Studies of host specificity in tropical insect herbivores are evolving from a. Components of host plant quality such as carbon, nitrogen, and defensive metabolites directly affect potential and achieved herbivore fecundity. Leaf chewers showed similar levels of species richness and host specificity in both forests. Low host specificity of herbivorous insects in a tropical forest. Why are phytophagous insects typically specialists. Apr 25, 2002 low host specificity of tropical herbivores reduces global estimates of arthropod diversity from 31 million ref.
Apr 25, 2002 host specificity and species richness of tropical insects are also key parameters in mapping global patterns of biodiversity. Host specificity of lepidoptera in tropical and temperate. Mutualism favours higher host specificity than does. So there had always been a plan to write such a paper. Genomics of adaptation to hostplants in herbivorous insects. Pdf two decades of research have not established whether tropical insect herbivores are dominated by specialists or generalists. Host specificity in variable environments sciencedirect. Host specialization of leafachewing insects in a new guinea.
The high rate of diversification in herbivorous insects is thought to result from their specialization to distinct host plants, which creates conditions favorable for the buildup of reproductive isolation and speciation. An understanding of the behavioral processes involved in selection of a host plant can be used to. But insect weengs are in motion, wi flappin an vibrations, resultin in churnin an eddies, an the misconception that pheesics says bumbees canna flee perseestit. Herbivorous insects have long served as models for the study of specialization, because they use a variety of plant resources in many different ways, and their host plants are discrete resources. The database included studies that provided information on herbivory folivory and also described the herbivore groups.
Host specificity of insect is required for their larval development. Several factors like tradeoff, characteristics of host plant, insects neural system are responsible to an insect for becoming a specialist. Low beta diversity was also documented in groups with differing host specificity fruitflies and ambrosia beetles, suggesting. Part of the series entomologica book series sent, volume 42. Pages in category herbivorous insects the following 2 pages are in this category, out of 2 total. The range of plants on which a herbivorous insect feeds is known as its host range. Insect simple english wikipedia, the free encyclopedia. Low host specificity of tropical herbivores reduces global estimates of arthropod diversity from 31 million ref. Although hypotheses exist that emphasize the role of evolutionary history e.
Few insects live in the oceans or in very cold places, such as antarctica. Many insects, like caterpillars and leaf beetles, feed on plants. Host specificity, representing the number andor diversity of host species a parasite is capable of infecting, is considered a key indicator of its propensity to shift hosts. Abstract testing the host specificity of potential agents is an important part of biocontrol methodology. Some people call all insects bugs, but this is not correct. A small number of insects are monophagous, feeding on a single plant. The impact of microbial symbionts on host plant utilization. Even so, the relative influence of plant species composition, herbivore host specificity, or herbivore dispersal on the largescale distribution of tropical insects remains unknown. Some species of cereal leaf beetle cooccur in the same localities, but the host specificity of the wasp to these crop pests has not yet been examined in detail. Buy evolution book online at low prices in india evolution.
Biological journal of the linnean society 67, 477499. The host specificity, taxonomic composition and feeding guild of rare species were studied in communities of herbivorous insects in new guinea. Plants can sense being touched, and they can use several strategies to defend against damage caused by herbivores. If the larvae or nymphs feed on plants, the insect mother usually lays her eggs on a host plant.
Specialization character of phytophagous insects is one of the key examples of insectplant relationship. Futuyma is distinguished professor in the department of ecology and evolution at the state university of new york at stony brook, usa. Specialist versus generalist insect herbivores and plant. Host specificity is a topic of considerable interest in the fields of disease ecology and one health that is quickly becoming a key feature of research agendas.
Jun 07, 2005 host specificity of insect herbivores in tropical forest communities. Miller smithsonian national museum of natural history. Even so, the relative influence of plant species composition, herbivore host specificity, or herbivore dispersal on the largescale distribution of. Herbivorous insects represent the most speciesrich lineages of metazoans. Often though, stages of the same insect are not specific to the same host or the same stage of one host.
Host specificity of insect herbivores in tropical forests. Low host specificity of tropical herbivores reduces global estimates of arthropod diversity from 31. Host specificity is common among many insects during all stages of their life cycles. Blastophaga psenes is typical of the agaonids, the insect group showing the greatest host specificity. Host specificity varies among species from specialists that can parasitize one or only a few hosts to generalists that can use a wide variety of species 215,218,220,441,668. When discussing the subject of host specificity, a note of caution should be injected. A central mission in ecology has been to explain differences in biodiversity across the world and across groups of organisms. The global distribution of diet breadth in insect herbivores. Host plant selection by phytophagous insects pdf download. Host specificity and species richness of tropical insects are also key parameters in mapping global patterns of biodiversity. His major research interests include evolution of host specificity in herbivorous insects and of interactions among insects and plants, speciation, and evolution of community structure. Despite its limited scope, the analysis characterized host specificity of 8793% of all individuals in the herbivore communities studied, providing thus a sufficiently comprehensive estimate of their host specificity. It is divided into four sections, wherein the first two sections deal with neurophysiology and the diversity of behavioral induction cues. Host plant quality and fecundity in herbivorous insects.
Pdf low host specificity of herbivorous insects in a tropical forest. Some of the more polyphagous insects like grasshoppers and armyworms will consume every part of their host plant. The responses of insect herbivores to changes in host plant quality vary within and between feeding guilds. Screening for host specificity of proposed biocontrol agents might profitably be based on large samples, with special attention paid to rare variants. T1 low host specificity of herbivorous insects in a tropical forest. Host plant quality is a key determinant of the fecundity of herbivorous insects. Dspace repository low host specificity of herbivorous insects in a tropical forest. Birgitta bremer born 17 january 1950, swedish botanist and academic, is professor at stockholm university, and director of the bergius botanic garden. Insects are among the most diverse groups of animals on the planet, including more than a million described species and representing more than half of all known living organisms. Concepts in insect hostplant selection behavior and their.
Concepts in insect hostplant selection behavior and their application to host specificity testing. These results concur with the work of many et al in suggesting that plants that have previously been fed on by other insects are less favourable food sources to other insects. Low beta diversity of herbivorous insects in tropical forests nature. Rare species in communities of tropical insect herbivores. The strategy of diet specialization, relatively small body size and ability to undergo a complete metamorphosis. Similarly, higher host specificity in tropical insects. The name true bugs is sometimes limited to the suborder heteroptera. The wet forest was 37% more species rich than the dry forest due to more saproxylic species and flower visitors. On the factors that promote the diversity of herbivorous insects and. In a novel approach, we simultaneously sampled invertebrates from multiple canopy. In the present study, only 1422% of species were sufficiently abundant for host specificity analysis.
The parasitic wasp anaphes flavipes forster, 1841 hymenoptera. Hence, there are more studies on herbivore host specificity. Low beta diversity of herbivorous insects in tropical forests. Some phytophagous insects eat a variety of plant species, while others specialize in eating only one, or just a few. Phytochemical uniqueness of the host plants was an important factor to explain insect species richness. Only some insects are true bugs, which is a particular order of insects. In writing this book, we hope to draw attention to this central role of behavior and, hopefully, encourage a few students to. The mouthparts very greatly among insects of different orders but there are two main functional groups.
Spatiotemporal dynamics and resource use in the canopy, edited by basset, yves, novotny, vojtech, miller, scott e. It is divided into four sections, wherein the first two sections deal with neurophysiology. Host specificity of insect herbivores in tropical forest communities. One salient theme to emerge from early investigations was that distinct microbial symbionts, or communities of microbial symbionts, were especially common in insects that feed on restricted andor relatively refractory food resources. Diva portal is a finding tool for research publications and student theses written at the following 49 universities and research institutions. A lack of knowledge of host specificity can have a negative effect on the use of this wasps in. Insects are a major force in most ecosystems, yet in studies of biodiversity they often receive less attention than birds, mammals and plants. With specialization, it was proposed that alongside the loss of ability to use many host plants, herbivores would gain the. Here lies the theoretical basis for why ecologists and plant scientists have long argued that specialist insect herbivores, as compared with generalists, will have distinct and predictable interactions with their host plants.
This can be wide or narrow, but it never includes all plants. For example, nothofagus alessandrii, the species with the most unique chemistry, had very few and mostly specialised herbivores, whereas nothofagus dombeyi, with the least unique chemistry, had the highest number of related insect species. When available, the chemical search also included books written on chemical characterizations of different families, genera. Recently, a novel approach using mass insect collect. Finally, only a single guild of herbivores was studied, viz. The paper is called low host specificity and the study of host specificity of tropical herbivorous insects was the primary motivation for the underlying study the grant proposal for us nsf and the field study. Low host specificity of herbivorous insects in a tropical. Species richness of insects herbivores on ficus spp.
Studies of host specificity in tropical insect herbivores are evolving from a focus on insect distribution data obtained by canopy fogging and other mass collecting methods, to a focus on. Yet the whole process of hostplant selection and hostplant specificity amongst insects depends on behavior, and selection for behavioral differences must be a prime factor in the evolution of hostplant specificity. This constant herbivore pressure will favor plants that produce novel. Plant defense against herbivory or host plant resistance hpr describes a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. For example, insects with high host specificity may have adaptations that allow them to tolerate increases in plant defensive compounds in their host plants and related species better than generalist insects, but responses will also differ between feeding guilds i. On the factors that promote the diversity of herbivorous. Haustellate mouthparts are those used for sucking liquids and can be further classified, by the presence of stylets, which include. Hence, there are more studies on herbivore host specificity than on their. Insects class insecta are a major group of arthropods and the most diverse group of animals on the earth, with over a million described speciesmore than half of all known living organisms with published estimates of undescribed species as high as 30 million, thus potentially representing over 90% of the life forms on the planet. Pdf low host specificity of herbivorous insects in a. Host specificity of insect herbivores in tropical forests ncbi.
Host specificity patterns of individuals in herbivore communities have received so little attention that even the simple but fundamental question of whether a herbivorous insect selected at random from tropical vegetation is likely to be a generalist or a specialist has yet to be answered novotny et al. Insect flicht haes been a topic o great interest in aerodynamics due pairtly tae the inabeelity o steadystate theories tae expleen the lift generatit bi the tottie weengs o insects. Taxonomic composition and host specificity of phytophagous beetles in a dry forest in panama. Saproxylic species and flower visitors were also more host specific in the wet forest. Potential evolution of host range in herbivorous insects. N2 herbivory, defined as feeding on live plant tissues, is characteristic of highly successful and diverse groups of insects and represents an evolutionarily derived mode of feeding. Insects free fulltext host specificity of the parasitic. Here we analyse data for over 900 herbivorous species feeding on 51 plant species in new guinea and show that most herbivorous species feed on several closely related plant species. Host specificity of weedfeeding insects springerlink. Pdf low beta diversity of herbivorous insects in tropical. Saving the forest for the trees the high stakes of weiblens research in papua new guinea. Host seeking behavior and mechanisms addresses mechanisms of searching behavior leading ultimately to host location of herbivorous insects. Species richness of herbivorous insects on nothofagus. Yet the whole process of host plant selection and host plant specificity amongst insects depends on behavior, and selection for behavioral differences must be a prime factor in the evolution of host plant specificity.
Taken together, the present results on host specificity of diphtheroptila, caloptilia, cuphodes and glochidionfeeding, nongracillariid lepidopterans all indicate that the level of host specialization in epicephala is higher than would be expected if host specificity were determined solely by the herbivorous habit of the moths. Host specificity, seasonality and bionomics of leptinotarsa beetles. Mymaridae is an important egg parasitoid of cereal leaf beetles. Massey et al also showed that some insects are better at coping with high levels of silica than others but all insects do prefer to feed on leaves low in silica. Chemical basis of host selection and plant resistance in oligophagous insects. Wherever possible, data for feeding guilds and insect orders coleoptera, diptera, hemiptera, lepidoptera, orthoptera and phasmatodea, abbreviated by the first letter of their name are separated. The silkworm larva is one of these, with mulberry leaves being the only food consumed. Host plant quality also affects insect reproductive. Here we analyse data for over 900 herbivorous species feeding on 51 plant species in new guinea and show that most herbivorous species feed on.
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