蝗虫微孢子虫病在草原蝗虫优势种种群及空间的分布

在采用蝗虫微孢子虫Nosema locustae防治过的草场中进行抽样调查,研究了草原蝗虫优势种类、混合种群平均密度与蝗虫微孢子虫疾病分布之关系,以及该疾病的空间分布。在防治后的当年,蝗虫微孢子虫疾病的感染率随着混合种群平均密度及靶标蝗虫亚洲小车蝗Oedaleus asiaticus的感病率的下降而降低。但是,次靶标蝗虫如宽须蚁蝗Myrmeleotettixpalpalis(一种中后期发生的种类)其感病率呈上升趋势,表明该疾病可在不同发生期种类蝗虫之间进行有效地传播。病蝗虫在防治后第7d其空间分布呈随机分布(Poisson),第28d 则是聚集分布,第40d时也呈聚集分布。于1993年、1994年对1988年(样区Ⅱ)、1989 年(样区Ⅲ)采用微孢子虫防治过的草场进行抽样调查。结果表明,在二个样区中,二年混合种群平均虫口密度与混合种群的平均感病率呈正相关(相关系数分别为r=0.289, r=0.479)。蝗虫微孢子虫病在主要优势种,如亚洲小车蝗、宽须蚁蝗、白边痂蝗Bryode maluctuosumluctuosum、皱膝蝗Angaracris /I>spp.、毛足棒角蝗Dasyhippus barbipes均有分布。二个样区中的混合蝗虫种群的平均感病率在1994年显著低于1993年。混合蝗虫种群的种类组成也有所变化,与1993年相比,1994年宽须蚁蝗及白边痂蝗的比例上升较大,而亚洲小车蝗的比例下降。经过5—7年的扩散,蝗虫微孢子虫病至少可扩散距防治区1 000m,其扩散方向可能与风及地势等有关。     

荒漠草原蝗虫群落空间格局的研究

应用种－面积关系模型,计算出宁夏荒漠草原蝗虫群落最小调查面积;通过２×２联列表,用点相关系数和相关系数公式对蝗虫种间分布关系进行分析,用模糊聚类法将调查蝗虫划分为４个类群;以６项聚集指标和新提出的混合度指数,对９种蝗虫种群及群落分布型进行了分析,用主成分分析法进行了排序归类。最后依据种群数量、混合度指数、分布型相似性提出群落格局的“主导分布型”新概念,认为宁夏束颈蝗种群分布型为宁夏荒漠草原蝗虫群落空间格局的“主导分布型”     

五种蝌蚪口器及舌鳃骨的结构比较

采用体视显微镜和骨骼双染色法对5种不同栖息环境的无尾两栖动物蝌蚪的口器和舌鳃骨的形态结构特征进行了观察。5种蝌蚪口器由唇齿行、唇乳突和角质颌等组成。舌鳃骨是由关联骨Ⅰ、关联骨Ⅱ、角舌骨、舌鳃骨盘和角鳃骨等骨骼组成。蝌蚪的梅氏软骨若较发达,其摄食方式可能为刮食;蝌蚪的舌鳃骨发达,其摄食方式则可能为滤食。角质颌、唇齿以及角鳃骨上鳃耙的出现显著增强了蝌蚪主动摄食能力和对食物与非食物的主动选择性。     

蝗虫(直翅目:蝗总科)口器感受器的扫描电镜观察

对蝗总科8种蝗虫的口器感受器的超微结构、类型和分布进行了观察分析,共观察到6种蝗虫口器感受器:毛形感受器、锥形感受器、腔锥形感受器、B(o)hm氏鬃毛、刺形感受器I和刺形感受器Ⅱ,其中B(o)hm氏鬃毛是首次报道.同时对观察到的3种角质齿进行了描述.     

荒漠草原三种蝗虫成虫种内和种间竞争的研究

荒漠草原三种蝗虫成虫种内和种间竞争的研究贺达汉方成郑哲民（宁夏农学院农学系,永宁７５０１０５）（陕西师范大学动物研究所,西安７１００６２）Ｉｎｔｒａ＿ａｎｄＩｎｔｅｒｓｐｅｃｉｆｉｃＣｏｍｐｅｔｉｔｉｏｎａｍｏｎｇｔｈｅＡｄｕｌｔｓｏｆＴｈｒｅｅＧｒ...     

蝗虫消化道结构的比较研究

采用扫描仪分析方法对10种蝗虫消化道形态结构进行了观察比较,发现蝗虫不同类群个体其中肠占消化道总长的比例依进化地位呈现递增趋势,胃盲囊和后肠则呈递减趋势.这种趋势可能是随着蝗虫类群的进化,中肠在消化道所占的比例逐渐增大,对食物的消化吸收能力逐渐增强,与之相应的是胃盲囊呈退化趋势,同时后肠所排泄的残渣逐渐减少,导致蝗虫消化道形态发生适应性变化的结果.     

内蒙古锡林河流域三种草原蝗虫对植物高度选择的观察

在实验条件下,观察了发生期及个体大小不一致的3种草原蝗虫对植物高度选择情况．结果表明：蝗虫对植物高度的选择与其本身发生时期及个体大小相关,是物种长期进化的结果,同时,还探讨了蝗虫对植物高度的选择与温度、温度及光照强度之间的关系．     

内蒙古11种主要草原蝗虫16S rDNA序列分析

测定了内蒙古11种主要草原蝗虫的线粒体基因组16S rDNA序列,并构建了其分子系统树。在获得的505 pb序列中,G+C占302%,A+T占698%,表现出A/T偏向性。在505 bp个碱基中检测到156个多态性位点,占碱基总数的309%。156个多态性位点中包括50个单变异多态性位点（占总位点数的321%）和106个简约信息位点（占总位点数的679%）。分别采用NJ、ME、MP和UPGMA聚类方法构建系统发生树。结果表明,4科的17种蝗虫共聚为6支,其中槌角蝗科、斑腿蝗科与网翅蝗科3个科的蝗虫先聚在一起,再与斑翅蝗科相聚。4种聚类方法中UPGMA聚类法更为符合传统的以形态学为基础的分类体系。     

草原蝗虫营养生态位的研究*

本文采用嗉囊内含物显微分析技术系统地研究了内蒙古典型草原蝗虫的选食特性和食物利用诺。根据11种蝗虫嗉囊内含物分析的结果,定量地研究了蝗虫的营养生态位以及生态位的重叠和宽度。11-种蝗虫依据生态位分化的特点,被划分为5个不同的营养需求类群：禾草取食者、禾草-杂草取食者、杂草-禾草取食者、杂草取食者和杂食者。作者通过对蝗虫食性及生物量的研究,提出了蝗虫潜在严重值和实际严重值的概念和计算方法,也就蝗虫在草原生态系统中的相互作用关系及共存关系进行了讨论。     

Temporal expression of c-kit in spermatogenesis of two grasshopper species

Two species of grasshoppers, Calliptamus abbreviatus （Ikonn.） and Shirakiacris shirakii （I. Bol.）, were collected randomly in the Siping area of Jilin Province, China. By using immunohistochemical methods and statistical analysis, we observed and compared the temporal expression of c-kit protein in four representative stages of spermatogenesis of the two grasshoppers, namely： spermatogonia; primary spermatocyte; secondary spermatocyte; and mature sperm. Results showed that there was c-kit positive temporal expression at each stage of spermatogenesis, but there were different positive expression levels： （i） weak positive expression of c-kit protein appeared in spermatogonia and the positive granules were thinner; （ii） strong positive expression of c-kit protein existed in primary spermatocyte and positive granules became biggest among all developmental stages; （iii） c-kit positive expression stayed stronger in secondary spermatocyte while positive granules became thinner; （iv） there was a strong positive expression of c-kit and thinner positive granules in mature sperm, which distributed on head and tail; （v） the biggest c-kit positive granules had been found massing at the end of spermary; and （vi） significant differences of c-kit positive expression existed in spermatogenesis between two species of grasshoppers. The results indicated that c-kit protein may play a crucial role in spermatogenesis and even retain the physiological action of sperms and fertilization in grasshoppers.     

Traits of dominant plant species drive normalized difference vegetation index in grasslands globally

Aim

Theoretical, experimental and observational studies have shown that biodiversity–ecosystem functioning (BEF) relationships are influenced by functional community structure through two mutually non-exclusive mechanisms: (1) the dominance effect (which relates to the traits of the dominant species); and (2) the niche partitioning effect [which relates to functional diversity (FD)]. Although both mechanisms have been studied in plant communities and experiments at small spatial extents, it remains unclear whether evidence from small-extent case studies translates into a generalizable macroecological pattern. Here, we evaluate dominance and niche partitioning effects simultaneously in grassland systems world-wide.

Location

Two thousand nine hundred and forty-one grassland plots globally.

Time period

2000–2014.

Major taxa studied

Vascular plants.

Methods

We obtained plot-based data on functional community structure from the global vegetation plot database “sPlot”, which combines species composition with plant trait data from the “TRY” database. We used data on the community-weighted mean (CWM) and FD for 18 ecologically relevant plant traits. As an indicator of primary productivity, we extracted the satellite-derived normalized difference vegetation index (NDVI) from MODIS. Using generalized additive models and deviation partitioning, we estimated the contributions of trait CWM and FD to the variation in annual maximum NDVI, while controlling for climatic variables and spatial structure.

Results

Grassland communities dominated by relatively tall species with acquisitive traits had higher NDVI values, suggesting the prevalence of dominance effects for BEF relationships. We found no support for niche partitioning for the functional traits analysed, because NDVI remained unaffected by FD. Most of the predictive power of traits was shared by climatic predictors and spatial coordinates. This highlights the importance of community assembly processes for BEF relationships in natural communities.

Main conclusions

Our analysis provides empirical evidence that plant functional community structure and global patterns in primary productivity are linked through the resource economics and size traits of the dominant species. This is an important test of the hypotheses underlying BEF relationships at the global scale.     

汉中地区三个自然保护区蝗虫种类调查

汉中有陕西长青国家级自然保护区、陕西洋县朱自然保护区和陕西省佛坪国家级自然保护区。经过调查,3个自然保护区共有蝗虫39种,隶属5科27属,其中锥头蝗科Pyrgomorphidae仅1属1种,斑腿蝗科Catantopidae8属16种,网翅蝗科Arcyperidae5属9种,斑翅蝗科Oedipodidae9属9种,剑角蝗科Acrididae4属4种。3个自然保护区中,斑腿蝗科物种和属的多样性较为丰富。3个自然保护区的蝗虫区系组成包括东洋区种类17种、古北区7种、两区共有种8种和秦巴山区特有种7种。秦巴山区特有种的相对数量比较多(179%),这反映出汉中自然环境的特殊性。     

Evolutionarily conserved coding properties of auditory neurons across grasshopper species

We investigated encoding properties of identified auditory interneurons in two not closely related grasshopper species (Acrididae). The neurons can be homologized on the basis of their similar morphologies and physiologies. As test stimuli, we used the species-specific stridulation signals of Chorthippus biguttulus, which evidently are not relevant for the other species, Locusta migratoria. We recorded spike trains produced in response to these signals from several neuron types at the first levels of the auditory pathway in both species. Using a spike train metric to quantify differences between neuronal responses, we found a high similarity in the responses of homologous neurons: interspecific differences between the responses of homologous neurons in the two species were not significantly larger than intraspecific differences (between several specimens of a neuron in one species). These results suggest that the elements of the thoracic auditory pathway have been strongly conserved during the evolutionary divergence of these species. According to the 'efficient coding' hypothesis, an adaptation of the thoracic auditory pathway to the specific needs of acoustic communication could be expected. We conclude that there must have been stabilizing selective forces at work that conserved coding characteristics and prevented such an adaptation.     

Differential responses to warming and increased precipitation among three contrasting grasshopper species

We conducted a field manipulation experiment to investigate developmental and demographic responses to warming and increased precipitation in three Inner Mongolian grasshopper species that differ in phenology (an early-season species Dasyhippus barbipes , a mid-season species Oedaleus asiaticus , and a late-season species Chorthippus fallax ). Infrared heaters were used for warming the ground surface by 1–2 °C above the ambient condition and periodic irrigations were applied to simulate a 50% increase in annual precipitation. We found that warming advanced the timing for egg hatching and grasshopper eclosion in each of the three species. However, grasshopper diapause and increased precipitation appeared to offset the effect of warming on egg development. Hatching and development were more strongly affected by warming in the mid-season O. asiaticus and the late-season C. fallax relative to the early-season D. barbipes . Warming by ∼1.5 °C advanced the occurrence of the mid-season O. asiaticus by an average of 4.96 days; while warming and increased precipitation interactively affected the occurrence of the late-season C. fallax , which advanced by 5.53 days. Our data and those of others suggest that most grasshopper species in the Inner Mongolian grassland are likely to extend their distribution northward with climate change. However, because of the differential response to warming we demonstrate for these species, the different grasshopper species are predicted to aggregate toward the middle period of the growing season, potentially increasing interspecific competition and grazing pressure on grasslands.     

烟粉虱在七种寄主植物上的生命表参数分析

在恒温25℃下,组建了烟粉虱在黄瓜、茄子、番茄、烟草、辣椒、甘蓝和菜豆等7种寄主植物上的实验种群生命表。结果表明,烟粉虱在不同寄主植物上的存活曲线差异明显,各寄主植物上以1,2龄若虫和成虫死亡率最高,3龄和伪蛹期死亡较少甚至不死亡;各寄主植物上烟粉虱的内禀增长率在0．2445～0．3424之间,以番茄上的rm最大,菜豆上的rm最小。讨论了烟粉虱的发展趋势和防治对策。     

Influence of plant silicon and sugarcane cultivar on mandibular wear in the stalk borer Eldana saccharina

1 Silicon can increase the resistance of plants to attack by herbivorous insects. The present study aimed to determine the effect of silicon and cultivar on mandibular wear in larvae of the sugarcane stalk borer Eldana saccharina Walker (Lepidoptera: Pyralidae).
2 Four sugarcane cultivars, resistant (N21, N33) and susceptible (N11, N26) to E. saccharina were grown in a pot trial in silicon deficient river sand, with (Si+) and without (Si−) calcium silicate. Individual third-instar larvae were confined on the sugarcane stalk at three known feeding sites (leaf bud, root band and internode) and left to feed for 21 days.
3  Eldana saccharina larval heads were mounted on stubs, with the mandibles oriented horizontally and photographed under a scanning electron microscope. Mandibular wear was measured from the digital images using a quantitative method.
4 Although there was a trend for increased wear in larvae that developed on Si+ cane, no significant effect of silicon, cultivar or site on mandibular wear of E. saccharina was shown.
5 This is the first study to accurately and quantitatively measure the mandibular wear of an insect fed on Si+ plants.     

Grain-dependent relationships between plant productivity and invertebrate species richness and biomass in calcareous grasslands

The relationships among productivity, species richness and consumer biomass are of fundamental importance for understanding determinants of biodiversity. These relationships may depend on grain size. We examined the relationships between productivity (above-ground phytomass) and plant species richness and between productivity and species richness and biomass of gastropods and grasshoppers using sampling units of different sizes (0.5, 2.75 and 23 m²) in nutrient-poor, calcareous grasslands in north-western Switzerland in two successive years. Species richness of forbs had a unimodal relationship with productivity in sampling units of 0.5 m² and was negatively correlated with productivity at the other two plot sizes in one year. In the other year, forb species richness tended to decrease with productivity in sampling units of 23 m². No similar relationship was found for grasses. Gastropod biomass had a unimodal relationship with productivity at 0.5 m² in the first year. Grasshopper species richness was correlated with forb species richness at plot sizes of 2.75 and 23 m². This study demonstrates that patterns detected between productivity and diversity and between productivity and biomass of consumers depend on the grain size used in the investigation and vary among years.Die Zusammenhänge zwischen Produktivität, Artenreichtum und Biomasse von Konsumenten sind wichtig, um zu verstehen, was Biodiversität beeinflußt. Diese Zusammenhänge können von der Größe der Untersuchungsfläche abhängig sein. Wir untersuchten während zwei aufeinanderfolgenden Jahren die Zusammenhänge zwischen Produktivität (oberirdische Pflanzenbiomasse) und Artenreichtum von Gefäßpflanzen, sowie zwischen Produktivität und Artenreichtum und Biomasse von Schnecken und Heuschrecken bezüglich dreier räumlicher Skalen (0,5, 2,75 und 23 m²) in Kalkmagerrasen in der Nordwestschweiz. Der Zusammenhang zwischen dem Artenreichtum von Kräutern und der Produktivität war unimodal in Flächeneinheiten von 0,5 m² und negativ in Flächeneinheiten von 2,75 und 23 m² im ersten Jahr und war tendenziell negativ in Flächeneinheiten von 23 m² im zweiten Jahr, während kein solcher Zusammenhang bei Gräsern gefunden wurde. Der Zusammenhang zwischen Produktivität und Biomasse von Schnecken war unimodal in Flächeneinheiten von 0,5 m² im ersten Jahr. Außerdem bestand ein Zusammenhang zwischen dem Artenreichtum von Kräutern und Heuschrecken in Flächeneinheiten von 2,75 und 23 m². Diese Arbeit zeigt, daß Zusammenhänge zwischen Produktivität und Diversität sowie zwischen Produktivität und Biomasse von Konsumenten von der Größe der Untersuchungsfläche abhängen und zwischen Jahren variieren.     

Mechanical functions of setae from the mouth apparatus of seven species of decapod crustaceans

The mouthpart setae of seven species of decapods were examined with macro-video recordings and scanning electron microscopy. The general mechanical (nonsensory) functions of the different mouthparts are described and an account of their setation is given. This offers the possibility to determine the mechanical functions of the different types of setae. Pappose setae do not participate in food handling but in general make setal barriers. Plumose setae likewise do not contact food objects but assist in current generation. Papposerrate setae are rare but they were seen to assist in pushing food particles into the mouth. Serrulate setae are very common and mainly participate in gentle food handling and grooming. Serrate setae are used for more rough food manipulation and grooming. The roughest shredding, tearing, and manipulation of prey items are handled by the cuspidate setae. Simple setae seem to be divided into two populations with very different functions. On the maxillipeds of Panulirus argus they are used for shredding, tearing, and holding the food objects, but on the basis of maxilla 2 of three other species they appear to have very little mechanical influence and only when handling small prey items. The functional scheme seems to be consistent within the Decapoda.