Sex Pheromone Components in Defense of Melon Fly, Bactrocera cucurbitae Against Asian House Gecko, Hemidactylus frenatus

The Asian house gecko, Hemidactylus frenatus, after being acclimatized to feeding on the melon fly, Bactrocera cucurbitae, consumed fewer numbers of 15-day-old (DO) and older male melon flies compared to sexually immature flies 10 DO and younger. The first male melon fly that performed mating did so on the 10th day after eclosion (DAE), but >80% of the males performed their first mating between 10 and 15 DAE. This confirmed that between 10 and 15 DAE most male melon flies are already sexually mature and producing sex pheromone. Synthetic 1,3-nonanediol, a component of male melon fly sex pheromone produced endogenously, when topically applied onto the thorax of housefly Musca domestica at ca. 80 or 320 ng/fly, reduced consumption by geckos compared with untreated flies in subsequent days after the first day in a four-day feeding test. Raspberry ketone (RK) is consumed and sequestered into the pheromonal gland and later released as a pheromonal component of male melon fly. Houseflies topically treated with 2.6 g RK/fly did not deter predation by geckos. However, houseflies treated with 5.1 g RK/fly caused geckos to consume fewer flies, especially on the third and fourth days during a four-day feeding test, compared with the period when they were offered untreated flies.     

Defensive role ofAllium sulfur compounds for leek mothAcrolepiopsis assectella Z. (Lepidoptera) against generalist predators

It has been shown previously that sulfur volatiles produced byAllium plants affect the behavior of their specialist phytophages and of their specialist entomophages. The action of these compounds in protecting the leek mothAcrolepiopsis assectella against generalist entomophages was studied in comparison to the proposed original defensive role of these compounds against generalist herbivorous insects. Two ants species,Formica selysi andF. fusca, were used as generalist predators. Six behavioral criteria of the predatory behavior of the ants were studied in presence of the last-instar caterpillars (C₅). C₅ reared on artificial diets with or without leek components were tested, as well as C₅ soaked in frass of leek-reared caterpillars or disulfide solutions. In addition, the response of the ants to pure chemicals found in leek was studied using honey solutions with or without sulfur compounds. The sulfur allelochemicals ofAllium plants have a negative action on predatory ants. Interestingly, the nonvolatile precursors of sulfur volatiles ofAllium plants seem to have a protective role for their phytophagous insects against generalist entomophages.     

Temporal patterns in phytoplankton,zooplankton and fish composition,abundance and biomass in Shirati Bay,Lake Victoria,Tanzania

Shirati Bay is among the important breeding and nursery sites for major fish species in Lake Victoria. Weekly samplings were conducted to assess the temporal patterns in phytoplankton, zooplankton and fish composition, abundance and biomass in relation to prevailing water quality parameters. The study also determined the influences of plankton dynamics and water quality on the fish catch composition and biomass. It was hypothesized that temporal patterns in the composition, abundance and biomass in the plankton in the bay are controlled by water quality parameters that, in turn, affect the composition and biomass of fish catches. The phytoplankton comprised mainly cyanophytes and bacillariophytes, while the zooplankton were dominated by copepods. The heavy rain season exhibited a significantly higher plankton abundance and biomass than the dry season. The plankton abundances in both seasons exhibited significant positive correlations with water temperature and transparency. The phytoplankton community was controlled by calanoid and cyclopoid species. At higher trophic levels, Lates niloticus juveniles, Oreochromis niloticus juveniles and haplochromines controlled Cladocera and Cyclopoid copepods, while Tilapia rendalli juveniles controlled the Rotifera. This study revealed that Cyanophyta and Bacillariophyta are the dominant phytoplankton, whereas cyclopoids dominate the zooplankton species in the bay. These dominant plankton groups are partly controlled by rainfall, water temperature and transparency. Fish biomass, zooplankton and phytoplankton exhibit a typical predator–prey inverse relationship. Thus, evaluation of the plankton composition, abundance and biomass should be mandatory during fisheries stock assessments to effectively manage the fishery resources in the bay.     

原位剩余污泥减量技术的研究进展

日益突出的污泥问题,使实现污泥减量化变得更加迫切．总结了近年来国内外在剩余污泥减量化方面的研究进展,介绍了溶胞-隐性生长、解偶联代谢、维持代谢和生物捕食等原位剩余污泥减量的理论与技术,分析了各种污泥减量技术的特点及其应用情况,并指出了目前剩余污泥减量技术存在的问题和需要进一步研究的工作．     

基于 IPPA 优化 PNN 的变压器故障诊断研究

针对变压器故障诊断精度低的问题,本文提出一种改进寄生捕食算法(IPPA)优化概率神经网络(PNN)的电力变压器 故障诊断模型,首先利用主成分分析(PCA)对故障数据进行数据降维减少无效特征,然后利用混沌反向学习,柯西变异算子和 融合贝塔分布的线性递减函数的权重等多策略改进寄生捕食算法( IPPA),提高其优化能力,并使用改进后的 IPPA 算法优化 PNN 网络的平滑因子,以提高 PNN 的分类精度和鲁棒性。 最后将 PCA 处理后的数据输入到 IPPA-PNN 模型中进行故障诊断 并以变压器数据为依据进行测试,测试结果表明,IPPA-PNN 模型准确率达到 93%相比于 PPA-PNN 和 PSO-PNN 模型提高了 7%和 10%能够有效地提高变压器的故障诊断性能。     

Induction of pseudopterosin biosynthesis in the gorgonian Pseudopterogorgia elisabethae

A number of biological and physical stimuli have been evaluated as inducers of pseudopterosin biosynthesis in the sea whip Pseudopterogorgia elisabethae. Data indicate that the production of pseudopterosins can be significantly increased in response to high levels of predation by the mollusk Cyphoma gibbosum and in response to decreased levels of UV/visible radiation. High levels of feeding by Chaetodon capistratus and an artificial wounding of the sea whip did not result in increased pseudopterosin levels.     

Spider Mites Assess Predation Risk by Using the Odor of Injured Conspecifics

When a predatory mite, Amblyseius womersleyi is present, Tetranychus kanzawai takes refuge on its webs during a quiescent stage. To examine the factors responsible for the antipredator behavior of T. kanzawai, we exposed T. kanzawai to the odor of conspecifics, A. womersleyi, and both T. kanzawai and A. womersleyi. The proportion of T. kanzawai females that took refuge was significantly higher when they were exposed to the odor of `both T. kanzawai and A. womersleyi.' Furthermore, the proportion of T. kanzawai females that took refuge was significantly higher when they were exposed to injured conspecifics than to intact conspecifics. These results suggest that T. kanzawai assesses predation risk, at least in part, by using the odor of injured conspecifics.     

AGGREGATION,EMERGENCE AND IMMERGENCE IN HIERARCHICALLY ORGANIZED SYSTEMS

Abstract

The aim of this work is to show that couplings between fast micro-dynamics and slow macro-dynamics can make emerge global properties. Emergence corresponds to a bottom-up coupling, that is to the effect exerted by a micro-level at a macro-level. Immergence corresponds to the inverse process, that is to an up-down coupling. As an example, we present a prey-predator model with different time scales in a heterogeneous environment. A fast time scale is associated to the migration process on spatial patches and a slow time scale is associated to growth and interactions between the populations. Preys go on spatial patches where resources are located and where predators can attack them. The efficiency of predators is patch-dependent. Perturbation theory is used in order to aggregate the initial system of ordinary differential equations for patch sub-populations into a macro-system of two differential equations governing total populations. First, we study a case of density-independent migrations, for which no emergence occurs. Then, we study some examples of density-dependent migrations. In this case, emerging properties appear at the population level.     

Light aversion in mice depends on nonimage-forming irradiance detection.

Detection of light in the eye underlies image-forming vision, but also regulates adaptive responses in physiology and behavior. Typically these adaptive responses do not involve image-forming vision, but depend on a relatively absolute measure of brightness (nonimage-forming irradiance detection). The goal of this study was to further understand how image-forming vision and nonimage-forming irradiance detection contribute to the effects of light on behavior. Three light dependent behaviors were assessed in wild-type, Rpe65-/- and rd1 mice. In Rpe65-/- mice, nonimage-forming irradiance detection is severely attenuated, but rod based visual acuity is relatively preserved. In rd1 mice visual acuity is nonrecordable, but nonimage-forming responses are less severely attenuated than Rpe65-/-. Positive masking, an image-forming vision dependent increase in wheel running, was absent in rd1 and restricted to higher irradiances in Rpe65-/-. Negative masking, a suppression of wheel running sensitivity with nonimage-forming irradiance detection input, was increased in rd1, but reduced in Rpe65-/- mice. By contrast, light aversion, an avoidance of brightly lit areas, was abolished in both Rpe65-/- and rd1. This shows that image-forming vision is not sufficient for light aversion, suggesting nonimage-forming irradiance detection motivates this behavior. Further, the differing effects of disease suggest that negative masking and light aversion are distinct responses with specialized nonimage-forming irradiance detection pathways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Size-selective predation by round gobies (Neogobius melanostomus) on dreissenid mussels in the field

Although numerous studies have shown that round gobies (Neogobius melanostomus) prey on dreissenid mussels (Dreissena polymorpha and Dreissena bugensis), there is an apparent shortage of detailed field studies on the subject. The 5-month field study described here quantifies predation by round gobies on dreissenids in Presque Isle Bay, Lake Erie. Dreissenids dominated the diet of round gobies, composing 92% of the prey items recovered. Over half of the 3870 valves (1935 mussels) recovered from 155 round gobies were crushed, while the remainder were swallowed whole. Crushed dreissenids were larger than those swallowed whole, and the tendency to crush dreissenids did not vary among three length classes of round goby. Round goby length was positively related to average size of dreissenids consumed, average size of whole and crushed dreissenids, largest whole dreissenid consumed, and largest crushed dreissenid consumed. Indices of selectivity revealed similarly shaped curves for three length classes of round gobies, a shift toward larger dreissenid size classes with an increase in round goby length, and peak preferences for 8-11 mm dreissenids. Factors such as gape limitation, availability and accessibility of differently sized dreissenids, forces generated while removing mussels from the substrate and crushing them, and caloric content of dreissenids all likely play roles in the observed size-selectivity and differential processing of dreissenids. Although factors influencing size-selectivity are not completely understood, the observed preference of round gobies for dreissenids near the size when they are first reproductive could impact the demography of dreissenid populations.