入侵杂草小飞蓬和钻形紫菀种子风传扩散生物学特性研究

种子的风传扩散是菊科入侵杂草的主要扩散方式之一,植物自身的传播特性和外在环境因子决定了种子扩散格局。从种子释放高度、沉降速度、脱落行为等内在因子出发,研究了两种在我国广泛分布的典型菊科入侵种小飞蓬和钻形紫菀自身的传播特性与风传扩散特征的关系。结果表明,小飞蓬和钻形紫菀的沉降速度均较小,分别为41.4cm·s-1和30.7cm·s-1,在空中停留时间长,且种子的脱落方式为非随机脱落,脱落概率大致与风速的平方成正比;种子的释放高度在种群内部存在很大的差异,显著影响种子的扩散距离。相比而言,小飞蓬种子的沉降速度大、释放高度高、远距离扩散(>100m)的概率大,扩散距离更远。研究表明了植物自身的传播特性对种子风传扩散的重要性,也为其他菊科入侵杂草种子风传扩散的研究提供了科学依据。     

平腹小蜂扩散行为与距离的初步研究

对荔枝果园中平腹小蜂的田间扩散行为和扩散距离进行了初步研究,结果表明,平腹小蜂的活动高峰时间是在中午11:00到下午17:00,其主要在60m范围内扩散飞行,少量个体可扩散100m远,这种扩散飞行是不连续式渐进性的;距放蜂点60m以内处植株上寄主卵的寄生率与60m以外的寄生率有明显的差异,故其有效的扩散寄生范围约为60m,而方位和植株的高度对平腹小蜂的扩散和寄生行为没有影响。     

Olfactory plasticity is regulated by pheromonal signaling in Caenorhabditis elegans

Population density-dependent dispersal is a well-characterized strategy of animal behavior in which dispersal rate increases when population density is higher. Caenorhabditis elegans shows positive chemotaxis to a set of odorants, but the chemotaxis switches from attraction to dispersal after prolonged exposure to the odorants. We show here that this plasticity of olfactory behavior is dependent on population density and that this regulation is mediated by pheromonal signaling. We show that a peptide, suppressor of NEP-2 (SNET-1), negatively regulates olfactory plasticity and that its expression is down-regulated by the pheromone. NEP-2, a homolog of the extracellular peptidase neprilysin, antagonizes SNET-1, and this function is essential for olfactory plasticity. These results suggest that population density information is transmitted through the external pheromone and endogenous peptide signaling to modulate chemotactic behavior.     

Effects of landscape corridors on seed dispersal by birds

Habitat fragmentation threatens biodiversity by disrupting dispersal. The mechanisms and consequences of this disruption are controversial, primarily because most organisms are difficult to track. We examined the effect of habitat corridors on long-distance dispersal of seeds by birds, and tested whether small-scale (<20 meters) movements of birds could be scaled up to predict dispersal of seeds across hundreds of meters in eight experimentally fragmented landscapes. A simulation model accurately predicted the observed pattern of seed rain and revealed that corridors functioned through edge-following behavior of birds. Our study shows how models based on easily observed behaviors can be scaled up to predict landscape-level processes.     

西方蜜蜂产浆适龄幼虫及取浆时间

对西方（ＡｐｉｓｍｅｌｉｆｅｒａＬ．）采用１和２日龄工蜂幼虫产浆的王台接受率和不同时间取浆浆量进行研究，结果显示：（１）２日龄工蜂幼虫的王台接受率（８０．６７％）极显著高于１日龄（４９．３３％）（Ｐ＜０．０１）；（２）１和２日龄幼虫产浆的台平均产浆量最高峰分别在各自移虫后第８４ｈ和第７２ｈ，浆量较高时段分别在移虫后第７８—９０ｈ和第６８—７８ｈ．２个日龄幼虫产浆最高浆量之间及浆量较高时段的浆量均无显著差异，但采用２日龄幼虫产浆的比１日龄幼虫的提前１２ｈ达到台平均产浆量高峰和浆量较高时段．（３）采用２日龄幼虫产浆其总产浆量可比采用１日龄的增加５６％．通过试验认为，西方蜜蜂产浆采用２日龄幼虫，并在移虫后第６６—７８ｈ内取浆最适     

醉马草种子风传扩散特性

【目的】 研究醉马草种子风传扩散特性。【方法】 以草原毒害草醉马草(Achnatherum inebrians)为材料,测定种子在静止空气中的垂直沉降时间,在不同风速下的水平移动距离,分析沉降时间与移动距离之间的相关性;测定自然风力条件下种子扩散距离并建立种子扩散距离模型,分析风力对醉马草种子扩散的影响。【结果】 醉马草有芒种子的沉降速度显著小于去芒种子;种子水平移动距离随风速的增加而增加,且芒对水平移动距离无影响。在自然风力作用下,高、中、低植株扩散距离为0~220 cm,种子二次扩散距离范围为0~18 cm。在3种株高中,中植株的拟合效果最好,其模型为:Y_中= 0.002 88+0.006 5 X-0.000 042 46 X²+0.000 000 062 284 X³。【结论】 附属物芒、高风速都促进醉马草种子风媒扩散。醉马草种子在风传扩散中属于短距离扩散。     

椰心叶甲取食行为及取食为害量研究

观察了椰心叶甲Brontispa longissima(Gestro)的取食行为、为害状以及幼虫对几种棕榈植物的取食量．结果表明,1、2龄幼虫取食量少,取食斑细,为害较少引起病斑;3、4、5龄幼虫取食痕较宽,被取食叶片形成的病斑大,易腐烂．成虫取食线虽然较细,但深而密,引起病斑较大,危害严重．幼虫期总取食叶面积为40～48cm^2．幼虫龄期越大,取食量越大．如1、2、3、4、5龄幼虫对椰子的取食量分别为1．7、3．7、6．9、12．6、22．8cm^2．在此基础上建立了对几种寄主植物的取食面积与椰心叶甲幼虫龄期之间关系的模型．     

昭通市苹果绵蚜的越冬情况

苹果绵蚜在云南昭通市10月下旬部分虫就进入越冬期,翌年1月中下旬开始迁移活动。冬季,苹果绵蚜主要集中在主干上的结疤、剪锯伤口等部位,各龄虫均能越冬,其中,以2龄虫为主,1龄虫、2龄虫、3龄虫、4龄虫和成虫占总虫量的比例分别为8.4%、34.9%、23.2%、19.9%和13.7%。在田间尚未采集到性蚜和卵。与发生高峰期比较,冬季田间蚜群量和每蚜群虫量分别下降31.2%和67.3%。     

The influence of Late Quaternary climate-change velocity on species endemism

The effects of climate change on biodiversity should depend in part on climate displacement rate (climate-change velocity) and its interaction with species' capacity to migrate. We estimated Late Quaternary glacial-interglacial climate-change velocity by integrating macroclimatic shifts since the Last Glacial Maximum with topoclimatic gradients. Globally, areas with high velocities were associated with marked absences of small-ranged amphibians, mammals, and birds. The association between endemism and velocity was weakest in the highly vagile birds and strongest in the weakly dispersing amphibians, linking dispersal ability to extinction risk due to climate change. High velocity was also associated with low endemism at regional scales, especially in wet and aseasonal regions. Overall, we show that low-velocity areas are essential refuges for Earth's many small-ranged species.     

“保蚕宁3号”防治柞蚕再感染脓病和空胴病小区试验

用“保蚕宁3号”喷洒不同龄期柞蚕,对柞蚕再感染的脓病、空胴病都有明显的防治效果;以在3龄期或4龄期喷洒,防治效果最佳,平均防治效果高达81.9%以上。     

基于Crosby生长法则的蔗根土天牛幼虫龄期划分

[目的]探寻蔗根土天牛幼虫最佳分龄结构并判断幼虫的龄数,为研究蔗根土天牛的发生规律及生物学特性,制定防治技术等提供理论依据.[方法]通过田间取样和室内饲养孵化的方法收集蔗根土天牛幼虫,分别测量幼虫的头口宽和前胸背板宽,并采用Crosby生长法则和线性回归方法进行分析.[结果]频次分布图显示蔗根土天牛幼虫头口宽、前胸背板宽均有18个左右的分布区,其中以头口宽分布较为明显,头口宽的峰值分别为0.6、1.2、1.6、2.2、2.5、3.0、3.5、4.0、4.5、5.0、5.5、6.0、6.5、7.0、7.5、8.0、8.5和9.0 mm.[结论]蔗根土天牛幼虫共分18龄,头口宽是判定蔗根十天牛幼虫虫龄的最佳指标.     

华山松球蚜形态特征及生物学特性研究

华山松球蚜是华山松的重要害虫，在昆明地区1年发生8代，春夏季平均42d1代，秋冬季51d1代，世代重叠，无明显的休眠现象，在海拔2600m以上的寒冷地区多以无翅蚜和老熟若虫在合拢的1年生针叶及松梢芽苞片内越冬，少数以卵在1年生或2年生针叶背面越冬，雌虫平均卵量(2～4月)50粒，产卵历期5～12d，卵孵化率90％以上，若虫4龄，1龄若虫经2～4d后在当年生针叶上固定直至发育为成虫，行孤雌生殖，有翅蚜于3月下旬开始分化，4月中旬至5月上旬是有翅蚜的峰期，有翅蚜的分化是球蚜种群迁移扩散和扩大增殖的重要因素。     

烟盲蝽5龄若虫对菜蚜低龄若蚜的捕食效能

[目的]了解烟盲蝽5龄若虫对菜蚜低龄若蚜的捕食能力。[方法]在试验室条件下,分别研究了培养皿中和小纱筒中烟盲蝽5龄若虫对6个密度菜蚜低龄若蚜的捕食功能反应,并对烟盲蝽5龄若虫自身密度的干扰效应进行了观察。[结果]烟盲蝽5龄若虫对低龄菜蚜的捕食功能反应可用HollingⅡ型圆盘方程拟合。其自身密度对捕食作用的干扰效应符合Hassel-Verley的干扰效应模型。[结论]烟盲蝽5龄若虫对低龄菜蚜的捕食量随猎物密度的不同而有较大差异,烟盲蝽5龄若虫自身密度对功能反应存在密度制约作用。     

Population cycles in small rodents

We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive potential and are able to exploit a new environment rapidly. Dispersing voles seem to be r strategists. Young females in breeding condition were over-represented in dispersing female Microtus (17). The Tf(C)/Tf(E) females, which were more common among dispersers during the phase of population increase (Fig. 6), also have a slight reproductive advantage over the other Tf genotypes (19). Thus in Microtus populations the animals with the highest reproductive potential, the r strategists, are dispersing. The segment of the population which remains behind after the selection-via-dispersal are those individuals which are less influenced by increasing population densities. These are the individuals which maximize use of the habitat, the K strategists in MacArthur and Wilson's terminology, or voles selected for spacing behavior. Thus we can describe population cycles in Microtus in the same theoretical framework as colonizing species on islands. Our work on Microtus is consistent with the hypothesis of genetic and behavioral effects proposed by Chitty (6) (Fig. 7) in that it shows both behavioral differences in males during the phases of population fluctuation and periods of strong genetic selection. The greatest gaps in our knowledge are in the area of genetic-behavioral interactions which are most difficult to measure. We have no information on the heritability of aggressive behavior in voles. The pathways by which behavioral events are translated into physiological changes which affect reproduction and growth have been carefully analyzed by Christian and his associates (28) for rodents in laboratory situations, but the application of these findings to the complex field events described above remains to be done. Several experiments are suggested by our work. First, other populations of other rodent species should increase to abnormal densities if enclosed in a large fenced area (29). We need to find situations in which this prediction is not fulfilled. Island populations may be an important source of material for such an experiment (30). Second, if one-way exit doors were provided from a fenced area, normal population regulation through dispersal should occur. This experiment would provide another method by which dispersers could be identified. Third, if dispersal were prevented after a population reached peak densities, a normal decline phase should occur. This prediction is based on the assumption that dispersal during the increase phase is sufficient to ensure the decline phase 1 or 2 years later. All these experiments are concerned with the dispersal factor, and our work on Microtus can be summarized by the admonition: study dispersal.     

寄生不同虫龄小菜蛾对菜蛾啮小蜂生物学特性的影响

以小菜蛾重要的幼虫-蛹跨期寄生蜂菜蛾啮小蜂为研究对象,在(25±1)℃条件下研究了1,2,3,4龄初和4龄末小菜蛾幼虫被寄生后,对菜蛾啮小蜂生物学特性的影响.结果表明,寄生各个虫龄小菜蛾的啮小蜂从卵到羽化的发育历期、羽化后成蜂寿命没有明显的差异.不同虫龄被寄生小菜蛾羽化出的啮小蜂的性比只在3龄末和4龄末之间存在显著性差异,寄生4龄末小菜蛾育出的雄蜂比例最高.菜蛾啮小蜂对各虫龄小菜蛾幼虫产卵寄生没有表现出明显的偏好性,但相比2龄和4龄小菜蛾幼虫,3龄末小菜蛾幼虫仍是较适合的寄主,寄生3龄末小菜蛾幼虫羽化出的啮小蜂个体最大.     

七星瓢虫对常用杀虫剂的敏感性监测

采用FAO推荐的微量点滴法和药膜法,分别测定了七星瓢虫2、3、4龄幼虫和成虫对农田与果园常用杀虫剂的敏感性.结果表明,在供试药剂中,对不同龄期幼虫毒力高低顺序,2龄幼虫为:溴氰菊酯>啶虫脒>灭多威>齐螨素>吡虫啉>辛硫磷>氧乐果>氰戊菊酯:3龄幼虫为:啶虫脒>辛硫磷>溴氰菊酯>灭多威>吡虫啉>齐螨素>氧乐果>氰戊菊酯;4龄幼虫为:溴氰菊酯>啶虫脒>齐螨素>吡虫啉>氧乐果>灭多威>氰戊菊酯>辛硫磷;对其成虫的毒力高低顺序为:马拉硫磷>氧乐果>灭多威>溴氰菊酯>齐螨素>氯氟氰菊酯>啶虫眯>吡虫啉>辛硫磷>氰戊菊酯.药剂不同对七星瓢虫成虫及不同龄期的幼虫毒力大小不一样.反应出该虫不同虫态及龄期对常用杀虫剂的敏感性存在差异.旨在为保护农田及果园的天敌提供合理用药依据.     

球孢白僵菌对不同龄期棉蚜的毒力测定

通过室内试验,测定了球孢白僵菌菌株XW0107001对不同龄期棉蚜的毒力。结果表明:同一球孢白僵菌菌株对不同龄期棉蚜的毒力明显不同,随着龄期增加,球孢白僵菌对其毒力越来越大。     

枣实蝇幼虫龄期的测定

通过测定枣实蝇口钩长和头咽骨长2个形态指标,用最小二乘法对所测定的数据进行回归分析,结果表明,枣实蝇幼虫的头咽骨长度值在1龄与2龄之间有部分重叠;口钩长在龄期之间差异显著,可作为幼虫的分龄指标.1龄口钩长度为(0.0539±0.00063)mm;2龄为(0.0982±0.00109)mm;3龄为(0.1675±0.00296)mm;经F检验,枣实蝇各幼虫龄期数与口钩长度呈线性关系y=0.058x-0.011.     

人工饲料饲养舞毒蛾的试验

2000年和2001年利用人工饲料对舞毒蛾(Lymantria dispar L．)进行了饲养,并用柞树叶片饲养作对照：人工饲料饲养的1、2、3、4、5、6龄幼虫的平均发育历期分别为15、6、6、7、9、14d,幼虫发育总历期为57d;采用柞树叶片饲养的1、2、3、4、5、6龄幼虫的平均发育历期分别为12、6、6、6、8、14d,幼虫发育总历期为52d。从舞毒蛾幼虫头宽、体长比较来看,舞毒蛾1—4龄在头宽和体长上差异不大;5、6龄幼虫期间表现为：人工饲料饲养的舞毒蛾幼虫比柞树叶饲养的舞毒蛾幼虫头壳平均宽1mm左右,体长平均长2．4mm左右。     

青杨脊虎天牛幼虫龄期的划分1）

通过田间取样收集了青杨脊虎天牛（ Xylotrechus rusticus）幼虫,并根据6项测量指标（头壳宽、前胸背板宽、触角间距、上颚宽、体长、体宽）的频次分布结果初步确定龄期,然后运用Crosby生长法则和线性回归进行验证分析。结果表明：青杨脊虎天牛幼虫可分为13龄,除体宽不宜用于区分龄期外,其它5项测量指标均可用于分龄,其中前胸背板宽与虫龄的拟合度最高为最佳分龄指标,回归方程为y＝0．062e2．399x（p＜0．001,R2＝0．989）。此外,根据各龄期幼虫体宽、体长的平均值制作了相应龄期幼虫等比例背面观手绘图。