scholarly journals Biomechanical properties of a buzz-pollinated flower

2020 ◽  
Vol 7 (9) ◽  
pp. 201010
Author(s):  
Vinicius Lourenço Garcia Brito ◽  
Carlos Eduardo Pereira Nunes ◽  
Caique Rocha Resende ◽  
Fernando Montealegre-Zapata ◽  
Mario Vallejo-Marín
Keyword(s):  
Vibration Amplitude ◽  
Biomechanical Properties ◽  
Dominant Frequency ◽  
Laser Vibrometry ◽  
Mechanical Vibrations ◽  
Transmission Properties ◽  
Input Amplitude ◽  
Solanum Rostratum ◽  
Pollen Release

Approximately half of all bee species use vibrations to remove pollen from plants with diverse floral morphologies. In many buzz-pollinated flowers, these mechanical vibrations generated by bees are transmitted through floral tissues, principally pollen-containing anthers, causing pollen to be ejected from small openings (pores or slits) at the tip of the stamen. Despite the importance of substrate-borne vibrations for both bees and plants, few studies to date have characterized the transmission properties of floral vibrations. In this study, we use contactless laser vibrometry to evaluate the transmission of vibrations in the corolla and anthers of buzz-pollinated flowers of Solanum rostratum , and measure vibrations in three spatial axes. We found that floral vibrations conserve their dominant frequency (300 Hz) as they are transmitted throughout the flower. We also found that vibration amplitude at anthers and petals can be up to greater than 400% higher than input amplitude applied at the receptacle at the base of the flower, and that anthers vibrate with a higher amplitude velocity than petals. Together, these results suggest that vibrations travel differently through floral structures and across different spatial axes. As pollen release is a function of vibration amplitude, we conjecture that bees might benefit from applying vibrations in the axes associated with higher vibration amplification.

scholarly journals Biomechanical properties of a buzz-pollinated flower

2020 ◽  
Author(s):  
Vinicius Lourenço Garcia Brito ◽  
Carlos Eduardo Pereira Nunes ◽  
Caique Rocha Resende ◽  
Fernando Montealegre-Zapata ◽  
Mario Vallejo-Marín
Keyword(s):  
Vibration Amplitude ◽  
Pure Tone ◽  
Biomechanical Properties ◽  
Dominant Frequency ◽  
Laser Vibrometry ◽  
Mechanical Vibrations ◽  
Transmission Properties ◽  
Solanum Rostratum ◽  
Pollen Release

AbstractApproximately half of all bee species use vibrations to remove pollen from plants with diverse floral morphologies. In many buzz-pollinated flowers, these mechanical vibrations generated by bees are transmitted through floral tissues, principally pollen-containing anthers, causing pollen to be ejected from small openings (pores or slits) at the tip of the stamen. Despite the importance of substrate-borne vibrations for both bees and plants, few studies to date have characterised the transmission properties of floral vibrations. In this study, we use contactless laser vibrometry to evaluate the transmission of vibrations in the corolla and anthers of buzz-pollinated flowers of Solanum rostratum, and measured vibrations in three spatial axes. We found that floral vibrations conserve their dominant frequency (300Hz) as they are transmitted through the flower, but that vibrations in anthers and petals can gain additional harmonics relative to the pure tone of input vibrations. We also found that vibrations are generally amplified (up to >400%) as they travel from the receptacle at the base of the flower to other floral structures, and that anthers vibrate with a higher amplitude velocity than petals. Together, these results suggest that vibrations travel differently through floral structures and across different spatial axes. As pollen release is a function of vibration amplitude, we conjecture that bees might benefit from applying vibrations in the axes associated with higher vibration amplification.

scholarly journals Floral vibrations by buzz-pollinating bees achieve higher frequency, velocity and acceleration than flight and defence vibrations

2019 ◽  
Author(s):  
David J. Pritchard ◽  
Mario Vallejo-Marín
Keyword(s):  
Vibration Amplitude ◽  
Bombus Terrestris ◽  
Warning Signal ◽  
Biomechanical Properties ◽  
Pollen Foraging ◽  
Insect Behaviour ◽  
Pollen Collection ◽  
Pollen Removal ◽  
Foraging Decisions ◽  
Flight Muscles

AbstractVibrations play an important role in insect behaviour. In bees, vibrations are used in a variety of contexts including communication, as a warning signal to deter predators and during pollen foraging. However, little is known about how the biomechanical properties of bee vibrations vary across multiple behaviours within a species. In this study, we compared the properties of vibrations produced by Bombus terrestris audax (Hymenoptera: Apidae) workers in three contexts: during flight, during defensive buzzing, and in floral vibrations produced during pollen foraging on two buzz-pollinated plants (Solanum, Solanaceae). Using laser vibrometry, we were able to obtain contactless measures of both the frequency and amplitude of the thoracic vibrations of bees across the three behaviours. Despite all three types of vibrations being produced by the same power flight muscles, we found clear differences in the mechanical properties of the vibrations produced in different contexts. Both floral and defensive buzzes had higher frequency and amplitude velocity, acceleration, and displacement than the vibrations produced during flight. Floral vibrations had the highest frequency, amplitude velocity and acceleration of all the behaviours studied. Vibration amplitude, and in particular acceleration, of floral vibrations has been suggested as the key property for removing pollen from buzz-pollinated anthers. By increasing frequency and amplitude velocity and acceleration of their vibrations during vibratory pollen collection, foraging bees may be able to maximise pollen removal from flowers, although their foraging decisions are likely to be influenced by the presumably high cost of producing floral vibrations.

scholarly journals Divergent selection on the biomechanical properties of stamens under wind and insect pollination

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182251 ◽  
Author(s):  
David Timerman ◽  
Spencer C. H. Barrett
Keyword(s):  
Wind Tunnel ◽  
Biomechanical Properties ◽  
Experimental Manipulation ◽  
Biomechanical Analysis ◽  
Male Reproductive Success ◽  
Wind Pollination ◽  
Insect Pollination ◽  
Strong Negative Correlation ◽  
Transitional State ◽  
Pollen Release

Wind pollination has evolved from insect pollination in numerous angiosperm lineages and is associated with a characteristic syndrome of morphological traits. The traits initiating transitions to wind pollination and the ecological drivers involved are poorly understood. Here, we examine this problem in Thalictrum pubescens , an ambophilous (insect and wind pollination) species that probably represents a transitional state in the evolution of wind pollination. We investigated wind-induced pollen release by forced harmonic motion by measuring stamen natural frequency ( f n ), a key vibration parameter, and its variability among nine populations. We assessed the repeatability of f n over consecutive growing seasons, the effect of this parameter on pollen release in a wind tunnel, and male reproductive success in the field using experimental manipulation of the presence or absence of pollinators. We found significant differences among populations and high repeatability within genotypes in f n . The wind tunnel assay revealed a strong negative correlation between f n and pollen release. Siring success was greatest for plants with lower f n when pollinators were absent, but this advantage diminished when pollinators were present. Our biomechanical analysis of the wind–flower interface has identified f n as a key trait for understanding early stages in the transition from insect to wind pollination.

scholarly journals Are flowers tuned to buzzing pollinators? Variation in the natural frequency of stamens with different morphologies and its relationship to bee vibrations

2020 ◽  
Author(s):  
Carlos Eduardo Pereira Nunes ◽  
Lucy Nevard ◽  
Fernando Montealegre-Zapata ◽  
Mario Vallejo-Marin
Keyword(s):  
Natural Frequency ◽  
Fundamental Frequency ◽  
Vibration Amplitude ◽  
Natural Frequencies ◽  
Laser Doppler ◽  
Buzz Pollination ◽  
Laser Doppler Vibrometry ◽  
Pollen Removal ◽  
Pollen Release

AbstractDuring buzz pollination, bees use vibrations to remove pollen from flowers. Vibrations at the natural frequency of pollen-carrying stamens are amplified through resonance, resulting in higher-amplitude vibrations. Because pollen release depends on vibration amplitude, bees could increase pollen removal by vibrating at the natural frequency of stamens. Yet, few studies have characterized the natural frequencies of stamens and compared them to frequencies of buzz-pollinating bees. Here we use laser Doppler vibrometry to characterise natural frequencies of stamens of six buzz-pollinated Solanum taxa of contrasting stamen morphology. We also compare the fundamental frequency of bumblebee buzzes produced on two Solanum species with different natural frequencies. We found that stamen morphology and plant identity explain variation in natural frequency of stamens. Our results show that medium-sized pollinators, such as bumblebees, produce buzzes of frequencies higher than the natural frequency of most (5/6) of the Solanum species we studied. However, the observed natural frequency of Solanum stamens is at the low end of the range of frequencies produced by other buzz-pollinating bees. Thus, our findings suggest that in some buzz pollination interactions, but not others, stamen resonance may play a role in mediating pollen release.

Biomechanical Properties of the Stifle Joint Lateral Collateral Ligament in Dogs

1992 ◽  
Vol 05 (04) ◽  
pp. 158-162 ◽  
Author(s):  
D. Blackketter ◽  
J Harari ◽  
J. Dupuis
Keyword(s):  
Mechanical Properties ◽  
Cruciate Ligament ◽  
Lateral Collateral Ligament ◽  
Biomechanical Properties ◽  
Fibular Head ◽  
Joint Stability ◽  
Collateral Ligament ◽  
Cranial Cruciate Ligament ◽  
Stifle Joint

Bone/lateral collateral ligament/bone preparations were tested and structural mechanical properties compared to properties of cranial cruciate ligament in 15 dogs. The lateral collateral ligament has sufficient stiffness to provide stifle joint stability and strength to resist acute overload following fibular head transposition.

The influence of osteopathic correction on the rate of various rhythms of the body

2019 ◽  
pp. 64-71 ◽  
Author(s):  
A. E. Chernikova ◽  
Yu. P. Potekhina
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Age Groups ◽  
Biomechanical Properties ◽  
Dispersion Analysis ◽  
The Body ◽  
Body Tissues ◽  
Age Related ◽  
Significant Difference ◽  
Before And After

Introduction. An osteopathic examination determines the rate, the amplitude and the strength of the main rhythms (cardiac, respiratory and cranial). However, there are relatively few studies in the available literature dedicated to the influence of osteopathic correction (OC) on the characteristics of these rhythms.Goal of research — to study the influence of OC on the rate characteristics of various rhythms of the human body.Materials and methods. 88 adult osteopathic patients aged from 18 to 81 years were examined, among them 30 men and 58 women. All patients received general osteopathic examination. The rate of the cranial rhythm (RCR), respiratory rate (RR) heart rate (HR), the mobility of the nervous processes (MNP) and the connective tissue mobility (CTM) were assessed before and after the OC session.Results. Since age varied greatly in the examined group, a correlation analysis of age-related changes of the assessed rhythms was carried out. Only the CTM correlated with age (r=–0,28; p<0,05) in a statistically significant way. The rank dispersion analysis of Kruskal–Wallis also showed statistically significant difference in this indicator in different age groups (p=0,043). With the increase of years, the CTM decreases gradually. After the OC, the CTM, increased in a statistically significant way (p<0,0001). The RCR varied from 5 to 12 cycles/min in the examined group, which corresponded to the norm. After the OC, the RCR has increased in a statistically significant way (p<0,0001), the MNP has also increased (p<0,0001). The initial heart rate in the subjects varied from 56 to 94 beats/min, and in 15 % it exceeded the norm. After the OC the heart rate corresponded to the norm in all patients. The heart rate and the respiratory rate significantly decreased after the OC (р<0,0001).Conclusion. The described biorhythm changes after the OC session may be indicative of the improvement of the nervous regulation, of the normalization of the autonomic balance, of the improvement of the biomechanical properties of body tissues and of the increase of their mobility. The assessed parameters can be measured quickly without any additional equipment and can be used in order to study the results of the OC.

Influence of corneal biomechanical properties on IOP indices in patients with keratoconus

The Eye ◽  
2019 ◽  
Vol 21 (128) ◽  
pp. 15-19
Author(s):  
Irina Bubnova ◽  
Veronica Averich ◽  
Elena Belousova
Keyword(s):  
Disease Progression ◽  
Corneal Thickness ◽  
Central Zone ◽  
Biomechanical Properties ◽  
Resistance Factor ◽  
Corneal Resistance Factor ◽  
Mean Values ◽  
Coefficient Of Elasticity ◽  
D Values ◽  
Corneal Biomechanical Properties

Purpose: Evaluation of corneal biomechanical prop¬erties and their influence on IOP indices in patients with keratoconus. Material and methods. The study included 194 eyes with keratoconus (113 patients aged from 23 to 36 years old). Corneal refraction in central zone varied from 48.25 to 56.75 D, values of corneal thickness ranged from 279 to 558 μm. Patients were divided into 4 groups according to Amsler classification: I stage – 40 eyes; II stage – 78 eyes; III stage – 54 eyes and IV stage – 22 eyes. Standard ophthal¬mological examination was carried out including pneumo¬tonometry. IOP indices and values of biomechanical prop¬erties were evaluated by dynamic bidirectional pneumatic applanation and pneumatic impression. Results. Study of corneal biomechanical properties in patients with keratoconus showed a decrease of such biomechanical indices as corneal hysteresis (CH) on aver¬age to 8.42±1.12 mm Hg, corneal resistance factor (CRF) – to 7.45±0.96 mm Hg, coefficient of elasticity (CE) – 5.35± 0.87 mm Hg. Values of these indices strongly depended on the stage of keratoconus. In the whole sample, the aver¬age corneal compensated IOP (IOPcc) amounted to 15.08± 2.43 mm Hg, Goldman IOP (IOPg) was 11.61±2.37 mm Hg and pneumatic tonometry IOP (IOPp) was 10.13±2.94 mm Hg. IOPcc indices didn’t have any statistically significant differ¬ence in dependence on the stage of keratoconus (р>0.473), while in process of disease progression IOPg and IOPp indi¬ces showed statistically significant decrease of mean values. Conclusion. Progression of keratoconus led to a de¬crease in corneal biomechanical properties which deter¬mine reduction of such indices as IOPg and IOPp in contrast to IOPcc.

Modeling Vibration-Induced Tire-Pavement Interaction Noise in the Mid-frequency Range

2020 ◽  
Author(s):  
Sterling McBride ◽  
Ricardo Burdisso ◽  
Corina Sandu
Keyword(s):  
Sound Intensity ◽  
Element Model ◽  
Dominant Frequency ◽  
Contact Forces ◽  
Surface Velocity ◽  
New Wave ◽  
Normal Surface ◽  
Radiated Noise ◽  
Physical Effects ◽  
Effects Of Rotation

ABSTRACT Tire-pavement interaction noise (TPIN) is one of the main sources of exterior noise produced by vehicles traveling at greater than 50 kph. The dominant frequency content is typically within 500–1500 Hz. Structural tire vibrations are among the principal TPIN mechanisms. In this work, the structure of the tire is modeled and a new wave propagation solution to find its response is proposed. Multiple physical effects are accounted for in the formulation. In an effort to analyze the effects of curvature, a flat plate and a cylindrical shell model are presented. Orthotropic and nonuniform structural properties along the tire's transversal direction are included to account for differences between its sidewalls and belt. Finally, the effects of rotation and inflation pressure are also included in the formulation. Modeled frequency response functions are analyzed and validated. In addition, a new frequency-domain formulation is presented for the computation of input tread pattern contact forces. Finally, the rolling tire's normal surface velocity response is coupled with a boundary element model to demonstrate the radiated noise at the leading and trailing edge locations. These results are then compared with experimental data measured with an on-board sound intensity system.

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