DIVERSITY OF THE SOUTHERN GREEN STINK BUG NEZARA VIRIDULA (L.) (HETEROPTERA: PENTATOMIDAE)

The southern green stink bug Nezara viridula (L.) (Heteroptera: Pentatomidae) is a global pest of considerable ecological, agricultural and economical interest. The ancestral home of this species is supposed to be Africa and/or Mediterranean and presumably it was spread worldwide during the last two centuries with human trade and agriculture. Bugs found today on different continents do not differ morphologically, however there are substantial differences in their mating behaviour. We used horizontal starch gel electrophoresis to determine the suitability of biochemical markers for assessment of genetic variation between geographically isolated populations of N. viridula. The initial survey of populations from Slovenia, France, French West Indies and Brazil resulted in the resolution of polymorphic banding patterns within the following enzyme systems: GPI, IDH, MDH, ME, MPI and PGM. Results indicate there are consistent differences among tested populations

Interference of overlapping insect vibratory communication signals: an Eushistus heros Model.

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 cmmunicate with species and gender spe- cific 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 dif- ference between signals by changing the frequency level and frequency modulation pattern of their calls

On the evolution of the tymbalian tymbal organ: Comment on “Planthopper bugs use a fast, cyclic elastic recoil mechanism for effective vibrational communication at small body size” by Davranoglou et al. 2019

In ihrer kürzlich erschienenen Arbeit (Davranoglou et al. 2019) untersuchten die Autoren an lebenden Exemplaren von Agalmatium bilobium (Issidae) mit modernsten Methoden (microCT) die Interaktionen zwischen Muskulatur und bestimmten Anteilen des Exoskeletts zur Vibrationserzeugung und beschreiben deren biomechanische Grundlage. Auf der Basis des morphologischen Vergleichs mit Museumsmaterial von Vertretern der meisten Taxa der Fulgoromorpha (Spitzkopfzikaden) im Familienrang postulieren Davranoglou et al. (2019), ein „neues und bisher übersehenes“ Organ entdeckt zu haben, das sie als „snapping organ“ bezeichnen und als charakteristisch für die Fulgoromorpha (mit Ausnahme der Delphacidae) interpretieren. Wir sehen diese Ergebnisse aus folgenden Gründen kritisch: 1. In ihrer umfassenden Übersicht zu den vibrationserzeugenden Organen der Hemiptera stellten Wessel et al. (2014) die Hypothese auf, dass sich alle bisher bekannten Strukturen zur Schall- und Vibrationserzeugung auf ein Organ zurückführen lassen, das mit hoher Wahrscheinlichkeit bei der Stammart aller Hemipteren oberhalb der Sternorrhyncha vorhanden war, und eine Synapomorphie dieses Taxons, der sog. Tymbalia (Wessel et al. 2014), darstellt. Da aufgrund der morphologischen Disparität des Organs in den einzelnen Taxa die Homologieverhältnisse schwierig zu beurteilen sind, stellten Wessel et al. (2014) Kriterien für das „Tymbal der Tymbalia“ auf. Das sogenannte „snapping organ“ erfüllt alle Kriterien dieses Tymbal-Organes. Die Einführung eines neuen Begriffes für eine bestimmte Struktur in einer langen und komplexen Kette evolutionärer Transformationen ist daher unnötig, wenn nicht sogar irreführend. Wir empfehlen daher dringend, in zukünftigen Arbeiten den Begriff „tymbalian tymbal organ with a snapping mechanism“ zu verwenden. 2. Die Grundannahme von Davranoglou et al. (2019), dass – im Gegensatz zum neu entdeckten „snapping organ“ der Fulgoromorpha – allen Cicadomorpha ein „tymbal-ähnliches Or-gan“ gemeinsam sei, ist zu stark vereinfacht und vernachlässigt die enorme Vielfalt der Ausprägungen des Tymbals bei Nicht-Singzikaden innerhalb der Cicadomorpha. In Anbetracht der verfügbaren Studien scheint es daher zweifelhaft, dass sich die vibrationserzeugenden Strukturen dreimal unabhängig voneinander entwickelt haben sollen, wie es die phylogenetische Interpretation bei Davranoglou et al. (2019: Abb. 3) suggeriert

Measurement of Lagrangian velocity in fully developed turbulence

We have developed a new experimental technique to measure the Lagrangian velocity of tracer particles in a turbulent flow, based on ultrasonic Doppler tracking. This method yields a direct access to the velocity of a single particule at a turbulent Reynolds number $R_{\lambda} = 740$. Its dynamics is analyzed with two decades of time resolution, below the Lagrangian correlation time. We observe that the Lagrangian velocity spectrum has a Lorentzian form $E^{L}(\omega) = u_{rms}^{2} T_{L} / (1 + (T_{L}\omega)^{2})$, in agreement with a Kolmogorov-like scaling in the inertial range. The probability density function (PDF) of the velocity time increments displays a change of shape from quasi-Gaussian a integral time scale to stretched exponential tails at the smallest time increments. This intermittency, when measured from relative scaling exponents of structure functions, is more pronounced than in the Eulerian framework.Comment: 4 pages, 5 figures. to appear in PR

Fluid Particle Accelerations in Fully Developed Turbulence

The motion of fluid particles as they are pushed along erratic trajectories by fluctuating pressure gradients is fundamental to transport and mixing in turbulence. It is essential in cloud formation and atmospheric transport, processes in stirred chemical reactors and combustion systems, and in the industrial production of nanoparticles. The perspective of particle trajectories has been used successfully to describe mixing and transport in turbulence, but issues of fundamental importance remain unresolved. One such issue is the Heisenberg-Yaglom prediction of fluid particle accelerations, based on the 1941 scaling theory of Kolmogorov (K41). Here we report acceleration measurements using a detector adapted from high-energy physics to track particles in a laboratory water flow at Reynolds numbers up to 63,000. We find that universal K41 scaling of the acceleration variance is attained at high Reynolds numbers. Our data show strong intermittency---particles are observed with accelerations of up to 1,500 times the acceleration of gravity (40 times the root mean square value). Finally, we find that accelerations manifest the anisotropy of the large scale flow at all Reynolds numbers studied.Comment: 7 pages, 4 figure

DIVERSITY OF THE SOUTHERN GREEN STINK BUG NEZARA VIRIDULA (L.) (HETEROPTERA: PENTATOMIDAE)

The southern green stink bug Nezara viridula (L.) (Heteroptera: Pentatomidae) is a global pest of considerable ecological, agricultural and economical interest. The ancestral home of this species is supposed to be Africa and/or Mediterranean and presumably it was spread worldwide during the last two centuries with human trade and agriculture. Bugs found today on different continents do not differ morphologically, however there are substantial differences in their mating behaviour. We used horizontal starch gel electrophoresis to determine the suitability of biochemical markers for assessment of genetic variation between geographically isolated populations of N. viridula. The initial survey of populations from Slovenia, France, French West Indies and Brazil resulted in the resolution of polymorphic banding patterns within the following enzyme systems: GPI, IDH, MDH, ME, MPI and PGM. Results indicate there are consistent differences among tested populations

Bright ligand-activatable fluorescent protein for high-quality multicolor live-cell super-resolution microscopy

We introduce UnaG as a green-to-dark photoswitching fluorescent protein capable of high-quality super-resolution imaging with photon numbers equivalent to the brightest photoswitchable red protein. UnaG only fluoresces upon binding of a fluorogenic metabolite, bilirubin, enabling UV-free reversible photoswitching with easily controllable kinetics and low background under Epi illumination. The on- and off-switching rates are controlled by the concentration of the ligand and the excitation light intensity, respectively, where the dissolved oxygen also promotes the off-switching. The photo-oxidation reaction mechanism of bilirubin in UnaG suggests that the lack of ligand-protein covalent bond allows the oxidized ligand to detach from the protein, emptying the binding cavity for rebinding to a fresh ligand molecule. We demonstrate super-resolution single-molecule localization imaging of various subcellular structures genetically encoded with UnaG, which enables facile labeling and simultaneous multicolor imaging of live cells. UnaG has the promise of becoming a default protein for high-performance super-resolution imaging. Photoconvertible proteins occupy two color channels thereby limiting multicolour localisation microscopy applications. Here the authors present UnaG, a new green-to-dark photoswitching fluorescent protein for super-resolution imaging, whose activation is based on a noncovalent binding with bilirubin

Particle tracking velocimetry and accelerometry (PTVA) measurements applied to quasi-two-dimensional multi-scale flows

Accepted versio

Substrate-borne vibrations disrupt the mating behaviors of the neotropical brown stink bug, Euschistus heros: implications for pest management.

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