繁殖期白头鹤觅食地活动的时间分配和日节律

2004年4~6月在黑龙江大沾河湿地自然保护区内,采用野外直接观察法对野生白头鹤在觅食地的活动节律进行了研究.结果表明:①繁殖期白头鹤在觅食地各种行为活动有一定的时间分配规律.在繁殖前期,雌、雄白头鹤全天(5:30~18:00)成对在觅食地活动,雄性个体以取食、警戒、游走、保养和求偶为主要行为,雌性个体以取食、警戒、游走和保养为主要行为;到繁殖后期,雌、雄白头鹤每天有两个时间段单独在觅食地活动(4:00~6:00和17:00~19:00),无论雌雄个体,均无求偶行为.②白头鹤雌、雄个体间保养行为差异极显著(P<0.001),警戒和求偶行为差异显著(P<0.05),取食、游走行为具有一定的差异.③在麦田和池塘2种微地貌之间,白头鹤的取食、求偶行为具极显著差异(P<0.001),警戒行为具显著差异(P<0.05).④在繁殖期的不同阶段以及不同的天气情况下白头鹤的各种行为均具有一定差异.图1表2参15     

棉铃虫天敌中红侧沟茧蜂Microplitis mediator对不同处理棉花的趋性行为反应

采用机械损伤(处理A)、棉铃虫取食为害(处理B)、棉铃虫取食棉花 棉铃虫复合物(处理B H)、水杨酸诱导(处理C)、机械损伤加棉铃虫口腔分泌物(处理D)5种方式诱导现蕾期棉花植株,并应用Y型嗅觉仪测定处理后棉花对棉铃虫天敌中红侧沟茧蜂搜索寄主行为的影响.处理B、处理B H和处理C棉花对中红侧沟茧蜂有显著的引诱作用.健康棉株、处理A及处理D棉花对中红侧沟茧蜂没有明显的吸引.中红侧沟茧蜂对处理C、处理B H以及处理B棉花没有明显的趋性差异.利用气质联用系统对各处理棉花挥发性物质进行定性和定量分析.表明处理B、处理B H、处理C棉花挥发物种类和含量均比对照棉花多,处理A及处理D棉花与对照棉花挥发物种类和含量差异不显著.处理C、处理B及处理B H棉花中β-月桂烯、β-蒎烯、α-蒎烯的含量明显增加.处理C棉花柠檬烯的含量发生明显变化.图2表1参19     

转野生荠菜凝集素基因棉花对赤子爱胜蚓的影响

在实验室条件下分别给赤子爱胜蚓(Eisenia foetida)饲喂在自然状况下可能接受的棉叶最高添加量和2倍最高添加量的转野生荠菜凝集素(WSA)基因棉花(Gossypium hirsutum)叶片,并以其亲本棉花叶片为对照,以牛粪为阴性对照,以农药为阳性对照,研究种植转WSA基因棉花对赤子爱胜蚓死亡率、生长及繁殖的影响。结果表明,在49 d的试验周期内,与取食亲本棉花叶片的赤子爱胜蚓相比,取食转WSA基因棉花叶片的赤子爱胜蚓的死亡率,体质量,GST、SOD、纤维素酶活性以及蚓茧数和小蚯蚓数均无显著差异,未发现转WSA基因棉花对赤子爱胜蚓有不利影响。     

电子鼻zNose~(TM)构建棉花挥发物指纹图谱及被害棉花挥发物释放节律分析

采用电子鼻zNose~(TM)对棉花植株常见挥发性化合物进行定性分析,确定每类化合物的相对保留指数,构建棉花植株常见挥发性化合物特征谱库.采集棉铃虫幼虫取食诱导棉株挥发性化合物,利用电子鼻构建棉铃虫幼虫危害棉株的指纹图谱.比对健康棉株与棉铃虫幼虫危害棉株的色谱图及指纹图谱发现,棉铃虫幼虫危害棉株的挥发物的种类和含量均比健康棉株的多,而且未去除棉铃虫幼虫的危害处理与去除棉铃虫幼虫的危害处理相比,被诱导挥发物的含量显著升高.通过电子鼻实时监测棉花植株各处理β-蒎烯、β-月桂烯等挥发性化合物的释放节律.结果显示,当棉铃虫幼虫危害棉株2h后,β-蒎烯的释放量明显增加,与对照相比差异显著.β-月桂烯在棉铃虫幼虫危害2h的释放量与对照相比没有显著差异,在棉铃虫幼虫危害24h释放量显著增加.6～8h β-蒎烯和β-月桂烯分别达到各自最大释放量,随后缓慢回落,但仍然保持较高释放水平.图3表1参24     

茶刺蛾危害后茶树挥发性有机化合物释放变化

为筛选引诱天敌昆虫的化学信息素,以应用其防控茶刺蛾(Iragoides fasciata Moore),研究了茶树[Camelliasinensis(L.)O.Kuntze]被茶刺蛾危害后释放出的挥发性有机物的变化.应用同时萃取蒸馏法收集被茶刺蛾危害和未危害的茶叶的挥发性有机化合物,气相色谱/质谱联用仪(GC/MS)分析结果发现,未受害枝叶挥发性有机化合物共有63种组分,主要由酯类、醇类、烃类、酮类、杂环化合物、醛类、有机酸和醚类组成,烃类物质的相对含量占19.05%,而受害枝叶释放出的挥发物中烃类物质的相对含量增加到26.79%,反式-橙花叔醇、雪松醇、邻苯二甲酸二丁酯、邻苯甲酸二异丁酯相对含量显著增加,此外,产生了32种新的组分,包括10种酯类、5种醇类、5种烯烃类、4种杂环类、3种芳香烃类、3种烷烃类、1种醛和1种酮.     

不同水生植物对富营养化水体释放气体的影响

水体反硝化脱N、温室气体排放以及O2释放过程均是水体生态系统中发生的重要生化反应过程。为了明确不同类型水生植物对这些过程的影响程度,采用自主研发的原位收集水体释放气体装置,于2012年7—8月对滇池草海中自然生长的挺水植物〔菖蒲(Acorus calamus)〕、浮叶植物〔睡莲(Nymhaea tetragona)和荷花(Nelumbo nucifera)〕、漂浮植物〔凤眼莲(Eichhornia crassipes)〕、沉水植物〔狐尾藻(Myriophyllum verticillatum)和轮叶黑藻(Hydrilla verticillata)〕及对照(无植物)区域内释放的N2、CH4、O2、CO2和N2O的规律进行研究。结果表明,各种水生植物生长区及对照区释放气体主要由N2、CH4和O2组成,其余成分主要是CO2和N2O。沉水植物通过光合作用明显促进了水域内O2释放过程,进而提高了水体释放气体的速率及各气体成分通量值。而睡莲、荷花和凤眼莲由于叶片覆盖水面的影响,降低了水体藻类的光合能力,造成该区域水体释放气体的速率中值低于对照区,且各气体成分释放通量值也较低。各区域释放气体中CH4浓度无显著差异(P0.05),菖蒲区释放的气体中N2浓度显著高于对照区(P0.05)。     

铅在植物-环境体系中的吸收、分布和迁移规律的稳定同位素示踪法研究

以低浓度的稳定铅同位素为示踪剂,采用电感耦合等离子质谱法,通过盆栽实验,考察了在不同的pH值环境和不同铅源引入方式下,茶树植株对铅的吸收情况以及铅在植株体内的分布及迁移规律.结果表明:茶树植株对大气铅源污染的反应比土壤铅源污染灵敏;大气铅源污染有往顶端(芽)迁移的趋势,而土壤铅源污染则主要聚集在根部;低pH条件增强植株对铅的吸收且能促使植株体内的铅的往高处迁移.本实验方法危害小,更接近植株承受低浓度污染的实际情况,能区分实验引入铅源和环境引入铅源.     

城市道路旁小蜡叶片对重金属的富集特征

通过对合肥市市区交通干线、城郊公路和植物园道路(对照区)的土壤,以及道路绿化灌木小蜡(Ligustrum sinense)叶片中Cu,Zn,Pb,Cd和Cr含量的测定,分析城市交通产生的大气重金属污染物在土壤和植物叶片中的富集特征.结果表明,公路交通和车辆尾气排放产生的重金属污染物能够显著地在土壤和小蜡叶片中富集.公路土壤中富集的Cu,Zn,Pb和Cr之间有着较高的相关性,且富集量与道路车流量有着明显的正相关.小蜡叶片富集的Cu,Zn,Pb,Cd和Cr主要来自于道路交通产生的大气重金属污染物,同土壤中相应重金属元素的相关性较差,而且市区干线的叶片富集量高于城郊公路,城郊公路高于对照点.雨水的冲刷能够减少小蜡叶片表面重金属的含量,同时小蜡叶片对重金属的富集,在4月至7月的富集速度或富集增量高于7月至10月,这与小蜡叶片的生长趋势相一致.     

两种光照生境下4种常绿阔叶树的单位叶面积干重、光合能力与化学防御物质含量比较

亚热带常绿阔叶林下分布着可塑性强的耐荫植物,其叶片应对外界干扰的防御对策至少有物理性防御和化学性防御两种,这两种防御代价在一定的昆虫取食压力下在理论上应该存在权衡.为检验这种权衡是否普遍存在,分别测定了重庆缙云山4个常绿物种——光叶山矾(Symplocos lancifolia)、四川山矾(S.setchuensis)、四川毛蕊茶(Camellialawii)和细枝柃(Eurya loquaiana)在林窗和林下两种对照光环境下个体叶片的光饱和下的净光合速率、叶面积干重和部分化学防御物质含量.结果表明,4个物种生活在林窗的个体单位叶面积干重、叶片氮含量和单位面积净光合速率通常高于林下的个体,但是单位质量和单位面积的总酚含量和C/N值却低于林下的个体.蛋白质和非结构性碳水化合物含量在不同生境中没有显著差异.因为不同物种叶片对光照条件的响应不同,不同参数的变化在两种生境间的差异并不完全一致.本研究结果在一定程度上暗示了物种在林窗和林下分别倾向于采取物理和化学性防御对策,并初步证实了两种防御强度之间存在权衡关系.图4参40     

黑土微生物活力对不同养分的响应

土壤呼吸是土壤有机碳分解的主要生物化学过程,可反映土壤有机质的分解程度及有效养分供给水平,可用于评价土壤微生物活力状况.通过设置8个养分处理,对黑土进行41 d的室内好气培养,考查了黑土微生物活力对不同养分响应的规律.结果表明,单加N或P以及NP组合均不能提高黑土微生物活力;单加葡萄糖能够使土壤呼吸释放的CO2累积量达到对照的10倍以上,使黑土微生物活力显著提高.在可利用碳底物充足的条件下,N的加入能够显著提高黑土微生物活力,土壤呼吸释放出的CO2累积量达到对照的13倍以上,显著促进土壤有机质中无机养分的释放,CN交互作用显著;在C和N养分都充足的条件下,P的加入才能够对黑土微生物产生激发效应.不同养分状况下,黑土微生物活力达到峰值的时间不同,表现为,CNP(C N P)处理土壤呼吸强度在第3 d达到最高值,CN (C N)处理在第5天达到最高值,单加C和CP (C P)处理,在15 d左右达到最高值.     

Ontogenetic and spatio-temporal patterns of induced volatiles in <Emphasis Type="Italic">Glycine max</Emphasis> in the light of the optimal defence hypothesis

Summary. Plants attacked by herbivorous insects emit a blend of volatile compounds that serve as important host location cues for parasitoid wasps. Variability in the released blend may exist on the whole-plant and withinplant level and can affect the foraging efficiency of parasitoids. We comprehensively assessed the kinetics of herbivore-induced volatiles in soybean in the context of growth stage, plant organ, leaf age, and direction of signal transport. The observed patterns were used to test the predictions of the optimal defence hypothesis (OD). We found that plants in the vegetative stage emitted 10-fold more volatiles per biomass than reproductive plants and young leaves emitted >2.6 times more volatiles than old leaves. Systemic induction in single leaves was stronger and faster by one day in acropetal than in basipetal direction while no systemic induction was found in pods. Herbivore-damaged leaves had a 200-fold higher release rate than pods. To some extent these findings support the OD: i) indirect defence levels were increased in response to herbivory and ii) young leaves, which are more valuable, emitted more volatiles. However, the fact that reproductive structures emitted no constitutive or very few inducible volatiles is in seeming contrast to the OD predictions. We argue that in case of volatile emission the OD can only partially explain the patterns of defence allocation due to the peculiarity that volatiles act as signals not as toxins or repellents.     

Herbivore species, infestation time, and herbivore density affect induced volatiles in tea plants

In response to insect herbivory, plants emit volatiles that are used by the herbivores’ natural enemies to locate their host or prey. Herbivore attack also enhances tea aroma. Herbivore-induced plant volatiles (HIPVs) vary both quantitatively and qualitatively with infestation duration and herbivore density. Thus, whether HIPVs can reliably communicate the identities of herbivores is of interest. Here, we studied the tea plant volatiles induced by the tea leafhopper (Empoasca vitis, a piercing–sucking insect), the tea geometrid (Ectropis oblique, a chewing insect), and methyl jasmonate (MeJA, a plant hormone). Geometrid feeding induced more complex volatile blends than did leafhopper infestation. The volatiles induced by both herbivores significantly increased in quality and quantity with time during the first 16 h of infestation, after which the profiles of induced volatile blends and the emission of induced compounds varied diurnally. (E)-β-Ocimene displayed a unique rhythm in which emission peaked at night. The amount of HIPVs significantly increased, while their profiles changed little, with herbivore density. Overall, the leafhoppers and geometrids induced significantly different volatiles from tea plants, while the HIPV profiles varied with a circadian rhythm and were similar at different herbivore densities. Our findings also suggest a new method of enhancing tea flavor using exogenously applied plant hormones, because the volatiles induced by leafhoppers and MeJA were similar in general composition.     

Foraging tactics of two guilds of web-spinning spiders

Summary The foraging behavior of orbweaving and sheetweb weaving guilds of spiders was investigated. Orbweavers move among web-sites frequently, but sheetweb weavers do not. A simple model that examines the adaptive advantages of active foraging and sit-and-wait strategies leads to three predictions: 1) Orbweavers should have a simple decision rule for leaving web-sites, 2) Orbweavers' web-sites should have more variable payoffs than do the web-sites of sheetweb weavers, and 3) Orbweavers should have a lower cost of moving than do sheetweb weavers. Field and experimental data bear out each prediction. In addition, analysis of the residence times of spiders at web-sites that are used more than once reveals that members of the two guilds do not compete with each other for web-sites.The distinction between active foragers and sit-and-wait predators stems from the relative frequency of the decision to leave a foraging site. Thus active foragers are those predators that move often from patch to patch, and sit-and-wait predators are those that leave patches infrequently. In this sense, orbweaving spiders are active foragers and sheetweb weavers are sit-and-wait predators.     

Systemically-induced response of cabbage plants against a specialist herbivore, Pieris brassicae

Summary. Plant responses to herbivory might directly affect the herbivore (“direct” defences) or might benefit the plant by promoting the effectiveness of natural antagonists of the herbivores (“indirect” defences). Brussels sprouts attacked by Pieris brassicae larvae release volatiles that attract a natural antagonist of the herbivores, the parasitoid Cotesia glomerata, to the damaged plant. In a previous study, we observed that feeding by caterpillars on the lower leaves of the plant triggers the systemic release of volatiles detectable by the parasitoids from upper leaves of the same plant.?The role of these systemically induced volatiles as indirect defence and the dynamics of their emission were investigated in wind-tunnel dual choice tests with C. glomerata. The systemically induced emission of volatiles varied depending on leaf age and on plant age. Systemic induction affected parasitoid effectiveness, as induced plants could be more easily located by parasitoids than non-induced ones.?The role of the systemic induction as a direct defence was investigated through behavioural and feeding tests with P. brassicae. In dual choice assays, 1st instar larvae preferred to feed and fed more on systemically induced than on non-induced leaves. In single choice assays, the leaf area consumed by caterpillars was larger on systemically induced leaves than on non-induced control leaves. However, caterpillars fed on systemically induced leaves attained the same weight as those feeding on non-induced controls. In addition, P. brassicae pupae whose larvae were fed on systemically induced leaves had longer developmental times than those of larvae fed on non-induced leaves. Adult oviposition behavior was not influenced by systemic induction.?We conclude that systemically induced responses in cabbage might reduce P. brassicae fitness both directly, by affecting their development and feeding behavior and indirectly by making caterpillars and pupae more vulnerable to attack by carnivores. The occurrence of a possible relationship between direct and indirect defence is discussed. Received 24 January 2001; accepted 3 May 2001.     

Foraging responses of wild house mice to accumulations of conspecific odor as a predation risk

Many predators hunt using the social and waste odors of their prey. It is unknown, however, whether potential prey modify their behavior in response to the risks of predation associated with accumulations of conspecific odor. We examined this question by measuring foraging trade-offs of wild house mice (Mus domesticus) in the field where we increased both predation risk and conspecific odor at artificial food patches in a two-factor design. Mouse giving-up densities (GUDs) were significantly higher in open habitats than in closed habitats but did not differ with the addition of mouse odors. Fine-scale behavioral observations of captive mice confirmed their attraction to the conspecific odor in an enclosure experiment, without any change to the GUD. These results indicate that house mice continue to visit and forage at food patches despite accumulations of predator-attracting odors. This most likely occurs for the social benefits obtained from conspecific odor exploration; however, such behavior may cause mice to become vulnerable to considerable olfactory exploitation by their predators. Future work must therefore focus on how mice trade off the social benefits of investigating odors that also attract their enemies.     

Parent-offspring aggression in moorhens

Summary Colonial orb-weaving spiders from Mexico were studied to test predictions of risksensitive foraging theory: 1. group foraging increases prey capture/individual, and reduces prey variance; 2. spiders should be expected to exhibit risk-averse behavior (forage in groups) when the average level of prey exceeds individual needs, and exhibit risk-prone behavior (forage solitarily) when prey are searce. Laboratory and field studies show that group foraging increases capture efficiency and reduces variability in prey captured per spider. In desert/mesquite grassland habitat, where prey availability is low, M. atascadero forage solitarily in most cases. In tropical rainforest/agriculture sites, M. increassata forage in large colonies of thousands of webs. In intermediate habitats, M. spinipes forages solitarily or in groups, depending on prey availability. Over a range of sites with varying levels of prey, M. spinipes shifts from a risk-prone to a risk-averse group foraging strategy as prey increases.Group foraging behavior observed in colonial Metepeira fits the predictions of risk-sensitive foraging models. These findings explain why spiders tend to group webs together only in areas of superabundant prey. The role of risk-sensitivity in the evolution of coloniality in spiders is discussed.     

Spatial scale of the patchiness of plant poisons: a critical influence on foraging efficiency

Generalist mammalian browsers and folivores feed on a range of chemically different plant species, which may assist them in diluting toxins and diversifying nutrient consumption. The frequency and order in which their diets are mixed are important determinants of intake. As a result, the degree of plant heterogeneity in an environment, and the spatial scale at which this occurs, should directly influence herbivore foraging decisions. We tested whether altering the Spatial scale of plants, and thus plant secondary metabolites (PSMs), affected foraging efficiency of a generalist folivore, the common brushtail possum (Trichosurus vulpecula). First, we demonstrated that possums were able to consume more from a mixed diet of two chemically different species, Eucalyptus globulus and E. tenuiramis, than when either of these species was offered alone. We then tested whether altering the spatial scale between E. globulus and E. tenuiramis, as small- or large-scale plant heterogeneity "patches," affected possum foraging behavior and, ultimately, their foraging efficiency. Possums increased their foraging efficiency when the spatial scale of plant heterogeneity was small rather than large. We argue that the ability to regularly switch diets, when plant spatial distribution is at a small scale, reduces the negative effects of PSM ingestion. We predict that the heterogeneity of plant patches, in relation to PSM distribution, and the scale at which this occurs across a landscape, are critical factors that influence foraging efficiency and, ultimately, fitness of mammalian herbivores. This research provides a fundamental link between plant chemistry, foraging, and habitat heterogeneity.     

Leaf volatiles and polyphenols in pear trees infested byPsylla pyricola. Evidence of simultaneously induced responses

Summary Feeding by the homopteranPsylla pyricola on leaves of pear trees induces the production of volatile compounds, such as (E,E)--farnesene and methyl-salicylate, as well as the production of polyphenols. The inference on induction is based on GC-MS and HPLC chromatograms from the same samples ofPsylla infested leaves, leaves from the same pear tree beforePsylla infestation and uninfested leaves from other pear trees.Psylla infestation greatly enhanced the production of volatiles ((E,E)--farnesene, methyl-salicylate and others) and triggered the production of new polyphenols, characterized by much longer retention times.However, the responses to infestation depend critically on leaf age (defined by leaf distance to apex). With respect to the leaf volatiles it appears that infested, old leaves produce fewer compounds and lower amounts of the volatiles than infested, young leaves. Moreover, there seem to be differences in pattern. Relative to (E,E)--farnesene, methyl-salicylate was found in much lower amounts in heavily infested, old leaves. With respect to polyphenols it was found that infested old leaves collected in August have polyphenols with the same retention times, but more or less equal amounts as uninfested young leaves collected in May. This shows thatPsylla infestation causes the induced response mostly in young leaves.The induced leaf volatiles may act as synomones to heteropteran bugs. As shown elsewhere,Anthocoris nemoralis responds significantly to (E,E)--farnesene and methyl-salicylate when offered in pure form against clean air in a Y-tube olfactometer. The effect of polyphenols on the performance ofP. pyricola is not yet known. Hence, a role in direct defence is still to be investigated.     

Condition dependence of male display coloration in a jumping spider (Habronattus pyrrithrix)

In many animals, conspicuous coloration functions as a quality signal. Indicator models predict that such colors should be variable and condition dependent. In Habronattus pyrrithrix jumping spiders, females are inconspicuously colored, while males display brilliant red faces, green legs, and white pedipalps during courtship. We tested the predictions of the indicator model in a field study and found that male body condition was positively correlated with the size, hue, and red chroma of a male’s facial patch and negatively correlated with the brightness of his green legs. These traits were more condition dependent than non-display colors. We then tested a dietary mechanism for condition dependence using two experiments. To understand how juvenile diet affects the development of coloration, we reared juvenile spiders on high- and low-quality diets and measured coloration at maturity. To understand how adult diet affects the maintenance of coloration, we fed wild-caught adults with high- or low-quality diets and compared their coloration after 45 days. In the first experiment, males fed high-quality diet had redder faces, suggesting that condition dependence is mediated by juvenile diet. In the second experiment, red coloration did not differ between treatments, suggesting that adult diet is not important for maintaining the color after it is produced at maturity. Diet had no effect on green coloration in either experiment. Our results show different degrees of condition dependence for male display colors. Because red is dependent on juvenile diet, it may signal health or foraging ability. We discuss evidence that green coloration is age dependent and alternatives to indicator models for colorful displays in jumping spiders.     

Comparisons of forager distributions from matched honey bee colonies in suburban environments

We conducted experiments designed to examine the distribution of foraging honey bees (Apis mellifera) in suburban environments with rich floras and to compare spatial patterns of foraging sites used by colonies located in the same environment. The patterns we observed in resource visitation suggest a reduced role of the recruitment system as part of the overall colony foraging strategy in habitats with abundant, small patches of flowers. We simultaneously sampled recruitment dances of bees inside observation hives in two colonies over 4 days in Miami, Florida (1989) and from two other colonies over five days in Riverside, California (1991). Information encoded in the dance was used to determine the distance and direction that bees flew from the hive for pollen and nectar and to construct foraging maps for each colony. The foraging maps showed that bees from the two colonies in each location usually foraged at different sites, but occasionally they visited the same patches of flowers. Each colony shifted foraging effort among sites on different days. In both locations, the mean flight distances differed between colonies and among days within colonies. The flight distances observed in our study are generally shorter than those reported in a similar study conducted in a temperate deciduous forest where resources were less dense and floral patches were smaller.