搜索到29篇“ DAMSELFLY“的相关文章
Frequency-dependent resemblance of male-colored females to males in a damselfly
2019年
Dear editor, Mimetic protection is most effective when mimics are relatively rare (Pfennig et al.,2001). In polymorphic damselfly species, male-colored female morphs may avoid costly male mating attempts because they are not immediately recognized as a suitable mating partner (van Gossum et al.,2008). We investigated morphological resemblance of male-colored females to males across six populations of the polymorphic blue-tailed damselfly lschmira elegans (Vander Linden). We found that male-colored females resembled males more closely with an increasing ratio of male-colored females to other female morphs. Our results suggest that the degree of mimetic fidelity is frequencydependent.
Wicher VosJan KomdeurMartijn Hammers
关键词:EDITORFEMALEPOPULATIONS
Quantification of wing and body kinematics in connection to torque generation during damselfly yaw turn
2017年
This study provides accurate measurements of the wing and body kinematics of three different species of damselflies in free yaw turn fights. The yaw turn is characterized by a short acceleration phase which is immediately followed by an elongated deceleration phase. Most of the heading change takes place during the latter stage of the flight. Our observations showed that yaw turns are executed via drastic rather than subtle changes in the kinematics of all four wings. The motion of the inner and outer wings were found to be strongly linked through their orientation as well as their velocities with the inner wings moving faster than the outer wings. By controlling the pitch angle and wing velocity, a damselfly adjusts the angle of attack. The wing angle of attack exerted the strongest influence on the yaw torque, followed by the flapping and deviation velocities of the wings. Moreover, no evidence of active generation of counter torque was found in the flight data implying that deceleration and stopping of the maneuver is dominated by passive damping. The systematic analysis carried out on the free flight data advances our understanding of the mechanisms by which these insects achieve their observed maneuverability. In addition, the inspiration drawn from this study can be employed in the design of low frequency flapping wing micro air vehicles (MAV's).
Samane ZeyghamiAyodeji T. Bode-OkeHaiBo Dong
关键词:DAMSELFLY
Measurement of Vibrational Stiffness and Air Damping of Damselfly Wings
2016年
A simple cantilever beam vibration test method made of biomorph and insect wing, were used to measure the vibrational stiffness and the air damping of insect wings. Vibration tests were performed in vacuum pressures to atmosphere and the wing stiffness and air damping factor were measured. The test method was found to be a viable method for measuring wing stiffness, natural frequencies and mode shapes. The vibrational deformation of the insect wings was found to be combination of bending and torsion because of unsymmetrical geometry of wing. The measured stiffness (K) of damselfly wings varied from 0.18 to 0.31 N/m and the air damping ratio ranged from 0.72 to 0.79. The undamped natural frequency (fn) at 13 kPa varied from 249 to 299 Hz and at atmosphere it varied from 168 to 198 Hz.
Rupan TalukderKunigal N. Shivakumar
关键词:VIBRATIONSTIFFNESS
Tensile Properties of Veins of Damselfly Wing
2013年
Microtension test of Costa and Radius veins of damselfly wing was conducted to measure tensile strength and modulus. The specimens were classified into fresh and dry depending on when the samples were prepared and tested. Fresh samples tested immediately after extracting from the fly while the dry samples were tested one year after extraction and stored in a desiccator. Measured load-displacement response and fracture load were used to calculate modulus and strength. Field Emission Scanning Electron Microscope was used to measure the fracture morphology and cross-section of the vein. The results showed that the veins are brittle and fracture surface is flat. The average strength (232 - 285 MPa) and modulus (14 - 17 GPa) of the Costa and Radius veins were nearly same for both fresh and dry samples. The tensile modulus of the veins was 8% - 10% higher than the indentation (compressive) modulus and was nearly the same as that of human bones.
Rupan TalucdherKunigal Shivakumar
关键词:DAMSELFLYWINGTENSILETENSILEMODULUS
宁夏的蜻蜓目昆虫资源被引量:6
2007年
根据近些年对宁夏蜻蜓目昆虫资源的调查,并结合文献资料,现知在宁夏境内分布的蜻蜓目昆虫有7科20属共计38种。调查中发现宁夏新记录种6种,即红蜻Crocothemis servilia Drury、高斑蜻Libellula basilinea McLachlan、异色灰蜻Orthetrum melania Selys、Orthetrum sp.、竖眉赤蜻Sympetrum eroticum ardens McLachlan和长叶异痣Ischnura elegans(Van der Linden)。
张大治代金霞杨贵军田兴侠
关键词:蜻蜓目地理分布
SOME BIOLOGICAL ASPECTS AND A UNIQUE HABITAT CHOICE OF DAMSELFLY INDOCNEMIS ORANG FOERSTER(ODONATA:PLATYCNEMIDIDAE)FROM MALAYSIA被引量:2
2003年
The hemimetabolous preliminary studies on the life cycle of Indocnemis orang is here reported for the first time, being completed in 6 instars for a minimum duration of 69 days. It can be classified as a stenotopic species being sensitive to biotope requirements but having tolerance towards fluctuating water qualities during its developmental process. The need for caution in the interpretation of bioindicator species for habitat assessment and biomonitoring is here both indicated and discussed.
Y.Norma-Rashid
关键词:DRAGONFLIESLIFE-HISTORYMALAYSIAMORPHOMETRICS
昆虫界中的“蹭机客”
2013年
没有人喜欢被称为寄生虫——懒惰、不劳而获、靠别人养活自己的人。但是自然界里的寄生动植物不会担心这些,它们不以“盗窃他人财物”为耻,因为这是它们的生存之道。
吴勇
关键词:昆虫寄生虫动植物自然界
塞勒克斯公司首次展示Damselfly垂直起降无人机模型
2007年
日前,塞勒克斯(Selex)传感器与机载系统公司首次公开了其研制的Damselfly垂直起降无人机的模型。该无人机的原型机实际上已在2007年4月进行了首次试飞,但塞勒克斯公司至今不愿公开展示该原型机。
阿雯
关键词:垂直起降无人机机载系统原型机
Dragonfly Interaction Algorithm for Optimization of Queuing Delay in Industrial Wireless Networks
2024年
In industrial wireless networks,data transmitted from source to destination are highly repetitive.This often leads to the queuing of the data,and poor management of the queued data results in excessive delays,increased energy consumption,and packet loss.Therefore,a nature-inspired-based Dragonfly Interaction Optimization Algorithm(DMOA)is proposed for optimization of the queue delay in industrial wireless networks.The term“interaction”herein used is the characterization of the“flying movement”of the dragonfly towards damselflies(female dragonflies)for mating.As a result,interaction is represented as the flow of transmitted data packets,or traffic,from the source to the base station.This includes each and every feature of dragonfly movement as well as awareness of the rival dragonflies,predators,and damselflies for the desired optimization of the queue delay.These features are juxtaposed as noise and interference,which are further used in the calculation of industrial wireless metrics:latency,error rate(reliability),throughput,energy efficiency,and fairness for the optimization of the queue delay.Statistical analysis,convergence analysis,the Wilcoxon test,the Friedman test,and the classical as well as the 2014 IEEE Congress of Evolutionary Computation(CEC)on the benchmark functions are also used for the evaluation of DMOA in terms of its robustness and efficiency.The results demonstrate the robustness of the proposed algorithm for both classical and benchmarking functions of the IEEE CEC 2014.Furthermore,the accuracy and efficacy of DMOA were demonstrated by means of the convergence rate,Wilcoxon testing,and ANOVA.Moreover,fairness using Jain’s index in queue delay optimization in terms of throughput and latency,along with computational complexity,is also evaluated and compared with other algorithms.Simulation results show that DMOA exceeds other bio-inspired optimization algorithms in terms of fairness in queue delay management and average packet loss.The proposed algorithm is also evaluated for the con
Sanjay BhardwajDa-Hye KimDong-Seong Kim
关键词:DRAGONFLYDAMSELFLYINTERACTIONOPTIMIZATION
Behavioural observation on Platycnemis latipes revealing novel function of males'patrol
2023年
Males of Platycnemis latipes (Platycnemididae, Odonata) have enlarged tibiae (fans) and patrol using a special longitudinal zig-zag flight. By means of focal observations and experimental manipulations of the colour of abdomen and fans of mature males, we suggest that the zig-zag flight is used to avoid unnecessary harassment from other males and has not the function to attract females. The fans of P. latipes are mainly used as a tool to threaten rivals, but their effectiveness seems limited. Both abdomen and fans of a mature male can reflect UV light strongly.
Xin YuAdolfo Cordero-Rivera
关键词:DAMSELFLY