnamomum yabunikkei (Lauraceae) in central Japan. Thirteen species of arthropods were associated with M. onumae galls. Dominant arthropod species were represented by the larvae of a salpingid beetle (a spore feeder), a nitidulid beetle (a spore feeder), a cosmopterigid moth (a spore feeder), an unidentified moth (a gall tissue feeder), and a drosophilid species (a gall tissue feeder). Arthropod abundance and species richness were positively correlated with gall diameter. The majority of the most abundant species were more frequently found in large galls than in small ones, indicating that large fungal galls, which have more food and/or space for arthropods, could support a more abundant and diverse arthropod community.

  17. Application of a Computerized General Purpose Information Management System (SELGEM) (SELf-GEnerating Master) to Medically Important Arthropods (Diptera: Culicidae).

    DTIC Science & Technology

    1981-08-01

    APPLICATION OF A COMPUTERIZED GENERAL PURPOSE INFORMATION MANAGEMENT SYSTEM (SELGEM) TO MEDICALLY IMPORTANT ARTHROPODS (DIPTERA: CULICIDAE) I’ Annual Report...Bailey. 1981. Application of a com- puterized information management system (SELGEM) to medically important arthropods (National Museum Mosquito

  18. Dual-mass vibratory rate gyroscope with suppressed translational acceleration response and quadrature-error correction capability

    NASA Technical Reports Server (NTRS)

    Clark, William A. (Inventor); Juneau, Thor N. (Inventor); Lemkin, Mark A. (Inventor); Roessig, Allen W. (Inventor)

    2001-01-01

    A microfabricated vibratory rate gyroscope to measure rotation includes two proof-masses mounted in a suspension system anchored to a substrate. The suspension has two principal modes of compliance, one of which is driven into oscillation. The driven oscillation combined with rotation of the substrate about an axis perpendicular to the substrate results in Coriolis acceleration along the other mode of compliance, the sense-mode. The sense-mode is designed to respond to Coriolis accelerationwhile suppressing the response to translational acceleration. This is accomplished using one or more rigid levers connecting the two proof-masses. The lever allows the proof-masses to move in opposite directions in response to Coriolis acceleration. The invention includes a means for canceling errors, termed quadrature error, due to imperfections in implementation of the sensor. Quadrature-error cancellation utilizes electrostatic forces to cancel out undesired sense-axis motion in phase with drive-mode position.

  19. Vibratory response of a precision double-multi-layer monochromator positioning system using a generic modeling program with experimental verification.

    SciTech Connect

    Barraza, J.

    1998-07-29

    A generic vibratory response-modeling program has been developed as a tool for designing high-precision optical positioning systems. The systems are modeled as rigid-body structures connected by linear non-rigid elements such as complex actuators and bearings. The full dynamic properties of each non-rigid element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Thus, it is possible to have a suite of standardize structural elements for modeling many different positioning systems that use standardized components. This paper will present the application of this program to a double-multi-layer monochromator positioning system that utilizes standardized components. Calculated results are compared to experimental modal analysis results.

  20. [Round Table: Urticaria caused by arthropod bites and stings (excluding Hymenoptera)].

    PubMed

    Martínez-Molero, M I

    1999-01-01

    Adverse reactions to arthropod bites (hymenoptera excluded) can be faced with systemic reactions and local reaction. Among the numerous families of arthropods the species most commonly responsible are mosquitoes,. flea, horsefly and tick. In this article we explain the characteristics of reaction caused by arthropods and the mechanisms proposed. An IgE mechanism is incriminated in severe anaphylactic reactions. Various mechanisms have been proposed for local reactions. In order to know the incidence of sensitization and cross-reactivity with other arthropods, we have done a study where we have found that 31% of patients with reaction to mosquito bite had sensitization to Aedes communis and 53% of this group also had sensitization to other arthropods, probably due to a cross-reactivity.

  1. Ribosomal DNA phylogeny of the major extant arthropod classes and the evolution of myriapods.

    PubMed

    Friedrich, M; Tautz, D

    1995-07-13

    The evolutionary relationships among arthropods are of particular interest because the best-studied model system for ontogenetic pattern formation, the insect Drosophila, is a member of this phylum. Evolutionary inferences about the developmental mechanisms that have led to the various designs of the arthropod body plan depend on a knowledge of the phylogenetic framework of arthropod evolution. Based on morphological evidence, but also on palaeontological consideration, the sister group of the insects is believed to be found among the myriapods. Using nuclear ribosomal gene sequences for constructing a molecular phylogeny, we provide strong evidence that the crustaceans and not the myriapods should be considered to be the sister group of the insects. Moreover, the degree of sequence divergence suggests that the diversification of the myriapods occurred during the Cambrian. Our findings have general implications for the course of land colonization by the different arthropod groups, as well as for the interpretation of primitive and derived features of arthropod morphology.

  2. Introduction to the Arizona Sky Island Arthropod Project (ASAP): Systematics, Biogeography, Ecology, and Population Genetics of Arthropods of the Madrean Sky Islands

    PubMed Central

    Moore, Wendy; Meyer, Wallace M.; Eble, Jeffrey A.; Franklin, Kimberly; Wiens, John F.; Brusca, Richard C.

    2014-01-01

    The Arizona Sky Island Arthropod Project (ASAP) is a new multi-disciplinary research program at the University of Arizona that combines systematics, biogeography, ecology, and population genetics to study origins and patterns of arthropod diversity along elevation gradients and among mountain ranges in the Madrean Sky Island Region. Arthropods represent taxonomically and ecologically diverse organisms that drive key ecosystem processes in this mountain archipelago. Using data from museum specimens and specimens we obtain during long-term collecting and monitoring programs, ASAP will document arthropod species across Arizona's Sky Islands to address a number of fundamental questions about arthropods of this region. Baseline data will be used to determine climatic boundaries for target species, which will then be integrated with climatological models to predict future changes in arthropod communities and distributions in the wake of rapid climate change. ASAP also makes use of the natural laboratory provided by the Sky Islands to investigate ecological and genetic factors that influence diversification and patterns of community assembly. Here, we introduce the project, outline overarching goals, and describe preliminary data from the first year of sampling ground-dwelling beetles and ants in the Santa Catalina Mountains. PMID:25505938

  3. Introduction to the Arizona Sky Island Arthropod Project (ASAP): Systematics, Biogeography, Ecology, and Population Genetics of Arthropods of the Madrean Sky Islands.

    PubMed

    Moore, Wendy; Meyer, Wallace M; Eble, Jeffrey A; Franklin, Kimberly; Wiens, John F; Brusca, Richard C

    2013-01-01

    The Arizona Sky Island Arthropod Project (ASAP) is a new multi-disciplinary research program at the University of Arizona that combines systematics, biogeography, ecology, and population genetics to study origins and patterns of arthropod diversity along elevation gradients and among mountain ranges in the Madrean Sky Island Region. Arthropods represent taxonomically and ecologically diverse organisms that drive key ecosystem processes in this mountain archipelago. Using data from museum specimens and specimens we obtain during long-term collecting and monitoring programs, ASAP will document arthropod species across Arizona's Sky Islands to address a number of fundamental questions about arthropods of this region. Baseline data will be used to determine climatic boundaries for target species, which will then be integrated with climatological models to predict future changes in arthropod communities and distributions in the wake of rapid climate change. ASAP also makes use of the natural laboratory provided by the Sky Islands to investigate ecological and genetic factors that influence diversification and patterns of community assembly. Here, we introduce the project, outline overarching goals, and describe preliminary data from the first year of sampling ground-dwelling beetles and ants in the Santa Catalina Mountains.

  4. Modulating the Behaviors of Mesenchymal Stem Cells Via the Combination of High-Frequency Vibratory Stimulations and Fibrous Scaffolds

    PubMed Central

    Tong, Zhixiang; Duncan, Randall L.

    2013-01-01

    We are interested in the in vitro engineering of artificial vocal fold tissues via the strategic combination of multipotent mesenchymal stem cells (MSCs), physiologically relevant mechanical stimulations, and biomimetic artificial matrices. We have constructed a vocal fold bioreactor that is capable of imposing vibratory stimulations on the cultured cells at human phonation frequencies. Separately, fibrous poly (ɛ-caprolactone) (PCL) scaffolds emulating the ligamentous structure of the vocal fold were prepared by electrospinning, were incorporated in the vocal fold bioreactor, and were driven into a wave-like motion in an axisymmetrical fashion by the oscillating air. MSC-laden PCL scaffolds were subjected to vibrations at 200 Hz with a normal center displacement of ∼40 μm for a total of 7 days. A continuous (CT) or a 1 h-on-1 h-off (OF) regime with a total dynamic culture time of 12 h per day was applied. The dynamic loading did not cause any physiological trauma to the cells. Immunohistotochemical staining revealed the reinforcement of the actin filament and the enhancement of α5β1 integrin expression under selected dynamic culture conditions. Cellular expression of essential vocal fold extracellular matrix components, such as elastin, hyaluronic acid, and matrix metalloproteinase-1, was significantly elevated as compared with the static controls, and the OF regime is more conducive to matrix production than the CT vibration mode. Analyses of genes of typical fibroblast hallmarks (tenascin-C, collagen III, and procollagen I) as well as markers for MSC differentiation into nonfibroblastic lineages confirmed MSCs' adaptation of fibroblastic behaviors. Overall, the high-frequency vibratory stimulation, when combined with a synthetic fibrous scaffold, serves as a potent modulator of MSC functions. The novel bioreactor system presented here, as a versatile, yet well-controlled model, offers an in vitro platform for understanding vibration

  5. Arthropod Distribution in a Tropical Rainforest: Tackling a Four Dimensional Puzzle.

    PubMed

    Basset, Yves; Cizek, Lukas; Cuénoud, Philippe; Didham, Raphael K; Novotny, Vojtech; Ødegaard, Frode; Roslin, Tomas; Tishechkin, Alexey K; Schmidl, Jürgen; Winchester, Neville N; Roubik, David W; Aberlenc, Henri-Pierre; Bail, Johannes; Barrios, Héctor; Bridle, Jonathan R; Castaño-Meneses, Gabriela; Corbara, Bruno; Curletti, Gianfranco; Duarte da Rocha, Wesley; De Bakker, Domir; Delabie, Jacques H C; Dejean, Alain; Fagan, Laura L; Floren, Andreas; Kitching, Roger L; Medianero, Enrique; Gama de Oliveira, Evandro; Orivel, Jérôme; Pollet, Marc; Rapp, Mathieu; Ribeiro, Sérvio P; Roisin, Yves; Schmidt, Jesper B; Sørensen, Line; Lewinsohn, Thomas M; Leponce, Maurice

    2015-01-01

    Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents a first step towards scrutinizing the global distribution of biodiversity on Earth. To date most studies have focused on narrow taxonomic groups or lack a design that allows partitioning of the components of diversity. Here, we consider an exceptionally large dataset (113,952 individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama, where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting the soil, litter, understory, lower and upper canopy habitats, replicated across seasons in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance, observed and estimated species richness, additive decomposition of species richness, multiplicative partitioning of species diversity, variation in species composition, species turnover and guild structure as components of diversity. At the scale of our study (2 km of distance, 40 m in height and 400 days), the effects related to the vertical and seasonal dimensions were most important. Most adult arthropods were collected from the soil/litter or the upper canopy and species richness was highest in the canopy. We compared the distribution of arthropods and trees within our study system. Effects related to the seasonal dimension were stronger for arthropods than for trees. We conclude that: (1) models of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods; (2) it is imperative that estimates of global biodiversity derived from mass collecting of arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning observed here; and (3) given the high species turnover observed between seasons, global climate change may have severe consequences for rainforest arthropods.

  6. Arthropod Distribution in a Tropical Rainforest: Tackling a Four Dimensional Puzzle

    PubMed Central

    Basset, Yves; Cizek, Lukas; Cuénoud, Philippe; Didham, Raphael K.; Novotny, Vojtech; Ødegaard, Frode; Roslin, Tomas; Tishechkin, Alexey K.; Schmidl, Jürgen; Winchester, Neville N.; Roubik, David W.; Aberlenc, Henri-Pierre; Bail, Johannes; Barrios, Héctor; Bridle, Jonathan R.; Castaño-Meneses, Gabriela; Corbara, Bruno; Curletti, Gianfranco; Duarte da Rocha, Wesley; De Bakker, Domir; Delabie, Jacques H. C.; Dejean, Alain; Fagan, Laura L.; Floren, Andreas; Kitching, Roger L.; Medianero, Enrique; Gama de Oliveira, Evandro; Orivel, Jérôme; Pollet, Marc; Rapp, Mathieu; Ribeiro, Sérvio P.; Roisin, Yves; Schmidt, Jesper B.; Sørensen, Line; Lewinsohn, Thomas M.; Leponce, Maurice

    2015-01-01

    Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents a first step towards scrutinizing the global distribution of biodiversity on Earth. To date most studies have focused on narrow taxonomic groups or lack a design that allows partitioning of the components of diversity. Here, we consider an exceptionally large dataset (113,952 individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama, where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting the soil, litter, understory, lower and upper canopy habitats, replicated across seasons in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance, observed and estimated species richness, additive decomposition of species richness, multiplicative partitioning of species diversity, variation in species composition, species turnover and guild structure as components of diversity. At the scale of our study (2km of distance, 40m in height and 400 days), the effects related to the vertical and seasonal dimensions were most important. Most adult arthropods were collected from the soil/litter or the upper canopy and species richness was highest in the canopy. We compared the distribution of arthropods and trees within our study system. Effects related to the seasonal dimension were stronger for arthropods than for trees. We conclude that: (1) models of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods; (2) it is imperative that estimates of global biodiversity derived from mass collecting of arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning observed here; and (3) given the high species turnover observed between seasons, global climate change may have severe consequences for rainforest arthropods. PMID:26633187

  7. Genetically based latitudinal clines in Artemisia californica drive parallel clines in arthropod communities.

    PubMed

    Pratt, Jessica D; Datu, Andrew; Tran, Thi; Sheng, Daniel C; Mooney, Kailen A

    2017-01-01

    Intraspecific variation in plant traits has been clearly shown to drive the structure of associated arthropod communities at the spatial scale of individual plant populations. Nevertheless, it is largely unknown whether plant trait variation among populations drives landscape-scale variation in arthropod communities, and how the strength of such plant genetic effects compares to, and interacts with, those of environmental variation. We documented the structure of arthropod communities on Artemisia californica for two consecutive years in a common garden of plants sourced from five populations along a 5° latitudinal gradient and grown under precipitation treatments approximating the four-fold difference between the north and south range margins for this species. Previous study of plant traits from this garden documented clinal genetic variation, suggesting local adaptation to this environmental gradient, as well as effects of precipitation manipulation that were consistent among populations (i.e., no genotype-by-environment interaction). Within the common garden, arthropod density, evenness, and diversity increased clinally with population source latitude, and arthropod community composition (i.e., species relative abundance) showed a north-south divide. The 2.6-fold cline of northward increase in arthropod density in the common garden was mirrored by a 6.4-fold increase in arthropod density on wild plants sampled along the species range. In contrast to the strong influence of plant genotype, the precipitation manipulation only influenced arthropod community composition, and plant genetic effects on arthropods operated independently of precipitation regime (no genotype-by-environment interaction). Accordingly, we conclude that the strongest driver of landscape-level variation in arthropod communities in this foundational plant species is not variation in the abiotic environment itself, but rather variation in plant traits underlain by the evolutionary process of

  8. Arthropods and associated arthropod-borne diseases transmitted by migrating birds. The case of ticks and tick-borne pathogens.

    PubMed

    Sparagano, Olivier; George, David; Giangaspero, Annunziata; Špitalská, Eva

    2015-09-30

    Geographic spread of parasites and pathogens poses a constant risk to animal health and welfare, particularly given that climate change is expected to potentially expand appropriate ranges for many key species. The spread of deleterious organisms via trade routes and human travelling is relatively closely controlled, though represents only one possible means of parasite/pathogen distribution. The transmission via natural parasite/pathogen movement between geographic locales, is far harder to manage. Though the extent of such movement may be limited by the relative inability of many parasites and pathogens to actively migrate, passive movement over long distances may still occur via migratory hosts. This paper reviews the potential role of migrating birds in the transfer of ectoparasites and pathogens between geographic locales, focusing primarily on ticks. Bird-tick-pathogen relationships are considered, and evidence provided of long-range parasite/pathogen transfer from one location to another during bird migration events. As shown in this paper not only many different arthropod species are carried by migrating birds but consequently these pests carry many different pathogens species which can be transmitted to the migrating birds or to other animal species when those arthropods are dropping during these migrations. Data available from the literature are provided highlighting the need to understand better dissemination paths and disease epidemiology.

  9. Interaction between arthropod filiform hairs in a fluid enviroment

    PubMed Central

    Cummins, Bree; Gedeon, Tomáš; Klapper, Isaac; Cortez, Ricardo

    2009-01-01

    Many arthropods use filiform hairs as mechanoreceptors to detect air motion. In common house crickets (Acheta domestica) the hairs cover two antenna-like appendages called cerci at the rear of the abdomen. The biomechanical stimulus-response properties of individual filiform hairs have been investigated and modeled extensively in several earlier studies. However, only a few previous studies have considered viscosity-mediated coupling between pairs of hairs, and only in particular configurations. Here we present a model capable of calculating hair-to-hair coupling in arbitrary configurations. We simulate the coupled motion of a small group of mechanosensory hairs on a cylindrical section of cercus. We have found that the coupling effects are non-negligible, and likely constrain the operational characteristics of the cercal sensory array. PMID:17434184

  10. Arthropod fossil data increase congruence of morphological and molecular phylogenies.

    PubMed

    Legg, David A; Sutton, Mark D; Edgecombe, Gregory D

    2013-01-01

    The relationships of major arthropod clades have long been contentious, but refinements in molecular phylogenetics underpin an emerging consensus. Nevertheless, molecular phylogenies have recovered topologies that morphological phylogenies have not, including the placement of hexapods within a paraphyletic Crustacea, and an alliance between myriapods and chelicerates. Here we show enhanced congruence between molecular and morphological phylogenies based on 753 morphological characters for 309 fossil and Recent panarthropods. We resolve hexapods within Crustacea, with remipedes as their closest extant relatives, and show that the traditionally close relationship between myriapods and hexapods is an artefact of convergent character acquisition during terrestrialisation. The inclusion of fossil morphology mitigates long-branch artefacts as exemplified by pycnogonids: when fossils are included, they resolve with euchelicerates rather than as a sister taxon to all other euarthropods.

  11. Plant diversity controls arthropod biomass and temporal stability.

    PubMed

    Borer, Elizabeth T; Seabloom, Eric W; Tilman, David; Novotny, Vojtech

    2012-12-01

    Understanding the linkages among species diversity, biomass production and stability underlies effective predictions for conservation, agriculture and fisheries. Although these relationships have been well studied for plants and, to a lesser extent, consumers, relationships among plant and consumer diversity, productivity, and temporal stability remain relatively unexplored. We used structural equation models to examine these relationships in a long-term experiment manipulating plant diversity and enumerating the arthropod community response. We found remarkably similar strength and direction of interrelationships among diversity, productivity and temporal stability of consumers and plants. Further, our results suggest that the frequently observed relationships between plant and consumer diversity occur primarily via changes in plant production leading to changed consumer production rather than via plant diversity directly controlling consumer diversity. Our results demonstrate that extinction or invasion of plant species can resonate via biomass and energy flux to control diversity, production and stability of both plant and consumer communities.

  12. Arthropod symbiotes of Laonastes aenigmamus (Rodentia:Diatomyidae).

    PubMed

    Bochkov, A V; Abramov, A V; Durden, L A; Apanaskevich, D A; Stekolnikov, A A; Stanyukovich, M K; Gnophanxay, S; Tikhonov, A N

    2011-04-01

    Arthropod symbiotes of the Laotian rock-rat, Laonastes aenigmamus (Rodentia:Diatomyidae), from Laos are examined. This host is a member of Diatomyidae previously thought to have gone extinct >10 million yr ago. Permanent symbiotes are represented by 2 species, a new species of sucking louse, Polyplax sp., near rhizomydis (Phthiraptera:Polyplacidae), and a new species of fur mite, Afrolistrophorus sp., near maculatus (Acariformes:Listrophoridae). The temporary parasites are represented by 18 species, i.e., 1 mesostigmatan species, i.e., a new species of Androlaelaps near casalis (Parasitiformes:Laelapidae); immature stages of 2 tick species, Ixodes granulatus and Haemaphysalis sp. (Parasitiformes:Ixodidae); and a rich fauna of chiggers (Acariformes:Trombiculidae) comprising 8 genera and 15 species. It is hypothesized that this host completely lost its initial fauna of ectosymbiotes and that ancestors of the recorded symbiotes switched to this host from rodents of the superfamily Muroidea.

  13. Phenoptosis in arthropods and immortality of social insects.

    PubMed

    Kartsev, V M

    2014-10-01

    In general, there are no drastic differences in phenoptosis patterns in plant and animal organisms. However, there are some specific features characteristic for insects and other arthropods: 1) their development includes metamorphosis with different biochemical laws at consecutive developmental stages; 2) arthropods can reduce or stop development and aging when in a state of diapause or temporal cold immobility; 3) their life cycle often correlates with seasonal changes of surroundings; 4) polymorphism is widespread - conspecifics differ by their lifespans and phenoptosis features; 5) lifespan-related sexual dimorphism is common; 6) significant situational plasticity of life cycle organization is an important feature; for example, the German wasp (Paravespula germanica) is obligatorily univoltine in the temperate zone, while in tropical regions its lifespan increases and leads to repeated reproduction; 7) life cycles of closely related species may differ significantly, for example, in contrast to German wasp, some tropical hornets (Vespa) have only one reproduction period. Surprisingly, many insect species have been shown to be subjected to gradual aging and phenoptosis, like the highest mammals. However, queens of social insects and some long-lived arachnids can apparently be considered non-aging organisms. In some species, lifespan is limited to one season, while others live much longer or shorter. Cases of one-time reproduction are rather rare. Aphagia is common in insects (over 10,000 species). Cannibalism is an important mortality factor in insects as well as in spiders. In social insects, which exist only in colonies (families), the lifetime of a colony can be virtually unlimited. However, in case of some species the developmental cycle and death of a colony after its completion are predetermined. Most likely, natural selection in insects does not lengthen individual lifespan, but favors increase in reproduction efficiency based on fast succession of

  14. New insights on arthropod toxins that potentiate erectile function.

    PubMed

    Nunes, Kenia P; Torres, Fernanda S; Borges, Marcia H; Matavel, Alessandra; Pimenta, Adriano M C; De Lima, Maria E

    2013-07-01

    The use of natural substances for the treatment of diseases or injuries is an ancient practice of many cultures. According to folklore, natural aphrodisiacs may help to raise libido and increase desire. The supposed aphrodisiacs mainly include a plethora of preparations of plants, among other substances. However, the real boundary between myth and reality has not been established yet in most cases and such boundaries must be drawn by scientific methods. A growing interest of the scientific community has been focused on animal venoms, especially those from arthropods, i.e. spiders and scorpions, which cause priapism, a prolonged and painful erection. This review highlights the studies that have been performed with venoms and toxins from arthropods known to cause priapism, among other toxic symptoms, pointing out some pharmacological approaches for better understanding this effect. To date, the venom of some spiders, mainly Phoneutria nigriventer, and scorpions, such as the yellow South American scorpion Tityus serrulatus, among others, have been known to cause priapism. Since erectile dysfunction (ED) is a growing health problem in the world, more common in patients with vascular diseases as diabetes and hypertension, the use of animal venoms and toxins as pharmacological tools could not only shed light to the mechanisms involved in erectile function, but also represent a possible model for new drugs to treat ED. Unfortunately, attempts to correlate the structure of those priapism-related toxins were unfruitful. Such difficulties lie firstly on the poor data concerning purified priapism-related toxins, instead of whole venoms and/or semi-purified fractions, and secondly, on the scarce available primary sequences and structural data, mainly from spider toxins. It has been shown that all these toxins modify the sodium (Na(+)) channel activity, mostly slowing down its inactivation current. Improving the knowledge on the tertiary structure of these toxins could provide

  15. Exploring the possibility of arthropod transmission of HCV.

    PubMed

    Houldsworth, Annwyne

    2017-02-01

    Hepatitis C virus (HCV) is a major cause of chronic hepatitis, cirrhosis, and liver cancer occurring in up to 3% of the world's population. Parenteral exposure to HCV is the major mode of transmission of infection. Once established, infection will persist in up to 85% of individuals with only a minority of patients clearing viremia. Egypt has possibly the highest HCV prevalence in the world where 10-20% of the general population are infected with HCV. Endemic HCV appears to be concentrated in the tropics and sub-tropics where there are higher biting rates from insects. The question as to whether a bridge vector transmission is possible, via arthropods, both between humans and/or from an animal reservoir to humans is explored. Mechanical transmission, as opposed to biological transmission, is considered. Mechanical transmission can be an efficient way of transmitting an infection, as effective as biological transmission. Probability of transmission can increase as to the immediate circumstances and conditions at the time. Several factors may enhance mechanical transmission, including high levels of microbes in the vector, frequent biting, the close proximity, and contact between vectors and recipients as well as high density of insects. HCV has been isolated from bodies or heads of mosquitoes collected from the houses of HCV-infected individuals. The possibility of enzootic cycles of HCV tangential transmission via bridging vectors, such as, arthropods needs to be further investigated and possible animal reservoirs, including domestic rural epizootic cycles for HCV infection, requires further research with particular initial emphasis on equine infections. J. Med. Virol. 89:187-194, 2017. © 2016 Wiley Periodicals, Inc.

  16. Acquisition of Cry1Ac Protein by Non-Target Arthropods in Bt Soybean Fields

    PubMed Central

    Yu, Huilin; Romeis, Jörg; Li, Yunhe; Li, Xiangju; Wu, Kongming

    2014-01-01

    Soybean tissue and arthropods were collected in Bt soybean fields in China at different times during the growing season to investigate the exposure of arthropods to the plant-produced Cry1Ac toxin and the transmission of the toxin within the food web. Samples from 52 arthropod species/taxa belonging to 42 families in 10 orders were analysed for their Cry1Ac content using enzyme-linked immunosorbent assay (ELISA). Among the 22 species/taxa for which three samples were analysed, toxin concentration was highest in the grasshopper Atractomorpha sinensis and represented about 50% of the concentration in soybean leaves. Other species/taxa did not contain detectable toxin or contained a concentration that was between 1 and 10% of that detected in leaves. These Cry1Ac-positive arthropods included a number of mesophyll-feeding Hemiptera, a cicadellid, a curculionid beetle and, among the predators, a thomisid spider and an unidentified predatory bug belonging to the Anthocoridae. Within an arthropod species/taxon, the Cry1Ac content sometimes varied between life stages (nymphs/larvae vs. adults) and sampling dates (before, during, and after flowering). Our study is the first to provide information on Cry1Ac-expression levels in soybean plants and Cry1Ac concentrations in non-target arthropods in Chinese soybean fields. The data will be useful for assessing the risk of non-target arthropod exposure to Cry1Ac in soybean. PMID:25110881

  17. [Population structure of soil arthropod in different age Pinus massoniana plantations].

    PubMed

    Tan, Bo; Wu, Fu-zhong; Yang, Wan-qin; Zhang, Jian; Xu, Zhen-feng; Liu, Yang; Gou, Xiao-lin

    2013-04-01

    An investigation was conducted on the population structure of soil arthropod community in the 3-, 8-, 14-, 31-, and 40-years old Pinus massoniana plantations in the upper reaches of the Yangtze River in spring (May) and autumn (October), 2011, aimed to search for the scientific management of the plantation. A total of 4045 soil arthropods were collected, belonging to 57 families. Both the individual density and the taxonomic group number of the soil arthropod community decreased obviously with increasing soil depth, and this trend increased with increasing stand age. The dominant groups and ordinary groups of the soil arthropod community varied greatly with the stand age of P. massoniana plantation, and a significant difference (P<0.05) was observed in the individual density and taxonomic group number among different age P. massoniana plantations. In comparison with other stand age P. massoniana plantations, 3years old P. massoniana plantation had a significant difference in the structure and diversity of soil arthropod community, and the similarity index of the soil arthropod community was lower. The individual density, taxonomic group number, and diversity of soil arthropod community were the highest in 8-years old P. massoniana plantation, and then, decreased obviously with increasing stand age. It was suggested that the land fertility of the P. massoniana plantations could be degraded with increasing stand age, and it would be appropriate to make artificial regulation and restoration in 8-years old P. massoniana plantation.

  18. Evolution of Ecdysis and Metamorphosis in Arthropods: The Rise of Regulation of Juvenile Hormone.

    PubMed

    Cheong, Sam P S; Huang, Juan; Bendena, William G; Tobe, Stephen S; Hui, Jerome H L

    2015-11-01

    Arthropods are the most successful group of animals, and are found in diverse habitats; they account for more than 80% of described animal species. A rigid exoskeleton is a common feature that is shared across the different groups of arthropods. The exoskeleton offers protection and is shed between developmental stages via a unique evolutionarily conserved process known as molting/ecdysis. Molting is triggered by steroid hormones, the ecdysteroids, and the regulation of their biosynthesis has long been proposed as a contributor to the success of arthropods during evolution. Nevertheless, how novelties arose that contributed to the diversifications of arthropods remain unclear. Juvenile hormones (JHs) are sequiterpenoids that were thought to be unique to insects, modulating the timing of metamorphosis in conjunction with the actions of ecdysteroids. Here, we revisit the old question of "the role that the sesquiterpenoids play in arthropod evolution" with a focus on the neglected non-insect arthropods. We hypothesize that the sesquiterpenoid, methyl farnesoate (MF), had already established regulatory functions in the last common ancestor of arthropods, and the difference in the regulation of biosynthesis and degradation of sesquiterpenoids, such as MF and JH, was another major driving force in the successful radiation of insects.

  19. Arthropod abundance and seasonal bird use of bottomland forest harvest gaps.

    SciTech Connect

    Moorman, Christopher, E.; Bowen, Liessa T.; Kilgo, John, C.; Hanula, James, L.; Horn, Scott; Ulyshen, Michael, D.

    2012-03-01

    We investigated the influence of arthropod abundance and vegetation structure on shifts in avian use of canopy gap, gap edge, and surrounding forest understory in a bottomland hardwood forest in the Upper Coastal Plain of South Carolina. We compared captures of foliage-gleaning birds among locations during four periods (spring migration, breeding, post-breeding, and fall migration). Foliage arthropod densities were greatest in the forest understory in all four seasons, but understory vegetation density was greatest in gaps. Foliage-gleaning bird abundance was positively associated with foliage-dwelling arthropods during the breeding (F = 18.5, P < 0.001) and post-breeding periods (F = 9.4, P = 0.004), and negatively associated with foliage-dwelling arthropods during fall migration (F = 5.4, P = 0.03). Relationships between birds and arthropods were inconsistent, but the arthropod prey base seemed to be least important during migratory periods. Conversely, bird captures were positively correlated with understory vegetation density during all four periods (P < 0.001). Our study suggests high bird abundance associated with canopy gaps during the non-breeding period resulted less from high arthropod food resource availability than from complex understory and midstory vegetation structure.

  20. Comparison of Arthropod Prey of Red-Cockaded Woodpeckers on the Boles of Longleaf and Loblolly Pines

    SciTech Connect

    Horn, S.; Hanula, J.

    2002-01-01

    Use of knockdown insecticides to sample arthropods on longleaf and loblolly pine to determine which harbored the greater abundance of potential prey. Alterations of longleaf pine bark surface to determine whether bark structure may affect arthropods residing on a tree's bole. Recovery revealed fewer arthropods from scraped trees. Results suggest the bark structure and not the chemical nature of the bark is responsible for differences in arthropod abundance and biomass. Retaining or restoring longleaf pine in red-cockaded woodpecker habitats should increase arthropod availability for this endangered bird and other back-foraging species.

  1. Future rainfall patterns will reduce arthropod abundance in model arable agroecosystems with different soil types

    NASA Astrophysics Data System (ADS)

    Zaller, Johann; Simmer, Laura; Tabi Tataw, James; Formayer, Herbert; Hösch, Johannes; Baumgarten, Andreas

    2013-04-01

    Climate change scenarios for eastern Austria predict a seasonal shift in precipitation patterns with fewer but heavier rainfall events and longer drought periods during the growing season and more precipitation during winter. This is expected to alter arthropods living in natural and agricultural ecosystems with consequences for several ecosystem functions and services. In order to better understand the effects of future rainfall patterns on aboveground arthropods inhabiting an agroecosystem, we conducted an experiment where we simulated rainfall patterns in model arable systems with three different soil types. Experiments were conducted in winter wheat cultivated in a lysimeter facility near Vienna, Austria, where three different soil types (calcaric phaeozem, calcic chernozem and gleyic phaeozem) were subjected to long-term current vs. predicted rainfall patterns according to regionalized climate change projections for 2071-2100. Aboveground arthropods were assessed by suction sampling in April, May and June 2012. We found significant differences in mean total arthropod abundances between the sampling dates with 20 ± 2 m-2, 90 ± 20 m-2 and 289 ± 54 m-2 in April, May and June, respectively. Across all three sampling dates, future rainfall patterns significantly reduced the abundance of Araneae (-43%), Auchenorrhyncha (-39%), Coleoptera (-48%), Carabidae (-41%), Chrysomelidae (-64%), Collembola (-58%), Diptera (-75%) and Neuroptera (-73%). Generally, different soil types had no effect on the abundance of arthropods. The diversity of arthropod communities was unaffected by rainfall patterns or soil types. Correlation analyses of arthropod abundances with crop biomass, weed density and abundance suggest that rainfall effects indirectly affected arthropods via changes on crops and weeds. In conclusion, these results show that future rainfall patterns will have detrimental effects on the abundance of a variety of aboveground arthropods in winter wheat with potential

  2. Grassland Arthropods Are Controlled by Direct and Indirect Interactions with Cattle but Are Largely Unaffected by Plant Provenance.

    PubMed

    Farrell, Kelly Anne; Harpole, W Stanley; Stein, Claudia; Suding, Katharine N; Borer, Elizabeth T

    2015-01-01

    Cattle grazing and invasion by non-native plant species are globally-ubiquitous changes occurring to plant communities that are likely to reverberate through whole food webs. We used a manipulative field experiment to quantify how arthropod community structure differed in native and non-native California grassland communities in the presence and absence of grazing. The arthropod community was strongly affected by cattle grazing: the biovolume of herbivorous arthropods was 79% higher in grazed than ungrazed plots, whereas the biovolume of predatory arthropods was 13% higher in ungrazed plots. In plots where non-native grasses were grazed, arthropod biovolume increased, possibly in response to increased plant productivity or increased nutritional quality of rapidly-growing annual plants. Grazing may thus affect plant biomass both through the direct removal of biomass, and through arthropod-mediated impacts. We also expected the arthropod community to differ between native and non-native plant communities; surprisingly, arthropod richness and diversity did not vary consistently between these grass community types, although arthropod abundance was slightly higher in plots with native and ungrazed grasses. These results suggest that whereas cattle grazing affects the arthropod community via direct and indirect pathways, arthropod community changes commonly associated with non-native plant invasions may not be due to the identity or dominance of the invasive species in those systems, but to accompanying changes in plant traits or functional group composition, not seen in this experiment because of the similarity of the plant communities.

  3. Grassland Arthropods Are Controlled by Direct and Indirect Interactions with Cattle but Are Largely Unaffected by Plant Provenance

    PubMed Central

    Farrell, Kelly Anne; Harpole, W. Stanley; Stein, Claudia; Suding, Katharine N.; Borer, Elizabeth T.

    2015-01-01

    Cattle grazing and invasion by non-native plant species are globally-ubiquitous changes occurring to plant communities that are likely to reverberate through whole food webs. We used a manipulative field experiment to quantify how arthropod community structure differed in native and non-native California grassland communities in the presence and absence of grazing. The arthropod community was strongly affected by cattle grazing: the biovolume of herbivorous arthropods was 79% higher in grazed than ungrazed plots, whereas the biovolume of predatory arthropods was 13% higher in ungrazed plots. In plots where non-native grasses were grazed, arthropod biovolume increased, possibly in response to increased plant productivity or increased nutritional quality of rapidly-growing annual plants. Grazing may thus affect plant biomass both through the direct removal of biomass, and through arthropod-mediated impacts. We also expected the arthropod community to differ between native and non-native plant communities; surprisingly, arthropod richness and diversity did not vary consistently between these grass community types, although arthropod abundance was slightly higher in plots with native and ungrazed grasses. These results suggest that whereas cattle grazing affects the arthropod community via direct and indirect pathways, arthropod community changes commonly associated with non-native plant invasions may not be due to the identity or dominance of the invasive species in those systems, but to accompanying changes in plant traits or functional group composition, not seen in this experiment because of the similarity of the plant communities. PMID:26158494

  4. Longleaf Pine Characterists Associated with Arthropods Available for Red-Cockaded Woodpeckers

    SciTech Connect

    Hanula, J.L.; Franzreb, K.E.; Pepper, W.D.

    1999-01-25

    The authors sampled arthropods on 300 longleaf pine under varying stand conditions and ranging in age from 20 to 100 years. The most diverse orders were beetles, spiders, ants, wasps and bees. The most abundant were aphids and Hymenoptera with a large number of ants. Arthropod biomass per tree increased in age up to 65-70 years, but biomass was highest in the youngest stands. Arthropods were positively correlated to bark thickness and tree diameter, but negatively related to the stand basal area. No relationships were found between abundance and ground vegetation conditions.

  5. Arthropods of forensic importance on pig carrion in the Coahuilan semidesert, Mexico.

    PubMed

    Valdes-Perezgasga, Ma Teresa; Sanchez-Ramos, Francisco Javier; Garcia-Martinez, Oswaldo; Anderson, Gail S

    2010-07-01

    This is the first report of an ongoing research to establish a sarcosaprophagous arthropod database in the Coahuilan semidesert. Seven pigs (Sus scrofa L.) were used as human models to determine succession in an open urban area during the 2007 winter-spring period. Arthropods were collected manually and from pitfall traps. Carcass biomass loss, as well as arthropod colonization, was recorded during 71 days postmortem. Five decomposition stages were identified during which most abundant orders were found to be Diptera, Coleoptera, and Hymenoptera. Lucilia sericata (Meigen), Chrysomya rufifacies (Macquart), Necrobia rufipes (DeGeer), Dermestes maculatus (DeGeer), Pheidole hyatti Emery, and Pogonomyrmex rugosus Emery stood out as dominant species.

  6. Mid-Cretaceous charred fossil flowers reveal direct observation of arthropod feeding strategies

    PubMed Central

    Hartkopf-Fröder, Christoph; Rust, Jes; Wappler, Torsten; Friis, Else Marie; Viehofen, Agnes

    2012-01-01

    Although plant–arthropod relationships underpin the dramatic rise in diversity and ecological dominance of flowering plants and their associated arthropods, direct observations of such interactions in the fossil record are rare, as these ephemeral moments are difficult to preserve. Three-dimensionally preserved charred remains of Chloranthistemon flowers from the Late Albian to Early Cenomanian of Germany preserve scales of mosquitoes and an oribatid mite with mouthparts inserted into the pollen sac. Mosquitoes, which today are frequent nectar feeders, and the mite were feeding on pollen at the time wildfire consumed the flowers. These findings document directly arthropod feeding strategies and their role in decomposition. PMID:21900310

  7. Changes in soil temperature during prescribed burns impact local arthropod communities

    NASA Astrophysics Data System (ADS)

    Verble-Pearson, Robin; Perry, Gad

    2016-04-01

    As wildfires increase in severity and intensity globally, the development of methods to assess their effects on soils is of increasing importance. We examined soil arthropod communities in the southern United States and estimated their abundance, species richness, and composition in areas recently impacted by prescribed burns. In addition, we placed thermal probes in soils and correlated soil temperatures to arthropod responses. Longer fire residence times resulted in greater soil heating which resulted in decreases in arthropod abundance and species richness and shifts in species composition. We believe that these results may be useful in developing tools to assess fire effects on soil systems.

  8. Unprecedented genomic diversity of RNA viruses in arthropods reveals the ancestry of negative-sense RNA viruses.

    PubMed

    Li, Ci-Xiu; Shi, Mang; Tian, Jun-Hua; Lin, Xian-Dan; Kang, Yan-Jun; Chen, Liang-Jun; Qin, Xin-Cheng; Xu, Jianguo; Holmes, Edward C; Zhang, Yong-Zhen

    2015-01-29

    Although arthropods are important viral vectors, the biodiversity of arthropod viruses, as well as the role that arthropods have played in viral origins and evolution, is unclear. Through RNA sequencing of 70 arthropod species we discovered 112 novel viruses that appear to be ancestral to much of the documented genetic diversity of negative-sense RNA viruses, a number of which are also present as endogenous genomic copies. With this greatly enriched diversity we revealed that arthropods contain viruses that fall basal to major virus groups, including the vertebrate-specific arenaviruses, filoviruses, hantaviruses, influenza viruses, lyssaviruses, and paramyxoviruses. We similarly documented a remarkable diversity of genome structures in arthropod viruses, including a putative circular form, that sheds new light on the evolution of genome organization. Hence, arthropods are a major reservoir of viral genetic diversity and have likely been central to viral evolution.

  9. Unprecedented genomic diversity of RNA viruses in arthropods reveals the ancestry of negative-sense RNA viruses

    PubMed Central

    Li, Ci-Xiu; Shi, Mang; Tian, Jun-Hua; Lin, Xian-Dan; Kang, Yan-Jun; Chen, Liang-Jun; Qin, Xin-Cheng; Xu, Jianguo; Holmes, Edward C; Zhang, Yong-Zhen

    2015-01-01

    Although arthropods are important viral vectors, the biodiversity of arthropod viruses, as well as the role that arthropods have played in viral origins and evolution, is unclear. Through RNA sequencing of 70 arthropod species we discovered 112 novel viruses that appear to be ancestral to much of the documented genetic diversity of negative-sense RNA viruses, a number of which are also present as endogenous genomic copies. With this greatly enriched diversity we revealed that arthropods contain viruses that fall basal to major virus groups, including the vertebrate-specific arenaviruses, filoviruses, hantaviruses, influenza viruses, lyssaviruses, and paramyxoviruses. We similarly documented a remarkable diversity of genome structures in arthropod viruses, including a putative circular form, that sheds new light on the evolution of genome organization. Hence, arthropods are a major reservoir of viral genetic diversity and have likely been central to viral evolution. DOI: http://dx.doi.org/10.7554/eLife.05378.001 PMID:25633976

  10. Comparative analysis of gene expression patterns in the arthropod labrum and the onychophoran frontal appendages, and its implications for the arthropod head problem.

    PubMed

    Janssen, Ralf

    2017-01-01

    The arthropod head problem has troubled scientists for more than a century. The segmental composition of the arthropod head, homology of its appendages, and especially the nature of the most anterior region of the head are still, at least partially, unclear. One morphological feature of the head that is in the center of current debate is the labrum (upper lip), a fleshy appendicular structure that covers the arthropod mouth. One hypothesis is that the labrum represents a fused pair of protocerebral limbs that likely are homologous with the frontal appendages (primary antennae) of extant onychophorans and the so-called great appendages of stem arthropods. Recently, this hypothesis obtained additional support through genetic data, showing that six3, an anterior-specific gene, is exclusively expressed in the arthropod labrum and the onychophoran frontal appendages, providing an additional line of evidence for homology. Here I present data that put this finding into perspective. The outcome of my study shows that the homologization of a morphological structure by the expression of a single genetic factor is potentially misleading.

  11. Is the risk for soil arthropods covered by new data requirements under the EU PPP Regulation No. 1107/2009?

    PubMed

    Kohlschmid, E; Ruf, D

    2016-12-01

    Testing of effects on earthworms and non-target foliar arthropods is an integral part of the ecotoxicological risk assessment for the authorization of plant protection products. According to the new data requirements, which came into force in 2014 for active substances and in 2016 for plant protection products, the chronic earthworm toxicity test with Eisenia fetida based on reproductive, growth, and behavioral effects instead of the acute earthworm toxicity test based on mortality, has to be conducted routinely. Additional testing of effects on soil arthropods (Folsomia candida, Hyposaspis aculeifer) is required if the risk assessment of foliar applications raises concerns regarding non-target foliar arthropods (Aphidius rhopalosiphi, Typhlodromus pyri) or if the product is applied directly on or into the soil. Thus, it was investigated whether the sublethal earthworm endpoint is more sensitive than the sublethal soil arthropod endpoint for different types of pesticides and whether the risk assessment for non-target arthropods would trigger the testing of effects on soil arthropods in the cases where soil arthropods are more sensitive than earthworms. Toxicity data were obtained from Swiss ecotoxicological database, EFSA Conclusions and scientific literature. For insecticides and herbicides, no general conclusion regarding differences in sensitivity of either earthworms or soil arthropods based on sublethal endpoints were possible. For fungicides, the data indicated that in general, earthworms seemed to be more sensitive than soil arthropods. In total, the sublethal F. candida or H. aculeifer endpoint was lower than the sublethal E. fetida endpoint for 23 (34 %) out of 68 active substances. For 26 % of these 23 active substances, testing of soil arthropods would not have been triggered due to the new data requirement. These results based on sublethal endpoints show that earthworms and soil arthropods differ in sensitivity toward certain active substances and

  12. Do Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs use vibrational communication?

    NASA Astrophysics Data System (ADS)

    Chuche, Julien; Thiéry, Denis; Mazzoni, Valerio

    2011-07-01

    Small Auchenorrhyncha use substrate-borne vibrations to communicate. Although this behaviour is well known in adult leafhoppers, so far no studies have been published on nymphs. Here we checked the occurrence of vibrational communication in Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs as a possible explanation of their aggregative distributions on host plants. We studied possible vibratory emissions of isolated and grouped nymphs, as well as their behavioural responses to vibration stimuli that simulated presence of conspecifics, to disturbance noise, white noise and predator spiders. None of our synthetic stimuli or pre-recorded substrate vibrations from nymphs elicited specific vibration responses and only those due to grooming or mechanical contacts of the insect with the leaf were recorded. Thus, S. titanus nymphs showed to not use species-specific vibrations neither for intra- nor interspecific communication and also did not produce alarm vibrations when facing potential predators. We conclude that their aggregative behaviour is independent from a vibrational communication.

  13. The Temporary Threshold Shift of Vibratory Sensation Induced by Hand-Arm Vibration Composed of Four One-Third Octave Band Vibrations

    NASA Astrophysics Data System (ADS)

    Nishiyama, K.; Taoda, K.; Yamashita, H.; Watanabe, S.

    1997-03-01

    The aim of the present study was to define the multiple effect hand-arm vibration composed of four equally effective one-third octave band vibrations (63 Hz, 125 Hz, 250 Hz and 500 Hz) on the temporary threshold shift in vibratory sensation.Seven healthy subjects were exposed to vibration by grasping a vibrated handle in a soundproof thermo-regulated room. The vibratory sensation threshold at 125 Hz was measured before and after vibration exposure at an exposed fingertip. At first we determined each acceleration of the component one-third octave band vibrations for each subject. These should induce the same magnitude of temporary threshold shift in vibratory sensation immediately after the vibration exposure (TTSv.0as induced by the reference one-third octave band vibration (250 Hz, 4g). We measured TTSv.tfor the exposures of the composed vibrations and the four component vibrations. TTSv.0was determined for each exposure according to the exponential recovery model stated in the previous study.The TTSv.0induced by the composite vibration was not longer than that which might have been induced by each component vibration. This result confirms our previous speculation that the component of the vibration inducing the largest TTSv.0determines TTSv.0by broadband random vibration.

  14. Can Row Spacing Influence Arthropod Communities in Soybean? Implications for Early and Late Planting.

    PubMed

    Buchanan, Amanda L; Zobel, Emily; Hinds, Jermaine; Rosario-Lebron, Armando; Hooks, Cerruti R R

    2015-06-01

    Row spacing in agricultural systems can influence crop yield as well as pest and predator abundances. Soybean (Glycine max L. Merrill) growers in Maryland typically plant in narrow (∼19 cm), medium (∼38 cm), or wide (∼76 cm)-spaced rows, and there is a general lack of information on how these row-spacing schemes influence arthropod abundance and soybean yields. A study was conducted during two growing seasons to determine the effect of soybean row spacing and planting date (early and late) on soybean arthropods and yield. Despite a great deal of variation in arthropod responses to row spacing, and interactions between row spacing and study year, leaf-feeding herbivores were generally more abundant in narrow-spaced soybeans. All arthropod functional groups were more abundant, and yield was greater in early-planted soybeans relative to late-planted soybeans. Potential causes and implications of these finding are discussed.

  15. Exceptional preservation of eye structure in arthropod visual predators from the Middle Jurassic

    PubMed Central

    Vannier, Jean; Schoenemann, Brigitte; Gillot, Thomas; Charbonnier, Sylvain; Clarkson, Euan

    2016-01-01

    Vision has revolutionized the way animals explore their environment and interact with each other and rapidly became a major driving force in animal evolution. However, direct evidence of how ancient animals could perceive their environment is extremely difficult to obtain because internal eye structures are almost never fossilized. Here, we reconstruct with unprecedented resolution the three-dimensional structure of the huge compound eye of a 160-million-year-old thylacocephalan arthropod from the La Voulte exceptional fossil biota in SE France. This arthropod had about 18,000 lenses on each eye, which is a record among extinct and extant arthropods and is surpassed only by modern dragonflies. Combined information about its eyes, internal organs and gut contents obtained by X-ray microtomography lead to the conclusion that this thylacocephalan arthropod was a visual hunter probably adapted to illuminated environments, thus contradicting the hypothesis that La Voulte was a deep-water environment. PMID:26785293

  16. Exceptional preservation of eye structure in arthropod visual predators from the Middle Jurassic.

    PubMed

    Vannier, Jean; Schoenemann, Brigitte; Gillot, Thomas; Charbonnier, Sylvain; Clarkson, Euan

    2016-01-19

    Vision has revolutionized the way animals explore their environment and interact with each other and rapidly became a major driving force in animal evolution. However, direct evidence of how ancient animals could perceive their environment is extremely difficult to obtain because internal eye structures are almost never fossilized. Here, we reconstruct with unprecedented resolution the three-dimensional structure of the huge compound eye of a 160-million-year-old thylacocephalan arthropod from the La Voulte exceptional fossil biota in SE France. This arthropod had about 18,000 lenses on each eye, which is a record among extinct and extant arthropods and is surpassed only by modern dragonflies. Combined information about its eyes, internal organs and gut contents obtained by X-ray microtomography lead to the conclusion that this thylacocephalan arthropod was a visual hunter probably adapted to illuminated environments, thus contradicting the hypothesis that La Voulte was a deep-water environment.

  17. Introduction to symposium: Arthropods and wildlife conservation: synergy in complex biological systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The symposium will discuss the effects of arthropods and other stressors on wildlife conservation programs. Speakers with affiliations in wildlife biology, parasitology and entomology will be included in the program. Research of national and international interest will be presented....

  18. Implication of haematophagous arthropod salivary proteins in host-vector interactions

    PubMed Central

    2011-01-01

    The saliva of haematophagous arthropods contains an array of anti-haemostatic, anti-inflammatory and immunomodulatory molecules that contribute to the success of the blood meal. The saliva of haematophagous arthropods is also involved in the transmission and the establishment of pathogens in the host and in allergic responses. This survey provides a comprehensive overview of the pharmacological activity and immunogenic properties of the main salivary proteins characterised in various haematophagous arthropod species. The potential biological and epidemiological applications of these immunogenic salivary molecules will be discussed with an emphasis on their use as biomarkers of exposure to haematophagous arthropod bites or vaccine candidates that are liable to improve host protection against vector-borne diseases. PMID:21951834

  19. Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care.

    PubMed

    Briggs, Derek E G; Siveter, Derek J; Siveter, David J; Sutton, Mark D; Legg, David

    2016-04-19

    The ∼430-My-old Herefordshire, United Kingdom, Lagerstätte has yielded a diversity of remarkably preserved invertebrates, many of which provide fundamental insights into the evolutionary history and ecology of particular taxa. Here we report a new arthropod with 10 tiny arthropods tethered to its tergites by long individual threads. The head of the host, which is covered by a shield that projects anteriorly, bears a long stout uniramous antenna and a chelate limb followed by two biramous appendages. The trunk comprises 11 segments, all bearing limbs and covered by tergites with long slender lateral spines. A short telson bears long parallel cerci. Our phylogenetic analysis resolves the new arthropod as a stem-group mandibulate. The evidence suggests that the tethered individuals are juveniles and the association represents a complex brooding behavior. Alternative possibilities-that the tethered individuals represent a different epizoic or parasitic arthropod-appear less likely.

  20. The importance of beta diversity in local gall-inducing arthropod distribution.

    PubMed

    Medianero, Enrique; Ibáñez, Alicia; Nieves-Aldrey, José L

    2010-01-01

    Many studies over the past twenty years have documented the richness of arthropod galling species around the world, and some have proposed hypotheses to explain local and global patterns of galling species richness. However, few studies have been directed toward understanding how the gall-inducing species are locally distributed. The aim of this study was to determine the distribution of gall-inducing arthropods species at Coiba National Park, a tropical habitat on the Pacific coast of Panama. Our results suggest that more gall-inducing species had an aggregated distribution, and gall-inducing arthropod diversity shows a strong beta diversity component. Geographic distance was not correlated with similarity in gall-inducing species composition between the studied sites. This fact has important implications when trying to estimate gall-inducing arthropod richness and general patterns, and could cause contradictory results for hypotheses that attempt to explain the local and global patterns of galling species richness.

  1. Genetic diversity within a dominant plant outweighs plant species diversity in structuring an arthropod community.

    PubMed

    Crawford, Kerri M; Rudgers, Jennifer A

    2013-05-01

    Plant biodiversity is being lost at a rapid rate. This has spurred much interest in elucidating the consequences of this loss for higher trophic levels. Experimental tests have shown that both plant species diversity and genetic diversity within a plant species can influence arthropod community structure. However, the majority of these studies have been conducted in separate systems, so their relative importance is currently unresolved. Furthermore, potential interactions between the two levels of diversity, which likely occur in natural systems, have not been investigated. To clarify these issues, we conducted three experiments in a freshwater sand dune ecosystem. We (1) independently manipulated plant species diversity, (2) independently manipulated genetic diversity within the dominant plant species, Ammophila breviligulata, and (3) jointly manipulated genetic diversity within the dominant plant and species diversity. We found that genetic diversity within the dominant plant species, Ammophila breviligulata, more strongly influenced arthropod communities than plant species diversity, but this effect was dependent on the presence of other species. In species mixtures, A. breviligulata genetic diversity altered overall arthropod community composition, and arthropod richness and abundance peaked at the highest level of genetic diversity. Positive nonadditive effects of diversity were detected, suggesting that arthropods respond to emergent properties of diverse plant communities. However, in the independent manipulations where A. breviligulata was alone, effects of genetic diversity were weaker, with only arthropod richness responding. In contrast, plant species diversity only influenced arthropods when A. breviligulata was absent, and then only influenced herbivore abundance. In addition to showing that genetic diversity within a dominant plant species can have large effects on arthropod community composition, these results suggest that understanding how species

  2. Nematode and Arthropod Genomes Provide New Insights into the Evolution of Class 2 B1 GPCRs

    PubMed Central

    Cardoso, João C. R.; Félix, Rute C.; Power, Deborah M.

    2014-01-01

    Nematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors (GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes. PMID:24651821

  3. Nematode and arthropod genomes provide new insights into the evolution of class 2 B1 GPCRs.

    PubMed

    Cardoso, João C R; Félix, Rute C; Power, Deborah M

    2014-01-01

    Nematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors (GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes.

  4. Ecosystem engineers on plants: indirect facilitation of arthropod communities by leaf-rollers at different scales.

    PubMed

    Vieira, Camila; Romero, Gustavo Q

    2013-07-01

    Ecosystem engineering is a process by which organisms change the distribution of resources and create new habitats for other species via non-trophic interactions. Leaf-rolling caterpillars can act as ecosystem engineers because they provide shelter to secondary users. In this study, we report the influence of leaf-rolling caterpillars on speciose tropical arthropod communities along both spatial scales (leaf-level and plant-level effects) and temporal scales (dry and rainy seasons). We predict that rolled leaves can amplify arthropod diversity at both the leaf and plant levels and that this effect is stronger in dry seasons, when arthropods are prone to desiccation. Our results show that the abundance, richness, and biomass of arthropods within several guilds increased up to 22-fold in naturally and artificially created leaf shelters relative to unaltered leaves. These effects were observed at similar magnitudes at both the leaf and plant scales. Variation in the shelter architecture (funnel, cylinders) did not influence arthropod parameters, as diversity, abundance, orbiomass, but rolled leaves had distinct species composition if compared with unaltered leaves. As expected, these arthropod parameters on the plants with rolled leaves were on average approximately twofold higher in the dry season. Empty leaf rolls and whole plants were rapidly recolonized by arthropods over time, implying a fast replacement of individuals; within 15-day intervals the rolls and plants reached a species saturation. This study is the first to examine the extended effects of engineering caterpillars as diversity amplifiers at different temporal and spatial scales. Because shelter-building caterpillars are ubiquitous organisms in tropical and temperate forests, they can be considered key structuring elements for arthropod communities on plants.

  5. Bison grazing increases arthropod abundance and diversity in a tallgrass prairie.

    PubMed

    Moran, Matthew D

    2014-10-01

    How grazing-induced ecosystem changes by ungulates indirectly affect other consumers is a question of great interest. I investigated the effect of grazing by American Bison (Bos bison L.) on an arthropod community in tallgrass prairie. Grazing increased the abundance of arthropods, an increase that was present in both herbivorous and carnivorous assemblages, but not in detritivores. The increase in herbivores and reduction in plant biomass from grazing resulted in an arthropod herbivore load almost three times higher in grazed plots compared with controls. Among herbivores, the sap-feeding insect guild was dramatically more abundant, while chewing herbivores were not affected. Herbivorous and carnivorous arthropod richness was higher in grazed plots, although the response was strongest among herbivores. Arthropod abundance on individual grasses and forbs was significantly higher in grazed areas, while plant type had no effect on abundance, indicating that the change was ecosystem-wide and not simply in response to a reduction in grass biomass from grazing. The response of arthropods to grazing was strongest in the early part of the growing season. Published research shows that ungulate grazing, although decreasing available biomass to other consumers, enhances plant quality by increasing nitrogen level in plants. The arthropod results of this study suggest higher plant quality outweighs the potential negative competitive effects of plant biomass removal, although other activities of bison could not be ruled out as the causative mechanism. Because arthropods are extremely abundant organisms in grasslands and a food source for other consumers, bison may represent valuable management tools for maintaining biodiversity.

  6. Design and Analysis of a Novel Fully Decoupled Tri-axis Linear Vibratory Gyroscope with Matched Modes.

    PubMed

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-07-13

    We present in this paper a novel fully decoupled silicon micromachined tri-axis linear vibratory gyroscope. The proposed gyroscope structure is highly symmetrical and can be limited to an area of about 8.5 mm × 8.5 mm. It can differentially detect three axes' angular velocities at the same time. By elaborately arranging different beams, anchors and sensing frames, the drive and sense modes are fully decoupled from each other. Moreover, the quadrature error correction and frequency tuning functions are taken into consideration in the structure design for all the sense modes. Since there exists an unwanted in-plane rotational mode, theoretical analysis is implemented to eliminate it. To accelerate the mode matching process, the particle swam optimization (PSO) algorithm is adopted and a frequency split of 149 Hz is first achieved by this method. Then, after two steps of manual adjustment of the springs' dimensions, the frequency gap is further decreased to 3 Hz. With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively. The cross-axis effect and scale factor of each mode are also simulated. All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

  7. Further Examination of the Vibratory Loads Reduction Results from the NASA/ARMY/MIT Active Twist Rotor Test

    NASA Technical Reports Server (NTRS)

    Wilbur, Matthew L.; Yeager, William T., Jr.; Sekula, Martin K.

    2002-01-01

    The vibration reduction capabilities of a model rotor system utilizing controlled, strain-induced blade twisting are examined. The model rotor blades, which utilize piezoelectric active fiber composite actuators, were tested in the NASA Langley Transonic Dynamics Tunnel using open-loop control to determine the effect of active-twist on rotor vibratory loads. The results of this testing have been encouraging, and have demonstrated that active-twist rotor designs offer the potential for significant load reductions in future helicopter rotor systems. Active twist control was found to use less than 1% of the power necessary to operate the rotor system and had a pronounced effect on both rotating- and fixed-system loads, offering reductions in individual harmonic loads of up to 100%. A review of the vibration reduction results obtained is presented, which includes a limited set of comparisons with results generated using the second-generation version of the Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD II) rotorcraft comprehensive analysis.

  8. Unilateral contact induced blade/casing vibratory interactions in impellers: Analysis for flexible casings with friction and abradable coating

    NASA Astrophysics Data System (ADS)

    Batailly, Alain; Legrand, Mathias

    2015-07-01

    This contribution addresses the vibratory analysis of unilateral contact induced structural interactions between a bladed impeller and its surrounding flexible casing. It extends the numerical developments exposed in a previous paper to flexible casings. The casing finite element model and the construction of the associated reduced-order model for efficient computations are first exposed in detail along with an extensive presentation of the smoothing strategy implemented on the contact interface. The proposed algorithms embedding unilateral contact conditions together with abradable coating removal are subsequently introduced and validated through a systematic analysis of (1) the nonlinear procedure for the computation of impeller/casing distances, (2) the treatment of three-dimensional friction and contact forces, (3) the correction of the displacements when unilateral contact or abradable removal arises, and (4) the possible hybrid contact scenarii involving localized total removal of the abradable coating. Finally, two illustrative case studies show that the linear interaction condition, commonly considered for the safe design of impellers and casings in turbomachinery, may be advantageously combined with the presented numerical strategy in order to assess the actual importance of predicted critical speeds.

  9. Analysis and design of a 3rd order velocity-controlled closed-loop for MEMS vibratory gyroscopes.

    PubMed

    Wu, Huan-ming; Yang, Hai-gang; Yin, Tao; Jiao, Ji-wei

    2013-09-18

    The time-average method currently available is limited to analyzing the specific performance of the automatic gain control-proportional and integral (AGC-PI) based velocity-controlled closed-loop in a micro-electro-mechanical systems (MEMS) vibratory gyroscope, since it is hard to solve nonlinear functions in the time domain when the control loop reaches to 3rd order. In this paper, we propose a linearization design approach to overcome this limitation by establishing a 3rd order linear model of the control loop and transferring the analysis to the frequency domain. Order reduction is applied on the built linear model's transfer function by constructing a zero-pole doublet, and therefore mathematical expression of each control loop's performance specification is obtained. Then an optimization methodology is summarized, which reveals that a robust, stable and swift control loop can be achieved by carefully selecting the system parameters following a priority order. Closed-loop drive circuits are designed and implemented using 0.35 μm complementary metal oxide semiconductor (CMOS) process, and experiments carried out on a gyroscope prototype verify the optimization methodology that an optimized stability of the control loop can be achieved by constructing the zero-pole doublet, and disturbance rejection capability (D.R.C) of the control loop can be improved by increasing the integral term.

  10. Step-response of a torsional device with multiple discontinuous non-linearities: Formulation of a vibratory experiment

    NASA Astrophysics Data System (ADS)

    Krak, Michael D.; Dreyer, Jason T.; Singh, Rajendra

    2016-03-01

    A vehicle clutch damper is intentionally designed to contain multiple discontinuous non-linearities, such as multi-staged springs, clearances, pre-loads, and multi-staged friction elements. The main purpose of this practical torsional device is to transmit a wide range of torque while isolating torsional vibration between an engine and transmission. Improved understanding of the dynamic behavior of the device could be facilitated by laboratory measurement, and thus a refined vibratory experiment is proposed. The experiment is conceptually described as a single degree of freedom non-linear torsional system that is excited by an external step torque. The single torsional inertia (consisting of a shaft and torsion arm) is coupled to ground through parallel production clutch dampers, which are characterized by quasi-static measurements provided by the manufacturer. Other experimental objectives address physical dimensions, system actuation, flexural modes, instrumentation, and signal processing issues. Typical measurements show that the step response of the device is characterized by three distinct non-linear regimes (double-sided impact, single-sided impact, and no-impact). Each regime is directly related to the non-linear features of the device and can be described by peak angular acceleration values. Predictions of a simplified single degree of freedom non-linear model verify that the experiment performs well and as designed. Accordingly, the benchmark measurements could be utilized to validate non-linear models and simulation codes, as well as characterize dynamic parameters of the device including its dissipative properties.

  11. Theory of vibratory mobilization and break-up of non-wetting fluids entrapped in pore constrictions

    NASA Astrophysics Data System (ADS)

    Beresnev, I.; Li, W.; Vigil, D.

    2006-12-01

    Quantitative dynamics of a non-wetting (e. g., NAPL) ganglion entrapped in a pore constriction and subjected to vibrations can be approximated by the equation of motion of an oscillator moving under the effect of the external pressure gradient, inertial oscillatory force, and restoring capillary force. The solution of the equation provides the conditions under which the droplet experiences forced oscillations without being mobilized or is liberated upon the acceleration of the wall exceeding an "unplugging" threshold. This solution provides a quantitative tool for the estimation of the parameters of vibratory fields needed to liberate entrapped non-wetting fluids. For typical pore sizes encountered in reservoirs and aquifers, wall accelerations must exceed at least several m/sec2 and even higher levels to mobilize the droplets of NAPL; however, in the populations of ganglia entrapped in natural porous environments, many may reside very near their mobilization thresholds and may be mobilized by extremely low accelerations as well. For given acceleration, lower seismic frequencies are more efficient. The ganglia may also break up into smaller pieces when passing through pore constrictions. The snap-off is governed by the geometry only; for constrictions with sinusoidal profile (spatial wavelength of L and maximum and minimum radii of rmax and rmin, the break-up occurs if L > 2π(rmin rmax)1/2. Computational fluid dynamics shows the details of the break-up process.

  12. Low-Level Liquid Waste Processing Pilot Studies Using a Vibratory Shear Enhancing Process (VSEP) for Filtration

    SciTech Connect

    Bushart, S.; Tran, P.; Asay, R.

    2002-02-25

    A previous EPRI study evaluated potential treatment methods for the removal of iron from BWR waste streams. Of the methods investigated, high shear filtration using the vibratory shear-enhanced process (VSEP) showed the most promise to effectively and economically remove high iron concentrations from backwash receiving tank waste. A VSEP filter uses oscillatory vibration to create high shear at the surface of the filter membrane. This high shear force significantly improves the filter's resistance to fouling thereby enabling high throughputs with very little secondary waste generation. With a VSEP filter, the waste feed stream is split into two effluents- a permeate stream with little or no suspended solids and a concentrate stream with a suspended solids concentration much higher than that of the feed stream. To evaluate the feasibility of using a VSEP concept for processing typical high iron containing BWR radwaste, a surrogate feedstream containing up to 1,700 ppm iron oxide (as Fe2O3) was used. This surrogate waste simulates radioactive waste found at Exelon's Limerick and Peach Bottom (powdered resin condensate) plants, and in Hope Creek's (deep bed condensate) radwaste systems. Testing was done using a series L (laboratory scale) VSEP unit at the manufacturer's and contractor's laboratories. These tests successfully demonstrated the VSEP capability for producing highly concentrated waste streams with totally ''recyclable'' permeate (e.g., greater than 95% recovery).

  13. Abundance and Diversity of Soil Arthropods in the Olive Grove Ecosystem

    PubMed Central

    Gonçalves, Maria Fátima; Pereira, José Alberto

    2012-01-01

    Arthropods are part of important functional groups in soil food webs. Recognizing these arthropods and understanding their function in the ecosystem as well as when they are active is essential to understanding their roles. In the present work, the abundance and diversity of soil arthropods is examined in olive groves in the northeast region of Portugal during the spring. Five classes of arthropods were found: Chilopoda, Malacostraca, Entognatha, Insecta, and Arachnida. Captures were numerically dominated by Collembola within Entognatha, representing 70.9% of total captures. Arachnida and Insecta classes represented about 20.4 and 9.0%, respectively. Among the predatory arthropods, the most representative groups were Araneae and Opiliones from Arachnida, and Formicidae, Carabidae, and Staphylinidae from Insecta. From the Formicidae family, Tetramorium semilaeve (Andre 1883), Tapinoma nigerrimum (Nylander 1856), and Crematogaster scutellaris (Olivier 1792) were the most representative ant species. Arthropods demonstrated preference during the day, with 74% of the total individuals recovered in this period, although richness and similarity were analogous during the day and night. PMID:22943295

  14. Emerging roles of aquaporins in relation to the physiology of blood-feeding arthropods.

    PubMed

    Benoit, Joshua B; Hansen, Immo A; Szuter, Elise M; Drake, Lisa L; Burnett, Denielle L; Attardo, Geoffrey M

    2014-10-01

    Aquaporins (AQPs) are proteins that span plasma membranes allowing the movement of water and small solutes into or out of cells. The type, expression levels and activity of AQPs play a major role in the relative permeability of each cell to water or other solutes. Research on arthropod AQPs has expanded in the last 10 years due to the completion of several arthropod genome projects and the increased availability of genetic information accessible through other resources such as de novo transcriptome assemblies. In particular, there has been significant advancement in elucidating the roles that AQPs serve in relation to the physiology of blood-feeding arthropods of medical importance. The focus of this review is upon the significance of AQPs in relation to hematophagy in arthropods. This will be accomplished via a narrative describing AQP functions during the life history of hematophagic arthropods that includes the following critical phases: (1) Saliva production necessary to blood feeding, (2) Intake and excretion of water during blood digestion, (3) Reproduction and egg development and (4) Off-host environmental stress tolerance. The concentration on these phases will highlight known vulnerabilities in the biology of hematophagic arthropods that could be used to develop novel control strategies as well as research topics that have yet to be examined.

  15. Abundance and diversity of soil arthropods in the olive grove ecosystem.

    PubMed

    Gonçalves, Maria Fátima; Pereira, José Alberto

    2012-01-01

    Arthropods are part of important functional groups in soil food webs. Recognizing these arthropods and understanding their function in the ecosystem as well as when they are active is essential to understanding their roles. In the present work, the abundance and diversity of soil arthropods is examined in olive groves in the northeast region of Portugal during the spring. Five classes of arthropods were found: Chilopoda, Malacostraca, Entognatha, Insecta, and Arachnida. Captures were numerically dominated by Collembola within Entognatha, representing 70.9% of total captures. Arachnida and Insecta classes represented about 20.4 and 9.0%, respectively. Among the predatory arthropods, the most representative groups were Araneae and Opiliones from Arachnida, and Formicidae, Carabidae, and Staphylinidae from Insecta. From the Formicidae family, Tetramorium semilaeve (Andre 1883), Tapinoma nigerrimum (Nylander 1856), and Crematogaster scutellaris (Olivier 1792) were the most representative ant species. Arthropods demonstrated preference during the day, with 74% of the total individuals recovered in this period, although richness and similarity were analogous during the day and night.

  16. Community structure and nutrient content of canopy arthropods in clearcut and uncut forest ecosystems

    SciTech Connect

    Schowalter, T.D.; Webb, J.W.; Crossley, D.A. Jr.

    1981-08-01

    This paper describes differences in canopy arthropod community structure, major cation content, and calculated nutrient consumption between clearcut and undisturbed hardwood forest watersheds at Coweeta Hydrologic Laboratory, North Carolina, USA, during the first two growing seasons following cutting. Although canopy arthropod biomass was about 0.08% of foliage biomass on both watersheds, aphid mass increased 23-fold and ant mass increased 6-fold per unit foliage mass following cutting. These groups in general had lower nutrient concentrations than did chewing herbivores and predators. Arthropod K concentrations were 33% lower on the clearcut; Na, K, and Mg concentrations were 20 to 50% higher in 1978 than in 1977. Arthropod Mg and Ca concentrations, but not Na and K, were reduced significantly more by the greater effect of drought on the clearcut watershed. Consumption estimates based in part on consumption rates reported by others indicated increased nutrient translocation from foilage via arthropods following cutting. These data indicated that canopy arthropod responses to changes in nutrient availability following disturbance could have increased nutrient cycling rates and contributed to nutrient retention by the recovering ecosystem.

  17. Relationships between arthropod richness, evenness, and diversity are altered by complementarity among plant genotypes.

    PubMed

    McArt, Scott H; Cook-Patton, Susan C; Thaler, Jennifer S

    2012-04-01

    Biodiversity is quantified via richness (e.g., the number of species), evenness (the relative abundance distribution of those species), or proportional diversity (a combination of richness and evenness, such as the Shannon index, H'). While empirical studies show no consistent relationship between these aspects of biodiversity within communities, the mechanisms leading to inconsistent relationships have received little attention. Here, using common evening primrose (Oenothera biennis) and its associated arthropod community, we show that relationships between arthropod richness, evenness, and proportional diversity are altered by plant genotypic richness. Arthropod richness increased with O. biennis genotypic richness due to an abundance-driven accumulation of species in response to greater plant biomass. Arthropod evenness and proportional diversity decreased with plant genotypic richness due to a nonadditive increase in abundance of a dominant arthropod, the generalist florivore/omnivore Plagiognathas politus (Miridae). The greater quantity of flowers and buds produced in polycultures-which resulted from positive complementarity among O. biennis genotypes-increased the abundance of this dominant insect. Using choice bioassays, we show that floral quality did not change in plant genotypic mixtures. These results elucidate mechanisms for how plant genotypic richness can modify relationships between arthropod richness, evenness, and proportional diversity. More broadly, our results suggest that trophic interactions may be a previously underappreciated factor controlling relationships between these different aspects of biodiversity.

  18. Limited Impact of a Fall-Seeded, Spring-Terminated Rye Cover Crop on Beneficial Arthropods.

    PubMed

    Dunbar, Mike W; Gassmann, Aaron J; O'Neal, Matthew E

    2017-03-03

    Cover crops are beneficial to agroecosystems because they decrease soil erosion and nutrient loss while increasing within-field plant diversity. Greater plant diversity within cropping systems can positively affect beneficial arthropod communities. We hypothesized that increasing plant diversity within annually rotated corn and soybean with the addition of a rye cover crop would positively affect the beneficial ground and canopy-dwelling communities compared with rotated corn and soybean grown without a cover crop. From 2011 through 2013, arthropod communities were measured at two locations in Iowa four times throughout each growing season. Pitfall traps were used to sample ground-dwelling arthropods within the corn and soybean plots and sweep nets were used to measure the beneficial arthropods in soybean canopies. Beneficial arthropods captured were identified to either class, order, or family. In both corn and soybean, community composition and total community activity density and abundance did not differ between plots that included the rye cover crop and plots without the rye cover crop. Most taxa did not significantly respond to the presence of the rye cover crop when analyzed individually, with the exceptions of Carabidae and Gryllidae sampled from soybean pitfall traps. Activity density of Carabidae was significantly greater in soybean plots that included a rye cover crop, while activity density of Gryllidae was significantly reduced in plots with the rye cover crop. Although a rye cover crop may be agronomically beneficial, there may be only limited effects on beneficial arthropods when added within an annual rotation of corn and soybean.

  19. Silurian horseshoe crab illuminates the evolution of arthropod limbs.

    PubMed

    Briggs, Derek E G; Siveter, Derek J; Siveter, David J; Sutton, Mark D; Garwood, Russell J; Legg, David

    2012-09-25

    The basic arrangement of limbs in euarthropods consists of a uniramous head appendage followed by a series of biramous appendages. The body is divided into functional units or tagmata which are usually distinguished by further differentiation of the limbs. The living horseshoe crabs are remnants of a much larger diversity of aquatic chelicerates. The limbs of the anterior and posterior divisions of the body of living horseshoe crabs differ in the loss of the outer and inner ramus, respectively, of an ancestral biramous limb. Here we report a new fossil horseshoe crab from the mid-Silurian Lagerstätte in Herefordshire, United Kingdom (approximately 425 Myr B.P.), a site that has yielded a remarkably preserved assemblage of soft-bodied fossils. The limbs of the new form can be homologized with those of living Limulus, but retain an ancestral biramous morphology. Remarkably, however, the two limb branches originate separately, providing fossil evidence to suggest that repression or loss of gene expression might have given rise to the appendage morphology of Limulus. Both branches of the prosomal limbs of this new fossil are robust and segmented in contrast to their morphology in Cambrian arthropods, revealing that a true biramous limb was once present in chelicerates as well as in the mandibulates.

  20. Linking membrane physical properties and low temperature tolerance in arthropods.

    PubMed

    Waagner, Dorthe; Bouvrais, Hélène; Ipsen, John H; Holmstrup, Martin

    2013-12-01

    Maintenance of membrane fluidity is of crucial importance in ectotherms experiencing thermal changes. This maintenance has in ectotherms most often been indicated using indirect measures of biochemical changes of phospholipid membranes, which is then assumed to modulate the physico-chemical properties of the membrane. Here, we measure bending rigidity characterizing the membrane flexibility of re-constituted membrane vesicles to provide a more direct link between membrane physical characteristics and low temperature tolerance. Bending rigidity of lipid bilayers was measured in vitro using Giant Unilamellar Vesicles formed from phospholipid extracts of the springtail, Folsomia candida. The bending rigidity of these membranes decreased when exposed to 0.4 vol% ethanol (0.23 mM/L). Springtails exposed to ethanol for 24h significantly increased their cold shock tolerance. Thus, by chemically inducing decreased membrane rigidity, we have shown a direct link between the physico-chemical properties of the membranes and the capacity to tolerate low temperature in a chill-susceptible arthropod.

  1. The ubiquity of intraguild predation among predatory arthropods.

    PubMed

    Gagnon, Annie-Ève; Heimpel, George E; Brodeur, Jacques

    2011-01-01

    Intraguild predation (IGP) occurs when one predator species attacks another predator species with which it competes for a shared prey species. Despite the apparent omnipresence of intraguild interactions in natural and managed ecosystems, very few studies have quantified rates of IGP in various taxa under field conditions. We used molecular analyses of gut contents to assess the nature and incidence of IGP among four species of coccinellid predators in soybean fields. Over half of the 368 predator individuals collected in soybean contained the DNA of other coccinellid species indicating that IGP was very common at our field site. Furthermore, 13.2% of the sampled individuals contained two and even three other coccinellid species in their gut. The interaction was reciprocal, as each of the four coccinellid species has the capacity to feed on the others. To our knowledge, this study represents the most convincing field evidence of a high prevalence of IGP among predatory arthropods. The finding has important implications for conservation biology and biological control.

  2. RNA interference, arthropod-borne viruses, and mosquitoes.

    PubMed

    Sanchez-Vargas, Irma; Travanty, Emily A; Keene, Kimberly M; Franz, Alexander W E; Beaty, Barry J; Blair, Carol D; Olson, Ken E

    2004-06-01

    RNA interference (RNAi) probably functions as an antiviral mechanism in most eukaryotic organisms. Variations in the activity of this antiviral pathway in mosquitoes could explain, in part, why some mosquitoes are competent vectors of medically important, arthropod-borne viruses (arboviruses) and others are not. There are three lines of evidence that show the RNAi pathway exists in Aedes species that transmit arboviruses. The first is that recombinant Sindbis viruses expressing a RNA fragment from a genetically unrelated dengue-2 virus (DENV-2) interfere with DENV-2 replication in Aedes aegypti mosquitoes by a mechanism similar to virus-induced gene silencing described in plants. The second is that transfection of C6/36 (Aedes albopictus) cells with either double-stranded RNA or synthetic small interfering RNAs derived from an arbovirus genome interferes with replication of the homologous virus. The third is that a hairpin DENV-2-specific RNA transcribed from a plasmid can generate virus-resistant C6/36 cells. We hypothesize that genetically modified mosquitoes can be generated that transcribe a flavivirus-specific dsRNA, triggering the RNAi response soon after ingestion of a blood meal. This could induce the RNAi pathway in the midgut prior to establishment of virus infection and profoundly change vector competence. Towards this goal, we are developing transgenic A. aegypti lines that are refractory to DENV by exploiting the RNAi pathway.

  3. Arthropod eye-inspired digital camera with unique imaging characteristics

    NASA Astrophysics Data System (ADS)

    Xiao, Jianliang; Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B.; Huang, Yonggang; Rogers, John A.

    2014-06-01

    In nature, arthropods have a remarkably sophisticated class of imaging systems, with a hemispherical geometry, a wideangle field of view, low aberrations, high acuity to motion and an infinite depth of field. There are great interests in building systems with similar geometries and properties due to numerous potential applications. However, the established semiconductor sensor technologies and optics are essentially planar, which experience great challenges in building such systems with hemispherical, compound apposition layouts. With the recent advancement of stretchable optoelectronics, we have successfully developed strategies to build a fully functional artificial apposition compound eye camera by combining optics, materials and mechanics principles. The strategies start with fabricating stretchable arrays of thin silicon photodetectors and elastomeric optical elements in planar geometries, which are then precisely aligned and integrated, and elastically transformed to hemispherical shapes. This imaging device demonstrates nearly full hemispherical shape (about 160 degrees), with densely packed artificial ommatidia. The number of ommatidia (180) is comparable to those of the eyes of fire ants and bark beetles. We have illustrated key features of operation of compound eyes through experimental imaging results and quantitative ray-tracing-based simulations. The general strategies shown in this development could be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

  4. A survey for gregarines (Protozoa: Apicomplexa) in arthropods in Spain.

    PubMed

    Criado-Fornelio, A; Verdú-Expósito, C; Martin-Pérez, T; Heredero-Bermejo, I; Pérez-Serrano, J; Guàrdia-Valle, L; Panisello-Panisello, M

    2017-01-01

    Gregarines thrive in the digestive tract of arthropods and may be deleterious to their hosts, especially when present in high densities. The impact of parasites on these invertebrates may affect both the ecosystem equilibrium and human economic activities. However, information available on gregarines in Spain is limited. Therefore, a microscopic study on prevalence of gregarine infection in 560 insects and crustaceans was undertaken in Madrid and Tarragona.Gregarina ormierei (78 % prevalence), Stylocephalus gigas (56 %), Oocephalus hispanus (13 %) and Actinocephalus permagnus (only one infected out of six beetles examined) were found in coleopteran hosts. Gregarina ovata and G. chelidurellae showed moderate frequency of infection (35 %) in dermapterans. An undescribed Gregarina sp. (76 % prevalence) was observed for the first time in freshwater decapod crustaceans. Interestingly, G. ormierei showed a noticeable phenotypic dimorphism, which justifies its redescription based on modern taxonomic criteria. Sequences of the 18S rRNA gene could be obtained only in the presence of highly prevalent gregarines. G. ormierei and Gregarina sp. were related (85 and 94 % identity by BLASTN, respectively) to G. basiconstrictonea and G. cloptoni, respectively, whereas S. gigas was closely related to both Xiphocephalus ellisi and S. giganteus (>97 % identity). Phylogenetic trees based on ribosomal sequences unequivocally grouped these new isolates either with the Gregarinidae (G. ormierei and Gregarina sp.) or the Stylocephalidae (S. gigas).

  5. Arthropod phylogeny based on eight molecular loci and morphology

    NASA Technical Reports Server (NTRS)

    Giribet, G.; Edgecombe, G. D.; Wheeler, W. C.

    2001-01-01

    The interrelationships of major clades within the Arthropoda remain one of the most contentious issues in systematics, which has traditionally been the domain of morphologists. A growing body of DNA sequences and other types of molecular data has revitalized study of arthropod phylogeny and has inspired new considerations of character evolution. Novel hypotheses such as a crustacean-hexapod affinity were based on analyses of single or few genes and limited taxon sampling, but have received recent support from mitochondrial gene order, and eye and brain ultrastructure and neurogenesis. Here we assess relationships within Arthropoda based on a synthesis of all well sampled molecular loci together with a comprehensive data set of morphological, developmental, ultrastructural and gene-order characters. The molecular data include sequences of three nuclear ribosomal genes, three nuclear protein-coding genes, and two mitochondrial genes (one protein coding, one ribosomal). We devised new optimization procedures and constructed a parallel computer cluster with 256 central processing units to analyse molecular data on a scale not previously possible. The optimal 'total evidence' cladogram supports the crustacean-hexapod clade, recognizes pycnogonids as sister to other euarthropods, and indicates monophyly of Myriapoda and Mandibulata.

  6. Lessons from genome skimming of arthropod-preserving ethanol.

    PubMed

    Linard, B; Arribas, P; Andújar, C; Crampton-Platt, A; Vogler, A P

    2016-11-01

    Field-collected specimens of invertebrates are regularly killed and preserved in ethanol, prior to DNA extraction from the specimens, while the ethanol fraction is usually discarded. However, DNA may be released from the specimens into the ethanol, which can potentially be exploited to study species diversity in the sample without the need for DNA extraction from tissue. We used shallow shotgun sequencing of the total DNA to characterize the preservative ethanol from two pools of insects (from a freshwater habitat and terrestrial habitat) to evaluate the efficiency of DNA transfer from the specimens to the ethanol. In parallel, the specimens themselves were subjected to bulk DNA extraction and shotgun sequencing, followed by assembly of mitochondrial genomes for 39 of 40 species in the two pools. Shotgun sequencing from the ethanol fraction and read-matching to the mitogenomes detected ~40% of the arthropod species in the ethanol, confirming the transfer of DNA whose quantity was correlated to the biomass of specimens. The comparison of diversity profiles of microbiota in specimen and ethanol samples showed that 'closed association' (internal tissue) bacterial species tend to be more abundant in DNA extracted from the specimens, while 'open association' symbionts were enriched in the preservative fluid. The vomiting reflex of many insects also ensures that gut content is released into the ethanol, which provides easy access to DNA from prey items. Shotgun sequencing of DNA from preservative ethanol provides novel opportunities for characterizing the functional or ecological components of an ecosystem and their trophic interactions.

  7. No Accumulation of Transposable Elements in Asexual Arthropods.

    PubMed

    Bast, Jens; Schaefer, Ina; Schwander, Tanja; Maraun, Mark; Scheu, Stefan; Kraaijeveld, Ken

    2016-03-01

    Transposable elements (TEs) and other repetitive DNA can accumulate in the absence of recombination, a process contributing to the degeneration of Y-chromosomes and other nonrecombining genome portions. A similar accumulation of repetitive DNA is expected for asexually reproducing species, given their entire genome is effectively nonrecombining. We tested this expectation by comparing the whole-genome TE loads of five asexual arthropod lineages and their sexual relatives, including asexual and sexual lineages of crustaceans (Daphnia water fleas), insects (Leptopilina wasps), and mites (Oribatida). Surprisingly, there was no evidence for increased TE load in genomes of asexual as compared to sexual lineages, neither for all classes of repetitive elements combined nor for specific TE families. Our study therefore suggests that nonrecombining genomes do not accumulate TEs like nonrecombining genomic regions of sexual lineages. Even if a slight but undetected increase of TEs were caused by asexual reproduction, it appears to be negligible compared to variance between species caused by processes unrelated to reproductive mode. It remains to be determined if molecular mechanisms underlying genome regulation in asexuals hamper TE activity. Alternatively, the differences in TE dynamics between nonrecombining genomes in asexual lineages versus nonrecombining genome portions in sexual species might stem from selection for benign TEs in asexual lineages because of the lack of genetic conflict between TEs and their hosts and/or because asexual lineages may only arise from sexual ancestors with particularly low TE loads.

  8. Silurian horseshoe crab illuminates the evolution of arthropod limbs

    NASA Astrophysics Data System (ADS)

    Briggs, Derek E. G.; Siveter, Derek J.; Siveter, David J.; Sutton, Mark D.; Garwood, Russell J.; Legg, David

    2012-09-01

    The basic arrangement of limbs in euarthropods consists of a uniramous head appendage followed by a series of biramous appendages. The body is divided into functional units or tagmata which are usually distinguished by further differentiation of the limbs. The living horseshoe crabs are remnants of a much larger diversity of aquatic chelicerates. The limbs of the anterior and posterior divisions of the body of living horseshoe crabs differ in the loss of the outer and inner ramus, respectively, of an ancestral biramous limb. Here we report a new fossil horseshoe crab from the mid-Silurian Lagerstätte in Herefordshire, United Kingdom (approximately 425 Myr B.P.), a site that has yielded a remarkably preserved assemblage of soft-bodied fossils. The limbs of the new form can be homologized with those of living Limulus, but retain an ancestral biramous morphology. Remarkably, however, the two limb branches originate separately, providing fossil evidence to suggest that repression or loss of gene expression might have given rise to the appendage morphology of Limulus. Both branches of the prosomal limbs of this new fossil are robust and segmented in contrast to their morphology in Cambrian arthropods, revealing that a true biramous limb was once present in chelicerates as well as in the mandibulates.

  9. Mineral cycling in soil and litter arthropod food chains. Progress report, November 1, 1980-October 31, 1981

    SciTech Connect

    Crossley, D.A. Jr.

    1980-06-15

    Progress and current status are reported for research projects concerned with mineral element and nutrient dynamics in soil arthropod food chains. Research is performed within the larger context of terrestrial decomposition, in which soil arthropods may act as regulators of nutrient dynamics during decomposition. Research is measuring rates of nutrient accumulation and excretion by using radioactive tracer analogs of nutrients. This year, emphasis has been placed on field work in which soil arthropod population size and nutrients inputs were varied experimentally. The presence of microarthropods in field microcosms increased the mineralization of N and P in each case, but rates were not correlated with arthropod densities. Experiments recently started are using both arthropod and microfloral inhibitors, in open systems on the forest floor, with the objective of quantifying arthropod enhancement of microbial immobilization of nutrients.

  10. Temporal variation in the arthropod community of desert riparian habitats with varying amounts of saltcedar (Tamarix ramosissima)

    USGS Publications Warehouse

    Durst, S.L.; Theimer, T.C.; Paxton, E.H.; Sogge, M.K.

    2008-01-01

    We used Malaise traps to examine the aerial arthropod community in riparian habitats dominated by native willow, exotic saltcedar, or a mixture of these two tree species in central Arizona, USA. Over the course of three sampling periods per year in 2003 and 2004, native habitats had significantly greater diversity (Shannon-Wiener) and supported different arthropod communities compared to exotic habitats, while mixed habitats were intermediate in terms of diversity and supported an arthropod community statistically indistinguishable from the exotic site. The composition of arthropod communities varied significantly between the two years, and there was an approximately two-fold difference in richness and diversity. Overall, we documented complex interactions indicating that differences among the arthropod communities of riparian habitats may be driven not only by the composition of native and exotic tree species making up these habitats, but also by year and season of arthropod sampling.

  11. Mineral cycling in soil and litter arthropod food chains. Three-year progress report, February 1, 1984-January 31, 1987

    SciTech Connect

    Crossley, D.A. Jr.

    1986-08-29

    This report summarizes progress in a three-year research project on the influence of soil arthropods (mites, collembolans, insects, millipedes and others) upon decomposition rates and nutrient dynamics in decaying vegetable matter. Research has concentrated on two aspects of elemental dynamics in decomposing organic matter: Effects of arthropods on rates of decomposition and nutrient loss (mineralization of carbon and other elements), and arthropod stimulation of microbial immobilization of nutrient elements during decomposition.

  12. Large-scale experimental landscapes reveal distinctive effects of patch shape and connectivity on arthropod communities.

    SciTech Connect

    Orrock, John, L.; Curler, Gregory, R.; Danielson, Brent, J.; Coyle, David. R.

    2011-09-14

    The size, shape, and isolation of habitat patches can affect organism behavior and population dynamics, but little is known about the relative role of shape and connectivity in affecting ecological communities at large spatial scales. Using six sampling sessions from July 2001 until August 2002, we collected 33,685 arthropods throughout seven 12-ha experimental landscapes consisting of clear-cut patches surrounded by a matrix of mature pine forest. Patches were explicitly designed to manipulate connectivity (via habitat corridors) independently of area and edge effects. We found that patch shape, rather than connectivity, affected ground-dwelling arthropod richness and beta diversity (i.e. turnover of genera among patches). Arthropod communities contained fewer genera and exhibited less turnover in high-edge connected and high-edge unconnected patches relative to low-edge unconnected patches of similar area. Connectivity, rather than patch shape, affected the evenness of ground-dwelling arthropod communities; regardless of patch shape, high-edge connected patches had lower evenness than low- or high-edge unconnected patches. Among the most abundant arthropod orders, increased richness in low-edge unconnected patches was largely due to increased richness of Coleoptera, whereas Hymenoptera played an important role in the lower evenness in connected patches and patterns of turnover. These findings suggest that anthropogenic habitat alteration can have distinct effects on ground-dwelling arthropod communities that arise due to changes in shape and connectivity. Moreover, this work suggests that corridors, which are common conservation tools that change both patch shape and connectivity, can have multiple effects on arthropod communities via different mechanisms, and each effect may alter components of community structure.

  13. Habitat and species identity, not diversity, predict the extent of refuse consumption by urban arthropods.

    PubMed

    Youngsteadt, Elsa; Henderson, Ryanna C; Savage, Amy M; Ernst, Andrew F; Dunn, Robert R; Frank, Steven D

    2015-03-01

    Urban green spaces provide ecosystem services to city residents, but their management is hindered by a poor understanding of their ecology. We examined a novel ecosystem service relevant to urban public health and esthetics: the consumption of littered food waste by arthropods. Theory and data from natural systems suggest that the magnitude and resilience of this service should increase with biological diversity. We measured food removal by presenting known quantities of cookies, potato chips, and hot dogs in street medians (24 sites) and parks (21 sites) in New York City, USA. At the same sites, we assessed ground-arthropod diversity and abiotic conditions, including history of flooding during Hurricane Sandy 7 months prior to the study. Arthropod diversity was greater in parks (on average 11 hexapod families and 4.7 ant species per site), than in medians (nine hexapod families and 2.7 ant species per site). However, counter to our diversity-based prediction, arthropods in medians removed 2-3 times more food per day than did those in parks. We detected no effect of flooding (at 19 sites) on this service. Instead, greater food removal was associated with the presence of the introduced pavement ant (Tetramorium sp. E) and with hotter, drier conditions that may have increased arthropod metabolism. When vertebrates also had access to food, more was removed, indicating that arthropods and vertebrates compete for littered food. We estimate that arthropods alone could remove 4-6.5 kg of food per year in a single street median, reducing its availability to less desirable fauna such as rats. Our results suggest that species identity and habitat may be more relevant than diversity for predicting urban ecosystem services. Even small green spaces such as street medians provide ecosystem services that may complement those of larger habitat patches across the urban landscape.

  14. Geographic variation in a facultative mutualism: consequences for local arthropod composition and diversity.

    PubMed

    Rudgers, Jennifer A; Savage, Amy M; Rúa, Megan A

    2010-08-01

    Geographic variation in the outcome of interspecific interactions may influence not only the evolutionary trajectories of species but also the structure of local communities. We investigated this community consequence of geographic variation for a facultative mutualism between ants and wild cotton (Gossypium thurberi). Ants consume wild cotton extrafloral nectar and can protect plants from herbivores. We chose three sites that differed in interaction outcome, including a mutualism (ants provided the greatest benefits to plant fitness and responded to manipulations of extrafloral nectar), a potential commensalism (ants increased plant fitness but were unresponsive to extrafloral nectar), and a neutral interaction (ants neither affected plant fitness nor responded to extrafloral nectar). At all sites, we manipulated ants and extrafloral nectar in a factorial design and monitored the abundance, diversity, and composition of other arthropods occurring on wild cotton plants. We predicted that the effects of ants and extrafloral nectar on arthropods would be largest in the location with the mutualism and weakest where the interaction was neutral. A non-metric multidimensional scaling analysis revealed that the presence of ants altered arthropod composition, but only at the two sites in which ants increased plant fitness. At the site with the mutualism, ants also suppressed detritivore/scavenger abundance and increased aphids. The presence of extrafloral nectar increased arthropod abundance where mutual benefits were the strongest, whereas both arthropod abundance and morphospecies richness declined with extrafloral nectar availability at the site with the weakest ant-plant interaction. Some responses were geographically invariable: total arthropod richness and evenness declined by approximately 20% on plants with ants, and extrafloral nectar reduced carnivore abundance when ants were excluded from plants. These results demonstrate that a facultative ant-plant mutualism

  15. Elongation factor-2: a useful gene for arthropod phylogenetics.

    PubMed

    Regier, J C; Shultz, J W

    2001-07-01

    Robust resolution of controversial higher-level groupings within Arthropoda requires additional sources of characters. Toward this end, elongation factor-2 sequences (1899 nucleotides) were generated from 17 arthropod taxa (5 chelicerates, 6 crustaceans, 3 hexapods, 3 myriapods) plus an onychophoran and a tardigrade as outgroups. Likelihood and parsimony analyses of nucleotide and amino acid data sets consistently recovered Myriapoda and major chelicerate groups with high bootstrap support. Crustacea + Hexapoda (= Pancrustacea) was recovered with moderate support, whereas the conflicting group Myriapoda + Hexapoda (= Atelocerata) was never recovered and bootstrap values were always <5%. With additional nonarthropod sequences included, one indel supports monophyly of Tardigrada, Onychophora, and Arthropoda relative to molluscan, annelidan, and mammalian outgroups. New and previously published sequences from RNA polymerase II (1038 nucleotides) and elongation factor-1alpha (1092 nucleotides) were analyzed for the same taxa. A comparison of bootstrap values from the three genes analyzed separately revealed widely varying values for some clades, although there was never strong support for conflicting groups. In combined analyses, there was strong bootstrap support for the generally accepted clades Arachnida, Arthropoda, Euchelicerata, Hexapoda, and Pycnogonida, and for Chelicerata, Myriapoda, and Pancrustacea, whose monophyly is more controversial. Recovery of some additional groups was fairly robust to method of analysis but bootstrap values were not high; these included Pancrustacea + Chelicerata, Hexapoda + Cephalocarida + Remipedia, Cephalocarida + Remipedia, and Malaocostraca + Cirripedia. Atelocerata (= Myriapoda + Hexapoda) was never recovered. Elongation factor-2 is now the second protein-encoding, nuclear gene (in addition to RNA polymerase II) to support Pancrustacea over Atelocerata. Atelocerata is widely cited in morphology-based analyses, and the

  16. Indirect suppression of photosynthesis on individual leaves by arthropod herbivory

    PubMed Central

    Nabity, Paul D.; Zavala, Jorge A.; DeLucia, Evan H.

    2009-01-01

    Background Herbivory reduces leaf area, disrupts the function of leaves, and ultimately alters yield and productivity. Herbivore damage to foliage typically is assessed in the field by measuring the amount of leaf tissue removed and disrupted. This approach assumes the remaining tissues are unaltered, and plant photosynthesis and water balance function normally. However, recent application of thermal and fluorescent imaging technologies revealed that alterations to photosynthesis and transpiration propagate into remaining undamaged leaf tissue. Scope and Conclusions This review briefly examines the indirect effects of herbivory on photosynthesis, measured by gas exchange or chlorophyll fluorescence, and identifies four mechanisms contributing to the indirect suppression of photosynthesis in remaining leaf tissues: severed vasculature, altered sink demand, defence-induced autotoxicity, and defence-induced down-regulation of photosynthesis. We review the chlorophyll fluorescence and thermal imaging techniques used to gather layers of spatial data and discuss methods for compiling these layers to achieve greater insight into mechanisms contributing to the indirect suppression of photosynthesis. We also elaborate on a few herbivore-induced gene-regulating mechanisms which modulate photosynthesis and discuss the difficult nature of measuring spatial heterogeneity when combining fluorescence imaging and gas exchange technology. Although few studies have characterized herbivore-induced indirect effects on photosynthesis at the leaf level, an emerging literature suggests that the loss of photosynthetic capacity following herbivory may be greater than direct loss of photosynthetic tissues. Depending on the damage guild, ignoring the indirect suppression of photosynthesis by arthropods and other organisms may lead to an underestimate of their physiological and ecological impacts. PMID:18660492

  17. Design and Analysis of a Novel Fully Decoupled Tri-axis Linear Vibratory Gyroscope with Matched Modes

    PubMed Central

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-01-01

    We present in this paper a novel fully decoupled silicon micromachined tri-axis linear vibratory gyroscope. The proposed gyroscope structure is highly symmetrical and can be limited to an area of about 8.5 mm × 8.5 mm. It can differentially detect three axes’ angular velocities at the same time. By elaborately arranging different beams, anchors and sensing frames, the drive and sense modes are fully decoupled from each other. Moreover, the quadrature error correction and frequency tuning functions are taken into consideration in the structure design for all the sense modes. Since there exists an unwanted in-plane rotational mode, theoretical analysis is implemented to eliminate it. To accelerate the mode matching process, the particle swam optimization (PSO) algorithm is adopted and a frequency split of 149 Hz is first achieved by this method. Then, after two steps of manual adjustment of the springs’ dimensions, the frequency gap is further decreased to 3 Hz. With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively. The cross-axis effect and scale factor of each mode are also simulated. All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit. PMID:26184217

  18. A novel vibratory stimulation-based occlusal splint for alleviation of TMD painful symptoms: a pilot study.

    PubMed

    Hara, E S; Witzel, A L; de Luca, C E P; Ballester, R Y; Kuboki, T; Bolzan, M C

    2013-03-01

    This pilot study introduces a novel vibratory stimulation-based occlusal splint (VibOS) for management of pain related to temporomandibular disorders (TMD). The study sample consisted of 10 patients (mean age: 40·5 ± 13·7 years, male/female: 3/7) who were using stabilisation splints for more than 2 months prior to the study onset and still complained of pain. Patients utilised the active and inactive VibOS during 15 days in a crossover designed clinical trial. The analysed variables were self-reported VAS pain levels and number of painful sites to palpation (PSP). Statistical analysis was performed with repeated measures anova. At baseline, mean VAS pain levels for group I and II were 45·6 ± 21·0 mm and 37·4 ± 16·3 mm, respectively. Comparison between these baseline values showed no statistical difference (P > 0·05, unpaired t-test). In group I, the inactive VibOS caused a slight increase in VAS pain levels, whereas the active VibOS promoted a significant decrease in VAS pain levels and PSP (P < 0·01). In group II, which received the active VibOS first, a significant decrease in VAS levels (P < 0·05) and in PSP (P < 0·01) was observed. No significant decrease in VAS pain levels or PSP (P > 0·05) was observed with the use of the inactive VibOS. In conclusion, this study demonstrated a good tendency of this novel VibOS in the alleviation of painful symptoms related to TMD after a 15-day management period compared to control VibOS.

  19. Oak Tree Canker Disease Supports Arthropod Diversity in a Natural Ecosystem

    PubMed Central

    Lee, Yong-Bok; An, Su Jung; Park, Chung Gyoo; Kim, Jinwoo; Han, Sangjo; Kwak, Youn-Sig

    2014-01-01

    Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease. PMID:25288984

  20. The origins of the arthropod nervous system: insights from the Onychophora.

    PubMed

    Whitington, Paul M; Mayer, Georg

    2011-05-01

    A revision of evolutionary relationships of the Arthropoda has provided fresh impetus to tracing the origins of the nervous system of this group of animals: other members of the Ecdysozoa possess a markedly different type of nervous system from both the arthropods and the annelid worms, with which they were previously grouped. Given their status as favoured sister taxon of the arthropods, Onychophora (velvet worms) are a key group for understanding the evolutionary changes that have taken place in the panarthropod (Arthropoda + Onychophora + Tardigrada) lineage. This article reviews our current knowledge of the structure and development of the onychophoran nervous system. The picture that emerges from these studies is that the nervous system of the panarthropod ancestor was substantially different from that of modern arthropods: this animal probably possessed a bipartite, rather than a tripartite brain; its nerve cord displayed only a limited degree of segmentation; and neurons were more numerous but more uniform in morphology than in living arthropods. These observations suggest an evolutionary scenario, by which the arthropod nervous system evolved from a system of orthogonally crossing nerve tracts present in both a presumed protostome ancestor and many extant worm-like invertebrates, including the onychophorans.

  1. Surviving in a frozen desert: environmental stress physiology of terrestrial Antarctic arthropods.

    PubMed

    Teets, Nicholas M; Denlinger, David L

    2014-01-01

    Abiotic stress is one of the primary constraints limiting the range and success of arthropods, and nowhere is this more apparent than Antarctica. Antarctic arthropods have evolved a suite of adaptations to cope with extremes in temperature and water availability. Here, we review the current state of knowledge regarding the environmental physiology of terrestrial arthropods in Antarctica. To survive low temperatures, mites and Collembola are freeze-intolerant and rely on deep supercooling, in some cases supercooling below -30°C. Also, some of these microarthropods are capable of cryoprotective dehydration to extend their supercooling capacity and reduce the risk of freezing. In contrast, the two best-studied Antarctic insects, the midges Belgica antarctica and Eretmoptera murphyi, are freeze-tolerant year-round and rely on both seasonal and rapid cold-hardening to cope with decreases in temperature. A common theme among Antarctic arthropods is extreme tolerance of dehydration; some accomplish this by cuticular mechanisms to minimize water loss across their cuticle, while a majority have highly permeable cuticles but tolerate upwards of 50-70% loss of body water. Molecular studies of Antarctic arthropod stress physiology are still in their infancy, but several recent studies are beginning to shed light on the underlying mechanisms that govern extreme stress tolerance. Some common themes that are emerging include the importance of cuticular and cytoskeletal rearrangements, heat shock proteins, metabolic restructuring and cell recycling pathways as key mediators of cold and water stress in the Antarctic.

  2. Oak tree canker disease supports arthropod diversity in a natural ecosystem.

    PubMed

    Lee, Yong-Bok; An, Su Jung; Park, Chung Gyoo; Kim, Jinwoo; Han, Sangjo; Kwak, Youn-Sig

    2014-03-01

    Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease.

  3. Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods.

    PubMed

    Longcore, Travis; Aldern, Hannah L; Eggers, John F; Flores, Steve; Franco, Lesly; Hirshfield-Yamanishi, Eric; Petrinec, Laina N; Yan, Wilson A; Barroso, André M

    2015-05-05

    Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods.

  4. Building a DNA barcode library of Alaska's non-marine arthropods.

    PubMed

    Sikes, Derek S; Bowser, Matthew; Morton, John M; Bickford, Casey; Meierotto, Sarah; Hildebrandt, Kyndall

    2017-03-01

    Climate change may result in ecological futures with novel species assemblages, trophic mismatch, and mass extinction. Alaska has a limited taxonomic workforce to address these changes. We are building a DNA barcode library to facilitate a metabarcoding approach to monitoring non-marine arthropods. Working with the Canadian Centre for DNA Barcoding, we obtained DNA barcodes from recently collected and authoritatively identified specimens in the University of Alaska Museum (UAM) Insect Collection and the Kenai National Wildlife Refuge collection. We submitted tissues from 4776 specimens, of which 81% yielded DNA barcodes representing 1662 species and 1788 Barcode Index Numbers (BINs), of primarily terrestrial, large-bodied arthropods. This represents 84% of the species available for DNA barcoding in the UAM Insect Collection. There are now 4020 Alaskan arthropod species represented by DNA barcodes, after including all records in Barcode of Life Data Systems (BOLD) of species that occur in Alaska - i.e., 48.5% of the 8277 Alaskan, non-marine-arthropod, named species have associated DNA barcodes. An assessment of the identification power of the library in its current state yielded fewer species-level identifications than expected, but the results were not discouraging. We believe we are the first to deliberately begin development of a DNA barcode library of the entire arthropod fauna for a North American state or province. Although far from complete, this library will become increasingly valuable as more species are added and costs to obtain DNA sequences fall.

  5. Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods

    PubMed Central

    Zou, Yi; van Telgen, Mario D.; Chen, Junhui; Xiao, Haijun; de Kraker, Joop; Bianchi, Felix J. J. A.; van der Werf, Wopke

    2016-01-01

    Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropod populations in rice. When used in combination with an enclosure, application of this sampling device provides absolute estimates of the populations of arthropods as numbers per standardized sampling area. The sampling efficiency depends critically on the sampling duration. In a mature rice crop, a two-minute sampling in an enclosure of 0.13 m2 yields more than 90% of the arthropod population. The device also allows sampling of arthropods dwelling on the water surface or the soil in rice paddies, but it is not suitable for sampling fast flying insects, such as predatory Odonata or larger hymenopterous parasitoids. The modified blower-vac is simple to construct, and cheaper and easier to handle than traditional suction sampling devices, such as D-vac. The low cost makes the modified blower-vac also accessible to researchers in developing countries. PMID:27584040

  6. Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods

    PubMed Central

    Longcore, Travis; Aldern, Hannah L.; Eggers, John F.; Flores, Steve; Franco, Lesly; Hirshfield-Yamanishi, Eric; Petrinec, Laina N.; Yan, Wilson A.; Barroso, André M.

    2015-01-01

    Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods. PMID:25780237

  7. NDVI as a predictor of canopy arthropod biomass in the Alaskan arctic tundra.

    PubMed

    Sweet, Shannan K; Asmus, Ashley; Rich, Matthew E; Wingfield, John; Gough, Laura; Boelman, Natalie T

    2015-04-01

    The physical and biological responses to rapid arctic warming are proving acute, and as such, there is a need to monitor, understand, and predict ecological responses over large spatial and temporal scales. The use of the normalized difference vegetation index (NDVI) acquired from airborne and satellite sensors addresses this need, as it is widely used as a tool for detecting and quantifying spatial and temporal dynamics of tundra vegetation cover, productivity, and phenology. Such extensive use of the NDVI to quantify vegetation characteristics suggests that it may be similarly applied to characterizing primary and secondary consumer communities. Here, we develop empirical models to predict canopy arthropod biomass with canopy-level measurements of the NDVI both across and within distinct tundra vegetation communities over four growing seasons in the Arctic Foothills region of the Brooks Range, Alaska, USA. When canopy arthropod biomass is predicted with the NDVI across all four growing seasons, our overall model that includes all four vegetation communities explains 63% of the variance in canopy arthropod biomass, whereas our models specific to each of the four vegetation communities explain 74% (moist tussock tundra), 82% (erect shrub tundra), 84% (riparian shrub tundra), and 87% (dwarf shrub tundra) of the observed variation in canopy arthropod biomass. Our field-based study suggests that measurements of the NDVI made from air- and spaceborne sensors may be able to quantify spatial and temporal variation in canopy arthropod biomass at landscape to regional scales.

  8. Arthropod and oligochaete assemblages from grasslands of the southern Kenai Peninsula, Alaska

    PubMed Central

    Bowser, Matthew L.; Morton, John M.; Hanson, John Delton; Magness, Dawn R.; Okuly, Mallory

    2017-01-01

    Abstract Background By the end of this century, the potential climate-biome of the southern Kenai Peninsula is forecasted to change from transitional boreal forest to prairie and grasslands, a scenario that may already be playing out in the Caribou Hills region. Here, spruce (Picea × lutzii Little [glauca × sitchensis]) forests were heavily thinned by an outbreak of the spruce bark beetle (Dendroctonus rufipennis (Kirby, 1837)) and replaced by the native but invasive grass species, Calamagrostis canadensis (Michx.) P. Beauv. As part of a project designed to delimit and characterize potentially expanding grasslands in this region, we sought to characterize the arthropod and earthworm communities of these grasslands. We also used this sampling effort as a trial of applying high-throughput sequencing metabarcoding methods to a real-world inventory of terrestrial arthropods. New information We documented 131 occurrences of 67 native arthropod species at ten sites, characterizing the arthropod fauna of these grasslands as being dominated by Hemiptera (60% of total reads) and Diptera (38% of total reads). We found a single exotic earthworm species, Dendrobaena octaedra (Savigny, 1826), at 30% of sites and one unidentified enchytraeid at a single site. The utility of high-throughput sequencing metabarcoding as a tool for bioassessment of terrestrial arthropod assemblages was confirmed. PMID:28325976

  9. Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods.

    PubMed

    Zou, Yi; van Telgen, Mario D; Chen, Junhui; Xiao, Haijun; de Kraker, Joop; Bianchi, Felix J J A; van der Werf, Wopke

    2016-08-10

    Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropod populations in rice. When used in combination with an enclosure, application of this sampling device provides absolute estimates of the populations of arthropods as numbers per standardized sampling area. The sampling efficiency depends critically on the sampling duration. In a mature rice crop, a two-minute sampling in an enclosure of 0.13 m(2) yields more than 90% of the arthropod population. The device also allows sampling of arthropods dwelling on the water surface or the soil in rice paddies, but it is not suitable for sampling fast flying insects, such as predatory Odonata or larger hymenopterous parasitoids. The modified blower-vac is simple to construct, and cheaper and easier to handle than traditional suction sampling devices, such as D-vac. The low cost makes the modified blower-vac also accessible to researchers in developing countries.

  10. An armoured Cambrian lobopodian from China with arthropod-like appendages.

    PubMed

    Liu, Jianni; Steiner, Michael; Dunlop, Jason A; Keupp, Helmut; Shu, Degan; Ou, Qiang; Han, Jian; Zhang, Zhifei; Zhang, Xingliang

    2011-02-24

    Cambrian fossil Lagerstätten preserving soft-bodied organisms have contributed much towards our understanding of metazoan origins. Lobopodians are a particularly interesting group that diversified and flourished in the Cambrian seas. Resembling 'worms with legs', they have long attracted much attention in that they may have given rise to both Onychophora (velvet worms) and Tardigrada (water bears), as well as to arthropods in general. Here we describe Diania cactiformis gen. et sp. nov. as an 'armoured' lobopodian from the Chengjiang fossil Lagerstätte (Cambrian Stage 3), Yunnan, southwestern China. Although sharing features with other typical lobopodians, it is remarkable for possessing robust and probably sclerotized appendages, with what appear to be articulated elements. In terms of limb morphology it is therefore closer to the arthropod condition, to our knowledge, than any lobopodian recorded until now. Phylogenetic analysis recovers it in a derived position, close to Arthropoda; thus, it seems to belong to a grade of organization close to the point of becoming a true arthropod. Further, D. cactiformis could imply that arthropodization (sclerotization of the limbs) preceded arthrodization (sclerotization of the body). Comparing our fossils with other lobopodian appendage morphologies--see Kerygmachela, Jianshanopodia and Megadictyon--reinforces the hypothesis that the group as a whole is paraphyletic, with different taxa expressing different grades of arthropodization.

  11. Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider.

    PubMed

    Jager, Muriel; Murienne, Jérôme; Clabaut, Céline; Deutsch, Jean; Le Guyader, Hervé; Manuel, Michaël

    2006-05-25

    Arthropod head segments offer a paradigm for understanding the diversification of form during evolution, as a variety of morphologically diverse appendages have arisen from them. There has been long-running controversy, however, concerning which head appendages are homologous among arthropods, and from which ancestral arrangement they have been derived. This controversy has recently been rekindled by the proposition that the probable ancestral arrangement, with appendages on the first head segment, has not been lost in all extant arthropods as previously thought, but has been retained in the pycnogonids, or sea spiders. This proposal was based on the neuroanatomical analysis of larvae from the sea spider Anoplodactylus sp., and suggested that the most anterior pair of appendages, the chelifores, are innervated from the first part of the brain, the protocerebrum. Our examination of Hox gene expression in another sea spider, Endeis spinosa, refutes this hypothesis. The anterior boundaries of Hox gene expression domains place the chelifore appendages as clearly belonging to the second head segment, innervated from the second part of the brain, the deutocerebrum. The deutocerebrum must have been secondarily displaced towards the protocerebrum in pycnogonid ancestors. As anterior-most appendages are also deutocerebral in the other two arthropod groups, the Euchelicerata and the Mandibulata, we conclude that the protocerebral appendages have been lost in all extant arthropods.

  12. Disturbance and Recovery of Salt Marsh Arthropod Communities following BP Deepwater Horizon Oil Spill

    PubMed Central

    McCall, Brittany D.; Pennings, Steven C.

    2012-01-01

    Oil spills represent a major environmental threat to coastal wetlands, which provide a variety of critical ecosystem services to humanity. The U.S. Gulf of Mexico is a hub of oil and gas exploration activities that historically have impacted intertidal habitats such as salt marsh. Following the BP Deepwater Horizon oil spill, we sampled the terrestrial arthropod community and marine invertebrates found in stands of Spartina alterniflora, the most abundant plant in coastal salt marshes. Sampling occurred in 2010 as oil was washing ashore and a year later in 2011. In 2010, intertidal crabs and terrestrial arthropods (insects and spiders) were suppressed by oil exposure even in seemingly unaffected stands of plants; however, Littoraria snails were unaffected. One year later, crab and arthropods had largely recovered. Our work is the first attempt that we know of assessing vulnerability of the salt marsh arthropod community to oil exposure, and it suggests that arthropods are both quite vulnerable to oil exposure and quite resilient, able to recover from exposure within a year if host plants remain healthy. PMID:22412916

  13. Impact of chemically contaminated sewage sludge on the collard arthropod community

    SciTech Connect

    Culliney, T.W.; Pimentel, D.; Lisk, D.J.

    1986-08-01

    Stress effects on a terrestrial arthropod community were evident in a study of collards grown in soil amended with chemically contaminated sewage sludge. Plant growth in the contaminated sludge was significantly reduced compared with growth in plots treated with relatively uncontaminated sludge from two small towns or with mature alone. Population densities of major arthropod taxa tended to be lower in plots of contaminated sludge than they were in uncontaminated sludge and manure plots. Species richness and diversity were also reduced in contaminated-sludge plots compared with those of uncontaminated sludge and manure treatments. In general, few differences were observed in plant growth and arthropod numbers between the uncontaminated-sludge treatment, or uncontaminated sludge treated with cadmium or with the insecticide dieldrin. Because cadmium and dieldrin were applied at dosages of cadmium and polychlorinated biphenyls (PCB's) found in the contaminated sludge, results suggested that these two toxins were not responsible for the effects on plants and arthropods observed in the contaminated-sludge treatment. Results of this study indicated the potential for sludge-borne contaminants to suppress growth in crop plants and reduce abundance of their associated arthropods.

  14. Additive and interactive effects of plant genotypic diversity on arthropod communities and plant fitness.

    PubMed

    Johnson, Marc T J; Lajeunesse, Marc J; Agrawal, Anurag A

    2006-01-01

    Recent research suggests that genetic diversity in plant populations can shape the diversity and abundance of consumer communities. We tested this hypothesis in a field experiment by manipulating patches of Evening Primrose (Oenothera biennis) to contain one, four or eight plant genotypes. We then surveyed 92 species of naturally colonizing arthropods. Genetically diverse plant patches had 18% more arthropod species, and a greater abundance of omnivorous and predacious arthropods, but not herbivores, compared with monocultures. The effects of genotypic diversity on arthropod communities were due to a combination of interactive and additive effects among genotypes within genetically diverse patches. Greater genetic diversity also led to a selective feedback, as mean genotype fitness was 27% higher in diverse patches than in monocultures. A comparison between our results and the literature reveals that genetic diversity and species diversity can have similar qualitative and quantitative effects on arthropod communities. Our findings also illustrate the benefit of preserving genetic variation to conserve species diversity and interactions within multitrophic communities.

  15. Seasonal Distribution and Diversity of Ground Arthropods in Microhabitats Following a Shrub Plantation Age Sequence in Desertified Steppe

    PubMed Central

    Liu, Rentao; Zhu, Fan; Song, Naiping; Yang, Xinguo; Chai, Yongqing

    2013-01-01

    In desertified regions, shrub-dominated patches are important microhabitats for ground arthropod assemblages. As shrub age increases, soil, vegetation and microbiological properties can change remarkably and spontaneously across seasons. However, relatively few studies have analyzed how ground arthropods respond to the microhabitats created by shrubs of different plantation ages across seasons. Using 6, 15, 24 and 36 year-old plantations of re-vegetated shrubs (Caragana koushinskii) in the desert steppe of northwestern China as a model system, we sampled ground arthropod communities using a pitfall trapping method in the microhabitats under shrubs and in the open areas between shrubs, during the spring, summer and autumn. The total ground arthropod assemblage was dominated by Carabidae, Melolonthidae, Curculionidae, Tenebrionidae and Formicidae that were affected by plantation age, seasonal changes, or the interaction between these factors, with the later two groups also influenced by microhabitat. Overall, a facilitative effect was observed, with more arthropods and a greater diversity found under shrubs as compared to open areas, but this was markedly affected by seasonal changes. There was a high degree of similarity in arthropod assemblages and diversity between microhabitats in summer and autumn. Shrub plantation age significantly influenced the distribution of the most abundant groups, and also the diversity indices of the ground arthropods. However, there was not an overall positive relationship between shrub age and arthropod abundance, richness or diversity index. The influence of plantation age on arthropod communities was also affected by seasonal changes. From spring through summer to autumn, community indices of ground arthropods tended to decline, and a high degree of similarity in these indices (with fluctuation) was observed among different ages of shrub plantation in autumn. Altogether the recovery of arthropod communities was markedly affected by

  16. Seasonal distribution and diversity of ground arthropods in microhabitats following a shrub plantation age sequence in desertified steppe.

    PubMed

    Liu, Rentao; Zhu, Fan; Song, Naiping; Yang, Xinguo; Chai, Yongqing

    2013-01-01

    In desertified regions, shrub-dominated patches are important microhabitats for ground arthropod assemblages. As shrub age increases, soil, vegetation and microbiological properties can change remarkably and spontaneously across seasons. However, relatively few studies have analyzed how ground arthropods respond to the microhabitats created by shrubs of different plantation ages across seasons. Using 6, 15, 24 and 36 year-old plantations of re-vegetated shrubs (Caragana koushinskii) in the desert steppe of northwestern China as a model system, we sampled ground arthropod communities using a pitfall trapping method in the microhabitats under shrubs and in the open areas between shrubs, during the spring, summer and autumn. The total ground arthropod assemblage was dominated by Carabidae, Melolonthidae, Curculionidae, Tenebrionidae and Formicidae that were affected by plantation age, seasonal changes, or the interaction between these factors, with the later two groups also influenced by microhabitat. Overall, a facilitative effect was observed, with more arthropods and a greater diversity found under shrubs as compared to open areas, but this was markedly affected by seasonal changes. There was a high degree of similarity in arthropod assemblages and diversity between microhabitats in summer and autumn. Shrub plantation age significantly influenced the distribution of the most abundant groups, and also the diversity indices of the ground arthropods. However, there was not an overall positive relationship between shrub age and arthropod abundance, richness or diversity index. The influence of plantation age on arthropod communities was also affected by seasonal changes. From spring through summer to autumn, community indices of ground arthropods tended to decline, and a high degree of similarity in these indices (with fluctuation) was observed among different ages of shrub plantation in autumn. Altogether the recovery of arthropod communities was markedly affected by

  17. Infection with hemotropic Mycoplasma species in patients with or without extensive arthropod or animal contact.

    PubMed

    Maggi, Ricardo G; Compton, Sarah M; Trull, Chelsea L; Mascarelli, Patricia E; Mozayeni, B Robert; Breitschwerdt, Edward B

    2013-10-01

    PCR amplification targeting the 16S rRNA gene was used to test individuals with and without extensive arthropod and animal contact for the possibility of hemotropic mycoplasma infection. The prevalence of hemotropic mycoplasma infection (4.7%) was significantly greater in previously reported cohorts of veterinarians, veterinary technicians, spouses of veterinary professionals, and others with extensive arthropod exposure and/or frequent animal contact than in a previously reported cohort of patients examined by a rheumatologist because of chronic joint pain or evidence of small-vessel disease (0.7%). Based upon DNA sequence analysis, a Mycoplasma ovis-like species was the most prevalent organism detected; however, infection with "Candidatus Mycoplasma haematoparvum" and a potentially novel, but incompletely characterized, hemotropic Mycoplasma species was also documented. Historical exposure to animals and arthropod vectors that can harbor hemotropic Mycoplasma spp. should be considered during epidemiological investigations and in the evaluation of individual patients.

  18. Function and hydrostatics in the telson of the Burgess Shale arthropod Burgessia.

    PubMed

    Lin, Jih-Pai

    2009-06-23

    Burgessia bella is a characteristic Burgess Shale arthropod (508 Ma), but the unusual preservation of its telson in both straight and bent modes leads to contradictory interpretations of its function. A reinvestigation of the fossil material, including burial attitudes, combined with a comparison with the decay sequence and mechanics of the telson in living Limulus, demonstrates that the telson of Burgessia was flexible in its relaxed state but could be stiffened in life. Evidence of fluid within the telson indicates that this manoeuvrability was achieved by changes in hydrostatic pressure and muscular control. The dual mode in the Burgessia telson is, to my knowledge, the first documented among fossil arthropods. It indicates that the requirement for a rigid telson, which is resolved by a thick sclerotized cuticle in most arthropods, may first have been achieved by hydrostatic means.

  19. Function and hydrostatics in the telson of the Burgess Shale arthropod Burgessia

    PubMed Central

    Lin, Jih-Pai

    2009-01-01

    Burgessia bella is a characteristic Burgess Shale arthropod (508 Ma), but the unusual preservation of its telson in both straight and bent modes leads to contradictory interpretations of its function. A reinvestigation of the fossil material, including burial attitudes, combined with a comparison with the decay sequence and mechanics of the telson in living Limulus, demonstrates that the telson of Burgessia was flexible in its relaxed state but could be stiffened in life. Evidence of fluid within the telson indicates that this manoeuvrability was achieved by changes in hydrostatic pressure and muscular control. The dual mode in the Burgessia telson is, to my knowledge, the first documented among fossil arthropods. It indicates that the requirement for a rigid telson, which is resolved by a thick sclerotized cuticle in most arthropods, may first have been achieved by hydrostatic means. PMID:19324649

  20. Preservation of three-dimensional anatomy in phosphatized fossil arthropods enriches evolutionary inference.

    PubMed

    Schwermann, Achim H; Dos Santos Rolo, Tomy; Caterino, Michael S; Bechly, Günter; Schmied, Heiko; Baumbach, Tilo; van de Kamp, Thomas

    2016-02-05

    External and internal morphological characters of extant and fossil organisms are crucial to establishing their systematic position, ecological role and evolutionary trends. The lack of internal characters and soft-tissue preservation in many arthropod fossils, however, impedes comprehensive phylogenetic analyses and species descriptions according to taxonomic standards for Recent organisms. We found well-preserved three-dimensional anatomy in mineralized arthropods from Paleogene fissure fillings and demonstrate the value of these fossils by utilizing digitally reconstructed anatomical structure of a hister beetle. The new anatomical data facilitate a refinement of the species diagnosis and allowed us to reject a previous hypothesis of close phylogenetic relationship to an extant congeneric species. Our findings suggest that mineralized fossils, even those of macroscopically poor preservation, constitute a rich but yet largely unexploited source of anatomical data for fossil arthropods.

  1. Pesticide-Induced Stress in Arthropod Pests for Optimized Integrated Pest Management Programs.

    PubMed

    Guedes, R N C; Smagghe, G; Stark, J D; Desneux, N

    2016-01-01

    More than six decades after the onset of wide-scale commercial use of synthetic pesticides and more than fifty years after Rachel Carson's Silent Spring, pesticides, particularly insecticides, arguably remain the most influential pest management tool around the globe. Nevertheless, pesticide use is still a controversial issue and is at the regulatory forefront in most countries. The older generation of insecticide groups has been largely replaced by a plethora of novel molecules that exhibit improved human and environmental safety profiles. However, the use of such compounds is guided by their short-term efficacy; the indirect and subtler effects on their target species, namely arthropod pest species, have been neglected. Curiously, comprehensive risk assessments have increasingly explored effects on nontarget species, contrasting with the majority of efforts focused on the target arthropod pest species. The present review mitigates this shortcoming by hierarchically exploring within an ecotoxicology framework applied to integrated pest management the myriad effects of insecticide use on arthropod pest species.

  2. Preservation of three-dimensional anatomy in phosphatized fossil arthropods enriches evolutionary inference

    PubMed Central

    Schwermann, Achim H; dos Santos Rolo, Tomy; Caterino, Michael S; Bechly, Günter; Schmied, Heiko; Baumbach, Tilo; van de Kamp, Thomas

    2016-01-01

    External and internal morphological characters of extant and fossil organisms are crucial to establishing their systematic position, ecological role and evolutionary trends. The lack of internal characters and soft-tissue preservation in many arthropod fossils, however, impedes comprehensive phylogenetic analyses and species descriptions according to taxonomic standards for Recent organisms. We found well-preserved three-dimensional anatomy in mineralized arthropods from Paleogene fissure fillings and demonstrate the value of these fossils by utilizing digitally reconstructed anatomical structure of a hister beetle. The new anatomical data facilitate a refinement of the species diagnosis and allowed us to reject a previous hypothesis of close phylogenetic relationship to an extant congeneric species. Our findings suggest that mineralized fossils, even those of macroscopically poor preservation, constitute a rich but yet largely unexploited source of anatomical data for fossil arthropods. DOI: http://dx.doi.org/10.7554/eLife.12129.001 PMID:26854367

  3. Seasonal relationships between birds and arthropods in bottomland forest canopy gaps.

    SciTech Connect

    Bowen, Liessa, Thomas

    2004-12-31

    Bowen, Liessa, Thomas. 2004. Seasonal relationships between birds and arthropods in bottomland forest canopy gaps. PhD Dissertation. North Carolina State University. Raleigh, North Carolina. 98pp. I investigated the influence of arthropod availability and vegetation structure on avian habitat use at the center, edge, and adjacent to forest canopy gaps in 2001 and 2002. I used mist-netting and plot counts to estimate abundance of birds using three sizes (0.13, 0.26, and 0.5 ha) of 7-8 year old group-selection timber harvest openings during four seasons (spring migration, breeding, post-breeding, and fall migration) in a bottomland hardwood forest in the Upper Coastal Plain of South Carolina. I used foliage clipping, Malaise trapping, and pitfall trapping to determine arthropod abundance within each habitat, and I used a warm water crop-flush on captured birds to gather information about arthropods eaten. I observed more birds, including forest interior species, forest-edge spedge species, and several individual species, in early-successional canopy gap and gap-edge habitats than in surrounding mature forest during all seasons. I found a significant interaction between season and habitat type for several groups and individual species, suggesting a seasonal shift in habitat use. Captures of all birds, insectivorous birds, foliage- gleaners, ground-gleaners, aerial salliers, Hooded Warbler (Wilsonia citrina), Northern Cardinal (Cardinalis cardinalis), White-eyed Vireo (Vireo griseus), and Black-throated Blue Warbler (Dendroica caerulescens) were positively correlated with understory vegetation density during two or more seasons. I found relationships between insectivorous birds and leaf-dwelling Lepidoptera, insectivorous birds and ground-dwelling arthropods, foliage-gleaning birds and foliage-dwelling arthropods, and aerial salliers and flying arthropods, as well as between individual bird species and arthropods. Relationships were inconsistent, however, with many

  4. Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care

    NASA Astrophysics Data System (ADS)

    Briggs, Derek E. G.; Siveter, Derek J.; Siveter, David J.; Sutton, Mark D.

    2016-04-01

    The ˜430-My-old Herefordshire, United Kingdom, Lagerstätte has yielded a diversity of remarkably preserved invertebrates, many of which provide fundamental insights into the evolutionary history and ecology of particular taxa. Here we report a new arthropod with 10 tiny arthropods tethered to its tergites by long individual threads. The head of the host, which is covered by a shield that projects anteriorly, bears a long stout uniramous antenna and a chelate limb followed by two biramous appendages. The trunk comprises 11 segments, all bearing limbs and covered by tergites with long slender lateral spines. A short telson bears long parallel cerci. Our phylogenetic analysis resolves the new arthropod as a stem-group mandibulate. The evidence suggests that the tethered individuals are juveniles and the association represents a complex brooding behavior. Alternative possibilities—that the tethered individuals represent a different epizoic or parasitic arthropod—appear less likely.

  5. Manipulation of arthropod sex determination by endosymbionts: diversity and molecular mechanisms.

    PubMed

    Ma, W-J; Vavre, F; Beukeboom, L W

    2014-01-01

    Arthropods exhibit a large variety of sex determination systems both at the chromosomal and molecular level. Male heterogamety, female heterogamety, and haplodiploidy occur frequently, but partially different genes are involved. Endosymbionts, such as Wolbachia, Cardinium,Rickettsia, and Spiroplasma, can manipulate host reproduction and sex determination. Four major reproductive manipulation types are distinguished: cytoplasmic incompatibility, thelytokous parthenogenesis, male killing, and feminization. In this review, the effects of these manipulation types and how they interfere with arthropod sex determination in terms of host developmental timing, alteration of sex determination, and modification of sexual differentiation pathways are summarized. Transitions between different manipulation types occur frequently which suggests that they are based on similar molecular processes. It is also discussed how mechanisms of reproductive manipulation and host sex determination can be informative on each other, with a special focus on haplodiploidy. Future directions on how the study of endosymbiotic manipulation of host reproduction can be key to further studies of arthropod sex determination are shown.

  6. Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care

    PubMed Central

    Briggs, Derek E. G.; Siveter, Derek J.; Siveter, David J.; Sutton, Mark D.; Legg, David

    2016-01-01

    The ∼430-My-old Herefordshire, United Kingdom, Lagerstätte has yielded a diversity of remarkably preserved invertebrates, many of which provide fundamental insights into the evolutionary history and ecology of particular taxa. Here we report a new arthropod with 10 tiny arthropods tethered to its tergites by long individual threads. The head of the host, which is covered by a shield that projects anteriorly, bears a long stout uniramous antenna and a chelate limb followed by two biramous appendages. The trunk comprises 11 segments, all bearing limbs and covered by tergites with long slender lateral spines. A short telson bears long parallel cerci. Our phylogenetic analysis resolves the new arthropod as a stem-group mandibulate. The evidence suggests that the tethered individuals are juveniles and the association represents a complex brooding behavior. Alternative possibilities—that the tethered individuals represent a different epizoic or parasitic arthropod—appear less likely. PMID:27044103

  7. A Comparison of Conservation Reserve Program Habitat Plantings with Respect to Arthropod Prey for Grassland Birds

    USGS Publications Warehouse

    McIntyre, N.E.; Thompson, Thomas R.

    2003-01-01

    The Conservation Reserve Program (CRP) was designed to reduce soil erosion and curb agricultural overproduction by converting highly erodible agricultural land to various forms of perennial habitat. It has had an incidental benefit of providing habitat for wildlife and has been beneficial in reversing population declines of several grassland bird species. However, the mechanisms behind these reversals remain unknown. One such mechanism may be differences in food availability on CRP vs. non-CRP land or between different types of CRP. The influence of CRP habitat type on the abundance of arthropod prey used by grassland birds has not been previously explored. We compared the abundance and diversity of arthropods among four CRP habitat types in Texas [replicated plots of exotic lovegrass (Eragrostis curvula), Old World bluestem (Bothriochloa ischaemum), mixed native grasses with buffalograss (Buchloe?? dactyloides) and mixed native grasses without buffalograss] and native shortgrass prairie. Attention was focused on adult and juvenile spiders (Order Araneae), beetles (Coleoptera), orthopterans (Orthroptera: grasshoppers and crickets) and lepidopterans (Lepidoptera: butterflies and moths), as these taxa are the primary prey items of grassland birds during the breeding season. Arthropod diversity and abundance were higher on indigenous prairie compared to CRP, reflecting differences in vegetative diversity and structure, but there were no differences in arthropod richness or abundance among CRP types. These results indicate that, although CRP is not equivalent to native prairie in terms of vegetation or arthropod diversity, CRP lands do support arthropod prey for grassland birds. More direct assays of the survivorship and fitness of birds on CRP compared to native shortgrass prairie are clearly warranted.

  8. Convergent evolution of chemical defense in poison frogs and arthropod prey between Madagascar and the Neotropics.

    PubMed

    Clark, Valerie C; Raxworthy, Christopher J; Rakotomalala, Valérie; Sierwald, Petra; Fisher, Brian L

    2005-08-16

    With few exceptions, aposematically colored poison frogs sequester defensive alkaloids, unchanged, from dietary arthropods. In the Neotropics, myrmicine and formicine ants and the siphonotid millipede Rhinotus purpureus are dietary sources for alkaloids in dendrobatid poison frogs, yet the arthropod sources for Mantella poison frogs in Madagascar remained unknown. We report GC-MS analyses of extracts of arthropods and microsympatric Malagasy poison frogs (Mantella) collected from Ranomafana, Madagascar. Arthropod sources for 11 "poison frog" alkaloids were discovered, 7 of which were also detected in microsympatric Mantella. These arthropod sources include three endemic Malagasy ants, Tetramorium electrum, Anochetus grandidieri, and Paratrechina amblyops (subfamilies Myrmicinae, Ponerinae, and Formicinae, respectively), and the pantropical tramp millipede R. purpureus. Two of these ant species, A. grandidieri and T. electrum, were also found in Mantella stomachs, and ants represented the dominant prey type (67.3% of 609 identified stomach arthropods). To our knowledge, detection of 5,8-disubstituted (ds) indolizidine iso-217B in T. electrum represents the first izidine having a branch point in its carbon skeleton to be identified from ants, and detection of 3,5-ds pyrrolizidine 251O in A. grandidieri represents the first ponerine ant proposed as a dietary source of poison frog alkaloids. Endemic Malagasy ants with defensive alkaloids (with the exception of Paratrechina) are not closely related to any Neotropical species sharing similar chemical defenses. Our results suggest convergent evolution for the acquisition of defensive alkaloids in these dietary ants, which may have been the critical prerequisite for subsequent convergence in poison frogs between Madagascar and the Neotropics.

  9. Functional richness and ecosystem services: bird predation on arthropods in tropical agroecosystems.

    PubMed

    Philpott, Stacy M; Soong, Oliver; Lowenstein, Jacob H; Pulido, Astrid Luz; Lopez, Diego Tobar; Flynn, Dan F B; DeClerck, Fabrice

    2009-10-01

    In agroecosystems, biodiversity correlates with ecosystem function, yet mechanisms driving these relationships are often unknown. Examining traits and functional classifications of organisms providing ecosystem functions may provide insight into the mechanisms. Birds are important predators of insects, including pests. However, biological simplification of agroforests may decrease provisioning of this pest removal service by reducing bird taxonomic and functional diversity. A recent meta-analysis of bird exclosure studies from a range of agroecosystems in Central America concluded that higher bird richness is associated with significantly greater arthropod removal, yet the mechanism remains unclear. We conducted a meta-analysis of the same data to examine whether birds demonstrate functional complementarity in tropical agroforests. We classified birds according to relevant traits (body mass, foraging strategy, foraging Strata, and diet) and then examined how design of functional classification, including trait selection, classification methods, and the functional diversity metric used affect the suitability of different classifications as predictors of ecosystem services. We determined that vegetation characteristics are not likely drivers of arthropod removal by birds. For some functional classifications, functional richness positively correlated with arthropod removal, indicating that species complementarity may be an important mechanism behind this ecosystem function. The predictive ability of functional classifications increased with the number of traits included in the classification. For the two best classifications examined, functional group richness was a better predictor of arthropod reduction than other metrics of functional diversity (FD and Rao's Q). However, no functional classification predicted arthropod removal better than simple species richness; thus other factors may be important. Our analysis indicates that the sampling effect may also play a

  10. Rapid mortality of pest arthropods by direct exposure to a dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Bures, Brian Lee

    The spread of arthropods due to trade of agricultural commodities and travel of humans is a significant problem in many countries. Limiting the movement of pest species is commonly achieved by the use of chemical pesticides at quarantine facilities. One potential alternative to chemical pesticides is direct exposure of contaminated commodities to ambient pressure electrical discharges. The arthropods are directly exposed to a 5.0 cm helium discharge with power densities on the order of 60 mW/cm3. Direct measurement of chemical species and ambient gas temperature shows the DBD treatment remains effective when the chemically reactive species are suppressed by helium, and when the ambient gas temperature of the discharge is below 40°C. In addition to gas temperature measurements and chemical species identification, the electron temperature and electron density were measured using the neutral bremsstrahlung continuum technique. This study is the first successful implementation of the neutral bremsstrahlung continuum emission diagnostic to a barrier discharge. The primary advantages of the diagnostic for barrier discharges are the measurement is passive and the spatial resolution is only limited by the collimation of the light and the sensitivity of the detector. Although the electron temperature (1.0--1.5 eV) and electron density (˜108 cm-3) are modest, non-chemical dielectric barrier discharge (DBD) treatment of arthropods has proven effective in significantly reducing the population of some arthropods including human body lice, green peach aphids, and western flower thrips. However, the treatment was not universally effective on all arthropod species. German cockroaches and citrus mealy bugs showed substantial resistance to the treatment. The study has shown the treatment does not always induce instant mortality: however, the mortality increases over a 24 hr-period after treatment. Based upon visual observation and the time after treatment to reach maximum

  11. Elevated atmospheric CO2 alters the arthropod community in a forest understory

    NASA Astrophysics Data System (ADS)

    Hamilton, Jason; Zangerl, Arthur R.; Berenbaum, May R.; Sparks, Jed P.; Elich, Lauren; Eisenstein, Alissa; DeLucia, Evan H.

    2012-08-01

    The objective of this study was to determine the extent to which overall population sizes and community composition of arthropods in a naturally occurring forest understory are altered by elevated CO2. The Free Air Concentration Enrichment (FACE) method was used to fumigate large, replicated plots in the Piedmont region of North Carolina, USA to achieve the CO2 concentration predicted for 2050 (˜580 μl l-1). In addition, the extent to which unrestricted herbivorous arthropods were spatially delimited in their resource acquisition was determined. Stable isotope data for spiders (δ13C and δ15N) were collected in ambient and elevated CO2 plots and analyzed to determine whether their prey species moved among plots. Elevated CO2 had no effect on total arthropod numbers but had a large effect on the composition of the arthropod community. Insects collected in our samples were identified to a level that allowed for an assignment of trophic classification (generally to family). For the groups of insects sensitive to atmospheric gas composition, there was an increase in the numbers of individuals collected in primarily predaceous orders (Araneae and Hymenoptera; from 60% to more than 150%) under elevated CO2 and a decrease in the numbers in primarily herbivorous orders (Lepidoptera and Coleoptera; from -30 to -45%). Isotopic data gave no indication that the treatment plots represented a "boundary" to the movement of insects or that there were distinct and independent insect populations inside and outside the treatment plots. A simple two-ended mixing model estimates 55% of the carbon and nitrogen in spider biomass originated external to the elevated CO2 plots. In addition to changes in insect performance, decreases in herbivorous arthropods and increases in predaceous arthropods may also be factors involved in reduced herbivory under elevated CO2 in this forest.

  12. Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields.

    PubMed

    Martínez, Eliana; Rös, Matthias; Bonilla, María Argenis; Dirzo, Rodolfo

    2015-01-01

    The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

  13. Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields

    PubMed Central

    Martínez, Eliana; Rös, Matthias; Bonilla, María Argenis; Dirzo, Rodolfo

    2015-01-01

    The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity. PMID:26197473

  14. Experimental Manipulation of Grassland Plant Diversity Induces Complex Shifts in Aboveground Arthropod Diversity

    PubMed Central

    Hertzog, Lionel R.; Meyer, Sebastian T.; Weisser, Wolfgang W.; Ebeling, Anne

    2016-01-01

    Changes in producer diversity cause multiple changes in consumer communities through various mechanisms. However, past analyses investigating the relationship between plant diversity and arthropod consumers focused only on few aspects of arthropod diversity, e.g. species richness and abundance. Yet, shifts in understudied facets of arthropod diversity like relative abundances or species dominance may have strong effects on arthropod-mediated ecosystem functions. Here we analyze the relationship between plant species richness and arthropod diversity using four complementary diversity indices, namely: abundance, species richness, evenness (equitability of the abundance distribution) and dominance (relative abundance of the dominant species). Along an experimental gradient of plant species richness (1, 2, 4, 8, 16 and 60 plant species), we sampled herbivorous and carnivorous arthropods using pitfall traps and suction sampling during a whole vegetation period. We tested whether plant species richness affects consumer diversity directly (i), or indirectly through increased productivity (ii). Further, we tested the impact of plant community composition on arthropod diversity by testing for the effects of plant functional groups (iii). Abundance and species richness of both herbivores and carnivores increased with increasing plant species richness, but the underlying mechanisms differed between the two trophic groups. While higher species richness in herbivores was caused by an increase in resource diversity, carnivore richness was driven by plant productivity. Evenness of herbivore communities did not change along the gradient in plant species richness, whereas evenness of carnivores declined. The abundance of dominant herbivore species showed no response to changes in plant species richness, but the dominant carnivores were more abundant in species-rich plant communities. The functional composition of plant communities had small impacts on herbivore communities, whereas

  15. Onychophoran Hox genes and the evolution of arthropod Hox gene expression

    PubMed Central

    2014-01-01

    Introduction Onychophora is a relatively small phylum within Ecdysozoa, and is considered to be the sister group to Arthropoda. Compared to the arthropods, that have radiated into countless divergent forms, the onychophoran body plan is overall comparably simple and does not display much in-phylum variation. An important component of arthropod morphological diversity consists of variation of tagmosis, i.e. the grouping of segments into functional units (tagmata), and this in turn is correlated with differences in expression patterns of the Hox genes. How these genes are expressed in the simpler onychophorans, the subject of this paper, would therefore be of interest in understanding their subsequent evolution in the arthropods, especially if an argument can be made for the onychophoran system broadly reflecting the ancestral state in the arthropods. Results The sequences and embryonic expression patterns of the complete set of ten Hox genes of an onychophoran (Euperipatoides kanangrensis) are described for the first time. We find that they are all expressed in characteristic patterns that suggest a function as classical Hox genes. The onychophoran Hox genes obey spatial colinearity, and with the exception of Ultrabithorax (Ubx), they all have different and distinct anterior expression borders. Notably, Ubx transcripts form a posterior to anterior gradient in the onychophoran trunk. Expression of all onychophoran Hox genes extends continuously from their anterior border to the rear end of the embryo. Conclusions The spatial expression pattern of the onychophoran Hox genes may contribute to a combinatorial Hox code that is involved in giving each segment its identity. This patterning of segments in the uniform trunk, however, apparently predates the evolution of distinct segmental differences in external morphology seen in arthropods. The gradient-like expression of Ubx may give posterior segments their specific identity, even though they otherwise express the same

  16. [Alpha and beta arthropods diversity from the different environments of Parque Nacional Los Cardones, Salta, Argentina].

    PubMed

    Belén Cava, Maria; Antonio Corronca, José; José Echeverría, Alejandro

    2013-12-01

    The essential role of the National Parks is to protect nature, in order to prevent the deterioration and loss of the ecosystem under protection. Very few records about the diversity of arthropods are known from Los Cardones National Park, where three eco-regions are protected: Puna and Monte eco-regions and the High Andean Grassland of the Yungas. Here, we aimed to compare the alpha and beta diversity of arthropods in these eco-regions, and to prove if sites from the same ecoregion, show greater similarity between them in their assemblages, than with sites of the other eco-regions. We also identified arthropod orders with higher species richness, and indicated the families that contribute the most to the registered beta diversity. Three sampling sites were established on each eco-region and the arthropods were sampled using pitfall traps and suction samples. We evaluated the obtained inventory through nonparametric estimators of species richness, and compared diversity among eco-regions through "diversity profiles" and "effective number of species". Beta diversity was assessed by different methods such as the Morisita Index, nonmetric multidimentional scaling analysis, a multiple permutation procedure, and a Similarity Percentage analysis. We recorded 469 spp/morphospecies and recognized three arthropod orders (spiders, dipterans and hymenopterans) that are diverse and abundant in the Park. Besides, the diversity in Los Cardones National Park was found to be high, but it was observed higher in the High Andean Grassland of the Yungas, and lower in the Puna. The inventory obtained was good, reached up to the 81% of the species richness estimated by nonparametric estimators. Each eco-region of the park showed a very particular arthropod community that was tested by a multi-response permutation procedure. The species turnover between eco-regions was high, so that the different environments of the protected area are contributing to the maintenance of the regional

  17. Ebola virus and arthropods: a literature review and entomological consideration on the vector role.

    PubMed

    Dutto, M; Bertero, M; Petrosillo, N; Pombi, M; Otranto, D

    2016-10-01

    Ebola virus is a pathogen responsible for a severe disease that affects humans and several animal species. To date, the natural reservoir of this virus is not known with certainty, although it is believed that fruit bats (Chiroptera: Pteropodidae) play an important role in maintaining the virus in nature. Although information on viral transmission from animals to humans is not clear, the role of arthropods has come under suspicion. In this article, we review the potential role of arthropods in spreading Ebola virus, acting as mechanical or biological vectors.

  18. Experimental Manipulation of Grassland Plant Diversity Induces Complex Shifts in Aboveground Arthropod Diversity.

    PubMed

    Hertzog, Lionel R; Meyer, Sebastian T; Weisser, Wolfgang W; Ebeling, Anne

    2016-01-01

    Changes in producer diversity cause multiple changes in consumer communities through various mechanisms. However, past analyses investigating the relationship between plant diversity and arthropod consumers focused only on few aspects of arthropod diversity, e.g. species richness and abundance. Yet, shifts in understudied facets of arthropod diversity like relative abundances or species dominance may have strong effects on arthropod-mediated ecosystem functions. Here we analyze the relationship between plant species richness and arthropod diversity using four complementary diversity indices, namely: abundance, species richness, evenness (equitability of the abundance distribution) and dominance (relative abundance of the dominant species). Along an experimental gradient of plant species richness (1, 2, 4, 8, 16 and 60 plant species), we sampled herbivorous and carnivorous arthropods using pitfall traps and suction sampling during a whole vegetation period. We tested whether plant species richness affects consumer diversity directly (i), or indirectly through increased productivity (ii). Further, we tested the impact of plant community composition on arthropod diversity by testing for the effects of plant functional groups (iii). Abundance and species richness of both herbivores and carnivores increased with increasing plant species richness, but the underlying mechanisms differed between the two trophic groups. While higher species richness in herbivores was caused by an increase in resource diversity, carnivore richness was driven by plant productivity. Evenness of herbivore communities did not change along the gradient in plant species richness, whereas evenness of carnivores declined. The abundance of dominant herbivore species showed no response to changes in plant species richness, but the dominant carnivores were more abundant in species-rich plant communities. The functional composition of plant communities had small impacts on herbivore communities, whereas

  19. Of mites and millipedes: recent progress in resolving the base of the arthropod tree.

    PubMed

    Caravas, Jason; Friedrich, Markus

    2010-06-01

    Deep-level arthropod phylogeny has been in a state of upheaval ever since the emergence of molecular tree reconstruction approaches. While a consensus has settled in that hexapods are more closely related to crustaceans than to myriapods, the phylogenetic position of the latter has remained a matter of debate. Mitochondrial, nuclear, and genome-scale studies have proposed rejecting the long-standing superclade Mandibulata, which unites myriapods with insects and crustaceans, in favor of a clade that unites myriapods with chelicerates and has become known as Paradoxapoda or Myriochelata. Here we discuss the progress, problems, and prospects of arriving at the final arthropod tree.

  20. A survey of the foliar and soil arthropod communities in sunflower (Helianthus annuus) fields in central and eastern South Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The long coevolutionary history between sunflowers (Helianthus annuus, Asterales: Asteraceae) and arthropods in the Northern Great Plains has resulted in a commonly grown oilseed crop that harbors a large diversity of insects. A bioenventory of foliar and subterranean arthropods was performed in 22 ...

  1. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants.

    PubMed

    Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages.

  2. Application of a Computerized General Purpose Information Management System (SELGEM) (SELf-GEnerating Master) to Medically Important Arthropods (Diptera: Culicidae).

    DTIC Science & Technology

    1982-07-01

    GENERAL PURPOSE INFORMATION MANAGEMENT SYSTEM (SELGEM) TO MEDICALLY 0 IMPORTANT ARTHROPODS (DIPTERA: CULICIDAE) oAnnual Report Terry L. Erwin July...APPLICATION OF A COMPUTERIZED GENERAL PURPOSE Annual Report INFORMATION MANAGEMENT SYSTEM (SELGEM) TO July 1981 to June 1982 MEDICALLY IMPORTANT ARTHROPODS

  3. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants

    PubMed Central

    Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages. PMID:26731271

  4. The diversity and abundance of small arthropods in onion, Allium cepa, seed crops, and their potential role in pollination.

    PubMed

    Walker, M K; Howlett, B G; Wallace, A R; McCallum, J A; Teulon, D A J

    2011-01-01

    Onion, Allium cepa L. (Asparagales: Amaryllidaceae), crop fields grown for seed production require arthropod pollination for adequate seed yield. Although many arthropod species visit A. cepa flowers, for most there is little information on their role as pollinators. Small flower visiting arthropods (body width < 3 mm) in particular are rarely assessed. A survey of eight flowering commercial A. cepa seed fields in the North and South Islands of New Zealand using window traps revealed that small arthropods were highly abundant among all except one field. Insects belonging to the orders Diptera and Thysanoptera were the most abundant and Hymenoptera, Collembola, Psocoptera, Hemiptera, and Coleoptera were also present. To test whether small arthropods might contribute to pollination, seed sets from umbels caged within 3 mm diameter mesh cages were compared with similarly caged, hand-pollinated umbels and uncaged umbels. Caged umbels that were not hand-pollinated set significantly fewer seeds (average eight seeds/umbel, n = 10) than caged hand-pollinated umbels (average 146 seeds/umbel) and uncaged umbels (average 481 seeds/umbel). Moreover, sticky traps placed on umbels within cages captured similar numbers of small arthropods as sticky traps placed on uncaged umbels, suggesting cages did not inhibit the movement of small arthropods to umbels. Therefore, despite the high abundance of small arthropods within fields, evidence to support their role as significant pollinators of commercial A. cepa seed crops was not found.

  5. Deriving criteria to select arthropod species for laboratory tests to assess the ecological risks from cultivating transgenic crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arthropods form a major part of the biodiversity in agricultural landscapes. Many species are valued because they provide ecosystem services, including biological control, pollination, and decomposition, or because they are valued for cultural or economic reasons. Some arthropods reduce crop yield a...

  6. [Effects of cutting and reseeding on the ground-dwelling arthropod community in Caragana intermedia forest in desert steppe].

    PubMed

    Liu, Ren-Tao; Chai, Yong-Qing; Yang, Xin-Guo; Song, Nai-Ping; Wang, Xin-Yun; Wang, Lei

    2013-01-01

    Taking a 25-year-old Caragana intermedia forest in desert steppe as test object, an investigation was conducted on the ground-dwelling arthropod community in cutting and no-cutting stands with and without reseeding, aimed to understand the effects of cutting, reseeding and their interaction on the individual number and group richness of ground-dwelling arthropod in C. intermedia forest. There were significantly lower number and richness of ground-dwelling arthropod in the open spaces than under the shrubs in the no-cutting and no-reseeding stands. Cutting, reseeding and both of them could significantly increase the number and richness of ground-dwelling arthropod in the open spaces, but not under the shrubs, compared with no cutting or reseeding. Consequently, there were no significant differences in the distribution of ground-dwelling arthropod in the open spaces and under the shrubs in the cutting, reseeding, or cutting and reseeding stands. Further, there was a similar buffer effect between cutting and reseeding on the ground-dwelling arthropod. No significant differences were observed in the ground-dwelling arthropod distribution, between cutting stand and reseeding stand, between cutting stand and cutting and reseeding stand, and between reseeding stand and cutting and reseeding stand. It was suggested that cutting, reseeding, or both of them could significantly improve the ground-dwelling arthropod diversity especially in the open spaces, being beneficial for the restoration of degraded grassland ecosystem and the rational management on artificial C. intermedia forest in desert steppe.

  7. Relationship between land use pattern and the structure and diversity of soil meso-micro arthropod community.

    PubMed

    Zhang, Limin; Zhang, Xueping; Cui, Wei

    2014-05-01

    Soil arthropod communities can provide valuable information regarding the impacts of human disturbances on ecosystem structure. Our study evaluated the structure, composition and diversity of soil meso-micro arthropod communities, in six different vegetation types and assessed the impacts of human activity. A completely randomized design, including 3 replicates from 6 sites (mowing steppe, natural grassland, severe degradation grassland, farmland, artificial shelter forest, and wetland) was used. Soil samples from the depth of 0 to 20 cm were collected during May, July, and September 2007. Soil meso-micro arthropod were separated using the Tullgren funnels method, and were identified and counted. Soil pH value, organic matter, and total nitrogen were measured in topsoil (0-20 cm) from each site. A total of 5,602 soil meso-micro arthropod individuals were collected, representing 4 classes, 14 orders, and 57 families. Most soil arthropods were widely distributed; however, some species appeared to be influenced by environment variables, and might serve as bioindicators of adverse human impacts. Canonical correspondence analysis indicated the soil arthropod distribution in the severely degraded grassland, mowing steppe, farmland, and shelter forest differed from the natural grassland. Arthropod density and diversity were greatest in May, and the forestland community was the most stable. Because of the vital role soil arthropods have in maintaining a healthy ecosystem, mechanisms to maintain their abundance and diversity should be further evaluated.

  8. Recommendations for the design of laboratory studies on non-target arthropods for risk assessment of genetically engineered plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper provides recommendations on experimental design for early-tier laboratory studies used in the risk assessment process to evaluate potential adverse impacts of arthropod-resistant genetically-engineered plants on non-target arthropods. While we rely heavily on the currently used proteins f...

  9. Collection & Processing of Medically Important Arthropods for Arbovirus Isolation.

    ERIC Educational Resources Information Center

    Sudia, W. Daniel; Chamberlain, Roy W.

    The methods given for collecting, preserving, and processing mosquitoes and other archropods for isolation of arboviruses are those used by the National Communicable Disease Center. Techniques of collecting mosquitoes as they bite, using light or bait traps, and from their daytime resting sites are described and illustrated. Details of subsequent…

  10. Absent fetal movement response with a blunted cardioacceleratory fetal response to external vibratory acoustic stimulation in a fetus with the Pena-Shokeir syndrome (fetal akinesia and hypokinesia sequence).

    PubMed

    Sherer, D M; Sanko, S R; Metlay, L A; Woods, J R

    1992-01-01

    We present a case that describes a partial fetal response to external vibratory acoustic stimulation in that, although no fetal movements were elicited, a blunted, brief positive cardioacceleratory response was noted. This fetus exhibited features of the Pena-Shokeir syndrome, characterized by skeletal neurogenic atrophy, yet with a normal auditory system at autopsy. This observation may suggest that the prolonged increase in the basal fetal heart noted after fetal vibratory acoustic stimulation is sustained by active fetal movements, absent in this fetus due to joint contractures.

  11. Ultraviolet-LIGA-based fabrication and characterization of a nonresonant drive-mode vibratory gyro/accelerometer

    NASA Astrophysics Data System (ADS)

    Verma, Payal; Zaman Khan, Khamar; Khonina, Svetlana Nikolaevna; Kazanskiy, Nikolay Lvovich; Gopal, Ram

    2016-07-01

    A dual-purpose nonresonant 2-degrees of freedom (DOF) drive-mode and 1-DOF sense-mode vibratory gyro/accelerometer fabricated using the economical ultraviolet-lithographie-galvanoformung-abformung (UV-LIGA) fabrication process using SU-8 photoresist is reported. The dual-purpose device presented is capable of detecting acceleration at the lower-frequency band and angular rate at the operating frequency band thereby functioning as both accelerometer and gyroscope. This is achieved by designing the structure such that the frequency response of the drive oscillator has two drive resonances with a flat zone between them, while the sense oscillator has one resonance, which is deliberately placed in the flat region between the two drive resonances. For angular rate detection, the device is operated in the flat zone at the sense resonance frequency at which the device is less susceptible to frequency variations due to both environmental variation and fabrication imperfections and hence is said to be operating in robust mode. The steady-state response and discrimination for angular rate and acceleration sensing have been devised using analytical modeling. The fabrication process is optimized to realize a gyro/accelerometer that has a 9-μm-thick nickel structural layer and 4-μm capacitive gaps. The overall miniature device size is 2.0 mm×1.9 mm. The experimental frequency response of the fabricated devices shows drive-mode resonances at 2.85 and 4.96 kHz and sense resonance at 3.85 kHz compared to the respective design values of drive-mode resonance frequencies 2.97 and 4.81 kHz and sense resonance frequency of 4 kHz. To demonstrate the dual-purpose capability of the device, acceleration characterization has been carried out and presented. The fabricated sensor is packaged in a ceramic package and interfaced with a MS3110 differential capacitive read out IC to characterize the acceleration response of the sensor, using an out-of-plane shaker. The bandwidth for

  12. [Effects of plant viruses on vector and non-vector herbivorous arthropods and their natural enemies: a mini review].

    PubMed

    He, Xiao-Chan; Xu, Hong-Xing; Zhou, Xiao-Jun; Zheng, Xu-Song; Sun, Yu-Jian; Yang, Ya-Jun; Tian, Jun-Ce; Lü, Zhong-Xian

    2014-05-01

    Plant viruses transmitted by arthropods, as an important biotic factor, may not only directly affect the yield and quality of host plants, and development, physiological characteristics and ecological performances of their vector arthropods, but also directly or indirectly affect the non-vector herbivorous arthropods and their natural enemies in the same ecosystem, thereby causing influences to the whole agro-ecosystem. This paper reviewed the progress on the effects of plant viruses on herbivorous arthropods, including vector and non-vector, and their natural enemies, and on their ecological mechanisms to provide a reference for optimizing the management of vector and non-vector arthropod populations and sustainable control of plant viruses in agro-ecosystem.

  13. Experimental and analytical evaluation of the effects of simulated engine inlets on the blade vibratory stresses of the SR-3 model prop-fan

    NASA Technical Reports Server (NTRS)

    Bansal, Prem N.

    1985-01-01

    A cooperative wind tunnel test program, referred to as GUN-3, had been conducted previously to assess the effect of inlet configuration and location on the inlet face pressure recovery and inlet drag in the presence of a high-speed advanced turboprop. These tests were conducted with the inlets located just downstream of the SR-3 model Prop-Fan, a moderately swept, eight-bladed 62.2 cm (24.5 inch) diameter advanced, high-speed turboprop model fabricated from titanium. During these tests, two blades of the SR-3 model Prop-Fan were strain gaged to measure the vibratory blade stresses occurring during the inlet aerodynamic test program. The purpose of the effort reported herein was to reduce and analyze the test results related to the vibratory strain gage measurements obtained. Three inlet configurations had been tested. These were: (1) single scoop, (2) twin scoop, and (3) annular. Each of the three inlets was tested at a position just behind the rotor. The single scoop inlet was also tested at a position further aft. Tests were also done without an inlet. These results emphasize the importance of avoiding critical speeds in the continuous operating range.

  14. Temporal dynamics of arthropods on six tree species in dry woodlands on the Caribbean Island of Puerto Rico.

    PubMed

    Beltrán, William; Wunderle, Joseph M

    2014-01-01

    The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change. We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis-Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various arthropod taxa were highly variable from year to year. Abundance for most taxa did not show significant seasonality over the 3 yr, although most taxa had abundance peaks each year. However, Homoptera displayed high seasonality with significant temporal aggregations in each year. Formicidae, Orthoptera, and Coleoptera showed high variation in abundance between wet and dry periods, whereas Hemiptera were consistently more abundant in the wet period. Seasonal differences in mean abundance were found only in a few taxa on Tamarindus indica L., Bucida buceras L., Pithecellobium dulce, and (Roxburgh) Benth. Mean arthropod abundance varied among tree species, with highest numbers on Prosopis juliflora, (Swartz) De Candolle, Pi. dulce, Leucaena leucocephala, and (Lamarck) de Wit. Abundance of Araneae, Orthoptera, Coleoptera, Lepidoptera larvae, and all arthropods showed weak relationships with one or more climatic variables (rainfall, maximum temperature, or relative humidity). Body size of arthropods was usually largest during the dry periods. Overall, total foliage arthropod abundance showed no consistent seasonality among years, which may become a more common trend in dry forests and woodlands in the Caribbean if seasonality of rainfall becomes less predictable.

  15. Temporal Dynamics of Arthropods on Six Tree Species in Dry Woodlands on the Caribbean Island of Puerto Rico

    PubMed Central

    Beltrán, William; Wunderle, Joseph M.

    2014-01-01

    The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change. We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis–Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various arthropod taxa were highly variable from year to year. Abundance for most taxa did not show significant seasonality over the 3 yr, although most taxa had abundance peaks each year. However, Homoptera displayed high seasonality with significant temporal aggregations in each year. Formicidae, Orthoptera, and Coleoptera showed high variation in abundance between wet and dry periods, whereas Hemiptera were consistently more abundant in the wet period. Seasonal differences in mean abundance were found only in a few taxa on Tamarindus indica L., Bucida buceras L., Pithecellobium dulce, and (Roxburgh) Benth. Mean arthropod abundance varied among tree species, with highest numbers on Prosopis juliflora, (Swartz) De Candolle, Pi. dulce, Leucaena leucocephala, and (Lamarck) de Wit. Abundance of Araneae, Orthoptera, Coleoptera, Lepidoptera larvae, and all arthropods showed weak relationships with one or more climatic variables (rainfall, maximum temperature, or relative humidity). Body size of arthropods was usually largest during the dry periods. Overall, total foliage arthropod abundance showed no consistent seasonality among years, which may become a more common trend in dry forests and woodlands in the Caribbean if seasonality of rainfall becomes less predictable. PMID:25502036

  16. The midgut epithelium of aquatic arthropods: a critical target organ in environmental toxicology.

    PubMed Central

    Beaty, Barry J; Mackie, Ryan S; Mattingly, Kimberly S; Carlson, Jonathan O; Rayms-Keller, Alfredo

    2002-01-01

    The midgut epithelium of aquatic arthropods is emerging as an important and toxicologically relevant organ system for monitoring environmental pollution. The peritrophic matrix of aquatic arthropods, which is secreted by the midgut epithelium cells, is perturbed by copper or cadmium. Molecular biological studies have identified and characterized two midgut genes induced by heavy metals in the midgut epithelium. Many other metal-responsive genes (MRGs) await characterization. One of the MRGs codes for an intestinal mucin, which is critical for protecting the midgut from toxins and pathogens. Another codes for a tubulin gene, which is critical for structure and function of the midgut epithelial cells. Perturbation of expression of either gene could condition aquatic arthropod survivorship. Induction of these MRGs is a more sensitive and rapid indicator of heavy-metal pollution than biological assays. Characterization of genes induced by pollutants could provide mechanistic understanding of fundamental cellular responses to pollutants and insight into determinants of aquatic arthropod population genetic structure and survivorship in nature. PMID:12634118

  17. Evolutionary genomics place the origin of Wolbachia in nematodes, not arthropods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wolbachia, the most widely studied endosymbiont in arthropods, is a target for biological control of mosquito-borne diseases (malaria and dengue virus), and antibiotic elimination of infectious filarial nematodes. We sequenced and analyzed the genome of a new strain (wPpe) in the plant-parasitic nem...

  18. Teaching Students about Biodiversity by Studying the Correlation between Plants & Arthropods

    ERIC Educational Resources Information Center

    Richardson, Matthew L.; Hari, Janice

    2008-01-01

    On Earth there is a huge diversity of arthropods, many of which are highly adaptive and able to exploit virtually every terrestrial habitat. Because of their prevalence even in urban environments, they make an excellent model system for any life science class. Since plants also exploit virtually every terrestrial habitat, studying the relationship…

  19. Arthropod phylogeny: an overview from the perspectives of morphology, molecular data and the fossil record.

    PubMed

    Edgecombe, Gregory D

    2010-01-01

    Monophyly of Arthropoda is emphatically supported from both morphological and molecular perspectives. Recent work finds Onychophora rather than Tardigrada to be the closest relatives of arthropods. The status of tardigrades as panarthropods (rather than cycloneuralians) is contentious from the perspective of phylogenomic data. A grade of Cambrian taxa in the arthropod stem group includes gilled lobopodians, dinocaridids (e.g., anomalocaridids), fuxianhuiids and canadaspidids that inform on character acquisition between Onychophora and the arthropod crown group. A sister group relationship between Crustacea (itself likely paraphyletic) and Hexapoda is retrieved by diverse kinds of molecular data and is well supported by neuroanatomy. This clade, Tetraconata, can be dated to the early Cambrian by crown group-type mandibles. The rival Atelocerata hypothesis (Myriapoda+Hexapoda) has no molecular support. The basal node in the arthropod crown group is embroiled in a controversy over whether myriapods unite with chelicerates (Paradoxopoda or Myriochelata) or with crustaceans and hexapods (Mandibulata). Both groups find some molecular and morphological support, though Mandibulata is presently the stronger morphological hypothesis. Either hypothesis forces an unsampled ghost lineage for Myriapoda from the Cambrian to the mid Silurian.

  20. Positional specification in the segmental growth pattern of an early arthropod

    PubMed Central

    Fusco, Giuseppe; Hong, Paul S.; Hughes, Nigel C.

    2014-01-01

    In many arthropods, there is a change in relative segment size during post-embryonic development, but how segment differential growth is produced is little known. A new dataset of the highest quality specimens of the 429 Myr old trilobite Aulacopleura koninckii provides an unparalleled opportunity to investigate segment growth dynamics and its control in an early arthropod. Morphometric analysis across nine post-embryonic stages revealed a growth gradient in the trunk of A. koninckii. We contrastively tested different growth models referable to two distinct hypotheses of growth control for the developing trunk: (i) a segment-specific control, with individual segments having differential autonomous growth progression, and (ii) a regional control, with segment growth depending on their relative position along the main axis. We show that the trunk growth pattern of A. koninckii was consistent with a regional growth control producing a continuous growth gradient that was stable across all developmental stages investigated. The specific posterior-to-anterior decaying shape of the growth gradient suggests it deriving from the linear transduction of a graded signal, similar to those commonly provided by morphogens. A growth control depending on a form of positional specification, possibly realized through the linear interpretation of a graded signal, may represent the primitive condition for arthropod differential growth along the main body axis, from which the diverse and generally more complex forms of growth control in subsequent arthropods have evolved. PMID:24573851

  1. Arthropods, plants, and transmission lines in Arizona: secondary succession in a Sonoran Desert habitat

    SciTech Connect

    Johnson, C.D.; Ditsworth, T.M.; Beley, J.R.

    1981-09-01

    Overall arthropod densities were low at this site, but the arthropod densities on the disturbed areas appeared to be enhanced after several years. No taxa were found to be statistically different in density between control and disturbed plots. Diversity decreased on the disturbed area after construction. Arthropod community similarity (C) was lower after construction, but C values appear to be related to presence or absence of annual herbs and grasses and not to total cover. Except for globe mallow, there were no pioneer plant species on the experimental plot. Effects of powerline construction on the experimental plant community were a brief reduction in total cover and a slight increase in cover of herbs and annual grasses. The 1976 and 1977 samples exhibit comparable cover values of these plants on both experimental and control plots. The dominant arthropod taxa on the experimental area (especially Thysanoptera, Cicadellidae, Coccinellidae, and Melyridae) appear to be responding numerically to the annual herbs and grasses which are becoming established on the plot.

  2. Expression of arthropod distal limb-patterning genes in the onychophoran Euperipatoides kanangrensis.

    PubMed

    Oliveira, Marta Bastos; Liedholm, Simon Eckerström; Lopez, Jordi Estefa; Lochte, Annalena A; Pazio, Magdalena; Martin, Jesus Pena; Mörch, Patrik Rödin; Salakka, Seela; York, Julia; Yoshimoto, Andrew; Janssen, Ralf

    2014-03-01

    A current hypothesis states that the ancestral limb of arthropods is composed of only two segments. The proximal segment represents the main part of the modern leg, and the distal segment represents the tarsus and claw of the modern leg. If the distal part of the limb is an ancestral feature, one would expect conserved regulatory gene networks acting in distal limb development in all arthropods and possibly even their sister group, the onychophorans. We investigated the expression patterns of six genes known to function during insect distal limb development in the onychophoran Euperipatoides kanangrensis, i.e., clawless (cll), aristaless (al), spineless (ss), zinc finger homeodomain 2 (zfh2), rotund (rn), and Lim1. We find that all investigated genes are expressed in at least some of the onychophoran limbs. The expression patterns of most of these genes, however, display crucial differences to the known insect patterns. The results of this study question the hypothesis of conserved distal limb evolution in arthropods and highlight the need for further studies on arthropod limb development.

  3. Characterization of the Arthropod Community Associated with Switchgrass (Poales: Poaceae) in Nebraska

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) is a perennial warm-season grass, native to the North American Great Plains. Recently, this prairie grass has received increased attention as a potential biomass energy crop. Little is known about the arthropod community affecting switchgrass grown under either mana...

  4. A global meta-analytic contrast of cushion-plant effects on plants and on arthropods.

    PubMed

    Liczner, Amanda R; Lortie, Christopher J

    2014-01-01

    Nurse plant facilitation is a commonly reported plant-plant interaction and is an important factor influencing community structure in stressful environments. Cushion plants are an example of alpine nurse plants that modify microclimatic conditions within their canopies to create favourable environments for other plants. In this meta-analysis, the facilitative effects of cushion plants was expanded from previous syntheses of the topic and the relative strength of facilitation for other plants and for arthropods were compared globally.The abundance, diversity, and species presence/absence effect size estimates were tested as plant responses to nurse plants and a composite measure was tested for arthropods. The strength of facilitation was on average three times greater for arthropods relative to all plant responses to cushions. Plant species presence, i.e., frequency of occurrence, was not enhanced by nurse-plants. Cushion plants nonetheless acted as nurse plants for both plants and arthropods in most alpine contexts globally, and although responses by other plant species currently dominate the facilitation literature, preliminary synthesis of the evidence suggests that the potential impacts of nurses may be even greater for other trophic levels.

  5. First record of an arthropod from the Passaic Formation (Late Triassic), near Milford, New Jersey

    NASA Astrophysics Data System (ADS)

    Metz, Robert

    2012-03-01

    Mudstones of the Triassic Passaic Formation, near Milford, New Jersey, have yielded the first evidence of an arthropod impression in that formation. Associated trace fossils include Helminthoidichnites, Lockeia, Scoyenia, Spongeliomorpha, and the reptile footprint Rhynchosauroides, representing the Scoyenia ichnofacies. Associated sedimentary structures include desiccation cracks and raindrop impressions. The Passaic sediments were deposited under shallow water lacustrine shoreline conditions subject to periodic subaerial exposure.

  6. Arthropods (Acari, Mallophaga, Siphonaptera) collected from Procyon lotor (Linnaeus, 1758) (Mammalia, Carnivora, Procyonidae) in Poland.

    PubMed

    Haitlinger, Ryszard; Łupicki, Dariusz

    2009-01-01

    From 9 specimens of Procyon lotor collected in vicinity of Dobroszyn and Górzyca (Lubuskie province) 61 arthropods of 6 species were obtained: Siphonaptera (one specimen), Acari (3 species), Phthiraptera (one specimen--Trichodectes octomaculatus; new species to fauna of Poland) and one specimen of Psocoptera.

  7. Arthropods, plants and transmission lines in Arizona: community dynamics during secondary succession in a desert grassland

    SciTech Connect

    Butt, S.M.; Beley, J.R.; Ditsworth, T.M.; Johnson, C.D.; Balda, R.P.

    1980-11-01

    In 1972, access roads were constructed and then used by heavy equipment to build a 500 kV powerline in north central Arizona. Secondary succession of arthropods was studied till 1977 by comparing the initially bare soil of the roads with undisturbed control plots nearby. It was found that, after construction, total anthropod densities were reduced for two to three years, that after five years no anthropod taxa had greater densities on the disturbed areas, but some were significantly reduced, the diversity of arthropods dropped for a period of three or four years, that arthropod community similarity of the two study plots appeared to be related to total cover of plants and similarity of plant communities, the significant correlations between arthropod taxa suggested that the plant communities of the two plots are close in successional status, plant succession was not as rapid as expected, and the disturbed area had a great reduction in perennial grasses but an increase in annual herbs. The numerical dominance of herbivores on both disturbed and control plots, especially after construction, supports the hypothesis that linear, predominantly grazing food chains are characteristic of early successional stages.

  8. Francisella–Arthropod Vector Interaction and its Role in Patho-Adaptation to Infect Mammals

    PubMed Central

    Akimana, Christine; Kwaik, Yousef Abu

    2011-01-01

    Francisella tularensis is a Gram-negative, intracellular, zoonotic bacterium, and is the causative agent of tularemia with a broad host range. Arthropods such as ticks, mosquitoes, and flies maintain F. tularensis in nature by transmitting the bacteria among small mammals. While the tick is largely believed to be a biological vector of F. tularensis, transmission by mosquitoes and flies is largely believed to be mechanical on the mouthpart through interrupted feedings. However, the mechanism of infection of the vectors by F. tularensis is not well understood. Since F. tularensis has not been localized in the salivary gland of the primary human biting ticks, it is thought that bacterial transmission by ticks is through mechanical inoculation of tick feces containing F. tularensis into the skin wound. Drosophila melanogaster is an established good arthropod model for arthropod vectors of tularemia, where F. tularensis infects hemocytes, and is found in hemolymph, as seen in ticks. In addition, phagosome biogenesis and robust intracellular proliferation of F. tularensis in arthropod-derived cells are similar to that in mammalian macrophages. Furthermore, bacterial factors required for infectivity of mammals are often required for infectivity of the fly by F. tularensis. Several host factors that contribute to F. tularensis intracellular pathogenesis in D. melanogaster have been identified, and F. tularensis targets some of the evolutionarily conserved eukaryotic processes to enable intracellular survival and proliferation in evolutionarily distant hosts. PMID:21687425

  9. Formicine ants: An arthropod source for the pumiliotoxin alkaloids of dendrobatid poison frogs

    PubMed Central

    Saporito, Ralph A.; Garraffo, H. Martin; Donnelly, Maureen A.; Edwards, Adam L.; Longino, John T.; Daly, John W.

    2004-01-01

    A remarkable diversity of bioactive lipophilic alkaloids is present in the skin of poison frogs and toads worldwide. Originally discovered in neotropical dendrobatid frogs, these alkaloids are now known from mantellid frogs of Madagascar, certain myobatrachid frogs of Australia, and certain bufonid toads of South America. Presumably serving as a passive chemical defense, these alkaloids appear to be sequestered from a variety of alkaloid-containing arthropods. The pumiliotoxins represent a major, widespread, group of alkaloids that are found in virtually all anurans that are chemically defended by the presence of lipophilic alkaloids. Identifying an arthropod source for these alkaloids has been a considerable challenge for chemical ecologists. However, an extensive collection of neotropical forest arthropods has now revealed a putative arthropod source of the pumiliotoxins. Here we report on the presence of pumiliotoxins in formicine ants of the genera Brachymyrmex and Paratrechina, as well as the presence of these ants in the stomach contents of the microsympatric pumiliotoxin-containing dendrobatid frog, Dendrobates pumilio. These pumiliotoxins are major alkaloids in D. pumilio, and Brachymyrmex and Paratrechina ants now represent the only known dietary sources of these toxic alkaloids. These findings further support the significance of ant-specialization and alkaloid sequestration in the evolution of bright warning coloration in poison frogs and toads. PMID:15128938

  10. Somatic and Germline Diversification of a Putative Immunoreceptor within One Phylum: Dscam in Arthropods.

    PubMed

    Brites, Daniela; Du Pasquier, Louis

    2015-01-01

    Arthropod Dscam, the homologue of the human Down Syndrome cell adhesion molecule, is a receptor used by the nervous and immune systems. Unlike in vertebrates, evolutionary pressure has selected and maintained a vast Dscam diversity of isoforms, known to specifying neuronal identity during the nervous system differentiation. This chapter examines the different modes of Dscam diversification in the context of arthropods' evolution and that of their immune system, where its role is controversial. In the single Dscam gene of insects and crustaceans, mutually exclusive alternative splicing affects three clusters of duplicated exons encoding the variable parts of the receptor. The Dscam gene produces over 10,000 isoforms. In the more basal arthropods such as centipedes, Dscam diversity results from a combination of many germline genes (over 80) with, in about half of those, the possibility of alternative splicing affecting only one exon cluster. In the even more basal arthropods, such as chelicerates, no splicing possibility is detected, but there exist dozens of germline Dscam genes. Compared to controlling the expression of multiple germline genes, the somatic mutually alternative splicing within a single gene may offer a simplified way of expressing a large Dscam repertoire. Expressed by hemocytes, Dscam is considered a phagocytic receptor but is also encountered in solution. More information is necessary about its binding to pathogens, its role in phagocytosis, its possible role in specifying hemocyte identity, its kinetics of expression, and the regulation of its RNA splicing to understand how its diversity is linked to immunity.

  11. The Hunsrück biota: A unique window into the ecology of Lower Devonian arthropods.

    PubMed

    Rust, Jes; Bergmann, Alexandra; Bartels, Christoph; Schoenemann, Brigitte; Sedlmeier, Stephanie; Kühl, Gabriele

    2016-03-01

    The approximately 400-million-year old Hunsrück biota provides a unique window into Devonian marine life. Fossil evidence suggests that this biota was dominated by echinoderms and various classes of arthropods, including Trilobita, stem lineage representatives of Euarthropoda, Chelicerata and Eucrustacea, as well as several crown group Chelicerata and Eucrustacea. The Hunsrück biota's exceptional preservation allows detailed reconstructions and description of key-aspects of its fauna's functional morphologies thereby revealing modes of locomotion, sensory perception, and feeding strategies. Morphological and stratigraphic data are used for a critical interpretation of the likely habitats, mode of life and nutritional characteristics of this diverse fauna. Potential predators include pycnogonids and other chelicerates, as well as the now extinct stem arthropods Schinderhannes bartelsi, Cambronatus brasseli and Wingertshellicus backesi. Mainly the deposit feeding Trilobita, Marrellomorpha and Megacheira, such as Bundenbachiellus giganteus, represents scavengers. Possibly, opportunistic scavenging was also performed by the afore-mentioned predators. Most of the studied arthropods appear to have been adapted to living in relatively well-illuminated conditions within the photic zone. Fossil evidence for associations amongst arthropods and other classes of metazoans is reported. These associations provide evidence of likely community structures.

  12. The value of urban vacant land to support arthropod biodiversity and ecosystem services.

    PubMed

    Gardiner, Mary M; Burkman, Caitlin E; Prajzner, Scott P

    2013-12-01

    The expansion of urban areas is occurring globally, but not all city neighborhoods are gaining population. Because of economic decline and the recent foreclosure crisis, many U.S. cities are demolishing abandoned residential structures to create parcels of vacant land. In some cities, weak housing markets have, or will likely, recover in the near term, and these parcels will be redeveloped. However, in other cities, large numbers of abandoned parcels have no significant market value and no likelihood of near-term redevelopment. The creation of these vacated green spaces could offer opportunities to preserve declining species, restore ecosystem functions, and support diverse ecosystem services. Arthropods are an important indicator of the ability of urban vacant land to serve multiple functions, from conservation to food production. Across Europe, vacant lands have been found to support a diversity of rare species, and similar examinations of arthropods within this habitat are underway in the United States. In addition, using vacant land as a resource for local food production is growing rapidly worldwide. Arthropods play key roles in the sustainability of food production in cities, and land conversion to farming has been found to influence their community composition and function. A greater focus on quantifying the current ecological value of vacant land and further assessment of how changes in its ecosystem management affect biodiversity and ecosystem processes is clearly needed. Herein, we specifically focus on the role of arthropods in addressing these priorities to advance our ecological understanding of the functional role of vacant land habitats in cities.

  13. The Role of Dead Wood in Maintaining Arthropod Diversity on the Forest Floor

    SciTech Connect

    Hanula, James L.; Horn, Scott; Wade, Dale D.

    2006-08-01

    Dead wood is a major component of forests and contributes to overall diversity, primarily by supporting insects that feed directly on or in it. Further, a variety of organisms benefit by feeding on those insects. What is not well known is how or whether dead wood influences the composition of the arthropod community that is not solely dependent on it as a food resource, or whether woody debris influences prey available to generalist predators. One group likely to be affected by dead wood is ground-dwelling arthropods. We studied the effect of adding large dead wood to unburned and frequently burned pine stands to determine if dead wood was used more when the litter and understory plant community are removed. We also studied the effect of annual removal of dead wood from large (10-ha) plots over a 5-year period on ground-dwelling arthropods. In related studies, we examined the relationships among an endangered woodpecker that forages for prey on live trees, its prey, and dead wood in the forest. Finally, the results of these and other studies show that dead wood can influence the abundance and diversity of the ground-dwelling arthropod community and of prey available to generalist predators not foraging directly on dead trees.

  14. Disparate effects of plant genotypic diversity on foliage and litter arthropod communities

    SciTech Connect

    Crutsinger, Greg; Reynolds, Nicholas; Classen, Aimee T; Sanders, Dr. Nathan James

    2008-01-01

    Intraspecific diversity within plant species is increasingly recognized as an important influence on the structure of associated arthropod communities, though whether there are congruent responses of above- and belowground communities to intraspecific diversity remains unclear. In this study, we compare the effects of host-plant genotype and genotypic diversity of the perennial plant, Solidago altissima, on the arthropod community associated with living plant tissue (foliage-based community) and microarthropods associated with leaf litter (litter-based community). We found that variation among host-plant genotypes had strong effects on the diversity and composition of foliage-based arthropods, but only weak influence on litter-based microarthropods. Furthermore, host-plant genotypic diversity was positively related to the abundance and diversity of foliage-based arthropods, including herbivore and predator trophic levels. In contrast, there were minimal effects of genotypic diversity in litter on microarthropods. Our study illustrates that incorporating both above- and belowground perspective into community genetics studies leads to very different conclusions about the importance of intraspecific diversity, than when considering aboveground responses in isolation.

  15. Selected examples of dispersal of arthropods associated with agricultural crop and animal production

    NASA Technical Reports Server (NTRS)

    Henneberry, T. J.

    1979-01-01

    The economic importance of arthropods in agricultural production systems and the possibilities of using dispersal behavior to develop and manipulate control are examined. Examples of long and short distance dispersal of economic insect pests and beneficial species from cool season host reservoirs and overwintering sites are presented. Significant dispersal of these species often occurring during crop and animal production is discussed.

  16. Artificial neural network properties associated with wiring patterns in the visual projections of vertebrates and arthropods.

    PubMed

    Tosh, Colin R; Ruxton, Graeme D

    2006-08-01

    We model the functioning of different wiring schemes in visual projections using artificial neural networks and so speculate on selective factors underlying taxonomic variation in neural architecture. We model the high connective overlap of vertebrates (where networks have a dense mesh of connections) and the less overlapping, more modular architecture of arthropods. We also consider natural variation in these basic wiring schemes. Generally, arthropod networks are as efficient or more efficient in functioning compared to vertebrate networks. They do not show the confusion effect (decreasing targeting accuracy with increasing input group size), and they train as well or better. Arthropod networks are, however, generally poorer at reconstructing novel inputs. The ability of vertebrate networks to effectively process novel stimuli could promote behavioral sophistication and drive the evolution of vertebrate wiring schemes. Vertebrate networks with less connective overlap have, surprisingly, similar or superior properties compared to those with high connective overlap. Thus, the partial connective overlap seen in real vertebrate visual projections may be an optimal, evolved solution. Arthropod networks with and without whole-cell neural connections within neural layers have similar properties. This indicates that neural connections mediated by offshoots of single cells (dendrites) may be fundamental to generating the confusion effect.

  17. Removing external DNA contamination from arthropod predators destined for molecular gut-content analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular gut-content analysis enables detection of arthropod predation with minimal disruption of ecosystem processes. Field and laboratory experiments have demonstrated that mass-collection methods, such as sweep-netting, vacuum sampling, and foliage beating, can lead to contamination of fed pred...

  18. Mini-aspirator: A new device for collection and transfer of small arthropods to plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The process of collecting and/or infesting plants with a designated number of small arthropods in biological experiments is tedious and laborious. We developed a modified mini-aspirator, powered with a vacuum pump and fitted with a specially adapted (removeable) collecting vial to reduce the handli...

  19. Removing external DNA decontamination from arthropod predators destined for molecular gut-content analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular gut-content analysis enables detection of arthropod predation with minimal disruption of ecosystem processes. Field and laboratory experiments have demonstrated that mass-collection methods, such as sweep-netting, vacuum sampling, and foliage beating, can lead to contamination of fed pred...

  20. A global meta-analytic contrast of cushion-plant effects on plants and on arthropods

    PubMed Central

    Liczner, Amanda R.

    2014-01-01

    Nurse plant facilitation is a commonly reported plant–plant interaction and is an important factor influencing community structure in stressful environments. Cushion plants are an example of alpine nurse plants that modify microclimatic conditions within their canopies to create favourable environments for other plants. In this meta-analysis, the facilitative effects of cushion plants was expanded from previous syntheses of the topic and the relative strength of facilitation for other plants and for arthropods were compared globally.The abundance, diversity, and species presence/absence effect size estimates were tested as plant responses to nurse plants and a composite measure was tested for arthropods. The strength of facilitation was on average three times greater for arthropods relative to all plant responses to cushions. Plant species presence, i.e., frequency of occurrence, was not enhanced by nurse-plants. Cushion plants nonetheless acted as nurse plants for both plants and arthropods in most alpine contexts globally, and although responses by other plant species currently dominate the facilitation literature, preliminary synthesis of the evidence suggests that the potential impacts of nurses may be even greater for other trophic levels. PMID:24688848

  1. Density-Dependent Effects of an Invasive Ant on a Ground-Dwelling Arthropod Community.

    PubMed

    Cooling, M; Sim, D A; Lester, P J

    2015-02-01

    It is frequently assumed that an invasive species that is ecologically or economically damaging in one region, will typically be so in other environments. The Argentine ant Linepithema humile (Mayr) is listed among the world's worst invaders. It commonly displaces resident ant species where it occurs at high population densities, and may also reduce densities of other ground-dwelling arthropods. We investigated the effect of varying Argentine ant abundance on resident ant and nonant arthropod species richness and abundance in seven cities across its range in New Zealand. Pitfall traps were used to compare an invaded and uninvaded site in each city. Invaded sites were selected based on natural varying abundance of Argentine ant populations. Argentine ant density had a significant negative effect on epigaeic ant abundance and species richness, but hypogaeic ant abundance and species richness was unaffected. We observed a significant decrease in Diplopoda abundance with increasing Argentine ant abundance, while Coleoptera abundance increased. The effect on Amphipoda and Isopoda depended strongly on climate. The severity of the impact on negatively affected taxa was reduced in areas where Argentine ant densities were low. Surprisingly, Argentine ants had no effect on the abundance of the other arthropod taxa examined. Morphospecies richness for all nonant arthropod taxa was unaffected by Argentine ant abundance. Species that are established as invasive in one location therefore cannot be assumed to be invasive in other locations based on presence alone. Appropriate management decisions should reflect this knowledge.

  2. Plant diversity impacts decomposition and herbivory via changes in aboveground arthropods.

    PubMed

    Ebeling, Anne; Meyer, Sebastian T; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W

    2014-01-01

    Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning.

  3. Biostable agonists that match or exceed activity of native insect kinins on recombinant arthropod GPCRs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The multifunctional arthropod insect kinins share the evolutionarily conserved C-terminal pentapeptide motif Phe-X1-X2-Trp-Gly-NH2, where X1 = His, Asn, Ser, or Tyr and X2 = Ser, Pro, or Ala. Insect kinins regulate diuresis in many species of insects. Compounds with similar biological activity cou...

  4. Effects of the brown anole invasion and betelnut palm planting on arthropod diversity in southern Taiwan.

    PubMed

    Huang, Shao-Chang; Norval, Gerrut; Wei, Chia-Shian; Tso, I-Min

    2008-11-01

    The brown anole ( Anolis sagrei ) occurs naturally in various localities in Central America, and an exotic invasive population was first reported in Sheishan District, Chiayi County, Taiwan, in 2000. Previous studies showed that following the invasion of A. sagrei , the diversity and abundance of local terrestrial arthropods, such as orb spiders and arboreal insects, were severely affected. In this study, we assessed the impact of A. sagrei on arthropod diversity in Taiwan by comparing spider and insect diversities among betelnut palm plantations, in which this lizard species was either present or absent, and a secondary forest. In addition, enclosures were established in which the density of A. sagrei was manipulated to investigate the effect of this predator on spiders. The results of a lizard stomach content analysis showed that spiders comprised 7% and insects 90% of the prey consumed. Among the insects consumed by A. sagrei , more than 50% were ants. The abundances of the major arthropod prey of A. sagrei , such as jumping spiders and hymenopterans, in the lizard-present sites were much lower than in the lizard-removed sites. The enclosure experiments also showed that predation by the lizards significantly reduced the abundance of jumping spiders. All these results indicated that the introduced lizard greatly affected the diversity and abundance of terrestrial arthropods in agricultural areas in southern Taiwan.

  5. Differential Rickettsial Transcription in Bloodfeeding and Non-Bloodfeeding Arthropod Hosts

    PubMed Central

    Verhoeve, Victoria I.; Jirakanwisal, Krit; Utsuki, Tadanobu; Macaluso, Kevin R.

    2016-01-01

    Crucial factors influencing the epidemiology of Rickettsia felis rickettsiosis include pathogenesis and transmission. Detection of R. felis DNA in a number of arthropod species has been reported, with characterized isolates, R. felis strain LSU and strain LSU-Lb, generated from the cat flea, Ctenocephalides felis, and the non-hematophagous booklouse, Liposcelis bostrychophila, respectively. While it is realized that strain influence on host biology varies, the rickettsial response to these distinct host environments remained undefined. To identify a panel of potential rickettsial transmission determinants in the cat flea, the transcriptional profile for these two strains of R. felis were compared in their arthropod hosts using RNAseq. Rickettsial genes with increased transcription in the flea as compared to the booklouse were identified. Genes previously associated with bacterial virulence including LPS biosynthesis, Type IV secretion system, ABC transporters, and a toxin-antitoxin system were selected for further study. Transcription of putative virulence-associated genes was determined in a flea infection bioassay for both strains of R. felis. A host-dependent transcriptional profile during bloodfeeding, specifically, an increased expression of selected transcripts in newly infected cat fleas and flea feces was detected when compared to arthropod cell culture and incubation in vertebrate blood. Together, these studies have identified novel, host-dependent rickettsial factors that likely contribute to successful horizontal transmission by bloodfeeding arthropods. PMID:27662479

  6. Pax3/7 genes reveal conservation and divergence in the arthropod segmentation hierarchy.

    PubMed

    Davis, Gregory K; D'Alessio, Joseph A; Patel, Nipam H

    2005-09-01

    Several features of Pax3/7 gene expression are shared among distantly related insects, including pair-rule, segment polarity, and neural patterns. Recent data from arachnids imply that roles in segmentation and neurogenesis are likely to be played by Pax3/7 genes in all arthropods. To further investigate Pax3/7 genes in non-insect arthropods, we isolated two monoclonal antibodies that recognize the products of Pax3/7 genes in a wide range of taxa, allowing us to quickly survey Pax3/7 expression in all four major arthropod groups. Epitope analysis reveals that these antibodies react to a small subset of Paired-class homeodomains, which includes the products of all known Pax3/7 genes. Using these antibodies, we find that Pax3/7 genes in crustaceans are expressed in an early broad and, in one case, dynamic domain followed by segmental stripes, while myriapods and chelicerates exhibit segmental stripes that form early in the posterior-most part of the germ band. This suggests that Pax3/7 genes acquired their role in segmentation deep within, or perhaps prior to, the arthropod lineage. However, we do not detect evidence of pair-rule patterning in either myriapods or chelicerates, suggesting that the early pair-rule expression pattern of Pax3/7 genes in insects may have been acquired within the crustacean-hexapod lineage.

  7. Resistance mechanisms against arthropod herbivores in cotton and their interactions with natural enemies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton plants from the genus Gossypium are grown on more than 30 million hectares worldwide and are a major source of fiber. The plants possess a wide-range of indirect and direct-defense mechanisms against arthropod pests. Direct defense mechanisms include morphological traits such as trichomes and...

  8. A Nod to disease vectors: mitigation of pathogen sensing by arthropod saliva

    PubMed Central

    Sakhon, Olivia S.; Severo, Maiara S.; Kotsyfakis, Michail; Pedra, Joao H. F.

    2013-01-01

    Arthropod saliva possesses anti-hemostatic, anesthetic, and anti-inflammatory properties that facilitate feeding and, inadvertently, dissemination of pathogens. Vector-borne diseases caused by these pathogens affect millions of people each year. Many studies address the impact of arthropod salivary proteins on various immunological components. However, whether and how arthropod saliva counters Nod-like (NLR) sensing remains elusive. NLRs are innate immune pattern recognition molecules involved in detecting microbial molecules and danger signals. Nod1/2 signaling results in activation of the nuclear factor-κB and the mitogen-activated protein kinase pathways. Caspase-1 NLRs regulate the inflammasome~– a protein scaffold that governs the maturation of interleukin (IL)-1β and IL-18. Recently, several vector-borne pathogens have been shown to induce NLR activation in immune cells. Here, we provide a brief overview of NLR signaling and discuss clinically relevant vector-borne pathogens recognized by NLR pathways. We also elaborate on possible anti-inflammatory effects of arthropod saliva on NLR signaling and microbial pathogenesis for the purpose of exchanging research perspectives. PMID:24155744

  9. Effect of ground cover vegetation on the abundance and diversity of beneficial arthropods in citrus orchards.

    PubMed

    Silva, E B; Franco, J C; Vasconcelos, T; Branco, M

    2010-08-01

    The effect of ground cover upon the communities of beneficial arthropods established in the canopy of lemon trees was investigated, by comparing three ground-cover management treatments applied: RV, resident vegetation; S, sowed selected species; and BS, bare soil by controlling weeds with herbicide. Over two consecutive years, arthropod communities in the tree canopy were sampled periodically by beating and suction techniques. Significantly higher numbers of beneficial arthropods were found in the RV and S treatments in comparison with bare soil. Spiders and parasitoid wasps were the two most common groups, representing, respectively, 70% and 19% of all catches in beating samples and 33% and 53% in suction samples. For the RV and S treatments, significant seasonal deviations from the bare soil treatment were observed using principal response curves. Similar seasonal patterns were observed over the two years. The RV and S treatments showed significant positive deviations from the BS treatment in late spring and summer, accounted for the higher numbers of parasitoid wasps, coccinelids and lacewings present. By contrast, the seasonal deviations observed for the spider community differed from those of the remaining arthropods. During late winter and early spring, the RV and S treatments presented a higher abundance of spiders in the tree canopy, in comparison with bare soil, whereas in the summer significantly more spiders were found in the bare soil treatment. Spider movements between tree canopy and ground vegetation layers may justify this result.

  10. Diverse urban plantings managed with sufficient resource availability can increase plant productivity and arthropod diversity.

    PubMed

    Muller, Jonathon N; Loh, Susan; Braggion, Ligia; Cameron, Stephen; Firn, Jennifer L

    2014-01-01

    Buildings structures and surfaces are explicitly being used to grow plants, and these "urban plantings" are generally designed for aesthetic value. Urban plantings also have the potential to contribute significant "ecological values" by increasing urban habitat for animals such as arthropods and by increasing plant productivity. In this study, we evaluated how the provision of these additional ecological values is affected by plant species richness; the availability of essential resources for plants, such as water, light, space; and soil characteristics. We sampled 33 plantings located on the exterior of three buildings in the urban center of Brisbane, Australia (subtropical climatic region) over 2, 6 week sampling periods characterized by different temperature and rainfall conditions. Plant cover was estimated as a surrogate for productivity as destructive sampling of biomass was not possible. We measured weekly light levels (photosynthetically active radiation), plant CO2 assimilation, soil CO2 efflux, and arthropod diversity. Differences in plant cover were best explained by a three-way interaction of plant species richness, management water regime and sampling period. As the richness of plant species increased in a planter, productivity and total arthropod richness also increased significantly-likely due to greater habitat heterogeneity and quality. Overall we found urban plantings can provide additional ecological values if essential resources are maintained within a planter such as water, light and soil temperature. Diverse urban plantings that are managed with these principles in mind can contribute to the attraction of diverse arthropod communities, and lead to increased plant productivity within a dense urban context.

  11. Disparate effects of plant genotypic diversity on foliage and litter arthropod communities.

    PubMed

    Crutsinger, Gregory M; Reynolds, W Nicholas; Classen, Aimée T; Sanders, Nathan J

    2008-11-01

    Intraspecific diversity can influence the structure of associated communities, though whether litter-based and foliage-based arthropod communities respond to intraspecific diversity in similar ways remains unclear. In this study, we compared the effects of host-plant genotype and genotypic diversity of the perennial plant, Solidago altissima, on the arthropod community associated with living plant tissue (foliage-based community) and microarthropods associated with leaf litter (litter-based community). We found that variation among host-plant genotypes had strong effects on the diversity and composition of foliage-based arthropods, but only weak effects on litter-based microarthropods. Furthermore, host-plant genotypic diversity was positively related to the abundance and diversity of foliage-based arthropods, and within the herbivore and predator trophic levels. In contrast, there were minimal effects of plant genotypic diversity on litter-based microarthropods in any trophic level. Our study illustrates that incorporating communities associated with living foliage and senesced litter into studies of community genetics can lead to very different conclusions about the importance of intraspecific diversity than when only foliage-based community responses are considered in isolation.

  12. [Effects of different landscape patch structure on the diversity of arthropod community in tea plantations].

    PubMed

    Li, Jian-Long; Tang, Jin-Chi; Zhao, Chao-Yi; Tang, Hao; Li, Xiu-Di; Li, Hua-Shou

    2013-05-01

    A field survey with random block design was conducted to study the effects of different landscape patch structure on the arthropod community in tea plantations. In the tea plantations with small woodland (QM) or Acacia confuse (XS) patches, predatory spider had the highest proportion, occupying 62.3% and 69.5% of the total arthropods, respectively, being significantly higher than that in the tea plantations close to paddy field (DT) or near a village (RJ). The tea plantations with QM had the highest diversity index and species richness of arthropod community, while the evenness index and dominance index were not significantly different from the other tea plantations. The tea plantations with QM and XS had much richer natural enemies, and the order of the diversity index, evenness index, and richness index of natural enemies in the tea plantations ranked as QM > XS > DT > RJ. It was suggested that landscape patch structure had great effect on the diversity of arthropod community in tea plantations.

  13. Relationships between dead wood and arthropods in the Southeastern United States.

    SciTech Connect

    Ulyshen, Michael, Darragh

    2009-05-01

    The importance of dead wood to maintaining forest diversity is now widely recognized. However, the habitat associations and sensitivities of many species associated with dead wood remain unknown, making it difficult to develop conservation plans for managed forests. The purpose of this research, conducted on the upper coastal plain of South Carolina, was to better understand the relationships between dead wood and arthropods in the southeastern United States. In a comparison of forest types, more beetle species emerged from logs collected in upland pine-dominated stands than in bottomland hardwood forests. This difference was most pronounced for Quercus nigra L., a species of tree uncommon in upland forests. In a comparison of wood postures, more beetle species emerged from logs than from snags, but a number of species appear to be dependent on snags including several canopy specialists. In a study of saproxylic beetle succession, species richness peaked within the first year of death and declined steadily thereafter. However, a number of species appear to be dependent on highly decayed logs, underscoring the importance of protecting wood at all stages of decay. In a study comparing litter-dwelling arthropod abundance at different distances from dead wood, arthropods were more abundant near dead wood than away from it. In another study, grounddwelling arthropods and saproxylic beetles were little affected by large-scale manipulations of dead wood in upland pine-dominated forests, possibly due to the suitability of the forests surrounding the plots.

  14. Inherited microbial symbionts increase herbivore abundances and alter arthropod diversity on a native grass.

    PubMed

    Faeth, Stanley H; Shochat, Eyal

    2010-05-01

    Some microbial symbionts of plants are maternally inherited and thus functionally increase genetic and phenotypic variation within plant populations. This variation, coupled with that of the host plant and environment, may alter abundances, diversity, and trophic structure of associated plant and animal communities. Fungal endophytes in the genus Neotyphodium are vertically transmitted, asexual microbial symbionts of grasses that remain asymptomatic and rely upon their hosts for resources and transmission via seeds, often providing benefits to their hosts, including protection against herbivores. Endophyte infections may influence associated arthropod communities in agronomic grasses, but the long-term effects of endophytes and variation in host genotype and resource availability on arthropod communities in native grass populations are unknown. We conducted a long-term field experiment with four maternal genotypes of an infected (E+) native grass (Festuca arizonica) from whence the endophyte was experimentally removed (E-) and water availability was controlled, to test the effects of infection, plant genotype, and resources on abundances, biomass, diversity (richness and evenness), and trophic structure of the arthropod community. Generally, E+ grasses harbored more arthropods, including more herbivores, predators, and detritivores, suggesting that the effects of endophytes cascaded upward through trophic levels in terms of abundances, at least in early ontogeny of the host. That E+ plants harbored more herbivorous insects than E- plants suggests that infection does not increase but instead decreases resistance to herbivores, contrary to prevailing concepts of endophytes as defensive mutualists. Infection did not alter overall species richness of the arthropod community or richness of herbivores but reduced natural enemy richness, especially that of parasites, and increased richness of detritivores. Reduced richness and shifts in evenness of natural enemies on E

  15. Transracial Communication.

    ERIC Educational Resources Information Center

    Smith, Arthur L.

    This book explores and explains communication among different racial groups within the scope of existing communication theory. Following a brief introduction, chapters cover "Directions in Transracial Communication" (definitions, process, structurization, and purpose); "Culture and Transracial Communication" (a viewpoint on…

  16. Habitat connectivity shapes urban arthropod communities: the key role of green roofs.

    PubMed

    Braaker, S; Ghazoul, J; Obrist, M K; Moretti, M

    2014-04-01

    The installation of green roofs, defined here as rooftops with a shallow soil cover and extensive vegetation, has been proposed as a possible measure to mitigate the loss of green space caused by the steady growth of cities. However, the effectiveness of green roofs in supporting arthropod communities, and the extent to which they facilitate connectivity of these communities within the urban environment is currently largely unknown. We investigated the variation of species community composition (beta diversity) of four arthropod groups with contrasting mobility (Carabidae, Araneae, Curculionidae, and Apidae) on 40 green roofs and 40 extensively managed green sites on the ground in the city of Zurich, Switzerland. With redundancy analysis and variation partitioning, we (1) disentangled the relative importance of local environmental conditions, the surrounding land cover composition, and habitat connectivity on species community composition, (2) searched for specific spatial scales of habitat connectivity for the different arthropod groups, and (3) discussed the ecological and functional value of green roofs in cities. Our study revealed that on green roofs community composition of high-mobility arthropod groups (bees and weevils) were mainly shaped by habitat connectivity, while low-mobility arthropod groups (carabids and spiders) were more influenced by local environmental conditions. A similar but less pronounced pattern was found for ground communities. The high importance of habitat connectivity in shaping high-mobility species community composition indicates that these green roof communities are substantially connected by the frequent exchange of individuals among surrounding green roofs. On the other hand, low-mobility species communities on green roofs are more likely connected to ground sites than to other green roofs. The integration of green roofs in urban spatial planning strategies has great potential to enable higher connectivity among green spaces, so

  17. Complex responses to invasive grass litter by ground arthropods in a Mediterranean scrub ecosystem

    PubMed Central

    Bolger, Douglas T.; Holway, David A.

    2009-01-01

    Plant invasions have tremendous potential to alter food webs by changing basal resources. Recent studies document how plant invasions may contribute to increased arthropod abundances in detritus-based food webs. An obvious mechanism for this phenomenon—a bottom-up effect resulting from elevated levels of detritus from the invasive plant litter—has not been explicitly studied. We examined the effects of an annual grass invasion on ground arthropod assemblages in the coastal sage scrub (CSS) of southern California. Bottom-up food web theory predicts that the addition of detritus would increase generalist-feeding arthropods at all trophic levels; accordingly, we expected increases in fungi, Collembola, and common predators such as mites and spiders. For the common ant taxa, habitat alteration may also be important for predicting responses. Thus we expected that Forelius mccooki and Pheidole vistana, the most common ant species, would decline because of changes in soil temperature (F. mccooki) and habitat structure (P. vistana) associated with litter. We studied trends observationally and conducted a 3-year experiment in which we manipulated litter quantity. In contrast to other published studies, most detritus-based arthropod taxa declined in areas of high grass invasion, and, within trophic levels, responses often varied idiosyncratically. For the two most common taxa, a native ant (F. mccooki), and predatory mites in the Anystidae, we experimentally linked declines in abundance to increased levels of invasive grass litter. Such declines, especially those exhibited by the most common ant taxa, could have cascading effects on the CSS ecosystem, where ants are numerically dominant and thus may have broad influences on food web and ecosystem properties. Our results highlight that accurately predicting arthropod responses to invasive plant litter requires careful consideration of the structural and food resources provided by detritus to each particular food web

  18. Winter predation by insectivorous birds and consequences for arthropods and plants in summer.

    PubMed

    Barber, Nicholas A; Wouk, Jennifer

    2012-12-01

    Top-down effects of predators can have important consequences for ecosystems. Insectivorous birds frequently have strong predation effects on herbivores and other arthropods, as well as indirect effects on herbivores' host plants. Diet studies have shown that birds in temperate ecosystems consume arthropods in winter as well as in summer, but experimental studies of bird predation effects have not attempted to quantitatively separate winter predation impacts from those in summer. To understand if winter foraging by insectivorous birds has consequences for arthropods or plants, we performed a meta-analysis of published bird exclusion studies in temperate forest and shrubland habitats. We categorized 85 studies from 41 publications by whether birds were excluded year-round or only in summer, and analyzed arthropod and plant response variables. We also performed a manipulative field experiment in which we used a factorial design to exclude birds from Quercus velutina Lam. saplings in winter and summer, and censused arthropods and herbivore damage in the following growing season. In the meta-analysis, birds had stronger negative effects on herbivores in studies that included winter exclusion, and this effect was not due to study duration. However, this greater predation effect did not translate to a greater impact on plant damage or growth. In the field experiment, winter exclusion did not influence herbivore abundance or their impacts on plants. We have shown that winter feeding by temperate insectivorous birds can have important consequences for insect herbivore populations, but the strength of these effects may vary considerably among ecosystems. A full understanding of the ecological roles of insectivorous birds will require explicit consideration of their foraging in the non-growing season, and we make recommendations for how future studies can address this.

  19. The ABC gene family in arthropods: comparative genomics and role in insecticide transport and resistance.

    PubMed

    Dermauw, Wannes; Van Leeuwen, Thomas

    2014-02-01

    About a 100 years ago, the Drosophila white mutant marked the birth of Drosophila genetics. The white gene turned out to encode the first well studied ABC transporter in arthropods. The ABC gene family is now recognized as one of the largest transporter families in all kingdoms of life. The majority of ABC proteins function as primary-active transporters that bind and hydrolyze ATP while transporting a large diversity of substrates across lipid membranes. Although extremely well studied in vertebrates for their role in drug resistance, less is known about the role of this family in the transport of endogenous and exogenous substances in arthropods. The ABC families of five insect species, a crustacean and a chelicerate have been annotated in some detail. We conducted a thorough phylogenetic analysis of the seven arthropod and human ABC protein subfamilies, to infer orthologous relationships that might suggest conserved function. Most orthologous relationships were found in the ABCB half transporter, ABCD, ABCE and ABCF subfamilies, but specific expansions within species and lineages are frequently observed and discussed. We next surveyed the role of ABC transporters in the transport of xenobiotics/plant allelochemicals and their involvement in insecticide resistance. The involvement of ABC transporters in xenobiotic resistance in arthropods is historically not well documented, but an increasing number of studies using unbiased differential gene expression analysis now points to their importance. We give an overview of methods that can be used to link ABC transporters to resistance. ABC proteins have also recently been implicated in the mode of action and resistance to Bt toxins in Lepidoptera. Given the enormous interest in Bt toxicology in transgenic crops, such findings will provide an impetus to further reveal the role of ABC transporters in arthropods.

  20. Trophic phylogenetics: evolutionary influences on body size, feeding, and species associations in grassland arthropods.

    PubMed

    Lind, Eric M; Vincent, John B; Weiblen, George D; Cavender-Bares, Jeannine; Borer, Elizabeth T

    2015-04-01

    Contemporary animal-plant interactions such as herbivory are widely understood to be shaped by evolutionary history. Yet questions remain about the role of plant phylogenetic diversity in generating and maintaining herbivore diversity, and whether evolutionary relatedness of producers might predict the composition of consumer communities. We tested for evidence of evolutionary associations among arthropods and the plants on which they were found, using phylogenetic analysis of naturally occurring arthropod assemblages sampled from a plant-diversity manipulation experiment. Considering phylogenetic relationships among more than 900 arthropod consumer taxa and 29 plant species in the experiment, we addressed several interrelated questions. First, our results support the hypothesis that arthropod functional traits such as body size and trophic role are phylogenetically conserved in community ecological samples. Second, herbivores tended to cooccur with closer phylogenetic relatives than would be expected at random, whereas predators and parasitoids did not show phylogenetic association patterns. Consumer specialization, as measured by association through time with monocultures of particular host plant species, showed significant phylogenetic signal, although the. strength of this association varied among plant species. Polycultures of phylogenetically dissimilar plant species supported more phylogenetically dissimilar consumer communities than did phylogenetically similar polycultures. Finally, we separated the effects of plant species richness and relatedness in predicting the phylogenetic distribution of the arthropod assemblages in this experiment. The phylogenetic diversity of plant communities predicted the phylogenetic diversity of herbivore communities even after accounting for plant species richness. The phylogenetic diversity of secondary consumers differed by guild, with predator phylogenetic diversity responding to herbivore relatedness, while parasitoid

  1. Arthropod prey for riparian associated birds in headwater forests of the Oregon Coast Range

    USGS Publications Warehouse

    Hagar, Joan C.; Li, Judith; Sobota, Janel; Jenkins, Stephanie

    2012-01-01

    Headwater riparian areas occupy a large proportion of the land base in Pacific Northwest forests, and thus are ecologically and economically important. Although a primary goal of management along small headwater streams is the protection of aquatic resources, streamside habitat also is important for many terrestrial wildlife species. However, mechanisms underlying the riparian associations of some terrestrial species have not been well studied, particularly for headwater drainages. We investigated the diets of and food availability for four bird species associated with riparian habitats in montane coastal forests of western Oregon, USA. We examined variation in the availability of arthropod prey as a function of distance from stream. Specifically, we tested the hypotheses that (1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and (2) the abundances of aquatic and terrestrial arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that although adult aquatic insects were available for consumption throughout the study period, they represented a relatively small proportion of available prey abundance and biomass and were present in only 1% of the diet samples from only one of the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We conclude that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability. Because distinct vegetation may distinguish riparian from upland habitats for riparian-associated birds and their terrestrial arthropod prey, we suggest that understory communities be considered when defining management zones for riparian habitat.

  2. Complex responses to invasive grass litter by ground arthropods in a Mediterranean scrub ecosystem.

    PubMed

    Wolkovich, Elizabeth Mary; Bolger, Douglas T; Holway, David A

    2009-10-01

    Plant invasions have tremendous potential to alter food webs by changing basal resources. Recent studies document how plant invasions may contribute to increased arthropod abundances in detritus-based food webs. An obvious mechanism for this phenomenon-a bottom-up effect resulting from elevated levels of detritus from the invasive plant litter-has not been explicitly studied. We examined the effects of an annual grass invasion on ground arthropod assemblages in the coastal sage scrub (CSS) of southern California. Bottom-up food web theory predicts that the addition of detritus would increase generalist-feeding arthropods at all trophic levels; accordingly, we expected increases in fungi, Collembola, and common predators such as mites and spiders. For the common ant taxa, habitat alteration may also be important for predicting responses. Thus we expected that Forelius mccooki and Pheidole vistana, the most common ant species, would decline because of changes in soil temperature (F. mccooki) and habitat structure (P. vistana) associated with litter. We studied trends observationally and conducted a 3-year experiment in which we manipulated litter quantity. In contrast to other published studies, most detritus-based arthropod taxa declined in areas of high grass invasion, and, within trophic levels, responses often varied idiosyncratically. For the two most common taxa, a native ant (F. mccooki), and predatory mites in the Anystidae, we experimentally linked declines in abundance to increased levels of invasive grass litter. Such declines, especially those exhibited by the most common ant taxa, could have cascading effects on the CSS ecosystem, where ants are numerically dominant and thus may have broad influences on food web and ecosystem properties. Our results highlight that accurately predicting arthropod responses to invasive plant litter requires careful consideration of the structural and food resources provided by detritus to each particular food web.

  3. Employing citizen science to study defoliation impacts on arthropod communities on tamarisk

    NASA Astrophysics Data System (ADS)

    Kruse, Audrey L.

    The invasive tamarisk tree is widespread across the southwestern landscape of the United States and has been dominant in regulated river reaches, outcompeting native vegetation and impacting trophic webs in riparian ecosystems. The changes in riparian habitat and recreation opportunities along southwestern rivers, like the San Juan River in Utah, led to the implementation of a biocontrol program in the form of the tamarisk leaf beetle (Diorhabda spp.). It is unknown what the long term effects on riparian ecosystems are as a result of the beetles' defoliation of tamarisk each summer. This study sought to identify the current arthropod community composition and abundance over one growing season on the San Juan River between Bluff and Mexican Hat, UT and second, to involve the public in this research through a citizen science component. I found that non-native insects, including the tamarisk leaf beetle, dominated the arboreal arthropod communities within the tamarisk and there are relatively few native arthropods residing in tamarisk throughout the summer season. Foliation levels (the quantity of leaves in the canopy of tamarisk) were inconclusive predictors of arthropod abundances but varied by species and by feeding guild. This may indicate that the defoliation of the tamarisk is not necessarily negatively impacting trophic interactions in tamarisk. I incorporated youth participants on educational river rafting trips to assist in data collection of arthropods from tamarisk trees as a way to educate and bring attention to the issue of invasive species in the Southwest. After completing my own citizen science project and after doing a literature review of other, similar citizen science projects, I found that striving for both rigorous scientific data and quality educational programming is challenging for a small scale project that does not target broad spatial, geographic, or temporal data. Citizen science project developers should clearly identify their objectives

  4. Comparative Genomics Reveals the Origins and Diversity of Arthropod Immune Systems

    PubMed Central

    Palmer, William J.; Jiggins, Francis M.

    2015-01-01

    Insects are an important model for the study of innate immune systems, but remarkably little is known about the immune system of other arthropod groups despite their importance as disease vectors, pests, and components of biological diversity. Using comparative genomics, we have characterized the immune system of all the major groups of arthropods beyond insects for the first time—studying five chelicerates, a myriapod, and a crustacean. We found clear traces of an ancient origin of innate immunity, with some arthropods having Toll-like receptors and C3-complement factors that are more closely related in sequence or structure to vertebrates than other arthropods. Across the arthropods some components of the immune system, such as the Toll signaling pathway, are highly conserved. However, there is also remarkable diversity. The chelicerates apparently lack the Imd signaling pathway and beta-1,3 glucan binding proteins—a key class of pathogen recognition receptors. Many genes have large copy number variation across species, and this may sometimes be accompanied by changes in function. For example, we find that peptidoglycan recognition proteins have frequently lost their catalytic activity and switch between secreted and intracellular forms. We also find that there has been widespread and extensive duplication of the cellular immune receptor Dscam (Down syndrome cell adhesion molecule), which may be an alternative way to generate the high diversity produced by alternative splicing in insects. In the antiviral short interfering RNAi pathway Argonaute 2 evolves rapidly and is frequently duplicated, with a highly variable copy number. Our results provide a detailed analysis of the immune systems of several important groups of animals for the first time and lay the foundations for functional work on these groups. PMID:25908671

  5. Immunolocalization of serotonin in Onychophora argues against segmental ganglia being an ancestral feature of arthropods

    PubMed Central

    Mayer, Georg; Harzsch, Steffen

    2007-01-01

    Background Onychophora (velvet worms) represent the most basal arthropod group and play a pivotal role in the current discussion on the evolution of nervous systems and segmentation in arthropods. Although there is a wealth of information on the immunolocalization of serotonin (5-hydroxytryptamine, 5-HT) in various euarthropods, as yet no comparable localization data are available for Onychophora. In order to understand how the onychophoran nervous system compares to that of other arthropods, we studied the distribution of serotonin-like immunoreactive neurons and histological characteristics of ventral nerve cords in Metaperipatus blainvillei (Onychophora, Peripatopsidae) and Epiperipatus biolleyi (Onychophora, Peripatidae). Results We demonstrate that paired leg nerves are the only segmental structures associated with the onychophoran nerve cord. Although the median commissures and peripheral nerves show a repeated pattern, their arrangement is independent from body segments characterized by the position of legs and associated structures. Moreover, the somata of serotonin-like immunoreactive neurons do not show any ordered arrangement in both species studied but are instead scattered throughout the entire length of each nerve cord. We observed neither a serially iterated nor a bilaterally symmetric pattern, which is in contrast to the strictly segmental arrangement of serotonergic neurons in other arthropods. Conclusion Our histological findings and immunolocalization experiments highlight the medullary organization of the onychophoran nerve cord and argue against segmental ganglia of the typical euarthropodan type being an ancestral feature of Onychophora. These results contradict a priori assumptions of segmental ganglia being an ancestral feature of arthropods and, thus, weaken the traditional Articulata hypothesis, which proposes a sistergroup relationship of Annelida and Arthropoda. PMID:17629937

  6. Responses of arthropod populations to warming depend on latitude: evidence from urban heat islands.

    PubMed

    Youngsteadt, Elsa; Ernst, Andrew F; Dunn, Robert R; Frank, Steven D

    2017-04-01

    Biological effects of climate change are expected to vary geographically, with a strong signature of latitude. For ectothermic animals, there is systematic latitudinal variation in the relationship between climate and thermal performance curves, which describe the relationship between temperature and an organism's fitness. Here, we ask whether these documented latitudinal patterns can be generalized to predict arthropod responses to warming across mid- and high temperate latitudes, for taxa whose thermal physiology has not been measured. To address this question, we used a novel natural experiment consisting of a series of urban warming gradients at different latitudes. Specifically, we sampled arthropods from a single common street tree species across temperature gradients in four US cities, located from 35.8 to 42.4° latitude. We captured 6746 arthropods in 34 families from 111 sites that varied in summer average temperature by 1.7-3.4 °C within each city. Arthropod responses to warming within each city were characterized as Poisson regression coefficients describing change in abundance per °C for each family. Family responses in the two midlatitude cities were heterogeneous, including significantly negative and positive effects, while those in high-latitude cities varied no more than expected by chance within each city. We expected high-latitude taxa to increase in abundance with warming, and they did so in one of the two high-latitude cities; in the other, Queens (New York City), most taxa declined with warming, perhaps due to habitat loss that was correlated with warming in this city. With the exception of Queens, patterns of family responses to warming were consistent with predictions based on known latitudinal patterns in arthropod physiology relative to regional climate. Heterogeneous responses in midlatitudes may be ecologically disruptive if interacting taxa respond oppositely to warming.

  7. Comparative Genomics Reveals the Origins and Diversity of Arthropod Immune Systems.

    PubMed

    Palmer, William J; Jiggins, Francis M

    2015-08-01

    Insects are an important model for the study of innate immune systems, but remarkably little is known about the immune system of other arthropod groups despite their importance as disease vectors, pests, and components of biological diversity. Using comparative genomics, we have characterized the immune system of all the major groups of arthropods beyond insects for the first time--studying five chelicerates, a myriapod, and a crustacean. We found clear traces of an ancient origin of innate immunity, with some arthropods having Toll-like receptors and C3-complement factors that are more closely related in sequence or structure to vertebrates than other arthropods. Across the arthropods some components of the immune system, such as the Toll signaling pathway, are highly conserved. However, there is also remarkable diversity. The chelicerates apparently lack the Imd signaling pathway and beta-1,3 glucan binding proteins--a key class of pathogen recognition receptors. Many genes have large copy number variation across species, and this may sometimes be accompanied by changes in function. For example, we find that peptidoglycan recognition proteins have frequently lost their catalytic activity and switch between secreted and intracellular forms. We also find that there has been widespread and extensive duplication of the cellular immune receptor Dscam (Down syndrome cell adhesion molecule), which may be an alternative way to generate the high diversity produced by alternative splicing in insects. In the antiviral short interfering RNAi pathway Argonaute 2 evolves rapidly and is frequently duplicated, with a highly variable copy number. Our results provide a detailed analysis of the immune systems of several important groups of animals for the first time and lay the foundations for functional work on these groups.

  8. Arthropod communities in a selenium-contaminated habitat with a focus on ant species.

    PubMed

    De La Riva, Deborah G; Hladun, Kristen R; Vindiola, Beatriz G; Trumble, John T

    2017-01-01

    The selenium contamination event that occurred at Kesterson Reservoir (Merced Co., CA) during the 1970-80s is a frequently cited example for the negative effects of contamination on wildlife. Despite the importance of arthropods for ecosystem services and functioning, relatively little information is available as to the impacts of pollution on arthropod community dynamics. We conducted surveys of the arthropod community present at Kesterson Reservoir to assess the impacts of selenium contamination on arthropod diversity, with a focus on ant species richness, composition and density. Trophic groups were compared to determine which arthropods were potentially receiving the greatest selenium exposure. Plant samples were analyzed to determine the selenium content by site and by location within plant. Soil concentrations varied across the study sites, but not across habitat types. Topsoil contained higher levels of selenium compared to core samples. Plants contained similar concentrations of selenium in their leaves, stems and flowers, but flowers contained the greatest range of concentrations. Individuals within the detritivores/decomposers and predators accumulated the greatest concentrations of selenium, whereas nectarivores contained the lowest concentrations. Species composition differed across the sites: Dorymyrmex bicolor was located only at the site containing the greatest soil selenium concentration, but Solenopsis xyloni was found at most sites and was predominant at six of the sites. Selenium concentrations in ants varied by species and collection sites. Nest density was also found to differ across sites, but was not related to soil selenium or any of the habitat variables measured in our study. Selenium was not found to impact species richness, but was a significant variable for the occurrence of two out of the eight native species identified.

  9. Impact of Location, Cropping History, Tillage, and Chlorpyrifos on Soil Arthropods in Peanut.

    PubMed

    Cardoza, Yasmin J; Drake, Wendy L; Jordan, David L; Schroeder-Moreno, Michelle S; Arellano, Consuelo; Brandenburg, Rick L

    2015-08-01

    Demand for agricultural production systems that are both economically viable and environmentally conscious continues to increase. In recent years, reduced tillage systems, and grass and pasture rotations have been investigated to help maintain or improve soil quality, increase crop yield, and decrease labor requirements for production. However, documentation of the effects of reduced tillage, fescue rotation systems as well as other management practices, including pesticides, on pest damage and soil arthropod activity in peanut production for the Mid-Atlantic US region is still limited. Therefore, this project was implemented to assess impacts of fescue-based rotation systems on pests and other soil organisms when compared with cash crop rotation systems over four locations in eastern North Carolina. In addition, the effects of tillage (strip vs. conventional) and soil chlorpyrifos application on pod damage and soil-dwelling organisms were also evaluated. Soil arthropod populations were assessed by deploying pitfall traps containing 50% ethanol in each of the sampled plots. Results from the present study provide evidence that location significantly impacts pest damage and soil arthropod diversity in peanut fields. Cropping history also influenced arthropod diversity, with higher diversity in fescue compared with cash crop fields. Corn rootworm damage to pods was higher at one of our locations (Rocky Mount) compared with all others. Cropping history (fescue vs. cash crop) did not have an effect on rootworm damage, but increased numbers of hymenopterans, acarina, heteropterans, and collembolans in fescue compared with cash crop fields. Interestingly, there was an overall tendency for higher number of soil arthropods in traps placed in chlorpyrifos-treated plots compared with nontreated controls.

  10. Phase and speed synchronization control of four eccentric rotors driven by induction motors in a linear vibratory feeder with unknown time-varying load torques using adaptive sliding mode control algorithm

    NASA Astrophysics Data System (ADS)

    Kong, Xiangxi; Zhang, Xueliang; Chen, Xiaozhe; Wen, Bangchun; Wang, Bo

    2016-05-01

    In this paper, phase and speed synchronization control of four eccentric rotors (ERs) driven by induction motors in a linear vibratory feeder with unknown time-varying load torques is studied. Firstly, the electromechanical coupling model of the linear vibratory feeder is established by associating induction motor's model with the dynamic model of the system, which is a typical under actuated model. According to the characteristics of the linear vibratory feeder, the complex control problem of the under actuated electromechanical coupling model converts to phase and speed synchronization control of four ERs. In order to keep the four ERs operating synchronously with zero phase differences, phase and speed synchronization controllers are designed by employing adaptive sliding mode control (ASMC) algorithm via a modified master-slave structure. The stability of the controllers is proved by Lyapunov stability theorem. The proposed controllers are verified by simulation via Matlab/Simulink program and compared with the conventional sliding mode control (SMC) algorithm. The results show the proposed controllers can reject the time-varying load torques effectively and four ERs can operate synchronously with zero phase differences. Moreover, the control performance is better than the conventional SMC algorithm and the chattering phenomenon is attenuated. Furthermore, the effects of reference speed and parametric perturbations are discussed to show the strong robustness of the proposed controllers. Finally, experiments on a simple vibratory test bench are operated by using the proposed controllers and without control, respectively, to validate the effectiveness of the proposed controllers further.

  11. Mineral cycling in soil and litter arthropod food chains. Progress report, November 1, 1981-January 31, 1983

    SciTech Connect

    Crossley, D.A. Jr.

    1982-09-01

    Progress is reported for research projects on nutrient dynamics during terrestrial decomposition, as influenced by soil arthropods. Radioactive tracers are used as analogs of nutrients, to measure material movement along food chains and dynamics of processes during decomposition. Forest floor systems from which arthropods were excluded, or in which microfloral activity was depressed, trapped incoming nutrients from canopy throughfall at different rates. Faunal stimulation of microfloral activities could not be demonstrated, but drought conditions disturbed the experiment. Turnover measurements for radionuclides in collembolans are also reported, and compared with information on mites and other arthropods.

  12. Technical Work Plan For: Calculation of Waste Packave and Drip Shield Response to Vibratory Ground Motion and Revision of the Seismic Consequence Abstraction

    SciTech Connect

    M. Gross

    2006-12-08

    The overall objective of the work scope covered by this technical work plan (TWP) is to develop new damage abstractions for the seismic scenario class in total system performance assessment (TSPA). The new abstractions will be based on a new set of waste package and drip shield damage calculations in response to vibratory ground motion and fault displacement. The new damage calculations, which are collectively referred to as damage models in this TWP, are required to represent recent changes in waste form packaging and in the regulatory time frame. The new damage models also respond to comments from the Independent Validation Review Team (IVRT) postvalidation review of the draft TSPA model regarding performance of the drip shield and to an Additional Information Need (AIN) from the U.S. Nuclear Regulatory Commission (NRC).

  13. Analysis of the effect of crushing of strontium hexaferrite powders in a vibratory mill on the properties of magnets on their basis

    NASA Astrophysics Data System (ADS)

    Kostishin, V. G.; Andreev, V. G.; Chitanov, D. N.; Timofeev, A. V.; Adamtsov, A. Yu.; Alekseev, A. A.

    2015-08-01

    We analyze the effect of duration of dry crushing of strontium hexaferrite powders (manufactured at joint-stock corporation Olkon) in a vibratory mill on the degree of disaggregation of powders and on the properties of articles on their basis. It is shown that an increase in the vibrational frequency of the vibromill from 25 to 50 Hz with the amplitude of vibrations maintained in the limits 3-4 mm makes it possible to reduce by 5 times the crushing time ensuring complete disaggregation of powders. An increase in the impact energy of balls with increasing vibrational frequency activates the powders due to microdistortions appearing in the crystal lattice. An increase in the degree of disaggregation of powders leads to sintering and formation of a dense fine-grain microstructure ensuring an increase in the maximal energy product ( BH)max of magnets by 15-20%.

  14. SEM characterization of anatomical variation in chitin organization in insect and arthropod cuticles.

    PubMed

    Chandran, Rakkiyappan; Williams, Lee; Hung, Albert; Nowlin, Kyle; LaJeunesse, Dennis

    2016-03-01

    The cuticles of insects and arthropods have some of the most diverse material properties observed in nature, so much so that it is difficult to imagine that all cutciles are primarily composed of the same two materials: a fibrous chitin network and a matrix composed of cuticle proteins. Various factors contribute to the mechanical and optical properties of an insect or arthropod cuticle including the thickness and composition. In this paper, we also identified another factor that may contribute to the optical, surface, and mechanical properties of a cuticle, i.e. the organization of chitin nanofibers and chitin fiber bundles. Self-assembled chitin nanofibers serve as the foundation for all higher order chitin structures in the cuticles of insects and other arthropods via interactions with structural cuticle proteins. Using a technique that enables the characterization of chitin organization in the cuticle of intact insects and arthropod exoskeletons, we demonstrate a structure/function correlation of chitin organization with larger scale anatomical structures. The chitin scaffolds in cuticles display an extraordinarily diverse set of morphologies that may reflect specific mechanical or physical properties. After removal of the proteinaceous and mineral matrix of a cuticle, we observe using SEM diverse nanoscale and micro scale organization of in-situ chitin in the wing, head, eye, leg, and dorsal and ventral thoracic regions of the periodical cicada Magicicada septendecim and in other insects and arthropods. The organization of chitin also appears to have a significant role in the organization of nanoscale surface structures. While microscale bristles and hairs have long been known to be chitin based materials formed as cellular extensions, we have found a nanostructured layer of chitin in the cuticle of the wing of the dog day annual cicada Tibicen tibicens, which may be the scaffold for the nanocone arrays found on the wing. We also use this process to examine

  15. Habitat connectivity and local conditions shape taxonomic and functional diversity of arthropods on green roofs.

    PubMed

    Braaker, Sonja; Obrist, Martin Karl; Ghazoul, Jaboury; Moretti, Marco

    2017-05-01

    Increasing development of urban environments creates high pressure on green spaces with potential negative impacts on biodiversity and ecosystem services. There is growing evidence that green roofs - rooftops covered with vegetation - can contribute mitigate the loss of urban green spaces by providing new habitats for numerous arthropod species. Whether green roofs can contribute to enhance taxonomic and functional diversity and increase connectivity across urbanized areas remains, however, largely unknown. Furthermore, only limited information is available on how environmental conditions shape green roof arthropod communities. We investigated the community composition of arthropods (Apidae, Curculionidae, Araneae and Carabidae) on 40 green roofs and 40 green sites at ground level in the city of Zurich, Switzerland. We assessed how the site's environmental variables (such as area, height, vegetation, substrate and connectivity among sites) affect species richness and functional diversity using generalized linear models. We used an extension of co-inertia analysis (RLQ) and fourth-corner analysis to highlight the mechanism underlying community assemblages across taxonomic groups on green roof and ground communities. Species richness was higher at ground-level sites, while no difference in functional diversity was found between green roofs and ground sites. Green roof arthropod diversity increased with higher connectivity and plant species richness, irrespective of substrate depth, height and area of green roofs. The species trait analysis reviewed the mechanisms related to the environmental predictors that shape the species assemblages of the different taxa at ground and roof sites. Our study shows the important contribution of green roofs in maintaining high functional diversity of arthropod communities across different taxonomic groups, despite their lower species richness compared with ground sites. Species communities on green roofs revealed to be characterized

  16. [Assemblage effect of ground arthropod community in desert steppe shrubs with different ages].

    PubMed

    Liu, Ren-Tao; Zhu, Fan; Chai, Yong-Qing

    2014-01-01

    Taking the 6-, 15-, 24- and 36-year-old Caragana intermedia shrubs in desert steppe as a subject, an investigation on soil properties and ground arthropod community was carried out under the shrub and in the open to probe into the assemblage effect of ground arthropod community in desert steppe shrubs with different ages. The results were as follows: 1) In the 6-year-old shrubland, significant differences were only found in soil physical properties (soil texture, soil moisture and electrical conductivity) between the microhabitats under shrub and in the open. Beginning from the 15-year-old shrubland, however, soil organic matter and nutrition (N, P) increased significantly. 2) A total of 27 groups were captured in the studied sites which dominated by Carabidae, Tenebrionidae and Formicidae. From 6- to 15-year-old shrubland, the number of dominant groups decreased while that of common groups increased for the ground arthropod community under the shrub. From 15- to 24- and 36-year-old shrubland, the difference between the microhabitats under the shrub and in the open decreased firstly, and then increased. Some special groups appeared under the shrub in the 36-year-old shrubland, and dung beetles became dominant. 3) In the 6- and 24-year-old shrublands, there were no significant differences in group richness, abundance, and diversity index between the microhabitats under the shrub and in the open. As for the 15- and 36-year-old shrublands, however, significant differences were observed. 4) The shrub age had a stronger effect on the distribution of ground arthropods living under the shrubs compared to that in the open. The changes in soil texture, pH and electrical conductivity could significantly influence on the distribution of ground arthropods under the shrub, also in the open to some degree. It was suggested that the development of shrubland had strong impact on assemblage effect of ground arthropods, which was closely correlated with the stand age and would

  17. Mineral cycling in soil and litter arthropod food chains. Progress report, November 1, 1979-October 31, 1980

    SciTech Connect

    Crossley, Jr, D A

    1980-08-01

    Recent progress and current status are reported for research concerned with mineral element dynamics in soil arthropod food chains. Research is performed within the larger context of terrestrial decomposition systems, in which soil arthropods may act as regulators of nutrient dynamics during decomposition. Research is measuring rates of nutrient accumulation and excretion by using radioactive tracer techniques with radioactive analogs of nutrients. Experimental measurement of radioactive tracer excretion and nutrient element pools are reported for soil microarthropods, using new methods of counting and microprobe elemental analysis. Research on arthropod-fungal relations is utilizing high-efficiency extraction followed by dissection of 13 x 13 cm soil blocks. A two-component excretion model is reported for Cobalt-60 in earthworms (Eisenia foetida), demonstrating that no assimilation of cobalt occurs from the mineral soil fraction but is entirely from organic matter. Collection of data sets on soil arthropod communities and abundances is completed.

  18. Satellite Communication.

    ERIC Educational Resources Information Center

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  19. Non-structural proteins of arthropod-borne bunyaviruses: roles and functions.

    PubMed

    Eifan, Saleh; Schnettler, Esther; Dietrich, Isabelle; Kohl, Alain; Blomström, Anne-Lie

    2013-10-04

    Viruses within the Bunyaviridae family are tri-segmented, negative-stranded RNA viruses. The family includes several emerging and re-emerging viruses of humans, animals and plants, such as Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, La Crosse virus, Schmallenberg virus and tomato spotted wilt virus. Many bunyaviruses are arthropod-borne, so-called arboviruses. Depending on the genus, bunyaviruses encode, in addition to the RNA-dependent RNA polymerase and the different structural proteins, one or several non-structural proteins. These non-structural proteins are not always essential for virus growth and replication but can play an important role in viral pathogenesis through their interaction with the host innate immune system. In this review, we will summarize current knowledge and understanding of insect-borne bunyavirus non-structural protein function(s) in vertebrate, plant and arthropod.

  20. Elegant Shadow Making Tiny Force Visible for Water-Walking Arthropods and Updated Archimedes' Principle.

    PubMed

    Zheng, Yelong; Lu, Hongyu; Yin, Wei; Tao, Dashuai; Shi, Lichun; Tian, Yu

    2016-10-07

    Forces acted on legs of water-walking arthropods with weights in dynes are of great interest for entomologist, physicists, and engineers. While their floating mechanism has been recognized, the in vivo leg forces stationary have not yet been simultaneously achieved. In this study, their elegant bright-edged leg shadows are used to make the tiny forces visible and measurable based on the updated Archimedes' principle. The force was approximately proportional to the shadow area with a resolution from nanonewton to piconewton/pixel. The sum of leg forces agreed well with the body weight measured with an accurate electronic balance, which verified updated Archimedes' principle at the arthropod level. The slight changes of vertical body weight focus position and the body pitch angle have also been revealed for the first time. The visualization of tiny force by shadow is cost-effective and very sensitive and could be used in many other applications.

  1. Matching arthropod anatomy ontologies to the Hymenoptera Anatomy Ontology: results from a manual alignment

    PubMed Central

    Bertone, Matthew A.; Mikó, István; Yoder, Matthew J.; Seltmann, Katja C.; Balhoff, James P.; Deans, Andrew R.

    2013-01-01

    Matching is an important step for increasing interoperability between heterogeneous ontologies. Here, we present alignments we produced as domain experts, using a manual mapping process, between the Hymenoptera Anatomy Ontology and other existing arthropod anatomy ontologies (representing spiders, ticks, mosquitoes and Drosophila melanogaster). The resulting alignments contain from 43 to 368 mappings (correspondences), all derived from domain-expert input. Despite the many pairwise correspondences, only 11 correspondences were found in common between all ontologies, suggesting either major intrinsic differences between each ontology or gaps in representing each group’s anatomy. Furthermore, we compare our findings with putative correspondences from Bioportal (derived from LOOM software) and summarize the results in a total evidence alignment. We briefly discuss characteristics of the ontologies and issues with the matching process. Database URL: http://purl.obolibrary.org/obo/hao/2012-07-18/arthropod-mappings.obo PMID:23303300

  2. Goggatomy: A Method for Opening Small Cuticular Compartments in Arthropods for Physiological Experiments

    PubMed Central

    Kay, Alan R.; Raccuglia, Davide; Scholte, Jon; Sivan-Loukianova, Elena; Barwacz, Christopher A.; Armstrong, Steven R.; Guymon, C. Allan; Nitabach, Michael N.; Eberl, Daniel F.

    2016-01-01

    Most sense organs of arthropods are ensconced in small exoskeletal compartments that hinder direct access to plasma membranes. We have developed a method for exposing live sensory and supporting cells in such structures. The technique uses a viscous light cured resin to embed and support the structure, which is then sliced with a sharp blade. We term the procedure a “goggatomy,” from the Khoisan word for a bug, gogga. To demonstrate the utility of the method we show that it can be used to expose the auditory chordotonal organs in the second antennal segment and the olfactory receptor neurons in the third antennal segment of Drosophila melanogaster, preserving the transduction machinery. The procedure can also be used on other small arthropods, like mosquitoes and mites to expose a variety of cells. PMID:27695420

  3. [What gene and chromosomes say about the origin and evolution of insects and other arthropods].

    PubMed

    Lukhtanov, V A; Kuznetsova, V G

    2010-09-01

    At the turn of the 21st century, the use of molecular and molecular cytogenetic methods led to revolutionary advances in systematics of insects and other arthropods. Analysis of nuclear and mitochondrial genes, as well as investigation of structural rearrangements in the mitochondrial chromosome convincingly supported the Pancrustacea hypothesis, according to which insects originated directly from crustaceans, whereas myriapods are not closely related to them. The presence of the specific telomeric motif TTAGG confirmed the monophyletic origin of arthropods (Arthropoda) and the assignment of tongue worms (Pentastomida) to this type. Several different types of telomeric sequences have been found within the class of insects. Investigation of the molecular organization of these sequences may shed light on the relationships between the orders Diptera, Siphonaptera, and Mecoptera and on the origin of such enigmatic groups as the orders Strepsiptera, Zoraptera and suborder Coleorrhyncha.

  4. Goggatomy: A Method for Opening Small Cuticular Compartments in Arthropods for Physiological Experiments.

    PubMed

    Kay, Alan R; Raccuglia, Davide; Scholte, Jon; Sivan-Loukianova, Elena; Barwacz, Christopher A; Armstrong, Steven R; Guymon, C Allan; Nitabach, Michael N; Eberl, Daniel F

    2016-01-01

    Most sense organs of arthropods are ensconced in small exoskeletal compartments that hinder direct access to plasma membranes. We have developed a method for exposing live sensory and supporting cells in such structures. The technique uses a viscous light cured resin to embed and support the structure, which is then sliced with a sharp blade. We term the procedure a "goggatomy," from the Khoisan word for a bug, gogga. To demonstrate the utility of the method we show that it can be used to expose the auditory chordotonal organs in the second antennal segment and the olfactory receptor neurons in the third antennal segment of Drosophila melanogaster, preserving the transduction machinery. The procedure can also be used on other small arthropods, like mosquitoes and mites to expose a variety of cells.

  5. [Climate change influences the incidence of arthropod-borne diseases in the Netherlands].

    PubMed

    Rahamat-Langendoen, J C; van Vliet, J A; Reusken, C B E M

    2008-04-12

    Climate change is associated with changes in the occurrence of arthropod-borne diseases. It is difficult to foresee which arthropod-borne diseases will appear in the Netherlands due to climate change. Climate change influences the prevalence of ticks and may lead to a further increase in Lyme disease and an increased risk of the introduction of rickettsioses. With further warming of the climate there is a real possibility of settlement of the mosquito Aedes albopictus and introduction of the sandfly in the Netherlands. Whether this will lead to circulation of micro-organisms transmitted by these vectors (e.g. West Nile virus, Dengue virus, Leishmania) is not clear. Continued vigilance is necessary, even for vector-borne diseases that appear to be less relevant for the Netherlands.

  6. Adult carrion arthropod community in a tropical rainforest of Malaysia: analysis on three common forensic entomology animal models.

    PubMed

    Azwandi, A; Nina Keterina, H; Owen, L C; Nurizzati, M D; Omar, B

    2013-09-01

    Decomposing carrion provides a temporary microhabitat and food source for a distinct community of organisms. Arthropods constitute a major part of this community and can be utilized to estimate the postmortem interval (PMI) of cadavers during criminal investigations. However, in Malaysia, knowledge of carrion arthropod assemblages and their succession is superficial. Therefore, a study on three types of forensic entomology animal model was conducted from 27 September 2010 to 28 October 2010 in a tropical rainforest at National University of Malaysia, Bangi, Selangor, Malaysia. Over one month collections of arthropods were made on nine animal carcasses: three laboratory rats (Rattus norvegicus, mean weight: 0.508 ± 0.027 kg), three rabbits (Oryctolagus cuniculus, mean weight: 2.538 ± 0.109 kg) and three long tailed macaque (Macaca fascicularis, mean weight: 5.750 ± 0.551 kg). A total of 31,433 arthropods belonging to eight orders and twenty-eight families were collected from all carcasses. Among 2924 of adults flies collected, approximately 19% were calliphorids with Chrysomya megacephala (Fabricius, 1794) being the most abundant. Arthropod taxon richness was lower on rat carcasses compared to that of rabbit and monkey carcasses, and this was more apparent during the first week of decomposition. However, there were no significant differences in Shannon-Weiner index (H'), Simpson dominance index (C) and Pielou's Evenness index (J) between different animal model. The arthropod assemblages associated to animal model were different significantly (p<0.05) while decomposition stage was a significant factor influencing insect assemblages (p<0.05). Analysis on the arthropods succession indicated that some taxa have a clear visitation period while the others, particularly Coleoptera, did not show a clear successional pattern thus require futher insect succession study. Although human bodies were not possible for the succession study, most of the arthropods collected are

  7. Deep-time patterns of tissue consumption by terrestrial arthropod herbivores.

    PubMed

    Labandeira, Conrad C

    2013-04-01

    A survey of the fossil record of land-plant tissues and their damage by arthropods reveals several results that shed light on trophic trends in host-plant resource use by arthropods. All 14 major plant tissues were present by the end of the Devonian, representing the earliest 20% of the terrestrial biota. During this interval, two types of time lags separate the point between when tissues first originated from their earliest consumption by herbivorous arthropods. For epidermis, parenchyma, collenchyma and xylem, live tissue consumption was rapid, occurring on average 10 m.y. after the earliest tissue records. By contrast, structural tissues (periderm, sclerenchyma), tissues with actively dividing cells (apical, lateral, intercalary meristems), and reproductive tissues (spores, megagametophytes, integuments) experienced approximately a 9-fold (92 m.y.) delay in arthropod herbivory, extending well into the Carboniferous Period. Phloem similarly presents a delay of 85 m.y., but this incongruously long lag-time may be attributed to the lack of preservation of this tissue in early vascular plants. Nevertheless, the presence of phloem can be indicated from planar spaces adjacent well-preserved xylem, or inferred from a known anatomy of the same plant taxon in better preserved material, especially permineralisations. The trophic partitioning of epidermis, parenchyma, phloem and xylem increases considerably to the present, probably a consequence of dietary specialization or consumption of whole leaves by several herbivore functional feeding groups. Structural tissues, meristematic tissues and reproductive tissues minimally have been consumed throughout the fossil record, consistent with their long lags to herbivory during the earlier Paleozoic. Neither angiosperm dominance in floras nor global environmental perturbations had any discernible effect on herbivore trophic partitioning of plant tissues.

  8. The interactive effects of pulsed grazing disturbance and patch size vary among wetland arthropod guilds.

    PubMed

    Armitage, Anna R; Ho, Chuan-Kai; Quigg, Antonietta

    2013-01-01

    Pulse disturbances and habitat patch size can determine community composition independently or in concert, and may be particularly influential on small spatial scales for organisms with low mobility. In a field experiment, we investigated whether the effects of a pulsed disturbance that simulated a grazing event varied with habitat patch size. We focused on the short-term responses of multiple co-occurring emergent salt marsh arthropods with differing levels of mobility and dispersal potential. As part of a marsh restoration project, two types of emergent marsh structures were created: small circular mounds (0.5 m diameter) separated by several meters of aquatic habitat, and larger, elongated terraces (>50 m long). Study plots (0.25 m(2)) were established on both structures; in a subset of plots, we simulated a pulsed grazing disturbance event by clipping the aboveground tissue of emergent plants, primarily Spartina alterniflora. At the end of the two-month recovery period, Ischnodemus (Hemiptera: Blissidae) density was over 50% lower in disturbed treatments within both large (terrace) and small (mound) patches. Predatory spider treatment responses were similar to Ischnodemus responses, suggesting a trophic relationship between those two arthropod groups. Alternatively, spiders may have been directly affected by the loss of shelter in the disturbed plots. Prokelisia (Homoptera: Delphacidae), which are generally more mobile than Ischnodemus, were not affected by disturbance treatment or by patch size, suggesting the potential for rapid recolonization following disturbance. Larval stem borers decreased by an order of magnitude in disturbed plots, but only in the large patches. In general, the disturbance effects of vegetation removal on arthropod density and community composition were stronger than patch size effects, and there were few interactions between pulsed disturbance and patch size. Rather, emergent marsh arthropod responses to disturbance and habitat area

  9. Assessing Potential Impact of Bt Eggplants on Non-Target Arthropods in the Philippines

    PubMed Central

    Navasero, Mario V.; Candano, Randolph N.; Hautea, Desiree M.; Hautea, Randy A.; Shotkoski, Frank A.; Shelton, Anthony M.

    2016-01-01

    Studies on potential adverse effects of genetically engineered crops are part of an environmental risk assessment that is required prior to the commercial release of these crops. Of particular concern are non-target organisms (NTOs) that provide important ecosystem services. Here, we report on studies conducted in the Philippines over three cropping seasons with Bt eggplants expressing Cry1Ac for control of the eggplant fruit and shoot borer (EFSB), Leucinodes orbonalis, to examine potential effects on field abundance, community composition, structure and biodiversity of NTO’s, particularly non-target arthropod (NTA) communities. We document that many arthropod taxa are associated with Bt eggplants and their non-Bt comparators and that the number of taxa and their densities varied within season and across trials. However, we found few significant differences in seasonal mean densities of arthropod taxa between Bt and non-Bt eggplants. As expected, a lower abundance of lepidopteran pests was detected in Bt eggplants. Higher abundance of a few non-target herbivores was detected in non-Bt eggplants as were a few non-target beneficials that might control them. Principal Response Curve (PRC) analyses showed no statistically significant impact of Bt eggplants on overall arthropod communities through time in any season. Furthermore, we found no significant adverse impacts of Bt eggplants on species abundance, diversity and community dynamics, particularly for beneficial NTAs. These results support our previous studies documenting that Bt eggplants can effectively and selectively control the main pest of eggplant in Asia, the EFSB. The present study adds that it can do so without adverse effects on NTAs. Thus, Bt eggplants can be a foundational component for controlling EFSB in an Integrated Pest Management (IPM) program and dramatically reduce dependence on conventional insecticides. PMID:27798662

  10. Species Richness-Environment Relationships of European Arthropods at Two Spatial Grains: Habitats and Countries

    PubMed Central

    Entling, Martin H.; Schweiger, Oliver; Bacher, Sven; Espadaler, Xavier; Hickler, Thomas; Kumschick, Sabrina; Woodcock, Ben A.; Nentwig, Wolfgang

    2012-01-01

    We study how species richness of arthropods relates to theories concerning net primary productivity, ambient energy, water-energy dynamics and spatial environmental heterogeneity. We use two datasets of arthropod richness with similar spatial extents (Scandinavia to Mediterranean), but contrasting spatial grain (local habitat and country). Samples of ground-dwelling spiders, beetles, bugs and ants were collected from 32 paired habitats at 16 locations across Europe. Species richness of these taxonomic groups was also determined for 25 European countries based on the Fauna Europaea database. We tested effects of net primary productivity (NPP), annual mean temperature (T), annual rainfall (R) and potential evapotranspiration of the coldest month (PETmin) on species richness and turnover. Spatial environmental heterogeneity within countries was considered by including the ranges of NPP, T, R and PETmin. At the local habitat grain, relationships between species richness and environmental variables differed strongly between taxa and trophic groups. However, species turnover across locations was strongly correlated with differences in T. At the country grain, species richness was significantly correlated with environmental variables from all four theories. In particular, species richness within countries increased strongly with spatial heterogeneity in T. The importance of spatial heterogeneity in T for both species turnover across locations and for species richness within countries suggests that the temperature niche is an important determinant of arthropod diversity. We suggest that, unless climatic heterogeneity is constant across sampling units, coarse-grained studies should always account for environmental heterogeneity as a predictor of arthropod species richness, just as studies with variable area of sampling units routinely consider area. PMID:23029288

  11. Diverse urban plantings managed with sufficient resource availability can increase plant productivity and arthropod diversity

    PubMed Central

    Muller, Jonathon N.; Loh, Susan; Braggion, Ligia; Cameron, Stephen; Firn, Jennifer L.

    2014-01-01

    Buildings structures and surfaces are explicitly being used to grow plants, and these “urban plantings” are generally designed for aesthetic value. Urban plantings also have the potential to contribute significant “ecological values” by increasing urban habitat for animals such as arthropods and by increasing plant productivity. In this study, we evaluated how the provision of these additional ecological values is affected by plant species richness; the availability of essential resources for plants, such as water, light, space; and soil characteristics. We sampled 33 plantings located on the exterior of three buildings in the urban center of Brisbane, Australia (subtropical climatic region) over 2, 6 week sampling periods characterized by different temperature and rainfall conditions. Plant cover was estimated as a surrogate for productivity as destructive sampling of biomass was not possible. We measured weekly light levels (photosynthetically active radiation), plant CO2 assimilation, soil CO2 efflux, and arthropod diversity. Differences in plant cover were best explained by a three-way interaction of plant species richness, management water regime and sampling period. As the richness of plant species increased in a planter, productivity and total arthropod richness also increased significantly—likely due to greater habitat heterogeneity and quality. Overall we found urban plantings can provide additional ecological values if essential resources are maintained within a planter such as water, light and soil temperature. Diverse urban plantings that are managed with these principles in mind can contribute to the attraction of diverse arthropod communities, and lead to increased plant productivity within a dense urban context. PMID:25400642

  12. Deep-time patterns of tissue consumption by terrestrial arthropod herbivores

    NASA Astrophysics Data System (ADS)

    Labandeira, Conrad C.

    2013-04-01

    A survey of the fossil record of land-plant tissues and their damage by arthropods reveals several results that shed light on trophic trends in host-plant resource use by arthropods. All 14 major plant tissues were present by the end of the Devonian, representing the earliest 20 % of the terrestrial biota. During this interval, two types of time lags separate the point between when tissues first originated from their earliest consumption by herbivorous arthropods. For epidermis, parenchyma, collenchyma and xylem, live tissue consumption was rapid, occurring on average 10 m.y. after the earliest tissue records. By contrast, structural tissues (periderm, sclerenchyma), tissues with actively dividing cells (apical, lateral, intercalary meristems), and reproductive tissues (spores, megagametophytes, integuments) experienced approximately a 9-fold (92 m.y.) delay in arthropod herbivory, extending well into the Carboniferous Period. Phloem similarly presents a delay of 85 m.y., but this incongruously long lag-time may be attributed to the lack of preservation of this tissue in early vascular plants. Nevertheless, the presence of phloem can be indicated from planar spaces adjacent well-preserved xylem, or inferred from a known anatomy of the same plant taxon in better preserved material, especially permineralisations. The trophic partitioning of epidermis, parenchyma, phloem and xylem increases considerably to the present, probably a consequence of dietary specialization or consumption of whole leaves by several herbivore functional feeding groups. Structural tissues, meristematic tissues and reproductive tissues minimally have been consumed throughout the fossil record, consistent with their long lags to herbivory during the earlier Paleozoic. Neither angiosperm dominance in floras nor global environmental perturbations had any discernible effect on herbivore trophic partitioning of plant tissues.

  13. The phylogenetic status of arthropods, as inferred from 18S rRNA sequences.

    PubMed

    Turbeville, J M; Pfeifer, D M; Field, K G; Raff, R A

    1991-09-01

    Partial 18S rRNA sequences of five chelicerate arthropods plus a crustacean, myriapod, insect, chordate, echinoderm, annelid, and platyhelminth were compared. The sequence data were used to infer phylogeny by using a maximum-parsimony method, an evolutionary-distance method, and the evolutionary-parsimony method. The phylogenetic inferences generated by maximum-parsimony and distance methods support both monophyly of the Arthropoda and monophyly of the Chelicerata within the Arthropoda. These results are congruent with phylogenies based on rigorous cladistic analyses of morphological characters. Results support the inclusion of the Arthropoda within a spiralian or protostome coelomate clade that is the sister group of a deuterostome clade, refuting the hypothesis that the arthropods represent the "primitive" sister group of a protostome coelomate clade. Bootstrap analyses and consideration of all trees within 1% of the length of the most parsimonious tree suggest that relationships between the nonchelicerate arthropods and relationships within the chelicerate clade cannot be reliably inferred with the partial 18S rRNA sequence data. With the evolutionary-parsimony method, support for monophyly of the Arthropoda is found in the majority of the combinations analyzed if the coelomates are used as "outgroups." Monophyly of the Chelicerata is supported in most combinations assessed. Our analyses also indicate that the evolutionary-parsimony method, like distance and parsimony, may be biased by taxa with long branches. We suggest that a previous study's inference of the Arthropoda as paraphyletic may be the result of (a) having two few arthropod taxa available for analysis and (b) including long-branched taxa.

  14. Arthropod Pest Control for UK Oilseed Rape – Comparing Insecticide Efficacies, Side Effects and Alternatives

    PubMed Central

    Breeze, Tom; Bailey, Alison; Garthwaite, David; Harrington, Richard; Potts, Simon G.

    2017-01-01

    Oilseed rape (Brassica napus) is an important combinable break crop in the UK, which is largely protected from arthropod pests by insecticidal chemicals. Despite ongoing debate regarding the use of neonicotinoids, the dominant seed treatment ingredients used for this crop, there is little publicly available data comparing the efficacy of insecticides in controlling key arthropod pests or comparing the impacts on non-target species and the wider environment. To provide an insight into these matters, a UK-wide expert survey targeting agronomists and entomologists was conducted from March to June 2015. Based on the opinions of 90 respondents, an average of 20% yield loss caused by the key arthropod pests was expected to have occurred in the absence of insecticide treatments. Relatively older chemical groups were perceived to have lower efficacy for target pests than newer ones, partly due to the development of insecticide resistance. Without neonicotinoid seed treatments, a lack of good control for cabbage stem flea beetle was perceived. Wide spectrum foliar insecticide sprays were perceived to have significantly greater negative impacts than seed treatments on users’ health, natural enemies, pollinators, soil and water, and many foliar active ingredients have had potential risks for non-target arthropod species in UK oilseed rape fields for the past 25 years. Overall, 72% of respondents opposed the neonicotinoid restriction, while 10% supported it. Opposition and support of the restriction were largely based on concerns for pollinators and the wider environment, highlighting the uncertainty over the side effects of neonicotinoid use. More people from the government and research institutes leaned towards neutrality over the issue, compared to those directly involved in growing the crop. Neonicotinoid restriction was expected to result in greater effort and expenditure on pest control and lower production (0–1 t/ha less). Alternatives for future oilseed rape

  15. The effects of timing of grazing on plant and arthropod communities in high-elevation grasslands.

    PubMed

    Davis, Stacy C; Burkle, Laura A; Cross, Wyatt F; Cutting, Kyle A

    2014-01-01

    Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season.

  16. Avirulence Effector Discovery in a Plant Galling and Plant Parasitic Arthropod, the Hessian Fly (Mayetiola destructor)

    PubMed Central

    Aggarwal, Rajat; Subramanyam, Subhashree; Zhao, Chaoyang; Chen, Ming-Shun; Harris, Marion O.; Stuart, Jeff J.

    2014-01-01

    Highly specialized obligate plant-parasites exist within several groups of arthropods (insects and mites). Many of these are important pests, but the molecular basis of their parasitism and its evolution are poorly understood. One hypothesis is that plant parasitic arthropods use effector proteins to defeat basal plant immunity and modulate plant growth. Because avirulence (Avr) gene discovery is a reliable method of effector identification, we tested this hypothesis using high-resolution molecular genetic mapping of an Avr gene (vH13) in the Hessian fly (HF, Mayetiola destructor), an important gall midge pest of wheat (Triticum spp.). Chromosome walking resolved the position of vH13, and revealed alleles that determine whether HF larvae are virulent (survive) or avirulent (die) on wheat seedlings carrying the wheat H13 resistance gene. Association mapping found three independent insertions in vH13 that appear to be responsible for H13-virulence in field populations. We observed vH13 transcription in H13-avirulent larvae and the salivary glands of H13-avirulent larvae, but not in H13-virulent larvae. RNA-interference-knockdown of vH13 transcripts allowed some H13-avirulent larvae to escape H13-directed resistance. vH13 is the first Avr gene identified in an arthropod. It encodes a small modular protein with no sequence similarities to other proteins in GenBank. These data clearly support the hypothesis that an effector-based strategy has evolved in multiple lineages of plant parasites, including arthropods. PMID:24964065

  17. Biostable Agonists that Match or Exceed Activity of Native Insect Kinins on Recombinant Arthropod GPCRs

    DTIC Science & Technology

    2009-01-01

    diuresis in many species of insects. Compounds with similar biological activity could be exploited for the control of arthropod pest populations such as...species, insect kinins stimulate hindgut contractions, diuresis , digestive enzyme release and probably inhibit larval weight gain (Holman et al., 1990...conserved C-terminal pentapeptide motif Phe-X1-X2-Trp-Gly-NH2, where X1 = His, Asn, Ser, or Tyr and X2 = Ser, Pro, or Ala. Insect kinins regulate diuresis in

  18. Personal Protective Measures Against Insects and Other Arthropods of Military Significance

    DTIC Science & Technology

    2009-10-01

    Rocky Mountain spotted fever , and the human ehrlichioses. (b) Although some arthropods, notably filth flies, do not bite and are therefore not...Bartonellosis Ticks Hard ticks Dermacentor - Spotted fevers - Colorado tick fever Ixodes - Lyme disease - Babesiosis...versus combat. In 1898 during the Spanish-American war, Army disease casualties included 90,416 cases of malaria, 1,169 cases of yellow fever and

  19. Single-minded and the evolution of the ventral midline in arthropods.

    PubMed

    Linne, Viktoria; Eriksson, Bo Joakim; Stollewerk, Angelika

    2012-04-01

    In insects and crustaceans, ventral midline cells are present that subdivide the CNS into bilateral symmetric halves. In both arthropod groups unpaired midline neurons and glial cells have been identified that contribute to the embryonic patterning mechanisms. In the fruitfly Drosophila melanogaster, for example, the midline cells are involved in neural cell fate specification along the dorso-ventral axis but also in axonal pathfinding and organisation of the axonal scaffold. Both in insects and malacostracan crustaceans, the bHLH-PAS transcription factor single-minded is the master regulator of ventral midline development and homology has been suggested for individual midline precursors in these groups. The conserved arrangement of the axonal scaffold as well as the regular pattern of neural precursors in all euarthropod groups raises the question whether the ventral midline system is conserved in this phylum. In the remaining euarthropod groups, the chelicerates and myriapods, a single-minded homologue has been identified in the spider Achaearanea tepidariorum (chelicerate), however, the gene is not expressed in the ventral midline but in the median area of the ventral neuroectoderm. Here we show that At-sim is not required for ventral midline development. Furthermore, we identify sim homologues in representatives of arthropods that have not yet been analysed: the myriapod Strigamia maritima and a representative of an outgroup to the euarthropods, the onychophoran Euperipatoides kanangrensis. We compare the expression patterns to the A. tepidariorum sim homologue expression and furthermore analyse the nature of the arthropod midline cells. Our data suggest that in arthropods unpaired midline precursors evolved from the bilateral median domain of the ventral neuroectoderm in the last common ancestor of Mandibulata (insects, crustaceans, myriapods). We hypothesize that sim was expressed in this domain and recruited to ventral midline development. Subsequently, sim

  20. The Interactive Effects of Pulsed Grazing Disturbance and Patch Size Vary among Wetland Arthropod Guilds

    PubMed Central

    Armitage, Anna R.; Ho, Chuan-Kai; Quigg, Antonietta

    2013-01-01

    Pulse disturbances and habitat patch size can determine community composition independently or in concert, and may be particularly influential on small spatial scales for organisms with low mobility. In a field experiment, we investigated whether the effects of a pulsed disturbance that simulated a grazing event varied with habitat patch size. We focused on the short-term responses of multiple co-occurring emergent salt marsh arthropods with differing levels of mobility and dispersal potential. As part of a marsh restoration project, two types of emergent marsh structures were created: small circular mounds (0.5 m diameter) separated by several meters of aquatic habitat, and larger, elongated terraces (>50 m long). Study plots (0.25 m2) were established on both structures; in a subset of plots, we simulated a pulsed grazing disturbance event by clipping the aboveground tissue of emergent plants, primarily Spartina alterniflora. At the end of the two-month recovery period, Ischnodemus (Hemiptera: Blissidae) density was over 50% lower in disturbed treatments within both large (terrace) and small (mound) patches. Predatory spider treatment responses were similar to Ischnodemus responses, suggesting a trophic relationship between those two arthropod groups. Alternatively, spiders may have been directly affected by the loss of shelter in the disturbed plots. Prokelisia (Homoptera: Delphacidae), which are generally more mobile than Ischnodemus, were not affected by disturbance treatment or by patch size, suggesting the potential for rapid recolonization following disturbance. Larval stem borers decreased by an order of magnitude in disturbed plots, but only in the large patches. In general, the disturbance effects of vegetation removal on arthropod density and community composition were stronger than patch size effects, and there were few interactions between pulsed disturbance and patch size. Rather, emergent marsh arthropod responses to disturbance and habitat area