茴香薄翅野螟发生动态的调查

经调查研究表明:在青海省的油菜种植区,茴香薄翅野螟Evergestis extimalis Scopoli越冬幼虫从6月初开始化蛹,6月中旬化蛹率达为80%,到6月下旬化蛹率达到100%;成虫于7月上旬开始羽化,7月15～20日为成虫羽化高峰;田间卵始见期为6月下旬至7月上旬,7月中旬达到产卵高峰期;越冬幼虫平均死亡率为96.63%。     

库尔勒香梨上苹果蠹蛾发生规律及其性信息素迷向防控效果

【目的】苹果蠹蛾是我国进境检疫性有害生物。库尔勒香梨是苹果蠹蛾在新疆果树种植区的主要寄主。研究苹果蠹蛾性信息素迷向防控技术在新疆库尔勒香梨产区的应用效果,可为该害虫的绿色防控提供参考。【方法】通过持续监测与调查,掌握苹果蠹蛾在库尔勒香梨上的发生规律和危害特点,并通过定期调查诱蛾量和蛀果率,比较微胶囊迷向剂、迷向丝、常规化学农药对苹果蠹蛾的防治效果。【结果】库尔勒香梨产区苹果蠹蛾一年发生2~3代,以老熟幼虫越冬,且死亡率较低。4月中旬越冬代羽化出土,5月开始为害;第1代成虫高峰期为7月上中旬,第2代成虫高峰期为8月下旬至9月中旬。微胶囊迷向剂、迷向丝、常规化学农药处理区每周的平均诱蛾量分别为2.85、2.98、4.95头·台~(-1),平均蛀果率分别为2.25%、0.8%、0.99%,与空白对照区的差异均达极显著水平。【结论】使用性信息迷向剂能够降低苹果蠹蛾第1代、第2代幼虫及成虫的数量。     

基于综合气象干旱指数的石羊河流域近50年气象干旱特征分析

借助数理统计理论和GIS空间分析技术,利用综合气象干旱指数(composite index,CI),根据石羊河流域5个气象站1961-2010年实测气象资料,对石羊河流域近50a的干旱在时空上的变化特征进行分析.首先计算了各站历年逐日的CI指数,统计近50 a各站点出现的干旱过程、各时段的干旱事件,在此基础上分析了石羊河流域干旱发生的频率、覆盖范围和强度和不同等级干旱发生的多年平均日数.分析结果表明:(1)石羊河流域四季干旱发生频率均呈现北高南低的空间分布规律;在四季中,夏季干旱发生频率最高,冬季频率最低;极小值都在乌鞘岭,极大值略有不同:春、夏、冬季干旱发生频率极大值在民勤,秋季极大值在武威.(2)石羊河流域有大范围干旱发生的年份夏季和秋季较多分别有22 a、11a,冬季最少只有4a.(3)石羊河流域不同等级干旱日数总体上呈现夏季多冬季少、北部多南部少的规律,和降水量的空间分布有较好的负相关性.(4)干旱发生成因除了主要受东亚季风和西南季风的影响外,还应考虑到径流的影响.研究结果与实际情况相符,可为相关部门根据本地区干旱特征制定相应抗旱对策提供理论依据.     

Optimal behaviour can violate the principle of regularity

Understanding decisions is a fundamental aim of behavioural ecology, psychology and economics. The regularity axiom of utility theory holds that a preference between options should be maintained when other options are made available. Empirical studies have shown that animals violate regularity but this has not been understood from a theoretical perspective, such decisions have therefore been labelled as irrational. Here, I use models of state-dependent behaviour to demonstrate that choices can violate regularity even when behavioural strategies are optimal. I also show that the range of conditions over which regularity should be violated can be larger when options do not always persist into the future. Consequently, utility theory—based on axioms, including transitivity, regularity and the independence of irrelevant alternatives—is undermined, because even alternatives that are never chosen by an animal (in its current state) can be relevant to a decision.     

Alien spider introductions to Europe supported by global trade

Global trade is permanently ongoing and increases its volume every year. In this study, the occurrence of 87 unintentionally introduced spider species alien to Europe is analysed. The analysis includes (1) the introduction potential of six different origin areas of the world according to trade volume, area size, and geographical distance; (2) the body size of native and alien species; and (3) occurrence in or at buildings (synanthropic) or in natural habitats. We found the eastern Palearctic as the most influencing origin area with 44 introduced spider species to Europe. The eastern Palearctic and the Indomalayan provided a significantly higher number of introductions than expected, whereas the Nearctic, Neotropical, and Afrotropical provided a significantly lower number of introduced species than expected. This can be explained with their lower trade volume, smaller area, larger geographical distance to Europe, and stronger climate differences to Europe. Comparing the body size of introduced and native European spider species of the same family, we found for Theridiidae significantly larger alien spiders and for all other tested families a trend to a larger body size of alien species compared to the native spiders. The family affiliation of alien spiders is the most important factor for synanthropic occurrence in Europe. On the base of a very conservative estimation of spider species introductions to Europe combined with possible effects of climate change, we predict for the near future a permanent increase in the number of alien spider species in Europe.     

Seasonal acoustic occurrence,diel-vocalizing patterns and bioduck call-type composition of Antarctic minke whales off the west coast of South Africa and the Maud Rise,Antarctica

Seasonal occurrence, diel-vocalizing patterns, and call-types of Antarctic minke whales are described using bio-acoustic recordings from the west coast of South Africa and the Maud Rise, Antarctica. In Antarctica, minke whale bioduck calls were detected in seven of nine months of hydrophone deployment (peaking in May and September) while downsweeps were only detected in June. Bioduck calls were sporadically detected in South African waters with peak calling in September/October, and no bioducks were detected from March through August. Bioduck call occurrence was high during daytime in Antarctica but there was no diel-vocalizing pattern in South African waters. We split bioduck B call-type into two subtypes: B1 with 13 ± 1 pulses (Dominello & Širović, 2016) and B2 with 9 ± 1 pulses (this study). Bioduck B2 was detected both in Antarctic and South African waters, with harmonics up to 2 kHz. Similar bioduck call-types were detected in Antarctic and South African waters, with bioduck A2 being the most common. Month of the year was the most important predictor of bioduck occurrence both in Antarctic and South African waters. This is the first study to describe the seasonal occurrence, diel-vocalizing behavior and call-types of Antarctic minke whales off the South African west coast and eastern Weddell Sea.     

Coarse-Scale Distribution Surveys and Occurrence Probability Modeling for Wolverine in Interior Alaska

ABSTRACT We determined wolverine (Gulo gulo) distribution and occurrence probabilities using aerial surveys and hierarchical spatial modeling in a 180,000-km² portion of Interior Alaska, USA. During 8 February-12 March 2006, we surveyed 149 of 180 1,000-km² sample units for wolverine tracks. We observed wolverine tracks in 99 (66.4%) sample units. Wolverine detection probability was ≥69% throughout the survey period. Posterior occurrence probabilities of whether a wolverine track occurred in a sample unit was dependent on survey timing, number of transects flown, number of neighboring sample units with detected tracks, percentage of the sample unit with elevation ≤305 m, and human influences. Our model indicated strong evidence of occurrence (>0.80) in 72% of the 180 survey units, strong evidence of absence (<0.20) in 12%, and weak evidence of occurrence or absence (0.20–0.80) in 16%. Wolverine area of occupancy made up 83% of the study area. Simulations illustrated that 2–4 survey routes were necessary for the survey technique to provide strong evidence of wolverine presence or absence in Interior Alaska if a track was not identified along the first route. The necessary number of survey routes depends on the occurrence probability in a sample unit. We provided managers with a map of wolverine distribution in Interior Alaska and an efficient and lower-cost method to detect coarse-scale changes in wolverine distribution. Our technique was effective in both Interior Alaska and Ontario, Canada, suggesting it would be effective throughout most of the boreal forest range of wolverines where tracks can be readily observed from the air. The technique requires a certain skill level in recognizing tracks; it is essential that tracks are identified correctly and training may be necessary depending on surveyor experience.     

The ichnogenus Tremichnus in the Lower Silurian of western New York

Discovery of Tremichnus cysticus Brett on a crinoid pluricolumnal from the Willowvale Shale of western New York extends the range of this ichnogenus into the Lower Silurian. Pits attributable to Tremichnus apparently represent embedment sites of parasites or commensalistic, filter-feeding organisms of unknown affinities. Embedment of T. cysticus may have been accomplished by localized inhibition of stereom growth within the pits aided by secretion of substances that stimulated accretion of stereom by the host pelmatozoan in areas immediately surrounding the pits.     

Spatial and temporal variation in the diet of the sandy beach gastropod Olivella minuta

Marine gastropods exert a strong influence on the structure of marine ecosystems through their foraging activities, yet little is known about how environmental differences in space and time may affect their feeding behavior. To enhance the knowledge about the trophic ecology of coastal benthic species, we investigated temporal and spatial variations in the diet of the sandy beach gastropod Olivella minuta. We collected individuals of O. minuta seasonally, over 1 year, at two sandy beaches with different morphodynamic characteristics (Araçá Bay, an ultra‐dissipative tidal flat, and Barequeçaba Beach, a dissipative beach) and analyzed the stomach contents of specimens of O. minuta. We identified approximately 15,000 food items, which we grouped into 14 categories. Thirteen food categories were found at each area, but significant differences in diet were observed between sites and sampling periods. Individuals from Araçá consumed an overall larger quantity and diversity of food items, which consisted mainly of foraminiferans, polychaetes, and crustaceans. At Barequeçaba, diatoms were the most important item, followed by crustaceans and polychaetes. Temporal variation depended on sites: the number of food items in the stomachs of individuals of O. minuta and dietary composition was roughly constant over time at Araçá, whereas larger variations were observed at Barequeçaba. Although O. minuta has been previously characterized as a carnivore/scavenger, our results show that the diet of this species varies in space and time and comprises a large variety of food resources. The species thus plays a role in the cycling of both vegetal and animal organic matter. This generalist behavior may allow individuals to shift their diet according to habitat alterations and food availability, thereby enhancing the persistence and resilience of O. minuta in different environments or future climate change scenarios.     

Spatial analysis of ectomycorrhizal fungi reveals that root tip communities are structured by competitive interactions

Microbial ecology has made large advances over the last decade, mostly because of improvements in molecular analysis techniques that have enabled the detection and identification of progressively larger numbers of microbial species. However, determining the ecological patterns and processes taking place in communities of microbes remains a significant challenge. Are communities randomly assembled through dispersal and priority effects, or do species interact with each other leading to positive and negative associations? For mycorrhizal fungi, evidence is accumulating that stochastic and competitive interactions between species may both have a role in shaping community structure. Could the methodological approach, which is often incidence based, impact the outcomes detected? Here, we applied an incidence‐based Terminal Restriction Fragment Length Polymorphism (T‐RFLP) database approach to examine species diversity and ecological interactions within a community of ectomycorrhizal (ECM) fungi. Co‐occurrence analysis revealed that the ECM community colonizing root tips was strongly structured by competitive interactions, or ecological processes generating a similar spatial pattern, rather than neutral processes. Analysis of β‐diversity indicated that community structure was significantly more similar (spatially autocorrelated) at distances equal to or <3.41 m. The eight most frequently encountered species in the root tip community of ECM fungi displayed significant competitive interactions with at least one other species, showing that the incidence‐based approach was capable of detecting this sort of ecological information.