Reduction of female copulatory damage by resilin represents evidence for tolerance in sexual conflict

Intergenomic evolutionary conflicts increase biological diversity. In sexual conflict, female defence against males is generally assumed to be resistance, which, however, often leads to trait exaggeration but not diversification. Here, we address whether tolerance, a female defence mechanism known from interspecific conflicts, exists in sexual conflict. We examined the traumatic insemination of female bed bugs via cuticle penetration by males, a textbook example of sexual conflict. Confocal laser scanning microscopy revealed large proportions of the soft and elastic protein resilin in the cuticle of the spermalege, the female defence organ. Reduced tissue damage and haemolymph loss were identified as adaptive female benefits from resilin. These did not arise from resistance because microindentation showed that the penetration force necessary to breach the cuticle was significantly lower at the resilin-rich spermalege than at other cuticle sites. Furthermore, a male survival analysis indicated that the spermalege did not impose antagonistic selection on males. Our findings suggest that the specific spermalege material composition evolved to tolerate the traumatic cuticle penetration. They demonstrate the importance of tolerance in sexual conflict and genitalia evolution, extend fundamental coevolution and speciation models and contribute to explaining the evolution of complexity. We propose that tolerance can drive trait diversity

Patterns of load distribution among the legs in small water striders during standing and striding

Water striders (Gerris argentatus) move across the water surface by taking advantage of the surface tension, which supports their bodyweight without breaking. During locomotion, the midlegs are primarily responsible for generating thrust, whereas the other legs support the body. Although the aspects of standing and locomotion on the water surface are well understood, relatively fewer studies concerned the coordinated biomechanical movements of the legs. In order to maintain buoyancy of the body on the water surface, the leg positions must be adjusted to distribute the bodyweight appropriately. The present study investigates distribution of the bodyweight on the legs in relatively small water striders. We aimed to understand how loading on the legs changes during sculling that leads to sliding of the body on the water surface. The assistance of all legs at every moment enables the body to maintain its floating during standing and striding. Water striders can achieve a gentle striding through the midlegs driving phase in association with smooth load shifting among their legs, which are positioned in a specific configuration to support the insect on the water surface

Extensive collection of femtoliter pad secretion droplets in beetle Leptinotarsa decemlineata allows nanoliter microrheology

Pads of beetles are covered with long, deformable setae, each ending in a micrometric terminal plate coated with secretory fluid. It was recently shown that the layer of the pad secretion covering the terminal plates is responsible for the generation of strong attractive forces. However, less is known about the fluid itself because it is produced in extremely small quantity. We here present a first experimental investigation of the rheological properties of the pad secretion in the Colorado potato beetle {\it Leptinotarsa decemlineata}. Because the secretion is produced in an extremely small amount at the level of the terminal plate, we first develop a procedure based on capillary effects to collect the secretion. We then manage to incorporate micrometric beads, initially in the form of a dry powder, and record their thermal motion to determine the mechanical properties of the surrounding medium. We achieve such a quantitative measurement within the collected volume, much smaller than the $1 {\rm \mu}$l sample volume usually required for this technique. Surprisingly, the beetle secretion was found to behave as a purely viscous liquid, of high viscosity. This suggests that no specific complex fluid behaviour is needed during beetle locomotion. We build a scenario for the contact formation between the spatula at the setal tip and a substrate, during the insect walk. We show that the attachment dynamics of the insect pad computed from the high measured viscosity is in good agreement with observed insect pace. We finally discuss the consequences of the secretion viscosity on the insect adhesion

Micrometer-sized Water Ice Particles for Planetary Science Experiments: Influence of Surface Structure on Collisional Properties

Models and observations suggest that ice-particle aggregation at and beyond the snowline dominates the earliest stages of planet formation, which therefore is subject to many laboratory studies. However, the pressure–temperature gradients in protoplanetary disks mean that the ices are constantly processed, undergoing phase changes between different solid phases and the gas phase. Open questions remain as to whether the properties of the icy particles themselves dictate collision outcomes and therefore how effectively collision experiments reproduce conditions in protoplanetary environments. Previous experiments often yielded apparently contradictory results on collision outcomes, only agreeing in a temperature dependence setting in above ≈210 K. By exploiting the unique capabilities of the NIMROD neutron scattering instrument, we characterized the bulk and surface structure of icy particles used in collision experiments, and studied how these structures alter as a function of temperature at a constant pressure of around 30 mbar. Our icy grains, formed under liquid nitrogen, undergo changes in the crystalline ice-phase, sublimation, sintering and surface pre-melting as they are heated from 103 to 247 K. An increase in the thickness of the diffuse surface layer from ≈10 to ≈30 Å (≈2.5 to 12 bilayers) proves increased molecular mobility at temperatures above ≈210 K. Because none of the other changes tie-in with the temperature trends in collisional outcomes, we conclude that the surface pre-melting phenomenon plays a key role in collision experiments at these temperatures. Consequently, the pressure–temperature environment, may have a larger influence on collision outcomes than previously thought

Выбор математической модели объекта исследования в электроимпедансной томографии

Зроблено огляд наукових праць, що стосуються питань моделювання досліджуваних об’єктів у разі електроімпедансної томографії. Спираючись на тривимірність процесів, які відбуваються в об’єктах дослідження при застосуванні електроімпедансних томографів, показано, що для адекватного моделювання об’єктів дослідження необхідно застосовувати квазістатичний або повнопольовий електродинамічні підходи.Introduction. A brief review of scientific publications relating to questions of the object for study modeling that implements the EIT methods is given. Formulation of the problem. EIT features associated with three-dimensionality of processes taking place in the study objects during the measurement and the complexity of the reconstruction process are shown. A comparative analysis of the quasi-static and full-wave model of the object for study is presented. Conclusion. Based on three-dimensional processes that take place in the study objects using EIT has shown that adequate models of study objects should be based on quasi-static or full-wave electrodynamics approaches.Выполнен обзор научных работ, касающихся вопросов моделирования исследуемых объектов в электроипедансной томографии. С учетом трехмерности процессов, происходящих в исследуемых объектах при использовании электроимпедансных томографов, показано, что для адекватного моделирования объектов исследования необходимо применять квазистатический или полнополевой электродинамические подходы

Собственные волны в поперечно неоднородном открытом цилиндрическом диэлектрическом волноводе

Методом точкового узгодження, з врахуванням лише парних поздовжніх складових електричного поля, розв’язується задача на власні значення – сталі поширення хвиль в неоднорідному діелектричному хвилеводі. Розглядається наступна модель: діелектричний хвилевід кругового поперечного перетину з однією неоднорідністю кругової форми. Наведені результати чисельних досліджень залежності сталої поширення для різних типів хвиль в залежності від параметрів та місцеположення неоднорідності.Результати даної роботи можуть бути поширені для дослідження хвилеводів, які мають перетин іншої форми та/або містять декілька неоднорідних областей з різними параметрамиBy the point matching method, taking into account only the even electric longitudinal field components, is considered the eigenvalue problem - constant propagation in inhomogeneous dielectric waveguide. The following model is accepted: a dielectric waveguide of round cross-section with single circular heterogeneity. A result of numerical studies of the dependence of the propagation constant for different types of waves, depending on the parameters and the location of the in homogeneity, are introduced. The results of the study can be extended to the study of waveguides with a cross section of different shapes and/or contain multiple heterogeneous domains with different parametersМетодом точечного согласования, с учетом только четных продольных составляющих электрического поля, решается задача на собственные значения – постоянные распространения волн в неоднородном диэлектрическом волноводе. Рассматривается следующая модель: диэлектрический волновод круглого поперечного сечения с одной неоднородностью круглой формы. Приведены результаты численных исследований зависимости постоянной распространения для разных типов волн в зависимости от параметров и месторасположения неоднородности.Результаты данной работы можно расширить для исследования волноводов, имеющих сечение другой формы и/или содержащих несколько неоднородных областей с разными параметрам

InspiRat: biologisch inspirierter Kletterroboter für die externe Inspektion linearer Strukturen

TETRA GmbH Ilmenau und drei universitäre Lehrstühle zeigen im Projekt InspiRat, dass bei wissenschaftlicher Unterstützung auch die deutsche Industrie in der Lage ist, in der Robotik internationale Standards zu setzen. InspiRat und RatNics als Akronyme sollen Assoziationen wecken: Analyse des Kletterns insbesondere von Ratten trieb den Bau einer neuen Klasse von Robotern. Waren zu Beginn des Projektes integrierte Kletterroboter mit Massen > 35 kg verfügbar, so gibt es nun Maschinen mit 1 kg bis 2 kg Masse, experimentell modulare Systeme mit 250 g Masse. Nebenergebnis ist die weltweite Definition des Standes der Technik der Röntgenvideographie zusammen mit der Siemens® AG: biplanar 2.000 Röntgenbilder/Sekunde in HD. Ergebnisse universitärer Studien werden in Journalen publiziert, doch belegt die Nachfrage nach dem Abschlussbericht des Projektes für das BMBF das Interesse an einer übergreifenden, transdisziplinären Darstellung des bionischen Entwicklungsprozesses. Wir publizieren deswegen diesen Abschlussbericht nur geringfügig redaktionell überarbeitet. Er beschreibt somit den wissenschaftlichen Stand 2011 in einer auf den Fördermittelgeber zugeschnittenen Darstellungsweise. Die Wissenschaft ist nicht stehen geblieben, wir erleichtern die Nachverfolgung durch Angabe einiger Publikationen aus der Zeit nach Projektende. Doch ist unser Anspruch nicht prospektiv wie bei Zeitschriftenartikeln, wir wollen retrospektiv die Analyse eines erfolgreich abgeschlossenen Prozesses ermöglichen

Material stiffness variation in mosquito antennae

The antennae of mosquitoes are model systems for acoustic sensation, in that they obey general principles for sound detection, using both active feedback mechanisms and passive structural adaptations. However, the biomechanical aspect of the antennal structure is much less understood than the mechano-electrical transduction. Using confocal laser scanning microscopy, we measured the fluorescent properties of the antennae of two species of mosquito – Toxorhynchites brevipalpis and Anopheles arabiensis – and, noting that fluorescence is correlated with material stiffness, we found that the structure of the antenna is not a simple beam of homogeneous material, but is in fact a rather more complex structure with spatially distributed discrete changes in material properties. These present as bands or rings of different material in each subunit of the antenna, which repeat along its length. While these structures may simply be required for structural robustness of the antennae, we found that in FEM simulation, these banded structures can strongly affect the resonant frequencies of cantilever-beam systems, and therefore taken together our results suggest that modulating the material properties along the length of the antenna could constitute an additional mechanism for resonant tuning in these species