Anti-attachment Function and Biomimetic Application of Slippery Zone in Nepenthes Pitcher

Carnivorous plants of Nepenthes species have evolved particular organs named pitchers at the tips of their conspicuous leaves, allowing slippery trapping and effective digesting prey to acquire sufficient growing nutrients. Nepenthes pitchers are generally distinguished by several morphological regions exhibiting distinct functions in prey capturing, and combined effect of the several zones results in great trapping efficiency. Depending on specific micro-structures, slippery zone performs an important role in efficiently preying arthropods, and this prey ability inspires an idea for biomimetic development of slippery trapping plate used in controlling agricultural pests. In this paper, combined with our latest results, the authors introduced the recent studies of the slippery zone, including surface structures and anti-attachment functions. They also highlighted the biomimetic application of slippery zone in developing slippery trapping plate for controlling agricultural pest.

Investigation of the Anisotropic Morphology-Induced Effects of the Slippery Zone in Pitchers of Nepenthes alata

Plant of carnivorous genus Nepenthes alata has evolved specific pitchers to prey insects for survival in the barren habitat, especially its slippery zone. The excellent slippery function has received considerable interest because of its potential applica- tion in antifriction surface design. The surface morphologies of intact and de-waxed slippery zones were characterized using scanning electron microscope and scanning white-light interferometer. Hierarchical structures with anisotropic micro- lunate structure and nano- wax crystals were found on the slippery zone. Due to the hierarchical structures, the slippery zone is hy- drophobic. It shows a significant anisotropic wettability with static contact angles 153.3° and 140.1° in the directions perpen- dicular and parallel to the upward direction （toward the peristome）, respectively. The sliding angles are -3° and -10° in the downward and upward directions, respectively. Crawling experiments indicate that the microscopic surface roughness and the brittleness of the wax crystals may reduce insect attachment in different modes according to the insect mass differences. Moreover, artificial slippery surfaces inspired by the slippery zone of Nepenthes alata were fabricated. Traction experiments quantitatively verified that the friction force of replicated lunate structures with Ra-2.54 μm surface roughness was reduced by about 25% as compared to flat surface with Ra-0.56 μm surface roughness for cricket claws.

Slippery Surface of Nepenthes alata Pitcher： The Role of Lunate Cell and Wax Crystal in Restricting Attachment Ability of Ant Camponotus japonicus Mayr

This study attempts to investigate how the slippery surface of Nepenthes alata pitchers restricts the attachment ability of ant Camponotus japonicus Mayr, via climbing behavior observation and friction force measurement. Ants exhibited ineffective climbing behaviors and rather small friction forces when attached to upward-oriented slippery surfaces, but opposite phenomena were shown when on inverted surfaces. Friction forces of intact, claw tip-removed and pad-destroyed ants were measured on intact and de-waxed slippery surfaces, exploring the roles of wax crystals and lunate cells in restricting ant＇s attachment. On downward-directed slippery surfaces, greater forces were exhibited by intact and pad-destroyed ants; on the two slippery sur- faces, pad-destroyed ants presented slightly smaller forces and clawless ants generated considerably smaller forces. Somewhat different force was provided by clawless ants on upward and downward oriented slippery surfaces, and slightly higher force was shown when ants climbed on wax-removed surface. Results indicate that the lunate cells contribute greatly to decrease the friction force, whereas the wax crystals perform a supplementary role. Mechanical analysis suggests that the directionally growing lunate cells possess a sloped structure that effectively prevents the claw＇s mechanical interlock, reducing the ant＇s attachment ability considerably. Our conclusion supports a further interpretation of slippery surface＇s anti-attachment mecha- nism, also provides theoretical reference to develop biomimetic slippery plate to trap agricultural insect.

恶意软件捕获系统在实验教学中的应用

网络安全是高校计算机网络和信息安全相关专业的重要课程之一，为了满足课程实验教学需要，使学生更好的理解网络安全中恶意软件的工作机理，提高恶意软件防范能力，设计了一个恶意软件捕获与分析教学实验系统，系统基于VMware workstation虚拟平台和低交互蜜罐工具，实现了实验环境中恶意软件的自动捕获和分析，实际应用中有效提高了学生实践能力及对知识的理解。

食肉植物见闻

在那岩石歌唱,蚂蚁游泳的地方,动物被植物所食。听上去像丛林的咏叹,事实上这正是埃里克·汉森丛林之旅的真实经历。

PITCHER PLANTS RECORDED FROM BRIS FOREST IN JAMBU BONGKOK,KUALA TRENGGANU,MALAYSIA

A dichotomous key and descriptions of the species of pitcher plants recorded from bris forest at Jambu Bongkok is given.Three species of pitcher plants were recognized from the study area.They are Nepenthes rafflesiana,Nepenthes gracilis and Nepenthes mirabilis.These species can easily be identified by their morphological differences.Nepenthes gracilis differed from the other two species in having triangular stem,sessile leaves,winged leaf base,under lid surface of the pitcher sparsely covered with honey glands,inner pitcher cavity wall covered exposed digestive glands and very narrow peristome with the thickness of≤1 cm.On the other hand,Nepenthes rafflesiana and Nepenthes mirabilis have cylindrical stem,stalked leaves,semi-amplexicaul leaf base,under lid surface densely covered with honey glands,inner pitcher cavity wall covered with overarched digestive glands and broad peristome with a thickness of≥1 cm.Nepenthes rafflesiana can be differentiated from Nepenthes mirabilis by its infundibulate upper pitcher,ellipsoidal lower pitcher,inner pitcher wall cavity wholly covered with digestive glands whereas Nepenthes mirabilis have tublose-ventricose upper and lower pitchers,inner pitcher cavity wall of both pitchers partly covered with digestive glands.

Bioinspired Unidirectional Liquid Transport Micro-nano Structures:A Review

Unidirectional liquid transport without any need of external energy has drawn worldwide attention for its potential applications in various fields such as microfluidics,biomedicine and mechanical engineering.In nature,numerous creatures have evolved such extraordinary unidirectional liquid transport ability such as spider sik,Sarracenia's trichomes,and Nepenthes alata's peristome,etc.This review summarizes the current progresses of natural unidirectional liquid transport on 1-Dimensional(1D)linear structure and 2-Dimensional(2D)surface stucture.The driving force of unidirectional liquid transport which is determined by unique structure exist distinct differences in physics.The fundamental understanding of 1D and 2D unidirectionaliquid transport especially about hierarchical structural characteristics and their transport mechanism were concentrated,and various bioinspired fabrication methods are also introduced.The applications of bioinspired directional liquid transport are demonstrated especially in fields of microfluidies,biomedical devices and anti-icing surfaces.With newly developed smart materials,various liquid transport regulation strategies are also summarized for the control of transport speed,direction guiding,etc.Finally,we provide new insights and future perspectives of the directional transport materials.