Seed dispersal by hornets:An unusual insect-plant mutualism

Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four populations of Stemona tuberosa from 2011–2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in "long-distance" seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites.Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure "long-distance" seed dispersal in other myrmecochorous plants.

疆域智能发布千元无人机SpiderX和HornetS

12月10日下午,疆域智能新品无人机暨中兴微品智能007发布会在北京W酒店举行,吸引了近两百家媒体的到来,疆域智能CEO陈思达为我们带来两款无人机——Spider X和Hornet S。

IP over WDM城域环网的公平调度接入算法研究

提出了一种公平调度接入算法,适用于由斯坦福大学开发的IPoverWDM城域环网HORNET。该算法充分利用了HORNET提供节点对于信道可用信息的预知能力。仿真显示在不同的网络负载下该算法都能提供较好的公平性和较高的吞吐率。

Chasing the queens of the alien predator of honeybees: A water drop in the invasiveness ocean

The Yellow-legged hornet, Vespa velutina , was accidentally introduced in France in 2004, and then spread rapidly through the French territory but also to adjacent European countries (Spain, Portugal, and Belgium). During summer and autumn, V. velutina workers hunt domestic honeybees, Apis mellifera, for feeding their larvae. The impact of this alien species is mainly economic, beekeepers experiencing heavy colony losses, but also ecological, V. velutina hunting other pollinators. In their year-round life cycle, nest initiation by single queen during spring is the critical stage. In invaded areas, spring queen trapping using food baits has been promoted by apicultural unions in order to limit V. velutina population expansion. The goals of this work were 1) to evaluate the yield of this method, 2) to identify appropriate sites for trapping, 3) to identify potential optimal climatic windows of capture, and 4) to quantify the impact on local entomofauna. Our results showed that water proximity enhances trapping but not beehives proximity, and that trapping is inefficient if average week temperatures are below 10°C. Although the trapping effect on biodiversity should be studied more carefully, spring queen trapping is highly questionable unless specific attractants could be proposed.

基于改进YOLOv7的夜间行人检测算法

针对夜间行人检测任务中存在的检测速度慢、漏检率高、黑夜场景下识别效果差等问题,提出一种改进YOLOv7的夜间行人检测算法。改进算法中,使用YOLOv7-tiny网络作为baseline,以满足准确率的同时兼具较高的检测速度,在网络head部分,使用CSP HorNet模块实现关键特征之间的高阶交互,并引入SimAM注意力机制,在不增加模型复杂度的情况下,使网络聚焦更多重要的特征信息。实验结果表明,改进算法在测试集上准确率(Precision,P)达到91.7%,召回率(Recall,R)达到81.4%,均值平均精度(mean Average Precision,mAP)提升2.9个百分点。改进算法在真实场景检测任务中,有效降低了漏检率及错检率,表现出良好的性能。

Micromorphology and Maturation of the Yellow Granules in the Hornet Gastral Cuticle

The yellow granules in the gastral cuticle of the Oriental hornet Vespa oriental＆ （Hymenoptera, Vespinae） are located in yellow stripes. In the present study, we focus on the micromorphology and formation of the yellow granules from their inception to their spread in the regions which are destined to acquire a yellow color, The cuticle was observed with several methods of electron microscopy. The results showed that the yellow granules comprise a layer which is 20-25 μm thick, within the total cuticular thickness of 40-45 μm. In the mentioned regions one can see, from above, many apertures of about 0.5μm in diameter which extends into a peripheral photoreceptor cell. In each yellow granule, one discerns a myoid envelope inside which there are 9 fibrils arranged in a circle. Yellow granules maturation process involves infiltration of canals that give rise to the incipient ball-shaped primary granules which increase in number （as a result of continues budding off the walls of a canal） as the cuticle matures and transform into secondary barrel shaped granules, becoming elongated and then splitting into shorter barrels that fill up the entire area. Preliminary examinations have suggested liver-like function activity within the layer of yellow granules.

All optical wavelength converter and its application in optical network

All optical network （AON） is a hot topic in recent studies of optical fiber communications. Key techniques in AON include optical switching/routing, optical cross connection （OXC）, all optical wavelength conversion （AOWC）, all optical buffering, etc. Opti- cal switching/routing is in fact wavelength switching/ routing. OXC and wavelength conversion （WC） are introduced into cross nodes so that a virtual wavelength path is established. With WC, communication route is formed only if there is unused wavelength in an individual segment link. The rate wavelength usage is thus greatly increased. The blocking rate of network can be reduced by adding WCs, especially for huge capacity multiple nodes ones. Therefore, WC has attracted much attention in basic research of optical communication and is used in some experimental networks.This dissertation studies all optic wavelength conversion and its application, with the contributions in the following five aspects.

Vespa velutina nest distribution at a local scale： An 8-year survey of the invasive honeybee predator

Vespa velutina is an invasive species that was observed for the first time in France and Europe in 2004, which rapidly threatened domestic honeybees with active predation. For the first time in this study, we analyzed the distribution of V. velutina nests at a local scale to understand the pattern of nesting, and in 8 years of monitoring, a total of 528 nests were surveyed. With the exception of 2 years, the nests of V. velutina were randomly distributed within the monitored area, which suggested that intraspecific competition for nesting sites and/or food was unlikely. When the data for all years were combined, an aggregated distribution of nests at the seafront in the vicinity of the oyster farm and sportfishing activities was observed. This distribution suggested that seafood, attractive to vespids, might provide a valuable alternative food source that favored colony development. We also tested the effect of spring queen trapping of V. velutina on the distribution of nests in 2014, which was the year with the greatest number of colonies within the area; the position of the traps did not influence the distribution of the nests. For the first time, this study showed that （i） intraspecific competition was unlikely to be a mechanism for population regulation, （ii） some areas were more likely favored for hornet nests, and （iii） spring queen wasp trapping was inefficient as a method to limit the distribution of the V. velutina population.

Spatial distribution of Vespa velutina individuals hunting at domestic honeybee hives： heterogeneity at a local scale

Since its recent introduction into Europe, the yellow-legged hornet, Vespa velutina, has become a major predator of the domestic honeybee, Apis mellifera, but little is known about its hunting behavior. We studied V. velutina hunting behavior by a capture- mark-recapture procedure in an experimental apiary. A total of 360 hornets were captured and tagged, and we determined： （i） the number of hornets visiting the apiary and the changes in time, （ii） the average number of individual visits per half-day and the time elapsed between consecutive recaptures, and （iii） the individual and global distribution of the hornets in the apiary. More than 50% of the marked hornets were recaptured at least once, this increased to 74% in considering the first marked individuals. We estimated 350 hornets visiting the patch daily with at least 1 visit per half-day. The number of marked hornets decreased over time while the number of unmarked ones increased, suggesting a turnover of individuals. The reduction of the delay between consecutive visits indicates that hornets became more efficient over time. Most of the hornets （88%） were recaptured in front of different hives but, overall, the global distribution was aggregative. Hornets were mainly recaptured in front of 1 hive which was neither the smallest nor the biggest colony, suggesting that the major cue used by hornets is not the amount of food. We hypothesize that the defensive behavior of the honeybee colony could explain our results which may be promising to further studies.

Delayed sexual maturity in males of Vespa velutina

Vespa velutina var nigrithorax （Lepelletier, 1835） is an invasive predator of bees accidentally introduced in France in 2004, and it is having a serious impact on apiculture and ecosystems. Studying the reproduction of an invasive species is key to assess its population dynamic. This study explores the sexual maturation of IT. velutina males and the evolution of their fertility. The main studied parameters were physiologic （spermiogenesis, spermatogenesis） and anatomic （testes size and structure, head width）. Two populations of males were described based on their emergence period： early males in early summer or classic males in autumn. Each testis has an average of 108 testicular follicles. Spermatogenesis is synchronous, with only 1 sperm production wave, and completed, on average, at 10.3 d after emergence with the degeneration of the testes. The sperm counts in seminal vesicles of mature males are 3 x 106 in October/November and 0.8 ~ 106 in June. In com- parison, females store 0.1 x 106 sperm in their spermathecae. The early males emerged from colonies made by fertilized queens. The reproductive potential of these early males seemed limited, and their fimction in the colony is discussed. The sperm stock evolution in autumn males suggests the occurrence of a reproductive pattern of male competition for the access to females and a single copulation per male. The synchronicity of male and foundress emergences and sexual maturation is of primary importance for the mating success and the future colony development.

Viability of thermal imaging in detecting nests of the invasive hornet Vespa velutina

Vespa velutina is an invasive hornet species that is colonising Europe,generating considerable impacts on honeybees,beekeeping and biodiversity.Control and early warning strategies for this species are mainly based on monitoring plans and procedures of nest detection and destruction.Technological tools(harmonic radar,radio-telemetry)have been developed to increase the probabilities of nest detection in new outbreaks.Since hornets are able to regulate nest temperature,thermography may represent an additional technique that may be used,both alone or in support to other techniques.In this study,the viability of thermal imaging in detecting nests of V.velutina was evaluated in controlled conditions.The influence of different environmental and operative variables(time of the day,presence/absence of leaves covering the nest,distance between the nest and the operator)were tested on three nests detected during August 2018 in Italy.All the nests were detectable by thermal imaging,but environmental and operative variables affect their detectability.The temperature difference between the nests and the surrounding reaches its maximum before sunrise and without a tree canopy covering the nests.Although nests were visible in some cases from 30 m,the detectability was higher at shorter distances,even if this variable may also depend on infrared camera resolution.An increase in the environmental temperature also generates a decrease of nest detectability.Although some limitations could occur,these results show the applicability of thermography in detecting V velutina nests before the beginning of the reproductive phase,and consequently its potentiality in control strategies.

An Improved MAC Scheme of HORNET Based on Node Structure with Variable Optical Buffer

An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.

巴西陶鲁斯公司Raging Hornet转轮手枪

正这是一款大型民用运动转轮手枪,"Raging Hornet"意为愤怒的大黄蜂,隐喻其具有很强的攻击性。黑色握把后方安装了一个非常显眼的黄色握把后垫板,与大黄蜂这一昆虫的颜色相似,为其名称的来历增添了几分关联和遐想。该枪枪管长达254mm,甚至与短突击步枪的枪管长相当,全枪长419mm,与折叠后的冲锋枪长度相当,全枪质量1.418kg,是普通手枪质量的2倍,这样的体型在转轮手枪中当属绝对的"大块头"。该枪转轮弹膛量为8发,发射0.22英寸大黄蜂运运枪弹,枪身顶部可加装皮卡汀尼导轨,用于安装瞄准镜。