信息化合物对昆虫行为的影响

本文综述了来自寄主植物的挥发性物质和同种昆虫或异种昆虫释放的各种信息素及两者的协同作用的信息化合物对昆虫行为的影响。特别强调了寄主植物的气味物质和昆虫信息素协同作用在昆虫寻找寄主、求偶、交配及天敌在寄主识别过程中的重要地位。昆虫对寄主植物的识别是由于识别了植物气味的由一定组分、按照严格比例组成的化学指纹图。昆虫信息素与植物挥发性物质相结合为昆虫寻找求偶、交配场所提供更复杂或更全面的信息。许多昆虫只有在寄主植物或寄主植物气味存在时 ,才能释放性或聚集信息素。天敌在寄主识别、搜索及定位等一系列过程中 ,来自寄主的食料、寄主本身及两者的互作的信息化合物起重要的作用。研究信息化合物对昆虫行为的影响可以探索昆虫各种行为的内在机理 ,更好的了解寄主—昆虫—天敌三层营养关系的相互作用 ,对利用天然活性化合物防治害虫及生物防治提供理论依据     

Neural and environmental factors impacting maternal behavior differences in high- versus low-novelty-seeking rats

Selective breeding of rats exhibiting differences in novelty-induced locomotion revealed that this trait predicts several differences in emotional behavior. Bred High Responders (bHRs) show exaggerated novelty-induced locomotion, aggression, and psychostimulant self-administration, compared to bred Low Responders (bLRs), which are inhibited and prone to anxiety- and depression-like behavior. Our breeding studies highlight the heritability of the bHR/bLR phenotypes, although environmental factors like maternal care also shape some aspects of these traits. We previously reported that HR vs. LR mothers act differently, but it was unclear whether their behaviors were genetically driven or influenced by their pups. The present study (a) used cross-fostering to evaluate whether the bHR/bLR maternal styles are inherent to mothers and/or are modulated by pups; and (b) assessed oxytocin and oxytocin receptor mRNA expression to examine possible underpinnings of bHR/bLR maternal differences. While bHR dams exhibited less maternal behavior than bLRs during the dark/active phase, they were very attentive to pups during the light phase, spending greater time passive nursing and in contact with pups compared to bLRs. Cross-fostering only subtly changed bHR and bLR dams' behavior, suggesting that their distinct maternal styles are largely inherent to the mothers. We also found elevated oxytocin mRNA levels in the supraoptic nucleus of the hypothalamus in bHR versus bLR dams, which may play some role in driving their behavior differences. Overall these studies shed light on the interplay between the genetics of mothers and infants in driving differences in maternal style.     

Neural mechanisms in insect navigation: polarization compass and odometer

Insect navigation relies on path integration, a procedure by which information about compass bearings pursued and distances travelled are combined to calculate position. Three neural levels of the polarization compass, which uses the polarization of skylight as a reference, have been analyzed in orthopteran insects. A group of dorsally directed, highly specialized ommatidia serve as polarization sensors. Polarization-opponent neurons in the optic lobe condition the polarization signal by removing unreliable and irrelevant components of the celestial stimulus. Neurons found in the central complex of the brain possibly represent elements of the compass output. The odometer for measuring travelling distances in honeybees relies on optic flow experienced during flight, whereas desert ants most probably use proprioreceptive cues.     

Ex vivo observation of insect hemocyte behavior against beads and nematodes in the presence of insect plasma

Recognition of foreign targets by insect hemocytes is a crucial first step for insect immunity against invading multicellular organisms in the hemocoel. To understand the mechanism of recognition, we observed the hemocyte behavior of Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) larvae against beads and the nonparasitic nematode Caenorhabditis elegans (Maupas) (Rhabditida: Rhabditidae) in the presence of plasma ex vivo using time-lapse microscopy. Both granular cells and plasmatocytes adhered to and spread on the surface of beads and nematodes. In addition, the spread plasmatocytes actively moved over the beads and nematodes. These results suggest that not only granular cells but also plasmatocytes can recognize foreign targets in the presence of insect plasma and that spread plasmatocytes can actively search for foreign targets. Hemocyte adhesion to beads and nematodes ex vivo was similar to that of the in vivo 1?h after injection. A divalent cation chelator inhibited the spreading and adhesion of plasmatocytes ex vivo, but it did not affect the adhesion of granular cells. The present method enables the analysis of acute hemocyte response against foreign targets in the presence of plasma.

     

昆虫介体行为与植物病毒的传播

大多数植物病毒都是依赖昆虫介体进行传播,其中超过80%的传毒介体昆虫都是属于半翅目同翅亚目。昆虫介体识别寄主植物和取食的过程与病毒的传播密切相关,本文主要综述了同翅亚目昆虫、蓟马等介体昆虫取食行为与植物病毒的相互作用方面的研究进展,着重于介绍昆虫不同取食阶段的行为对植物病毒传播的影响,病毒侵染对介体取食和识别寄主行为的影响。     

Neural mechanisms for hedonistic behavior

Some neural mechanisms are described which interpret neurobiophysically the determination of the behavior of an individual by the maximizing of his satisfaction, or pleasure.     

Radio-tagging technology reveals extreme nest-drifting behavior in a eusocial insect

Kin-selection theory underlies our basic understanding of social evolution [1, 2]. Nest drifting in eusocial insects (where workers move between nests) presents a challenge to this paradigm, since a worker should remain as a helper on her natal colony, rather than visit other colonies to which she is less closely related. Here we reveal nest drifting as a strategy by which workers may maximize their indirect fitness by helping on several related nests, preferring those where the marginal return from their help is greatest. By using a novel monitoring technique, radio frequency identification (RFID) tagging, we provide the first accurate estimate of drifting in a eusocial insect: 56% of females drifted in a natural population of the eusocial paper wasp Polistes canadensis, exceeding previous records of drifting in natural populations by more than 30-fold. We demonstrate that drifting cannot be explained through social parasitism, queen succession, mistakes in nest identity, or methodological bias. Instead, workers appear to gain indirect fitness benefits by helping on several related colonies in a viscous population structure. The potential importance of this strategy as a component of the kin-selected benefits for a social insect worker has previously been overlooked because of methodological difficulties in quantifying and studying drifting.     

The functional role of octopaminergic neurons in insect motor behavior

The role of efferent, octopaminergic dorsal unpaired median (DUM) neurons in insects is examined by recording from them during motor behaviour. This population of neuromodulatory neurons is divided into sub-populations which are specifically activated or inhibited during ongoing motor behavior. These neurons are always activated in parallel to the respective motor circuits, and in addition to their modulatory effects on synaptic transmission may also cause metabolic changes in their target tissues.     

The structure and behavior of defoliating insect/forest systems

Using four detailed and complex simulation models we derive a framework for predicting behavior of any defoliating insect/forest system. The framework uses simple and easily gathered biological information on four sets of state variables, each with a characteristic temporal scale, to predict presence, absence or form of key ecological processes acting on or between the variables. The combination of these key processes enables prediction of system equilibrium structure and this structure can be used to derive the temporal behavior of the system. Four qualitatively different classes of system behavior arise from the equilibrium structures. The framework is tested against twelve other systems and field invalidation experiments are outlined. Forest defoliator research and management implications are discussed.     

Neural repair in an insect: cell recruitment and deployment following selective glial disruption

Summary In Periplaneta americana, SEM of abdominal nervous connectives revealed a rapid accumulation of haemocytes on the surface of the neural lamella within 24 h of selective disruption of the underlying neuroglia by ethidium bromide. After 4 days the neural lamella was effectively clear of adhering haemocytes, but showed characteristic blisters, which, it is postulated, represented the points of entry of the cells from the haemocoel into the underlying tissues. A notable subsequent feature was a substantial increase in the number of cells within repairing connectives. Initially, there was a marked asymmetry in their distribution, with significantly higher numbers of cells anterior to, and within, the lesion area. It seems likely that this polarity resulted from differential cell division within the connectives. The initial asymmetry disappeared after seven days. However, increased perineurial cell numbers were maintained in the lesion area after one month and were still apparent two months after selective glial disruption. There was no equivalent increase in cell numbers in the lesion zone of cultured cords or, in vivo, after injection of the DNA-scission drug, bleomycin, treatments which preclude haemocyte involvement. It is suggested that in the absence of haemocytes and with suppression of proliferation by endogenous cells, repair is achieved by redeployment or growth of adjacent, undamaged glia.     

昆虫卵子发生调控因素的研究进展

动物卵原细胞形成成熟卵细胞的过程称为卵子发生。昆虫卵子发生在卵巢里进行,经历了卵原细胞的增殖、卵母细胞的生长和卵母细胞的成熟三个阶段。在此过程中,昆虫卵子的发生受到很多内外因素的影响,如基因、细胞因子和环境等。卵子的发生影响着成熟卵细胞的质量以及卵细胞与精子的结合。本文就影响昆虫卵子发生的因素进行综述。     

拟寄生昆虫中的过寄生现象

对拟寄生昆虫同种过寄生现象做了综述。拟寄生昆虫的认识能力和寄生经历、其与寄主数量的相对比例、寄主的大小及两次被寄生的时间间隔等是导致过寄生是否出现的主要因素。过寄生常导致拟寄生昆虫发育历期延长、存活率下降、个体变小、子代雌性比降低。试验研究和大量饲养中应采取措施避免过寄生。