Field trials against Hoplia philanthus (Coleoptera: Scarabaeidae) with a combination of an entomopathogenic nematode and the fungus Metarhizium anisopliae CLO 53

The white grub, Hoplia philanthus Füessly (Coleoptera: Scarabaeidae), is a major pest of turf and ornamental plants in Belgium. Previously, the combination of lethal concentration of the entomopathogenic nematodes Heterorhabditis megidis or Steinernema glaseri with the entomopathogenic fungus Metarhizium anisopliae (strain CLO 53) caused additive or synergistic mortality to third-instar H. philanthus in the laboratory and greenhouse. In this present study, we examined this interaction under field conditions and compared a combination of a commercial formulation of Heterorhabditis bacteriophora (Nema-green^®) and M. anisopliae. Controls were M. anisopliae, chlorpyrifos (Dursban 5 Granules) and H. bacteriophora. Field applications (surface or subsurface) were made against a mixed population of second/third-instar H. philanthus at a sport field and lawn infested in the province of West-Flanders. In both trials, the combination of M. anisopliae with H. bacteriophora at 5 × 10¹² conidia/ha +2.5 × 10⁹ infective juveniles/ha resulted in additive or synergistic effects, causing more than 95% grub mortality when the nematodes was applied 4 weeks after the application of fungus. However, application of nematode, chlorpyrifos or fungus alone provided 39–66%, 42–60% (surface) and 33–76%, 82–100% or 37–65%, (subsurface) control of H. philanthus. We concluded that the pathogen combinations we tested are compatible elements of integrated pest management and are likely to improve control of H. philanthus larvae and perhaps other insect pests beyond what is expected from single application of the pathogen.     

蜣螂后胸叉骨形态演化趋势及其在系统发育分析中的意义(鞘翅目:金龟科)

后胸叉骨是昆虫胸部的内骨骼,是重要的肌肉联结点,在昆虫运动中起着不可替代的作用。该结构在鞘翅目高级阶元系统发育关系重建中扮演了重要角色,但由于其在低级阶元间的差异较小以及在形态分析中使用困难等因素限制,致使后胸叉骨的研究并未受到广泛重视。国内学者对于甲虫后胸叉骨的研究非常少,甚至长期以来没有中文名称,相关内容只零星散布于教科书和学位论文中,针对蜣螂后胸叉骨形态学研究尚未见报道。本文对金龟科蜣螂亚科9族65种的后胸叉骨进行了详细的比较形态学研究,归纳了族级形态特征,进而探究蜣螂后胸叉骨形态演化趋势及其在系统发育分析中的意义。此外,还对利用现代形态学和几何形态学等方法研究后胸叉骨功能形态的前景进行了阐述。     

盐池荒漠草地拟步甲昆虫群落时间结构和动态

从2009年3月到10月采用巴氏罐诱导法调查了宁夏盐池四墩子6个不同生境中的拟步甲的群落组成以及时间动态,结果表明,本次调查共采集拟步甲昆虫5431只,计10属20种,个体数最多的是弯齿琵甲Blapsfemoralis femoralis Fischer-Waldheim和克小鳖甲Microdera kraatzi kraatzi Reitter,分别占总数的47.30%和40.66%,不同季节的优势种类不同。从时间动态上看,拟步甲物种数和个体数成显著正相关(r=0.887,P=0.003),表现为5月和7—8月2个发生高峰期,且5月最高。从整个景观来看,优势种克小鳖甲的盛发期在5月和7月,弯齿琵甲的盛发期在5月和8月,不同景观样地略有差异。物种-时间对应分析表明,拟步甲成虫发生可以分为春季发生型、春夏发生型、夏季发生型、夏秋发生型和全年发生型5类。5月拟步甲群落多样性和丰富度最高,不同月的拟步甲群落相似性可以聚为3类,由于植被类型和干扰程度的差异,月间拟步甲群落相似性会有所差异。     

Terrestrial nest-building by wild chimpanzees (Pan troglodytes): implications for the tree-to-ground sleep transition in early hominins

Nest-building is a great ape universal and arboreal nesting in chimpanzees and bonobos suggests that the common ancestor of Pan and Homo also nested in trees. It has been proposed that arboreal nest-building remained the prevailing pattern until Homo erectus, a fully terrestrial biped, emerged. We investigated the unusual occurrence of ground-nesting in chimpanzees (Pan troglodytes), which may inform on factors influencing the tree-to-ground sleep transition in the hominin lineage. We used a novel genetic approach to examine ground-nesting in unhabituated chimpanzees at Seringbara in the Nimba Mountains, Guinea. Previous research showed that ground-nesting at Seringbara was not ecologically determined. Here, we tested a possible mate-guarding function of ground-nesting by analyzing DNA from shed hairs collected from ground nests and tree nests found in close proximity. We examined whether or not ground-nesting was a group-level behavioral pattern and whether or not it occurred in more than one community. We used multiple genetic markers to identify sex and to examine variation in mitochondrial DNA control region (HV1, HV2) sequences. Ground-nesting was a male-biased behavior and males constructed more elaborate ("night") nests than simple ("day") nests on the ground. The mate-guarding hypothesis was not supported, as ground and associated tree nests were built either by maternally-related males or possibly by the same individuals. Ground-nesting was widespread and likely habitual in two communities. We suggest that terrestrial nest-building may have already occurred in arboreally-adapted early hominins before the emergence of H. erectus.     

Role of intraguild predation in aphidophagous guilds

The concept of intraguild predation (IGP) appeared in 1987–1989 to describe trophic interactions within a guild of arthropods inhabiting a sand dune desert: consumers B prey on consumers A and both of them prey on a common resource. Theory predicts that the two types of consumers should only coexist if consumer A is more efficient in the conversion of the common resource than B. As a consequence, this resource is more abundant in the presence than in the absence of intraguild predators. Such a theoretical prediction probably explains the vivid interest shown by ecologists involved in biological control for IGP. It is therefore not surprising that many papers report on IGP among natural enemies of aphids. A close examination of these reported cases indicates that they rarely fulfil the theoretical requirements for IGP. That is, guilds of aphidophagous insects are rarely the theatre of IGP but frequently of interspecific predation. This is confirmed by experimental assessment of the cost of attacking and eating intraguild prey instead of extraguild in ladybird beetles.     

The effects of habitat,density, gender and duration on overwintering success in Bembidion lampros (Coleoptera: Carabidae)

In temperate climates, winter mortality is a key factor influencing insect survival. In Bembidion lampros (Coleoptera: Carabidae), an abundant polyphagous predator in arable farmland, we investigated how habitat, population density, gender and duration of overwintering affect the winter mortality and body condition of survivors. In a field experiment, we introduced beetles at two population densities into isolators placed either in the interior of the field or in the grassy boundary. Half of the isolators were collected in mid‐March, and the remaining half were collected in mid‐April. Across all treatments, 44–92% of the beetles survived until spring. Survival was significantly higher in the field interior than in the boundary. The longevity of individuals starved after overwintering was higher in females than in males and was positively related to the length of time spent at the overwintering site. Population density was positively related to percentage survival but did not affect body condition. Our results suggest that biotic factors such as population density and predation, though little studied, may have a similar significance as abiotic factors. Even ubiquitous carabid species inhabiting agroecosystems have specific requirements for overwintering. Understanding these requirements is useful for developing techniques to support their overwintering success.     

Radiative forcing of natural forest disturbances

Forest disturbances are major sources of carbon dioxide to the atmosphere, and therefore impact global climate. Biogeophysical attributes, such as surface albedo (reflectivity), further control the climate‐regulating properties of forests. Using both tower‐based and remotely sensed data sets, we show that natural disturbances from wildfire, beetle outbreaks, and hurricane wind throw can significantly alter surface albedo, and the associated radiative forcing either offsets or enhances the CO₂ forcing caused by reducing ecosystem carbon sequestration over multiple years. In the examined cases, the radiative forcing from albedo change is on the same order of magnitude as the CO₂ forcing. The net radiative forcing resulting from these two factors leads to a local heating effect in a hurricane‐damaged mangrove forest in the subtropics, and a cooling effect following wildfire and mountain pine beetle attack in boreal forests with winter snow. Although natural forest disturbances currently represent less than half of gross forest cover loss, that area will probably increase in the future under climate change, making it imperative to represent these processes accurately in global climate models.     

Area‐wide application of verbenone‐releasing flakes reduces mortality of whitebark pine Pinus albicaulis caused by the mountain pine beetle Dendroctonus ponderosae

• 1 DISRUPT Micro‐Flake Verbenone Bark Beetle Anti‐Aggregant flakes (Hercon Environmental, Inc., Emigsville, Pennsylvania) were applied in two large‐scale tests to assess their efficacy for protecting whitebark pine Pinus albicaulis Engelm. from attack by mountain pine beetle Dendroctonus ponderosae Hopkins (Coleoptera: Scolytinae) (MPB). At two locations, five plots of equivalent size and stand structure served as untreated controls. All plots had early‐ to mid‐outbreak beetle populations (i.e. 7.1–29.2 attacked trees/ha). Verbenone was applied at 370 g/ha in both studies. Intercept traps baited with MPB aggregation pheromone were placed near the corners of each plot after the treatment in order to monitor beetle flight within the plots. Trap catches were collected at 7‐ to 14‐day intervals, and assessments were made at the end of the season of stand structure, stand composition and MPB attack rate for the current and previous years.
• 2 Applications of verbenone flakes significantly reduced the numbers of beetles trapped in treated plots compared with controls at both sites by approximately 50% at the first collection date.
• 3 The applications also significantly reduced the proportion of trees attacked in both Wyoming and Washington using the proportion of trees attacked the previous year as a covariate in the model for analysis of current year attack rates; in both sites, the reduction was ≥ 50%.
• 4 The flake formulation of verbenone appears to have promise for area‐wide treatment by aerial application when aiming to control the mountain pine beetle in whitebark pine forests.

     

Population dynamics in changing environments: the case of an eruptive forest pest species

In recent decades we have seen rapid and co‐occurring changes in landscape structure, species distributions and even climate as consequences of human activity. Such changes affect the dynamics of the interaction between major forest pest species, such as bark beetles (Coleoptera: Curculionidae, Scolytinae), and their host trees. Normally breeding mostly in broken or severely stressed spruce; at high population densities some bark beetle species can colonise and kill healthy trees on scales ranging from single trees in a stand to multi‐annual landscape‐wide outbreaks. In Eurasia, the largest outbreaks are caused by the spruce bark beetle, Ips typographus (Linnaeus), which is common and shares a wide distribution with its main host, Norway spruce (Picea abies Karst.). A large literature is now available, from which this review aims to synthesize research relevant for the population dynamics of I. typographus and co‐occurring species under changing conditions. We find that spruce bark beetle population dynamics tend to be metastable, but that mixed‐species and age‐heterogeneous forests with good site‐matching tend to be less susceptible to large‐scale outbreaks. While large accumulations of logs should be removed and/or debarked before the next swarming period, intensive removal of all coarse dead wood may be counterproductive, as it reduces the diversity of predators that in some areas may play a role in keeping I. typographus populations below the outbreak threshold, and sanitary logging frequently causes edge effects and root damage, reducing the resistance of remaining trees. It is very hard to predict the outcome of interspecific interactions due to invading beetle species or I. typographus establishing outside its current range, as they can be of varying sign and strength and may fluctuate depending on environmental factors and population phase. Most research indicates that beetle outbreaks will increase in frequency and magnitude as temperature, wind speed and precipitation variability increases, and that mitigating forestry practices should be adopted as soon as possible considering the time lags involved.     

华南地区8种常见园林地被植物抗旱性比较研究

以华南地区8种常见园林地被植物为研究对象,在温室内设置盆栽控水试验,分组测定各参试植物的永久萎蔫率,叶片失水率、相对含水量、相对电导率、可溶性糖、脯氨酸以及丙二醛含量等生理生化指标,并用隶属函数法对其抗旱性进行综合评价。结果表明:(1)植物的永久萎蔫率和叶片失水率以鹅掌藤、白蝴蝶相对较低,其植株表现出较强的抗旱性。(2)随着持续干旱时间的延长,8种地被植物的叶片相对含水量呈不同程度下降趋势;叶片相对电导率、MDA含量均有不同程度升高;叶片可溶性糖和脯氨酸含量的变化趋势不一。(3)3种木本植物的抗旱性强弱依次为鹅掌藤>红花龙船花>红背桂,5种草本植物依次为水鬼蕉>蚌兰>白蝴蝶>葱兰>大叶红草。研究表明,植物的永久萎蔫率、叶片失水率、相对含水量、相对电导率、丙二醛含量与其实际抗旱性密切相关,可作为评价园林地被植物抗旱性的有效指标。