一种基于后缀排序快速实现Burrows-Wheeler变换的方法

近年来,Bzip2压缩算法凭借其在压缩率方面的优势,得到了越来越多的应用,Bzip2的核心算法是Burrows-Wheeler变换(BWT),BWT能有效的将数据中相同的字符聚集到一起,为进一步压缩创造条件。在硬件实现BWT时,常用的基于后缀排序的算法能有效克服BWT消耗存储资源大的问题,该文对基于后缀排序实现BWT的方法进行了详细分析,并且在此基础上提出了一种快速实现BWT的方法后缀段算法。仿真结果表明后缀段算法在处理速度上比传统的基于后缀排序的算法有很大的提高。

A Review of the Engineering Role of Burrowing Animals: Implication of Chinese Pangolin as an Ecosystem Engineer

Ecosystem engineers are organisms that alter the distribution of resources in the environment by creating,modifying,maintaining and/or destroying the habitat.They can affect the structure and function of the whole ecosystem furthermore.Burrowing engineers are an important group in ecosystem engineers as they play a critical role in soil translocation and habitat creation in various types of environment.However,few researchers have systematically summarized and analyzed the studies of burrowing engineers.We reviewing the existing ecological studies of burrowing engineer about their interaction with habitat through five directions:(1)soil turnover;(2)changing soil physicochemical properties;(3)changing plant community structure;(4)providing limited resources for commensal animals;and/or(5)affecting animal communities.The Chinese pangolin(Manis pentadactyla)is a typical example of burrowing mammals,in part(5),we focus on the interspecific relationships among burrow commensal species of Chinese pangolin.The engineering effects vary with environmental gradient,literature indicates that burrowing engineer play a stronger role in habitat transformation in the tropical and subtropical areas.The most common experiment method is comparative measurements(include different spatial and temporal scale),manipulative experiment is relatively few.We found that most of the engineering effects had positive feedback to the local ecosystem,increased plant abundance and resilience,increased biodiversity and consequently improved ecosystem functioning.With the global background of dramatic climate change and biodiversity loss in recent decades,we recommend future studies should improving knowledge of long-term engineering effects on population scale and landscape scale,exploring ecological cascades through trophic and engineering pathways,to better understand the attribute of the burrowing behavior of engineers to restore ecosystems and habitat creation.The review is presented as an aid to systematically expound the engineering effect of burrowing animals in the ecosystem,and provided new ideas and advice for planning and implementing conservation management.

Burrow Characteristics and Microhabitat Use of the Turpan Wonder Gecko Teratoscincus roborowskii (Squamata, Gekkonidae)

Burrow structural charactersitcs and microhabitat use of the Turpan wonder gecko Teratoscincus roborowskii （Gekkonidae） were studied between April and September of 2013 in the Turpan Eremophytes Botanic Garden, in the Turpan Depression of Western China. Burrow depth, entrance orientation, entrance height and width were observed. We assessed microhabitat selection and noted differences in microhabitat use among males, females, and juveniles. The magnitude of selection was measured using Jacobs＇ index of selectivity. Entrance height and width of the burrows of adults were significantly larger than those of juveniles, but the difference in burrow depth was not significant. The directional orientation of the burrow entrance showed a preference for the north-northeast and south-southeast, which were likely influenced by local prevailing winds and sunlight. Both the adult and juvenile geckos prefer to construct their burrows in sandy soil within a layer of loose soil whose thickness is greater than 30 cm. A majority of the burrows were located within 20 m of the nearest plant. Nearly half （48%） of the entrances of juveniles were located within 5 m of the nearest vegetation, significantly different from those of the adults. Results showed that the Turpan wonder gecko did not utilize microhabitats according to their availability, but rather that it preferred rnicrohabitats which contained dead wood or the caper bush. Our results suggested that burrow characteristics and microhabitat selection were important factors in T. roborowskii adaptation to harsh and arid desert habitats.

Large Tetrapod Burrows from the Permian Naobaogou Formation of the Daqingshan Area, Nei Mongol, China

Two new tetrapod burrow casts from the Naobaogou Formation （Middle or Late Permian） of Nei Mongol,China are described.It marks the first pre-Cenozoic tetrapod burrow from China,and one of the earliest records of tetrapod burrows.Comparison to other Permian and Triassic burrows suggests that these burrows were created by tetrapod slightly smaller than Lystrosaurus.Deduced from the morphology and sizes of two burrows and known tetrapods of the Naobaogou Formation,the burrow should be the production of a therapsid,most likely a dicynodon.These burrows indicate a seasonal climate and this area was semiarid or arid during that time.

Effect of mangrove restoration on crab burrow density in Luoyangjiang Estuary,China

Background： Mangrove restoration seeks to restore or rebuild degraded mangrove systems. The methods of mangrove restoration include ecological projects and restoration-oriented technologies, the latter of which are designed to restore the structure, processes as well as related physical, chemical and biological characteristics of wetlands and to ensure the provision of ecosystem services. As important components of mangrove ecosystem, benthic organisms and crabs play a key role in nutrient cycling. In addition, mangrove restoration, such as vegetation restoration measures, can lead to changes in the benthic faunal communities. This study investigates whether the presence of different mangrove species, age and canopy cover of mangrove communities affect the density of crab burrows. Methods： The Luoyangjiang Estuary, in the southeast of Fujian Province, was selected as our research area. A survey, covering 14 sites, was conducted to investigate the impacts of mangrove restoration on the density of crab burrows in four rehabilitated forests with different stand ages and canopy. Results： It was found that differences in vegetation types had a large impact on crab density and that the density of crab burrows was lower on exposed beaches （non-mangrove） than under mature Kondelio condel, Aegiceros corniculatum and Avicennio morina communities. In general, the amount of leaf litter and debris on mangrove mudfiats was greater than on the beaches as food sources for crabs. Two-factor analysis of variance （ANOVA） shows that changes in mangrove species and age since restoration had different effects on crab burrow density. The effect of canopy cover was highly significant on crab burrow density. Conclusions： The results suggest that in the process of mangrove restoration the combined effects of mangrove stand age, canopy cover and other factors should be taken into account. This study further supports the findings of the future scientific research and practice on mangrove restoration and management measures.

基于扩展Burrows-Wheeler算法重构禽流感病毒的进化树

基于核苷酸的物理化学性质,利用扩展Burrows-Wheeler算法和Burrows-Wheeler相似性分布,对80种H5NI病毒的DNA序列的HA片段进行相似性比较,同时构建序列进化树,得到较好的结果.通过分析禽流感病毒之间的相似度关系,可为研究禽流感区域蔓延的特点提供一定的理论依据.

The hypoxia adaptation of small mammals to plateau and underground burrow conditions

Oxygen is one of the important substances for the survival of most life systems on the earth,and plateau and underground burrow systems are two typical hypoxic environments.Small mammals living in hypoxic environments have evolved different adaptation strategies,which include increased oxygen delivery,metabolic regulation of physiological responses and other physiological responses that change tissue oxygen utilization.Multiomics predictions have also shown that these animals have evolved different adaptations to extreme environments.In particular,vascular endothelial growth factor(VEGF)and erythropoietin(EPO),which have specific functions in the control of O_(2) delivery,have evolved adaptively in small mammals in hypoxic environments.Naked mole-rats and blind mole-rats are typical hypoxic model animals as they have some resistance to cancer.This review primarily summarizes the main living environment of hypoxia tolerant small mammals,as well as the changes of phenotype,physiochemical characteristics and gene expression mode of their long-term living in hypoxia environment.

The effect of substrate grain size on burrowing ability and distribution characteristics of Perinereis aibuhitensis

Perinereis aibuhitensis(Grube, 1878) lives in marine sediments of estuary or shoal areas, where substrate has some crucial environmental factors affecting its burrowing and distribution. In order to provide basic data for the habitat selection and suitability evaluations of the artificial aquaculture of P. aibuhitensis, this paper conducted a quantified analysis of its burrowing ability and explored its behavioral preferences in different substrates,including mud(<75 μm), fine sand(125–250 μm), medium sand(250–500 μm), coarse sand(500–2 000 μm), gravel(2 000–4 000 μm) and ceramsite(4 000–8 000 μm). The research results revealed that substrate grain size significantly affected the burrowing time, burrowing rate, burrowing depth and distribution rate(P<0.01).Moreover, P. aibuhitensis demonstrated preferential selections relating to substrate grain sizes, had higher burrowing ability in ceramsite, mud and fine sand compared with other substrates. The strongest burrowing ability and the highest distribution rate were observed in ceramsite. The study indicated that P. aibuhitensis was sensitive to substrate grain size, which also had an impact on its burrowing process and population distribution.In the natural sea, substrates mainly composed of mud and fine sand are fit for aquaculture and stock enhancement. Based on behavioral preferences and ecological rehabilitation function of P. aibuhitensis, this paper proposes a symbiotic system of marine animals and halophytes, and constructs an ecosystem model of"Marine fish-Halophytes-Perinereis aibuhitensis" with P. aibuhitensis as the link.

The Habitats, Burrowing Behavior, Physiology Adaptation and Life Cycle of Spadefoot Toads (<i>Pelobates syriacus, Boettge</i>r, 1869) at the Southern Limit of Its Distribution in Israel

The present study describes the habitats, life cycle, larvae growth, burrowing behavior and terrestrial adaptation of Spadefoot toads in Israel based on observations and data collected during more than 30 years in northern Israel. The distribution area in Israel is from the north in the Upper Galilee and Golan Heights (annual rainfall range of 500 - 1000 mm) to the southern coastal plain (annual rainfall of about 250 mm). Among the 51 different breeding places of amphibians, only ponds where water was available for a few months were used by Spadefoot toads and metamorphosed populations were found around these ponds. The larvae underwent metamorphosis during the summer and autumn in northern Israel, and during the spring in central and southern Israel. A negative correlation exists between the percentage of toads burrowing and soil moisture levels, with greater burrowing behavior occurring under dry conditions. The plasma concentration increased during burrowing by electrolytes and urea accumulations. The burrowing behavior helped Spadefoot toads survive in this area at the southern border of its distribution.

Impact of Human Disturbance on Fiddler Crab (<i>Uca tangeri</i>) Burrow Morphology, Distribution and Chemistry at Eagle Island, Niger Delta, Nigeria

Fiddler crabs are described as ecosystem engineers because of their burrow constructing ability. It was hypothesized that human activity will impact crab burrows. The study area was delineated into lowly, medium and highly impacted plots. Crab holes were randomly counted and their width, length and surface area estimated. Burrow soils were collected and analyzed for Cadmium (Cd), Lead (Pb) and Zinc (Zn) using spectrophotometric method (HACH DR 890 colorimeter). The result indicates that burrow width was significantly different between impacted plots (P < 0.05). Lowly impacted plot had the largest width while highly impacted plot had the smallest width. In contrast, there was no significant difference in burrow length (P > 0.05), but highly impacted plot has the longest length while lowly impacted plot has the shortest length. Again, the surface area of crab burrow varies significantly (P < 0.05), and lowly impacted plot had the largest area (507.95 ± 61.84 cm2) followed by medium (390.30 ± 57.65 cm2) and high (265.16 ± 30.85 cm2) impacted plots. Similarly, lowly impacted area has more number of burrows (n = 55) followed by medium (n = 30) and highly (n = 23) impacted plots. Highly impacted plot had the highest Cd and Pb concentration whereas lowly impacted plot had the highest Zn concentration. This implies that burrow morphology and chemistry exemplify the level of anthropogenic impact.

Alpine grassland degradation intensifies the burrowing behavior of small mammals:evidence for a negative feedback loop

Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation process and these mammals are subject to lethal control.However,whether the negative impact of small mammals is solely a result of population size or also a result of activity and behavior has not been tested.In this study,we use plateau pika as a model to compare population size,core area of colony,and the number of burrow entrances and latrines between lightly and severely degraded grassland.We test whether the alleged contribution of pika to grassland degradation is a result of increased population size or increased burrowing activities of individuals in response to lower food abundance.We found that grassland degradation resulted in lower plant species richness,plant height,and biomass.Furthermore,the overall population size of pika was not significantly affected by location in lightly and severely degraded grassland.However,pika core areas in severely grassland degradation were significantly larger and had significantly higher densities of burrows and latrines.Our study provides convincing evidence that habitat-induced changes in the behavior of small,burrowing mammals,such as pika,can exacerbate grassland degradation.This finding has significant implications for managing small mammals and restoring degraded grassland ecosystems.

不同干扰强度高原鼠兔对高寒草甸土壤温室气体通量变化的影响

高原鼠兔通过取食植物、排泄粪尿及掘土等行为对土壤理化性质及土壤微生物产生广泛干扰,进而可能会影响高寒草甸土壤温室气体排放。本研究选择高密度组(H)、低密度组(L)、对照组(CK)3种鼠兔干扰强度的高寒草甸为研究对象,揭示温室气体排放速率对不同高原鼠兔干扰强度的响应规律及主要调控因素。结果表明,H组高寒草甸土壤CO_(2)排放速率为596.66 mg·(m^(2)·h)^(-1),显著低于CK组的695.45 mg·(m^(2)·h)^(-1)(P<0.05)。高原鼠兔干扰强度、地上生物量、土壤pH和土壤含水量是影响CO_(2)排放速率的主要调控因素。H组高寒草甸CH_(4)吸收速率为-43.46mg·(m^(2)·h)^(-1),显著低于L组的4.92mg·(m^(2)·h)^(-1)(P<0.05),H和L组高寒草甸N_(2)O排放速率分别为8.03、-2.39μg·(m^(2)·h)^(-1),均显著高于CK组的-16.69μg·(m^(2)·h)^(-1)(P<0.05)。土壤硝态氮和铵态氮含量、pH和含水量是影响CH_(4)吸收和N_(2)O排放的重要因素。因此,高原鼠兔干扰强度是影响温室气体排放速率的因素之一,进一步研究高原鼠兔对高寒草甸土壤温室气体排放速率的影响具有重要意义。

Burrow morphology of Uca uruguayensis and Uca leptodactylus(Decapoda:Ocypodidae)from a subtropical mangrove forest in the western Atlantic

The continuous excavation of burrows by fiddler crabs generates bioturbation in the sediment,which can be estimated from burrow morphology.The aim of the present study was to describe the burrow morphology of Uca uruguayensis and U.leptodactylus and its relationship with demography of resident individuals and to estimate the level of bioturbation in the sediment generated by each species.For all individuals from each of the 2 species,sex was determined and the carapace width(CW;mm)measured.Burrows were characterized according to burrow diameter(BD;mm),maximum burrow depth(MBD;mm)and burrow volume(BV;cm^(3)).The density of each species in the study area was also evaluated.In both species,the males were larger and occupied burrows with higher BV compared to females.Differences between sexes in relation to the burrow characteristics might reflect sexual dimorphism within the group and are probably related to the fact that males use the burrows for mating.BD and BV showed significant positive relationships with the size of resident crabs.The amount of sediment removed per burrow was estimated from mean BV:10.78 cm^(3)of sediment/burrow for U.uruguayensis and 12.38 cm^(3)of sediment/burrow for U.leptodactylus.Despite the density and depth differences between the 2 species,the similarity in burrow volume suggests that U.uruguayensis and U.leptodactylus present the same importance in terms of the bioturbation process.Burrow morphology is highly associated with characteristics of the occupant,although extrinsic factors should also be considered,and its description can provide estimates on the bioturbation generated by Uca species in mangrove forests.

不同缢蛏群体应对高盐养殖环境的潜沙和摄食响应能力

为研究缢蛏(Sinonovacula constricta)生态行为应对高盐养殖环境的响应能力,以2个缢蛏群体(“申浙一号”群体SZSC和自然群体ZRSC)为实验对象,研究了不同盐度(20、24、28和32)对缢蛏群体潜沙行为、摄食生理的影响。对比2个群体潜沙指标和摄食率(FR)的差异,其中,潜沙行为实验设置盐度应激组(缢蛏从暂养池取出放进各盐度组开始实验)和胁迫组(缢蛏在各盐度条件下胁迫24 h后开始实验)。结果显示,SZSC的120 h半致死盐度为34.04,ZRSC的120 h半致死盐度为32.04。应激组中,SZSC的半数潜沙时间(BT50)显著大于ZRSC(P<0.05),盐度为24时,SZSC的BT50为4.2 min,显著低于盐度为28和32时的BT50;盐度为32时,SZSC潜沙深度分布更集中,潜沙率为88.33%,显著高于ZRSC(P<0.05)。而在胁迫组,SZSC中BT50显著低于ZRSC,潜沙率显著大于ZRSC(P<0.05)。摄食生理上,除对照组外,SZSC的FR均显著大于ZRSC(P<0.05),SZSC的FR在盐度为24时达到最大值[89.54 mL/(g·h)],显著大于其他盐度组(P<0.05)。研究表明,2个群体的生态行为均会受到盐度的影响,盐度越高,应激反应越强烈,其中,SZSC对高盐环境具有较好的耐受性。本研究从生态行为水平评估了2个缢蛏群体对高盐环境的耐受性,揭示了高盐养殖环境下缢蛏在底泥中的垂直分布情况和摄食能力,研究结果为进一步开展缢蛏耐高盐新品系的选育提供了理论参考。

Calcite Cements in Burrows and Their Influence on Reservoir Property of the Donghe Sandstone, Tarim Basin, China

Abundant burrows of Skolithos linearis, Palaeophycus tubularis, and Taenidium barretti are preserved in the Upper Devonian Donghe sandstone of Tarim basin, China. They are commonly highlighted in core by the color of the burrow fill in contrast to the surrounding matrix and have dif-ferent textures and fabrics from the matrix. There are three kinds of calcite cements in burrows, microcrystalline-crystalline calcite cement, mosaic calcite cement, and ferroan calcite cement. Microcrystalline-crystalline calcite cement is widely distributed in the lower part of the Donghe sand-stone, but it is rare in burrows filling. It displays a globule structure under burial cementation and sel-dom replaces the quartz grains in shallow burial depth stage. Mosaiccalcite cement is widespread in the Donghe sansdtone reservoir of North Tarim basin. It shows chrysoidine, orange and bright orange lu-minescence, and intensely replaces the quartz grains, forming in early diagenetic and shallow burial depth stage. Ferroan calcite is asymmetrically distributed in the Donghe sandstone reservoir of Central Tarim basin. It fills the remanent pores in the shape of mosaic and replaces the quartz grains, matrix, and early calcite cement, forming in late diagenetic and deep burial depth stage. The burrows filled with white calcite cements have low oil saturation or may be oil-stained. In contrast, there is high oil saturation in the sandstone reservoir where the bioturbation is sparse or not present. With increased bioturbation, the porosity, permeability, and oil saturation decrease; thus, bioturbation intensity and reservoir property appear to be negatively correlated.

舀种勺舌式胡麻精量穴播器设计与试验

针对胡麻播种机用种量大、播量变异系数大、播种不均匀的问题,基于胡麻种子物理特性和种植农艺要求,设计一种舀种勺舌式胡麻精量穴播器。通过分析穴播器工作原理确定穴播器组成、舀种勺结构参数范围及安装数量;对舀种勺舀种过程和清种过程进行力学分析,确定穴播器角速度范围;通过EDEM仿真过程得知,花纹内壁聚种斜槽在不影响舀种勺填充效果的同时,不仅可以提高仿真效率,还可以增大种子流动性,便于舀种勺充种。以穴播器角速度、舀种勺顶端过渡圆角半径、种室隔离板高度为试验因素,穴播器排种合格率、漏播率和重播率为试验指标,利用EDEM离散元仿真软件开展二次旋转正交组合试验,得到最优参数组合为:穴播器角速度2.9 rad/s、舀种勺顶端过渡圆角半径2.5 mm、种室隔离板高6.8 mm;将该舀种勺3D打印制作进行排种性能试验验证,台架试验得到该舀种勺排种合格率、漏播率和重播率平均值分别为87.00%、6.33%、6.67%;田间试验得到该舀种勺排种合格率为88.33%,漏播率为6.67%,重播率为5.00%;胡麻平均种植密度为50株/m^(2),其台架试验与田间试验结果基本一致,性能满足胡麻精量播种农艺要求。

黄河三角洲盐沼湿地螃蟹洞穴形态结构对土壤水盐运移过程的影响

明晰潮汐驱动下螃蟹洞穴对盐沼湿地水盐运移过程的扰动效应,对基于生态过程的黄河三角洲盐沼湿地保护与修复具有重要的理论及现实意义。研究结合野外调查和室内水槽模拟实验,探究潮间带螃蟹洞穴形态与分布特征,分析了潮汐作用下不同螃蟹洞穴形态对水盐运移过程的影响。结果表明:(1)潮汐影响下,黄河三角洲潮间带螃蟹洞穴空间分布密度有差异,3条潮沟洞穴密度分别为(15.50±4.65)、(12.90±2.69)和(6.60±2.76)个·(0.25 m^(2))^(-1);(2)对螃蟹洞穴树脂模型进行简化归类,发现其主要形态结构为I型、L型、S型、X型、Y型,以上5种形态在获得的42个螃蟹洞穴中占比高达85.7%;(3)不同螃蟹洞穴形态在潮汐作用下土壤含水量变化趋势没有明显差异,而电导率随高潮与低潮呈现不同的升高与降低过程;(4)潮汐影响下,空白实验组潮汐水入渗量、孔隙水排泄量均显著低于有螃蟹洞穴的实验组,孔隙水排泄主要集中在水位下降时段,而L型洞穴因具有一定的储水能力,使更多的孔隙水在稳定时段排泄。(5)不同螃蟹洞穴形态对土壤盐排泄量有显著影响,S2、X和I组盐排泄量最高,空白组最低,仅为(0.403±0.003)g·d^(-1)。研究结果从水文学角度揭示了螃蟹洞穴的生态功能,将为后续的滨海湿地生态水文过程研究提供参考。

基于洞穴铸模对中华穿山甲洞穴结构特征的研究

中华穿山甲(Manis pentadactyla)夜行穴居,野外观测率极低,其洞穴是生态学研究的重要介质。然而,中华穿山甲洞穴结构特征量化研究极少,洞穴分类标准(居住洞、觅食洞)的验证未见报道。为探究中华穿山甲居住洞、觅食洞的形态结构差异,选取中华穿山甲遗弃的居住洞(4个)和觅食洞(3个)进行模型铸造,通过3D扫描技术构建三维数字模型。结果表明:7个洞穴洞口朝向皆为西,洞道直径普遍大于洞口直径,洞道首段长、洞穴全长、洞道角度(洞口向内第1个拐角)和洞穴体积均值分别为147.5 cm、322.7 cm、130.0°和0.0732 m^(3)。两种类型洞穴存在结构差异,居住洞的洞口朝向更偏北,其洞口、洞道直径、洞穴首段长、洞穴全长和洞穴体积均大于觅食洞;觅食洞的洞道拐角角度、白蚁巢穴数量大于居住洞。研究结果精准量化了中华穿山甲洞穴结构特征,验证了洞穴分类标准的准确性,为深入开展中华穿山甲洞穴生态学研究提供了参考。

不同海拔共栖物种对中华穿山甲洞穴利用的研究

自然界中许多穴居动物都会建造洞穴,这些洞穴会被其他穴居和非穴居动物广泛使用,不同海拔由于温度和降水等环境特征的变化,可能会影响动物对洞穴的利用模式。2018年12月—2022年2月,应用红外相机对广东省内3个地区的中华穿山甲Manis pentadactyla洞穴进行了监测。通过非加权组平均法将研究地区的海拔划分成低、中、高3组,运用相似性分析和线性模型探究共栖物种对中华穿山甲洞穴的利用模式及其与海拔的关系。结果表明:(1)不同海拔区间共栖物种的洞穴利用率存在显著差异(R=0.098,P=0.001),且与海拔显著正相关(t=2.093,P=0.038);(2)在共栖物种对洞穴的利用行为中,觅食(R=0.113,P=0.002)、探洞(R=0.116,P=0.036)、进出洞行为(R=0.077,P=0.042)占比与海拔均存在显著差异,觅食行为占比与海拔显著正相关(t=2.136,P=0.035),共栖物种在高海拔地区表现出更多的觅食行为。本研究阐明了不同海拔共栖物种对中华穿山甲洞穴的利用模式,明确了中华穿山甲洞穴在较高海拔地区对野生动物的重要性,建议加强对中华穿山甲野外种群的保护。

Motion Characteristics of the Appendages of Mole Crickets during Burrowing

Mole crickets,Gryllotalpa orientalis,have a pair of fully specialized forelegs for burrowing and employ an efficient underground excavating pattern,which provides excellent biological example for design of bionic underground excavation equipment.In this study,the excavating pattern and kinematic features of mole crickets were obtained by using high-speed motion capture system and employing a transparent hydrogel as the analogue for soil.The two-dimensional motion characteristics of the forelegs of mole crickets during burrowing were captured and analyzed.The results show that the forelegs of the mole cricket employ a unique excavating pattern,which consists of foreword digging and horizontal expansion.We label this pattern a digging-expanding mode.An excavating cycle includes the digging and expanding motion of the forelegs,rotation caused by the midlegs and hindlegs,and forward thrust by the hindlegs.The excavating motion of the left and right forelegs is alternately carried out.This study can inspire the design of bionic tunnelling mechanisms and underground excavation equipment.