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1.
Insect diversity of a Costa Rican dry forest: why keep it,and how?   总被引:2,自引:0,他引:2  
The dry forest of the 108 km2 Santa Rosa National Park in northwestern Costa Rica contains as many as 13 000 species of insects (including 3140 species of moths and butterflies) sustained by and sustaining about 700 species of plants and 400 species of vertebrates. These insects require explicit conservation attention. They are more than just decorations on the plants; rather, they are the building blocks and glue for much of the habitat. They are the food for much of the carnivore community, and the insect species are not merely interchangeable bits of nutrients. They are major killers of seeds, and thereby influence both the plant species composition of a habitat and prevent the better competitors from taking it over. They are the primary pollinators and are specific enough to be neither interchangeable nor replaceable with other animals; the seeds resulting from their pollination activities are major animal foods in the habitat. They are a diverse, puzzling, complex, intrinsically attractive, and major part of the intellectual display offered by tropical wildlands, the display that will be the eventual foundation for most of the reason why tropical wildlands will be retained as such in the future.
The retention and maintenance of insect species richness in a tropical wildland is strongly rooted in the preservation of plant species richness, in maintaining habitat mosaics (different members of which are used by a given insect in different seasons), in preserving a large diversity of habitats, and in recognizing the threat posed by insect crop associates in nearby agricultural lands.  相似文献   

2.
Oil plants in Middle Europe Renewable resources have an increasing impact on industry and technology. Oil plants supply vegetable oil, which is important for our nutrition but can also be used as an industrial resource. Plant oils have many non‐food uses. They are not only used as Biofuels, but can also be found in many technical products including industrial lubricants, hydraulic oils, washing agents, paints and varnishes, and much else. In Europe rapeseed, sunflower, and olive are the primary oil plants. Rapeseed oil is newly recommended for infant nutrition, as it contains a high concentration of α‐linolenic acid, which is an important building block in brain development.  相似文献   

3.
Humans, animals and plants suffer from similar types of diseases (e.g., fungal, viral etc.). These can “emerge” as new diseases by expanding their geographical range or by jumping species (from plants to plants, or from animals to humans). Emerging diseases place an additional burden on developing countries which are often struggling to manage the diseases they already have. New diseases spread through weather, insects or other vectors, or by the movement of people, animals or goods. This study examines the role of cross-border travel in the spread of diseases. A survey of travelers and of residents along the Malawi-Mozambique border found that most cross it frequently and that they rarely travel empty-handed, often taking plants and animals with them. People also cross borders seeking medical attention. Attempting to limit travel would hamper an already struggling economy, where many people make a living by producing, processing or transporting plants and animals for food. Cross border travel per se may pose slight danger for the spread of diseases, if governments can collaborate on sharing information about the status of diseases within their border.  相似文献   

4.
The Earth's surface temperature is rising, and precipitation patterns throughout the Earth are changing; the source of these shifts is likely anthropogenic in nature. Alterations in temperature and precipitation have obvious direct and indirect effects on both plants and animals. Notably, changes in temperature and precipitation alone can have both advantageous and detrimental consequences depending on the species. Typically, production of offspring is timed to coincide with optimal food availability; thus, individuals of many species display annual rhythms of reproductive function. Because it requires substantial time to establish or re‐establish reproductive function, individuals cannot depend on the arrival of seasonal food availability to begin breeding; thus, mechanisms have evolved in many plants and animals to monitor and respond to day length in order to anticipate seasonal changes in the environment. Over evolutionary time, there has been precise fine‐tuning of critical photoperiod and onset/offset of seasonal adaptations. Climate change has provoked changes in the availability of insects and plants which shifts the timing of optimal reproduction. However, adaptations to the stable photoperiod may be insufficiently plastic to allow a shift in the seasonal timing of bird and mammal breeding. Coupled with the effects of light pollution which prevents these species from determining day length, climate change presents extreme evolutionary pressure that can result in severe deleterious consequences for individual species reproduction and survival. This review describes the effects of climate change on plants and animals, defines photoperiod and the physiological events it regulates, and addresses the consequences of global climate change and a stable photoperiod.  相似文献   

5.
Pollination biology is often associated with mutualistic interactions between plants and their animal pollen vectors, with energy rewards as the foundation for co-evolution. Energy is supplied as food (often nectar from flowers) or as heat (in sun-tracking or thermogenic plants). The requirements of pollinators for these resources depend on many factors, including the costs of living, locomotion, thermoregulation and behaviour, all of which are influenced by body size. These requirements are modified by the availability of energy offered by plants and environmental conditions. Endothermic insects, birds and bats are very effective, because they move faster and are more independent of environmental temperatures, than are ectothermic insects, but they are energetically costly for the plant. The body size of endothermic pollinators appears to be influenced by opposing requirements of the animals and plants. Large body size is advantageous for endotherms to retain heat. However, plants select for small body size of endotherms, as energy costs of larger size are not matched by increases in flight speed. If high energy costs of endothermy cannot be met, birds and mammals employ daily torpor, and large insects reduce the frequency of facultative endothermy. Energy uptake can be limited by the time required to absorb the energy or eliminate the excess water that comes with it. It can also be influenced by variations in climate that determine temperature and flowering season.  相似文献   

6.
Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases.  相似文献   

7.
Plants,selenium and human health   总被引:23,自引:0,他引:23  
Selenium is an essential nutrient for animals, microorganisms and some other eukaryotes. Although selenium has not been demonstrated to be essential in vascular plants, the ability of some plants to accumulate and transform selenium into bioactive compounds has important implications for human nutrition and health, and for the environment. Selenium-accumulating plants provide unique tools to help us understand selenium metabolism. They are also a source of genetic material that can be used to alter selenium metabolism and tolerance to help develop food crops that have enhanced levels of anticarcinogenic selenium compounds, as well as plants that are ideally suited for the phytoremediation of selenium-contaminated soils.  相似文献   

8.
The extensive literature on natural antimicrobial systems in animals, plants, and microorganisms is surveyed and particular systems are discussed, viz., the peroxidase systems in saliva and milk, singlet oxygen in the phagosome, cecropins and attacins in insects, complement, lysozyme and, to a limited extent, phytoalexins. The review draws attention to the cardinal role of targets on the cell envelopes of alien cells, especially bacteria, and emphasizes a possible approach to preservation based on the selection of specific agents for particular targets. The available evidence suggests that the perturbation of the homeostasis of all the organisms in the mixed flora of a food is unlikely to be achieved by one antimicrobial substance in isolation. Future studies need to consider therefore a tandem approach with two or more agents chosen because of their complementary action. Alternatively, natural system(s) and an established preservative method, either chemical or physical, warrant investigation. The extensive literature on the mechanisms whereby specialist pathogens overcome the defenses of plants and animals emphasizes the inherent dangers of selection leading to the persistent contamination of food processing areas with organisms tolerant of a particular antimicrobial system.  相似文献   

9.
Rattus rattus slandeni的食性资料是在小良人工阔叶混交林中通过200个鼠箱观察残留食物的方法收集到的。屋顶鼠摄食植物39种,主要为果实、种子部分,并大量捕食金龟子、蝉和蝗虫等昆虫,偶尔捕食小脊椎动物。植物性和动物性两大类残食的总出现率相近,5-10月以动物性食物为主,11-4月以植物性食物为主。该鼠搬运和遗弃果实、种子的行为,有助于植物种类的传布,大量捕食害虫,有利于该系统的生态平衡,故对其益害问题应作客观评价。  相似文献   

10.
Molecular strategies of plant defense and insect counter-defense   总被引:13,自引:0,他引:13  
The prediction of human population growth worldwide indicates there will be a need to substantially increase food production in order to meet the demand on food supply.This can be achieved in part by the effective management of insect pests. Since plants have co-evolved with herbivorous insects for millions of years, they have developed an array of defense genes to protect themselves against a wide variety of chewing and sucking insects.Using these naturally-occurring genes via genetic engineering represents an environmentally friendly insect pest-control measure. Insects, however, have been actively evolving adaptive mechanisms to evade natural plant defenses. Such evolved adaptability undoubtedly has helped insects during the last century to rapidly overcome a great many humanimposed management practices and agents, including chemical insecticides and genetically engineered plants. Thus, better understanding of the molecular and genetic basis of plant defense and insect counter-defense mechanisms is imperative, not only from a basic science perspective, but also for biotechnology-based pest control practice. In this review, we emphasize the recent advance and understanding of molecular strategies of attack-counterattack and defense-counter-defense between plants and their herbivores.  相似文献   

11.
T. C. R. White 《Oecologia》1984,63(1):90-105
Summary It has previously been postulated that when plants are stressed by certain changes in patterns of weather they become a better source of food for invertebrate herbivores because this stress causes an increase in the amount of nitrogen available in their tissues for young herbivores feeding on them. And this may cause outbreaks of such phytophagous invertebrates.Evidence is now presented that a similar physiological mechanism appears to operate when a wide variety of apparently unrelated environmental factors impinge on plants or parts of plants in such a way as to perturb their metabolism. A broken branch, lightning strike, fire, nutrient deficiencies or an otherwise adverse site; all may have this effect. With the advent of modern man the available agencies increase and diversify to include pesticides, irradiation and air pollutants.One common metabolic response by plants to all such agents impinging on them seems to be equivalent to that found in senescing plant tissues — the breakdown and mobilization of nitrogen in soluble form away from the senescing/stressed tissues. Young herbivores which chance to feed on such stressed/senescing tissues have a greater and more readily available supply of nitrogen in their food than they would have had if feeding on unstressed plants. As a result many more of them survive, and there is an increase in abundance of their kind. Such increases may be quite localised and short-lived or more widespread and persistent, depending on the extent and duration of the stress experienced by the plants. And in the face of this improved nutrition and survival of the very young, predators and parasites seem to have only a minor influence on subsequent changes in abundance of their herbivorous prey.Another effect of increased mobilization of nitrogen in stressed plants is an increase in the quantity of the seed that they set. This has led to the conclusion that increased abundance of some species of birds at such times is due to a greater supply of seeds as winter food for recent fledglings. But it may be that the increased abundance is due to the synchronous increase in phytophagous insects providing a richer source of protein food for laying hens and growing nestlings.  相似文献   

12.
This paper presents the results of an exploratory study to determine whether vesicular-arbuscular mycorrhizal (VAM) fungi affect the success of insects used as weed biological agents. No direct correlation between the colonization by VAM fungi alone and the success of root- and shoot-feeding insects was found. However, in Centaurea diffusa , plants colonized by VAM fungi had a lower shoot root ratio and increased attack and survival of the root beetle, Sphenoptera jugoslavica , in the field. Beetle success was also best on C. diffusa when the plant was growing among determinate grasses that largely cease growing after flowering in the spring or early summer. This is consistent with other reports that VAM hyphae can transfer nutrients between plant species from low to high sinks. From these results and related reports in the literature, it is suggested that plants with many stenophagous root-insects are those in which VAM fungi colonization increases nutrient partitioning to the roots with little or no decrease in plant growth. Root-feeding, rather than foliage- or seed-feeding, insects seem to be particularly effective as biocontrol agents for plants of this type.  相似文献   

13.
Turchetto M  Vanin S 《Parassitologia》2004,46(1-2):187-190
The main aim of Forensic Entomology has always been, and is today, to establish the time of death (P.M.I.: Postmortem Period) or, more exactly, how long a carrion has been exposed in the environment. Most of the invertebrate fauna occurring on corpses consists of insects (mostly Diptera and Coleoptera). They are selectively attracted by the decomposing status of the carrion, and form complex communities or biocenosis within necrophagous or sarcophagous species and their predators, parasites and parasitoids, competing each one another. The rapid and continuos changes of the micro-ecosystem (the body), until its breakdown, does not permit the achievement of a steady state or an equilibrium in the animal communities. These continuous modifications give us the possibility to estimate when (and where) the death has occurred, by the identification of the species feeding on the corpse, the knowledge of their life history, and the length of each stage of their cycle at varying the temperature and the other abiotic factors, external to the carrion ecosystem. The P.M.I. today is still largely based on the tables of faunal succession on human cadavers recognised by Mégin in 1894, with few changes proposed by Authors from other countries. In the last years, however, it happens more and more often, that the natural communities are subverted by the presence of allocton species, which can compete, predate or parasite the most common local sarcophagous insects, modifying, this way, the succession waves and the trophic nets. The immission in the environment of foreign species may be voluntary or casual, but in any case is due to anthropic activities. The voluntary immission happens when some species, employed in the biological struggle against pest or dangerous insects, for pollination of allocton plants, or for other commercial utilities, are beyond man's control and swarm onto the environment; the casual spread is due to the globalisation phenomenon, that distributes the "little organisms" by chance, together with travellers, goods and food items. Together with human migratory flows, raw materials and vegetal foodstuffs travelling from Tropical developing Countries to the North of the world, also many tropical and subtropical insects can be carried out from their original lands. Eurioecious and polyphagous species, and species that evolved mechanisms (as diapausa or hibernation) to get over critical environmental conditions have the highest probability of survival. Saprophagous insects, and flies in particular, evolved such capabilities. The mortality of foreign species due to the difference of temperature and seasonally between tropical and temperate areas was, in the past, the most effective factor limiting the geographic propagation of insects. The ongoing global climate changes induce insect populations, now confined to the tropics, to most likely spread towards middle latitudes, where their specific competitors, predators and parasites, which regulate the population growth, are often absent. The lack of a biological control, the warming up of atmosphere temperature and the fall of the differences among seasons induce a more rapid development and an increased number of generations in new species, that often displace the autocton ones. This phenomenon is much more clear in little and simple ecosystems (such as carrion), mostly occur than in large and complex ecosystems, where many more components, vegetal organisms and phytophagous animals included, are present. To demonstrate how globalisation and climate changes are breaking the geographic barriers, we present some cases in which, during our entomoforensic investigations, performed mainly in North-eastern Italy, Neotropical, African and Asiatic necrophagous flies, beetles and wasp parasitoids have been collected, some of which rare or new for Italy or Paleartic Region. In particular, we report our studies on the american black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), that is showing a heavy competition with the local saprophagous species and is reaching great importance in some man activities and in cattle health.  相似文献   

14.
俞嘉瑞  袁海生 《菌物学报》2023,42(1):86-100
外生菌根真菌作为树木的共生伙伴,是森林生态系统重要组成部分,在森林天然更新、植物抗逆性形成、协助植物吸收限制性营养等方面扮演重要角色。真菌和植物跨界共生具有复杂的分子互作过程,在共生的不同阶段有不同的分子互作机制,其调控反馈网络还有许多未知。基因组与转录组研究技术和方法的进步,为一些新的信号分子、效应蛋白以及相关通路的发现提供了可能。真菌与宿主植物之间营养转移调控对共生的影响也逐渐受到关注,营养相关的转运蛋白对共生的建立和维持提供了物质基础。真菌的宿主选择机制是值得重点关注的领域,由于外生菌根真菌的多谱系起源和演化史中存在多次宿主转换事件,真菌演化出多样的应对机制用来区分相容性宿主、不相容性宿主和非宿主。通过对不同真菌与宿主植物的组学研究,宿主选择机制研究取得了一定进展。本文对近十年来国内外的研究报道进行梳理与总结,并对未来在该领域的探索方向做出展望。  相似文献   

15.
As drivers of global change, biological invasions have fundamental ecological consequences. However, it remains unclear how invasive plant effects on resident animals vary across ecosystems, animal classes, and functional groups. We performed a comprehensive meta‐analysis covering 198 field and laboratory studies reporting a total of 3624 observations of invasive plant effects on animals. Invasive plants had reducing (56%) or neutral (44%) effects on animal abundance, diversity, fitness, and ecosystem function across different ecosystems, animal classes, and feeding types while we could not find any increasing effect. Most importantly, we found that invasive plants reduced overall animal abundance, diversity and fitness. However, this significant overall effect was contingent on ecosystems, taxa, and feeding types of animals. Decreasing effects of invasive plants were most evident in riparian ecosystems, possibly because frequent disturbance facilitates more intense plant invasions compared to other ecosystem types. In accordance with their immediate reliance on plants for food, invasive plant effects were strongest on herbivores. Regarding taxonomic groups, birds and insects were most strongly affected. In insects, this may be explained by their high frequency of herbivory, while birds demonstrate that invasive plant effects can also cascade up to secondary consumers. Since data on impacts of invasive plants are rather limited for many animal groups in most ecosystems, we argue for overcoming gaps in knowledge and for a more differentiated discussion on effects of invasive plant on native fauna.  相似文献   

16.
Cyanogenesis in plants and arthropods   总被引:1,自引:0,他引:1  
Cyanogenic glucosides are phytoanticipins known to be present in more than 2500 plant species. They are regarded as having an important role in plant defense against herbivores due to bitter taste and release of toxic hydrogen cyanide upon tissue disruption, but recent investigations demonstrate additional roles as storage compounds of reduced nitrogen and sugar that may be mobilized when demanded for use in primary metabolism. Some specialized herbivores, especially insects, preferentially feed on cyanogenic plants. Such herbivores have acquired the ability to metabolize cyanogenic glucosides or to sequester them for use in their own defense against predators. A few species of arthropods (within diplopods, chilopods and insects) are able to de novo biosynthesize cyanogenic glucosides and some are able to sequester cyanogenic glucosides from their food plant as well. This applies to larvae of Zygaena (Zygaenidae). The ratio and content of cyanogenic glucosides is tightly regulated in Zygaena filipendulae, and these compounds play several important roles in addition to defense in the life cycle of Zygaena. The transfer of a nuptial gift of cyanogenic glucosides during mating of Zygaena has been demonstrated as well as the involvement of hydrogen cyanide in male attraction and nitrogen metabolism. As more plant and arthropod species are examined, it is likely that cyanogenic glucosides are found to be more widespread than formerly thought and that cyanogenic glucosides are intricately involved in many key processes in the life cycle of plants and arthropods.  相似文献   

17.
Aspergillus flavus is an imperfect filamentous fungus that is an opportunistic pathogen causing invasive and non-invasive aspergillosis in humans, animals, and insects. It also causes allergic reactions in humans. A. flavus infects agricultural crops and stored grains and produces the most toxic and potent carcinogic metabolites such as aflatoxins and other mycotoxins. Breakthroughs in A. flavus genomics may lead to improvement in human health, food safety, and agricultural economy. The availability of A. flavus genomic data marks a new era in research for fungal biology, medical mycology, agricultural ecology, pathogenicity, mycotoxin biosynthesis, and evolution. The availability of whole genome microarrays has equipped scientists with a new powerful tool for studying gene expression under specific conditions. They can be used to identify genes responsible for mycotoxin biosynthesis and for fungal infection in humans, animals and plants. A. flavus genomics is expected to advance the development of therapeutic drugs and to provide information for devising strategies in controlling diseases of humans and other animals. Further, it will provide vital clues for engineering commercial crops resistant to fungal infection by incorporating antifungal genes that may prevent aflatoxin contamination of agricultural harvest.  相似文献   

18.
唾液成分在刺吸式昆虫与植物关系中的作用   总被引:2,自引:0,他引:2  
严盈  刘万学  万方浩 《昆虫学报》2008,51(5):537-544
近年来,人们对刺吸式昆虫唾液成分的研究,揭示出其在刺吸式昆虫与植物关系中的重要作用。对多数刺吸式昆虫而言,他们取食时会分泌胶状和水状两种唾液,其中胶状唾液会在取食早期分泌形成唾液鞘来围绕并保护口针,通过直接和间接的作用来帮助取食;而水状唾液中则包含了果胶酶、纤维素酶、多酚氧化酶、过氧化物酶、碱性磷酸酯酶、蔗糖酶等组分,来帮助刺吸式昆虫对植物穿刺、消化食物、解毒次生物质并破坏植物的防御反应。有趣的是,唾液成分同时还可以诱导植物的防御反应,包括诱导植物的伤信号引起直接防御反应和诱导植物产生挥发物吸引植食者的天敌引起间接防御反应。并且,许多刺吸式昆虫取 食能够特异性地引发植物的病理反应,有研究推测刺吸式昆虫唾液中多聚半乳糖醛酸酶、碱性磷酸酯酶、蔗糖酶、多酚氧化酶等成分可能是某些植物特定病理反应的激发子,但是目前还没有定论,同时许多刺吸式昆虫唾液中的氨基酸和蛋白酶还是引起植物虫瘿的原因之一。 迄今的研究表明,刺吸式昆虫会根据不同的寄主植物和不同的生理需要,通过唾液组分的改变,来达到取食和发育的目的。对刺吸式昆虫唾液成分和作用机理的研究,可以为揭示刺吸式昆虫致害机理特别是传毒机理、指导害虫有效治理、阐明其与植物的协同进化等提供一定的思路。  相似文献   

19.
Y Li  Q Xiang  Q Zhang  Y Huang  Z Su 《Peptides》2012,37(2):207-215
Antimicrobial peptides (AMPs), which are produced by several species including insects, other animals, micro-organisms and synthesis, are a critical component of the natural defense system. With the growing problem of pathogenic organisms resistant to conventional antibiotics, especially with the emergence of NDM-1, there is increased interest in the pharmacological application of AMPs. They can protect against a broad array of infectious agents, such as bacteria, fungi, parasite, virus and cancer cells. AMPs have a very good future in the application in pharmaceuticals industry and food additive. This review focuses on the AMPs from different origins in these recent years, and discusses their various functions and relative mechanisms of action. It will provide some detailed files for clinical research of pharmaceuticals industry and food additive in application.  相似文献   

20.
昆虫抗菌肽结构与功能关系及其在分子设计中的应用   总被引:9,自引:0,他引:9  
昆虫抗菌肽在自然分布广泛,结构多样,其作用机制尚未确切阐明,但其结构上的某些共同特征与其功能密切相关,同时,对其结构与功能间关系的研究有利于设计合成新的抗菌肽,为以后发现活性更强,毒性更低且作用广谱的抗菌素奠定基础。  相似文献   

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