Do plant cues influence the oviposition behavior of Japanese beetles?

A bioassay arena was developed to test the response of the Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), to various plant‐derived factors that may influence the selection of oviposition sites. In choice experiments with natural and artificial plant cues, females preferred to lay eggs in ryegrass rather than in artificial resources. Artificial grass stems received more eggs on average than bare ground, indicating the role of vertical objects on the soil surface as oviposition cues. Popillia japonica females were able to discriminate between the quality and quantity of the artificial stems, as more eggs were laid in soil blocks that had larger diameter stems or a higher number of stems per soil block. Beetles were capable of evaluating plant characteristics on the soil surface and adjusted their investment accordingly; more eggs were laid in resources that were chosen more frequently. Observations of females in choice arenas revealed how surface cues influence digging behavior and the time spent under the soil surface. The number of digging events was not significantly different among the three treatments with surface cues (ryegrass, grass roots, and artificial grass), but beetles spent significantly more time in the soil under ryegrass than any of the other treatments. These findings suggest that oviposition by P. japonica is selective and is influenced by plant‐derived cues evaluated before and after digging into the soil.     

白龙江林区地表甲虫沿海拔梯度的群落结构及动态分析

【目的】揭示白龙江林区地表甲虫群落沿海拔梯度（927-2 735 m）的多样性格局、群落结构及动态变化,为林区内生物多样性长期监测及保护提供理论基础和依据。【方法】采用巴氏罐诱捕法,沿不同海拔梯度（927、1 794、2 376和2 735 m）设置陷阱诱集地表甲虫。【结果】共采集2 015头地表甲虫,包括18科95种。虎甲科Cicindelidae的个体数量最多（436只）占总数的21.6%,其次是叩甲科Elateridae、步甲科Carabidae、葬甲科Silphidae、隐翅甲科Staphylinidae。5个科的采集数量占到总数的75.1%,是白龙江地区优势种群。随着海拔梯度的升高,流域内地表甲虫的数量及优势种群数量都呈先上升后下降的趋势。在海拔2 376 m处,地表甲虫丰富度最高,诱集数量最多。低海拔地区地表甲虫丰富度低,诱集数量少。在种群动态变化中,中高海拔地区的优势种群在6-9月间的种群数量变化趋势呈单峰增长模式,且不同海拔高度不同科种群的诱集峰值不同。如在不同海拔梯度内诱集的步甲科数量均在7月份最多;在海拔2 376 m处,叩甲科个体数量在8月份最多,相比海拔较低的1 794 m处,则7月份数量最多,在低海拔927 m处和高海拔地区2 735 m处,叩甲科的个体数量急剧减少,且动态变化不明显。【结论】在白龙江林区拱坝河流域,地表甲虫种类丰富,优势种群明显。在不同海拔梯度上,其优势种群表现出不同的变化模式。根据地表甲虫群落在海拔梯度上的分布,可将地表甲虫分为三类。一是分布在中高海拔,包括步甲科、隐翅甲科及虎甲科等,在流域内4个不同海拔梯度都有分布。二是在中高海拔和高海拔处种类丰富,在低海拔处未诱集到相应甲虫,包括叩甲科及葬甲科。三是在不同海拔高度都有分布,但数量少,未形成优势种群,包括金龟科、象甲科及瓢虫科等。     

长三角地区土地利用时空变化对生态系统服务价值的影响

基于1980—2010年的土地利用数据,估算了各种土地利用类型的生态系统服务价值,分析了长三角30年来生态系统服务价值的时空动态及其对土地利用变化的响应。结果表明,1980—2010年,长三角建设用地面积变化最大,为446.1%,未利用地、耕地、草原、林地、水域的变化分别为285.9%、-31.5%、-76.2%、-5.4%、42.9%;1980—2010年,长三角地区的总生态系统服务价值减少了4.40%,水源涵养、休闲娱乐、废物处理生态系统服务功能价值上升;生态系统服务价值极低区域的面积增加且分布于城市扩张区域,生态系统服务价值中等区域逐年下降且被生态系统服务价值低区域所替代,高生态系统服务价值区域处于增加的趋势而极高区域基本维持不变;常州、湖州、嘉兴、南京、泰州的生态系统服务价值逐年增加,而其他城市的则处于下降趋势。     

Host suitability and diet mixing influence activities of detoxification enzymes in adult Japanese beetles

Induction of cytochrome P450, glutathione S transferase (GST), and carboxylesterase (CoE) activity was measured in guts of the scarab Popillia japonica Newman, after consumption of single or mixed plant diets of previously ranked preferred (rose, Virginia creeper, crape myrtle and sassafras) or non-preferred hosts (boxelder, riverbirch and red oak). The goal of this study was to quantify activities of P450, GST and CoE enzymes in the midgut of adult P. japonica using multiple substrates in response to host plant suitability (preferred host vs non-preferred hosts), and single and mixed diets. Non-preferred hosts were only sparingly fed upon, and as a group induced higher activities of P450, GST and CoE than did preferred hosts. However, enzyme activities for some individual plant species were similar across categories of host suitability. Similarly, beetles tended to have greater enzyme activities after feeding on a mixture of plants compared to a single plant type, but mixing per se does not seem as important as the species represented in the mix. Induction of detoxification enzymes on non-preferred hosts, or when switching between hosts, may explain, in part, the perceived feeding preferences of this polyphagous insect. The potential consequences of induced enzyme activities on the ecology of adult Japanese beetles are discussed.     

Distribution of Norway spruce bark and wood‐boring beetles along Alpine elevational gradients

相似文献   

Evaluation of two prototype traps and existing trap designs for captures of Japanese beetles (Coleoptera: Scarabaeidae)

Two prototype trap designs and four other trap designs currently on the market were evaluated for capture of Japanese beetles, Popillia japonica Newman. The standard Japanese beetle trap manufactured by Trece (Palo Alto, CA) and a prototype trap captured consistently more beetles than other trap designs tested. Traps that used a bag for collection of beetles were not as effective because beetles were able to escape through the holes made for drainage. The new trap design allows traps to be transported more easily and stored in a smaller area because of the collapsible design. This is a significant improvement for states that use thousands of traps for monitoring Japanese beetles.     

The influence of urban land use on seed dispersal and wetland invasibility

Urban habitats are generally considered highly invaded by exotic species due to the frequency and extent of disturbance caused by human activities and development. Our previous study had demonstrated that forested wetlands within residential areas are more extensively invaded than wetlands within industrial–commercial areas. In this study, we investigate whether the structure of the forest edge and seed dispersal can explain the differential in the invasion of wetlands surrounded by industrial and residential land use. Our results indicate that edges of industrially bordered wetlands are denser, with vegetation concentrated at the boundary of tree growth, whereas the edges of residentially bordered wetlands are more open and diffuse. This difference influences the number of seeds and species capable of dispersing into the wetland. Less dense edges resulted in a higher number of seeds entering residential wetlands; however, there were no differences in the numbers of exotic seeds or exotic species in the seed rain residential and industrial wetlands. Although seed dispersal could not directly explain differences in the current extent of invasion of these sites, seed dispersal did follow corridor pathways, including ditches and trails that breach the edges and extend through the wetlands. These disturbances act as corridors for seed dispersal into both types wetlands and may play a role in introducing new species to the interior of the wetland, an outcome supported by a higher number of exotic species in the seed banks of residential sites. Our results suggest that both the type of adjoining land use and the provision of access to people on trails in urban wetlands can affect the composition of these communities.     

Impact of land use change on soil aggregate dynamics in the dry tropics

A 2‐year study was conducted to elucidate land use change (LUC) impact on the distribution of aggregate size fractions and associated carbon (C) concentration involving natural forest (NF), degraded forest (DF), cropland (CL), and biofuel plantation (JP, Jatropha plantation) in the dry tropical region of India across the soil profile (0–10, 10–20, and 20–30 cm). Across the seasons and the land uses, the proportion of macro‐ and microaggregates was maximum at upper and minimum at lower layer whereas mesoaggregates increase with depth. The trend of macro‐ and microaggregate fractions through the soil profile was NF > JP > DF > CL whereas that of mesoaggregates was CL > DF < JP > NF. Dry mean weight diameter was highest at upper layer and decreased down the depth in all the land uses and followed the trend NF > JP > DF > CL. Aggregate associated organic carbon (OC) concentration in all the fractions decreased from NF to DF, CL, or JP indicates that macroaggregate associated OC concentration was more susceptible to loss than that of meso‐ and microaggregate associated OC concentration. LUC induced decline in macroaggregate associated OC stock and increase in meso‐ and microaggregate associated OC stock; indicated redistribution of OC stock among aggregate fractions. It may be concluded that JP in dry tropics can be an efficient strategy for rehabilitation of degraded land as it improves aggregate structure and stability in the whole profile and aggregate associated OC stock in upper layer of soil.     

Responses of grassland ecosystems to precipitation and land use along the Northeast China Transect

Abstracts. The Northeast China Transect (NECT) has been used to study how water availability influences the composition of plant functional types, soil organic matter, net primary production, trace gas flux, and land‐use patterns. We discuss relations of plant species number, soil C and N and above‐ground biomass with a precipitation gradient and interactions with land‐use practices (grassland fencing, mowing and grazing), on the basis of data from the west part of NECT. The results indicate: 1. The above‐ground biomass of grassland communities has a linear relationship with precipitation under three land‐use practices, while plant species number, soil C, and total soil N have linear relationships with precipitation under fencing and mowing; under grazing the relationships are non‐linear. 2. Plant species number, soil C and total soil N have strong linear relationships with above‐ground biomass under both fencing and mowing, while they seem to have nonlinear relationships under grazing. 3. Land‐use practices along the precipitation gradient result not only in changes in grassland communities but also in qualitative changes of their structure and function. 4. Grasslands are more vulnerable to changes in climate under mowing than under fencing, and are more capable to store C in soil and plants. 5. At a given precipitation level, number of plant species, above‐ground biomass, and soil C are higher under low to medium intensity of human activities (mowing and grazing). A better understanding of how different intensities of human activities will affect the structure and function of grassland will require further research.     

The influence of 3-years of warming and N-deposition on ecosystem dynamics is small compared to past land use in subalpine meadows

Background and aims

Drivers of ecosystem dynamics that are under human influence range from local, land-management decisions to global processes such as warming temperatures and N deposition. The goal of this study was to understand how multiple, potentially interacting factors influence net primary production, N mineralization, and water and soil CO₂ fluxes.

Methods

Here I report on a three-year experiment that manipulated air temperature using ITEX passive warming cones and N deposition in a mountain meadow ecosystems that were historically grazed or protected from grazing.

Results

The strongest and most consistent effect was due to the legacy of grazing, with previously grazed sites having lower primary production, lower soil respiration rates, lower soil moisture, and lower soil C and N stocks than historically ungrazed sites. Warming increased soil respiration, but the effect was transient, and decreased over the 3-year study. Nitrogen addition increased primary production in the second and third year of the experiment but had no significant effect on soil respiration. The effect of historical grazing on primary production was approximately double the effect of N addition. Temperature and N deposition rarely interacted except for increasing N availability during the warm, wet growing season of 2004.

Conclusions

These findings indicate that the legacies of land use, with their influence on plant community composition and hydrologic processes, are locally more important than short-term step changes in temperature and nutrient availability.     

长江口不同区段围垦区土地利用/覆被变化的时空动态

基于1987、1995、2000和2006年长江口TM、ETM遥感影像,利用RS、GIS与数学统计方法,对长江口不同围垦区土地利用动态进行了分析.结果表明：研究期间,不同围垦区草地面积所占比例在空间上的差异达显著水平（P＜0.05）,大棚用地和水田面积所占比例在时间序列上的差异达显著水平(P＜0.05);去除围垦时间的因素,不同围垦区土地利用多样性指数的变化无显著性差异;土地利用年变化速率在空间上差异不显著,在时间上具有显著差异的土地类型为大棚用地和建筑用地;不同围垦区的土地利用程度具有一致性,土地利用转移方向的差异也不显著,转移强度相似.长江口不同围垦区的土地利用动态主要受围垦时间的影响.     

The influence of habitat type on the population dynamics of ground beetles (Coleoptera: Carabidae) in marshland

This study presents qualitative and quantitative research on communities of ground beetles (Carabidae) occurring in 2001 and 2003 in three types of habitats located near Bydgoszcz city, Poland (UTM CD19), on the Vistula river floodplain: elm and ash riparian forest (RF), poplar monoculture (P), and unintensively-farmed meadows (M). During both studied years 57 species of ground beetles were found in riparian forests (RF), 56 species in plot P and 47 in plot M. In 2001 from all sample plots 3845 beetles were collected; in 2003- 9589. In both years most specimens came from plot RF (3123 in 2001 and 6224 in 2003). From plot P 2656 specimens of ground beetles were collected and from plot M 1430 specimens. Statistically significant differences were found in the abundance of Carabidae, among sampling areas and the years of study.     

Landscape responses to a century of land use along the northern Patagonian forest-steppe transition

Land use history reconstructions in temperate regions of the Northern Hemisphere indicate that periods of deforestation are often followed by natural afforestation, so that the long-term outcome at the landscape level will be a balance of retractions and advances of plant communities associated with varying local land uses. During the last decades of the XIX century, large forest areas were cleared in Northwestern Patagonia to open farmland. In this article, we compared historical land use/land cover maps with land cover maps derived from Landsat images to analyze the factors that may have influenced the dynamics of land cover change of the forest-steppe ecotone during the last 100 years. Our results indicate that Patagonian forests underwent a rapid initial recovery after the extensive fires of last century, replacing mainly shrublands. More than 50% of the old burns are currently covered by forests, and modern fires affect areas characterized by fire-prone vegetation. Whereas natural afforestation is an ongoing process positively associated with moisture, the rate of forest losses has increased during the last three decades, concentrating on xeric aspects and the vicinity of roads. We conclude that the outcome of the dynamics between fire-intolerant forests and fire-prone plant communities will largely depend on human-related activities, modeled by structural features of the landscape (i.e., topography, dominant winds), and processes triggered by past land uses.     

Edge and land use effects on dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) in Brazilian cerrado vegetation

The Edge Influence is one of the most pervasive effects of habitat fragmentation, as many forest remnants in anthropogenic landscapes are within 100 m of edges. Forest remnants may also affect the surrounding anthropogenic matrix, possibly resulting in a matrix–edge–remnant diversity gradient for some species groups. We sampled dung beetles in 15 agricultural landscapes using pitfall traps placed along transects in matrix–edge–remnant gradients. The remnants were a native savanna-like vegetation, the cerrado, and the matrix was composed of three human-dominated environments (sugarcane, eucalyptus, pasture). More species were observed in cerrado remnants than in adjacent land uses. Dung beetles were also more abundant in the cerrado than in the landscape matrix of sugarcane and eucalypt, but not of pasture. Dung beetles were severely affected by anthropogenic land uses, and notwithstanding their high abundance in some land uses such as pasture, the species richness in these areas tended to be smaller than in the cerrado remnants. We also found that the influence of the edge was evident only for abundance, particularly in landscapes with a pasture matrix. However, this land use disrupts the species composition of communities, indicating that communities located in cerrado and pasture have a distinct species composition, and that both communities are affected by edge distance. Thus, anthropogenic land uses may severely affect dung beetles, and this impact can extend to communities located in cerrado remnants as well as to those in matrices, with possible consequences for ecological processes such as decomposition and nutrient cycling.     

Persistent effects of aerial applications of disparlure on gypsy moth: trap catch and mating success

In forest plots treated aerially with a plastic laminated flake formulation (Disrupt^® II) of the gypsy moth sex pheromone disparlure to disrupt gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), mating was monitored the year of treatment and 1–2 years after treatment to determine the effects of the treatment on suppression of trap catch and mating success. In the year of treatment, there was a greater than 95% reduction in trap catch and a greater than 98% reduction in mating success compared to controls. One year after treatment at a dosage of 37.5 g active ingredient (a.i.) ha^?1, trap catch was reduced by 46–56% and mating success was reduced by 60–79%. Both trap catch and mating success were significantly reduced compared to controls in plots treated 1 year previously at 15 g a.i. ha^?1. Trap catch, but not mating success, was significantly reduced 2 years after treatment at 37.5 g a.i. ha^?1. The efficacy of mating disruption (MD) treatments in the Slow‐the‐Spread of the Gypsy Moth program was significantly reduced 2 years compared to 1 year after treatment. No such reduction was observed in plots treated with aerial applications of Bacillus thuringiensis kurstaki. The higher apparent efficacy of MD treatments 1 year after application may result to some extent from the suppression of moth capture in pheromone traps from the persistent effects of the previous year's treatment.     

Effect of semiochemicals and trap height on catch of Neocerambyx raddei in Jilin province,China

We conducted experiments in Jilin, China, in 2011 and 2014 in forest stands dominated by mature Quercus mongolica Fisch. ex Ledeb. (Fagaceae) to test the effects of longhorn beetle pheromones, plant volatiles, and trap height on catch of Neocerambyx raddei (Blessig & Solsky) (formerly Massicus raddei) (Coleoptera: Cerambycidae) in traps. Traps captured 276 specimens of N. raddei in 2011 and 379 specimens in 2014 (384 females, 271 males). Ethanol was attractive to female but not male N. raddei. However, N. raddei was not attracted to any of the longhorn beetle pheromones tested, which included racemic 3‐hydroxyhexan‐2‐one, racemic 3‐hydroxyoctan‐2‐one, syn‐2,3‐hexanediols, anti‐2,3‐hexanediols, racemic E,Z‐fuscumol, racemic E,Z‐fuscumol acetate, and monochamol, nor was it attracted to 2‐methyl‐3‐buten‐2‐ol. Traps placed in the tree canopy captured significantly more beetles than did traps in the understorey. Our results suggest that surveys for N. raddei should use ethanol‐baited traps placed in the tree canopy. If sex or aggregation pheromones are identified for N. raddei in the future, we predict that attraction to them will be enhanced by the presence of ethanol.     

Baseline time accounting: Considering global land use dynamics when estimating the climate impact of indirect land use change caused by biofuels

Purpose

Current estimations of the climate impact from indirect land use change (ILUC) caused by biofuels are heavily influenced by assumptions regarding the biofuel production period. The purpose of this paper is to propose a new method (baseline time accounting) that takes global land use dynamics into account that is consistent with the global warming potential, that is applicable to any phenomenon causing land use change, and that is independent of production period assumptions.

Methods

We consider ILUC in two forms. The first is called “accelerated expansion” and concerns ILUC in regions with an expanding agricultural area. The second is called “delayed reversion” and concerns ILUC in regions with a decreasing agricultural area. We use recent trends in international land use and projections of future land use change to assess how ILUC from biofuels will alter the development in global agricultural land use dynamics compared to the existing trend (i.e., the baseline development). We then use the definition of the global warming potential to determine the CO₂ equivalence of the change in land use dynamics.

Results and discussion

We apply baseline time accounting to two existing ILUC studies in the literature. With current trends in global agricultural land use, the method significantly reduces the estimated climate impact in the previous ILUC studies (by more than half). Sensitivity analyses show that results are somewhat sensitive to assumptions regarding carbon sequestration and assumptions regarding postreversion ecosystems.

Conclusions

The global dynamic development in land use has important implications for the time accounting step when estimating the climate impact of ILUC caused by biofuel production or other issues affecting land use. Ignoring this may lead to erroneous conclusions about the actual climate impact of ILUC. Several land use projections indicate that the global agricultural area will keep expanding up to and beyond 2050. We therefore recommend to apply the baseline time accounting concept as an integrated part of future ILUC studies and to update the results on a regular basis.