辽东栎叶片昆虫取食形状多样性及其变化模式

取食辽东栎(Quercus liaotungensis)叶片的植食性昆虫有丰富的多样性和重要的生态功能,昆虫取食叶片留下的形状变化多,易观察,可以作为昆虫物种多样性监测的手段之一。研究北京西部东灵山地区辽东栎叶片被植食性昆虫取食状况,发现昆虫对辽东栎叶片的危害非常普遍,叶片被食频率约为90％,被食面积约5％,取食状可分为9类,其中以缘食和孔食为主,共记录20余种植性昆虫,其中蛾类幼虫和甲虫是主要取食种类,植食性昆虫集中出现在叶片发育的早期阶段（5－6月份）,7月份后,大多数幼虫发育成熟,取食叶片的面积减少。各取食状所涉及昆虫种类的组成不同,面积呈不同的季节变化模式,其中缘食状和孔食状之间有显著的正相关关系;辽东栎叶片在展叶初的叶面积最低,在7月底均达到最大值,然后呈下降趋势,单位面积重量也在展叶初最低,在6月底接近最大值,不同坡向的辽东栎林和叶片面积,单位面积重量及叶片被食面积均有显著差异,偏阳坡（东南坡） 高于偏阴坡（西北坡）。以上结果表明,辽东栎叶片维持了昆虫物种多样性,昆虫的生长发育与辽东栎的物候规律相互协调,昆虫种类的取食呈季节和空间变化。     

森林冠层食叶昆虫取食水平的定量方法与研究进展

森林冠层叶片被取食水平具有高度的时空变异性.本文论述了定量冠层昆虫取食水平的研究意义和方法,分析了各类取样方法和技术的优缺点,并对国内相关研究案例进行了评述.本文将定量冠层食叶昆虫取食水平的研究方法区分为针对绿叶样品的方法和针对落叶样品的方法.对冠层内绿叶的取样包括破坏性采叶法和原位连续观测法,依据取样技术又可分为基于地面的取样技术和基于冠层的取样技术.针对落叶样品的研究方法是指通过对林分内的凋落叶进行系统性采样、测定叶面积缺失比例、继而评估林分尺度上冠层昆虫取食水平的方法.文末提出了与森林昆虫取食相关的3个重点研究领域.     

浙江天童常绿阔叶林中11种常绿乔灌木叶片虫食状分析

为探讨昆虫对植物叶片的取食行为和伤害方式,作者选择浙江天童常绿阔叶林内的11种常绿乔灌木为对象,对叶片虫食状类型和格局进行分析。结果如下:(1)共发现16种虫食状类型,每种植物叶片虫食状类型数在10–13种之间,每种虫食状出现频率在0.5–28.7%之间。缘食状出现频率最高(28.7%),虫瘿和泡状出现频率最低(0.5%)。(2)叶片虫食状分布格局可分为3种类型,即一种虫食状占绝对优势的单优格局,如马银花(Rhododendronovatum)和檵木(Loropetalumchinense);两种虫食状(缘食状和顶食状)共占优势的双优格局,仅有木荷(Schimasu-perba);3种及3种以上虫食状占优势的多优格局(其余8种植物)。(3)叶片虫食状多样性指数变化在1.57–2.23之间,最高为苦槠(Castanopsissclerophylla),最低为马银花;乔木的多样性指数(2.040)高于灌木(1.882),优势种多样性指数高于伴生种,但差异均不显著;多样性指数反映了虫食状类型和出现频率的综合差异。(4)16种虫食状类型中有8对显著正相关,4对显著负相关,可能反映出不同类型昆虫取食植物的趋同和差异。     

大气CO2浓度升高对森林食叶昆虫的潜在影响

评述了大气CO₂浓度升高对森林食叶昆虫的影响,昆虫对森林取食为害水平的潜在变化,以及研究中的主要实验方法.大气CO₂浓度升高通过引起叶片化学变化进而影响食叶昆虫个体的取食和生长;但物种对环境变化反应的特异性、植物化学对高浓度CO₂的反应强度、昆虫对植物生理变化的敏感性和适应性、研究周期的长短、其它环境因子的协同效应以及不同实验中植物生长条件和研究方法的差异均将影响昆虫反应的方向和强度;CO₂气体浓度增高本身可能不足以对食叶昆虫个体的新陈代谢构成影响;大气CO₂浓度升高也可能影响森林食叶昆虫种群的大小.     

二化螟越冬种群∶年龄结构对其冬后取食和化蛹动态的影响

调查了不同类型稻田及茭白田中二化螟的越冬年龄结构,比较了不同龄期幼虫之间的在冬后取食与化蛹动态方面的差异。结果表明,越冬虫龄以双季晚稻田中明显较低,中稻田与茭白田中相对较高。出现取食的个体比例在４－５龄幼虫之间差别不大;但取食的开始时间在龄期之间具明显差异,以４龄个体最早取食。未取食个体的化蛹进度明显快于取食个体;未取食个体中以４龄幼虫的化肾时间较早。     

思茅新木蛾幼虫取食行为的研究

本文对思茅新木蛾Neospastis simaona Wang幼虫的取食行为、取食偏好性以及明暗条件对其取食量的影响进行了观察研究,为该昆虫的防治提供了理论依据。研究结果表明:思茅新木蛾幼虫随着龄期的增加,取食次数增多,取食总时间增加,但一次取食时间无明显变化;思茅新木蛾幼虫对木荷(Schima superba)有强烈嗜食性,4龄幼虫喜食木荷幼叶,5、6龄幼虫对木荷幼叶、成熟叶无明显偏好性;明暗条件对思茅新木蛾4至6龄幼虫的取食量没有显著影响(P>0.05)。     

浙江西部山区白鹇生态的初步研究

1982—1987年在浙西的开化、衢州、建德、淳安等地对白鹇的生态进行了调查。白鹇分布于全省植被良好的山区,活动于乔木层覆盖率较高的针阔混交林和针叶林等生境,其种群密度受林下灌木层盖度的影响。白鹇的冬季食物以壳斗科植物为主,取食频度为53.5％,干重百分比达72.48％;同时也取食一定量的昆虫等动物性食物,取食频度达40％。白鹇的冬季食物可分为三种类型:1.最喜食食物,取食频度在50％以上;2.喜食食物,取食频度在10—40％;3.偶食食物,取食频度小于10％。     

普通丝瓜叶片成分和物理结构对黄足黑守瓜取食和定位的影响

黄足黑守瓜是普通丝瓜生长过程中危害叶片的主要害虫.本文对普通丝瓜不同部位叶片挥发性成分、营养成分和物理结构对黄足黑守瓜取食和定位的影响进行了系统研究.本实验采用顶空固相微萃取-气相色谱-质谱法分析了普通丝瓜不同部位叶片挥发性成分,研究结果表明,嫩叶主要挥发性成分有(Z)-3-己烯-1-醇(27.65%)和植醇(45.77%),成熟叶挥发性成分主要有(Z)-3-己烯-1-醇(49.34%),老叶挥发性成分主要有植醇(63.25%),且挥发性成分对黄足黑守瓜远距离定位起到了引导作用.同时,本研究还采用5点取样法、3,5-二硝基水杨酸法和考马斯亮蓝法分别研究了普通丝瓜不同部位叶片营养成分含量与黄足黑守瓜取食之间的关系,实验结果表明,黄足黑守瓜喜食植物叶片嫩叶部位,喜食部位叶片的总糖与还原糖含量、蛋白质含量都最高,且总糖含量与蛋白质含量比值最高.叶片物理结构调查采用石蜡切片法,发现叶片的物理结构对于黄足黑守瓜取食很少造成影响.通过研究,使我们充分地了解影响黄足黑守瓜取食不同部位叶片的因素,便于今后的育种和栽培过程中加强不利于黄足黑守瓜取食的因素,以达到安全、环保地进行农业生产的目的.     

新疆柽柳林地昆虫群落取食功能团结构及物种多样性研究

用网捕和手捕法对不同季节新疆北部大小不同的阜康和呼图壁柽柳林地昆虫和螨进行了采集调查,采到标本52 066头,隶属11个目、50科、近100种.根据营养级和取食方式归类出捕食者、寄生者、剥食者、吸食者、食花和种籽者、造瘿者和游历者等取食功能团.连续分布的阜康林地的总物种数多于孤立斑块的呼图壁林地,其中53种为两林地共有种.两林地各取食功能团物种数在群落中的比例基本相同,剥食、吸食和捕食性昆虫等取食功能团各约占群落总物种数的1/5以上.吸食和造瘿昆虫（螨）等个体数量在各时期均高于其他取食功能团,其次是剥食性的昆虫.在任一季节占昆虫群落总个体数量25%以上的物种有柽柳瘤瘿螨、柽柳白盾蚧、毛尾柽瘿蚊等,占5%～10%的物种有斯氏伞锥象、埃及柽麦蛾和柽柳条叶甲等.阜康林地昆虫群落的均匀度（J）和多样性（H＇）等指数在季节前期和中期均高于呼图壁林地,但在后期则低于呼图壁林地,其优势度指数均低于呼图壁林地.     

昆虫取食诱导的植物防御反应

植物被昆虫取食后可产生直接防御或间接防御。直接防御通过增加有毒的次生代谢产物或防御蛋白对昆虫生理代谢产生不利的影响,但对植物的消耗较大。间接防御通过释放挥发性化合物吸引天敌昆虫,并以此控制植食性昆虫。特异性的昆虫激发子(insect specific elicitors)能够诱导挥发性化合物的释放。多种信号途径参与昆虫取食诱导的植物防御反应,它们之间的相互作用协同或拮抗。了解昆虫取食诱导的植物防御反应,对于害虫综合治理策略的完善具有重要的意义。     

A comparison of artificial defoliation techniques using canola (<Emphasis Type="Italic">Brassica napus</Emphasis>)

We conducted two experiments that investigated how the method and location of artificial defoliation influenced growth, reproduction, and allocation in canola, Brassica napus. In one experiment, 0%, 25%, or 50% of leaf area was removed by cutting circular holes at three possible locations: concentrated at either the base of leaves or at their tips, or dispersed throughout leaf blades. Plants fully compensated for such damage; reproduction and allocation were unaffected by either defoliation intensity or wound location. In a second experiment, we again initiated three intensities of defoliation: non-damaged plants served as controls, while others had 25% or 50% of their leaf areas removed. The method of removal in the second experiment consisted of cutting either multiple, similar-sized, circular holes or single, contiguous patches of a leaf blade. At the highest defoliation intensity reproductive output and allocation were significantly less in plants treated with the former method than the latter, even though an equivalent initial amount of leaf area was removed in both treatments. We conclude that simulated herbivory studies must account for not only how much of the plant is damaged, but also the pattern of leaf damage itself, since both factors contribute to a plant’s physiological and ecological responses to grazing.     

Pattern of defoliation and its effect on photosynthesis and growth of Goldenrod

1. Leaf area was removed from Solidago altissima in either a dispersed pattern (half of every leaf removed) or a concentrated pattern (every other leaf removed) and effects on leaf gas exchange, vegetative growth and flowering were examined relative to undefoliated controls. Gas exchange was measured for leaves remaining after defoliation and for regrowth leaves that developed post-damage (at 7, 16 and 26 days post-defoliation).
2. Area-based photosynthetic rates of leaves remaining after defoliation were not affected by either dispersed or concentrated damage, but damage of both types enhanced area-based photosynthesis of regrowth leaves at 16 days post-defoliation and to a lesser extent at 26 days post-defoliation.
3. Dispersed damage, but not concentrated damage, stimulated mass-based photosynthesis of undamaged leaves remaining after defoliation. Undamaged leaves remaining after defoliation and regrowth leaves on damaged plants had higher specific leaf area (leaf area/leaf mass) than comparable leaves on control plants. Mass-based photosynthesis was more strongly elevated by defoliation than area-based photosynthesis because of this increase in specific leaf area.
4. Plants with dispersed damage recovered more quickly from defoliation; they had higher relative growth rates in the first week post-defoliation than plants with concentrated damage. Both types of defoliation caused similar reductions in flower production.
5. These results add to accumulating evidence that dispersed damage is generally less detrimental to plants than concentrated damage and suggest that physiological changes in leaves may be part of the reason.     

Complex feeding tracks of the sessile herbivorous insect Ophiomyia maura as a function of the defense against insect parasitoids

Because insect herbivores generally suffer from high mortality due to their natural enemies, reducing the risk of being located by natural enemies is of critical importance for them, forcing them to develop a variety of defensive measures. Larvae of leaf-mining insects lead a sedentary life inside a leaf and make conspicuous feeding tracks called mines, exposing themselves to the potential risk of parasitism. We investigated the defense strategy of the linear leafminer Ophiomyia maura Meigen (Diptera: Agromyzidae), by focusing on its mining patterns. We examined whether the leafminer could reduce the risk of being parasitized (1) by making cross structures in the inner area of a leaf to deter parasitoids from tracking the mines due to complex pathways, and (2) by mining along the edge of a leaf to hinder visually searching parasitoids from finding mined leaves due to effective background matching of the mined leaves among intact leaves. We quantified fractal dimension as mine complexity and area of mine in the inner area of the leaf as interior mine density for each sample mine, and analyzed whether these mine traits affected the susceptibility of O. maura to parasitism. Our results have shown that an increase in mine complexity with the development of occupying larvae decreases the probability of being parasitized, while interior mine density has no influence on parasitism. These results suggest that the larval development increases the host defense ability through increasing mine complexity. Thus the feeding pattern of these sessile insects has a defensive function by reducing the risk of parasitism.     

Photosynthetic responses of wheat, Triticum aestivum L., to defoliation patterns on individual leaves

The impact of defoliation by fall armyworm, Spodoptera frugiperda (J. E. Smith), on the photosynthetic rates of injured, individual wheat, Triticum aestivum L., leaves and the impact of different spatial patterns of artificial insect defoliation on photosynthesis of remaining leaf tissue of injured, individual wheat leaves were evaluated in this study. Photosynthesis, stomatal conductance, transpiration, and chlorophyll a fluorescence were recorded in the flag-leaves of wheat plants 1 and 24 h after defoliation in 2003 and at 1 h, 24 h, 7 d, and 14 d after defoliation in 2004. Photosynthesis of injured leaves was not significantly affected by any defoliation treatment (i.e., control, natural, and artificial). Similarly, we did not observe interactions between defoliation treatments and time after defoliation. Stomatal conductance was significantly affected by time after defoliation and by the interaction between defoliation treatment and time after defoliation. However, in general, our results showed that wheat responded similarly to insect defoliation and artificial defoliation, which, therefore, may be used to simulate leaf mass consumption. Spatial defoliation patterns had a significant effect on photosynthetic parameters of injured leaves, but responses were dependent on plant developmental stages. The chlorophyll a fluorescence data revealed no significant effects from any defoliation pattern on the photochemical efficiency of the injured leaf. No significant interactions between defoliation patterns and time after defoliation were observed. Our findings reveal that the spatial pattern of defoliation in wheat affects photosynthetic and other gas exchange responses, which suggests that when simulating insect defoliation in wheat, researchers need to be cognizant of the defoliation pattern to adequately simulate insect defoliation.     

Nonglandular leaf trichomes as short-term inducible defense of the grey alder,Alnus incana (L.), against the chrysomelid beetle,Agelastica alni L.

Summary The grey alder compensates leaf area losses due to insect grazing by continuously producing new leaves throughout the vegetative period. Different degrees of defoliation were attained experimentally by a controlled release of the oligophagous beetle Agelastica alni on arbitrarily selected trees from a homogenous population of young alders. The reduction in leaf area per tree significantly influenced the density of leaf trichomes, assessed 10–30 days later, on newly sprouting leaves only. Cross-correlations between leaf area reduction and trichome density were strongest for leaves which completed unfolding 14–21 days after damage. Dualchoice assays suggested a negative influence of trichomes on oviposition rate of A. alni. Removal of trichomes by shaving demonstrated the highly significant effect of trichomes on feeding behavior of adults and larvae in dual-choice assays. The role of the induced increase in trichome density as a possible short-term defense reaction against herbivorous insects is discussed.     

小型无脊椎动物对混播草地白三叶叶片伤害程度研究

采用非破坏性的田间观测方法,以主匍匐茎的叶片伤害数,叶片伤害率和叶片伤害程度3个变量为指标,综合评价了小型无脊椎动物对多年生黑麦草与白三叶的混播草地白三叶叶片的伤害程度,系统探讨了白三叶品种类型（Alice,Retor和Gwenda),刈割频率（高与低）及草地特征（如三叶含量,地上生物量和草层高度）对小型无脊椎动物对叶片伤害的影响。研究表明,高频率刈割的草地白三叶叶片总的伤害数及中等程度伤害的叶片数明显地高于低频率刈割处理（分别为21％和35％）,另外,研究期总的叶片伤害数不同程度伤害的叶片数因白三叶品种的不同而存在着很大差异,且这种差异在春季,夏末和秋季等3个时期均十分明显,在这3个时期,在两种频率刈割下,均是品种Retor的叶片伤害数和叶片伤害率明显高于品种Alice和Gwenda,研究还表明,叶片的伤害与白三叶种群特征如白三叶含量和地上生物量存在显著的负相关,白三叶含量和地上生物量越低,则叶片的伤害数和伤害率就越高,回归模型显示,白三叶含量和地上生物量可以解释叶片的伤害数在春季,夏末,秋季各65％,59％和50％的变异,可以解释叶片伤害率在这3个时期各58％,57％和45％。     

Leaf dynamics and insect herbivory in a Eucalyptus camaldulensis forest under moisture stress

Abstract The influence of soil moisture content on leaf dynamics and insect herbivory was examined between September 1991 and March 1992 in a river red gum (Eucalyptus camaldulensis) forest in southern central New South Wales. Long-term observations of leaves were made in trees standing either within intermittently flooded waterways or at an average of 37. 5m from the edge of the waterways. The mean soil moisture content was significantly (P≤0.05) greater in the waterways than in the non-flooded areas. Trees in the higher soil moisture regime produced significantly larger basal area increments and increased canopy leaf area. This increase in canopy leaf area was achieved, in part, through a significant increase in leaf longevity and mean leaf size. Although a greater number of leaves was initiated and abscissed per shoot from the non-flooded trees, more leaves were collected from litter traps beneath the denser canopies of the flooded trees. Consumption of foliage by insects on the trees subjected to flooding compared to the non-flooded trees was not significantly different. However, the relative impact of insect herbivory was significantly greater on the non-flooded trees. Leaf chewing was the most common form of damage by insects, particularly Chryso-melidae and Curculionidae. No species was present in outbreak during this study. Leaf survival decreased as the per cent area eaten per leaf increased. In addition, irrespective of the level of herbivory, leaf abscission tended to be higher in E. camaldulensis under moisture deficit. The influence of soil moisture content on the balance between river red gum growth and insect herbivory is discussed.     

西双版纳热带季节雨林林窗内幼树叶生长与虫食动态

 研究了西双版纳热带季节雨林6种乔木幼树在林窗中的叶生长与叶虫食动态。6种幼树叶生长主要在雨季(5～10月),在旱季雾凉期(11～2月)叶停止生长。阳性树种旱季干热期(3～4月)开始叶生长,顶极树种至5月雨季初才开始叶生长。表明雾凉期低温抑制两类树种叶生长,干热期水分不足抑制顶极树种叶生长。叶生长同步性(每两个月的叶生长量变异系数C．V．)顺序为：望天树(Shorea chinensis,1.42)>金钩花(Pseuduvaria indochinensis,1.41)>八宝树(Duabanga grandiflora, 1.02)>云南石梓(Gmelina arborea,0.98)>团花树(Anthocephalus chinensis,0.84)和铁刀木(Cassia siamea,0.84)。旱季造成一些种类幼树出现落叶高峰,严重叶虫食也导致云南石梓在7～8月出现落叶高峰。叶虫食主要出现在雨季,团花树和云南石梓在干热期叶生长能减少昆虫取食,但此时铁刀木叶同步生长却不能降低食叶昆虫危害。6种幼树叶生长量年进程与叶虫食量年进程间存在正相关,其中望天树、金钩花、八宝树和团花树分别达到显著(p<0.05)或极显著(p<0.01)水平。望天树和金钩花在雨季初叶同步生长能减轻叶虫食。食叶昆虫偏爱取食幼叶,6种幼树平均幼叶的虫食量占总虫食量的72.9％,幼叶虫食速率平均为成熟叶的4.3倍。