Back to the main Bees, Wasps and Ants page. Rhyssa persuasoria is a large Ichneumonid that is an ectoparasite on larvae of the Greater Horntail Urocerus gigas. These impressive insects are completely harmless. Females who lay eggs on insects in the open air have very small ovipositor ; those which attack larvae underground, or are protected by some shelter, have long ovipositors.
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The large number of Hymenoptera Parasitica combined with their ability to respond to the density of the populations of its hosts makes them essential to maintain ecological balance and a force that contributes to the diversity of other organisms.
The objective of this bibliographic study and present the characteristics of Hymenoptera Parasitic Insecta: Hymenoptera. Keywords: insetics, parasitoids, biocontrol, natural enemy, Brazil. Hymenoptera Parasitica represent the richest group of Hymenoptera and insect species; are common and abundant in all terrestrial ecosystems; develop as parasitoids of many insects, playing an important role in regulating pest populations and also phytophage insects, as they can lay their eggs on or directly within their host egg, larva, pupa or imago which is always dead due to the development of the larva that feeds on it.
Taxonomic knowledge, only, is not enough to protect the species; ecological information, evolutionary correlations are necessary to ensure its survival. In most terrestrial ecosystems, Hymenoptera Parasitica develop in trophic interactions, include "key species" and have the skills to regulate the populations of their hosts. Its removal can cause the "cascading effect", where the decrease in the host population leads to the decrease in parasitoid populations, after the increase in the host population, which compete with each other and therefore also decrease in number.
Parasitoid food chains contain more than half of the known species of Metazoa Price , Strong et al. Biological control is the best evidence that parasitoids can regulate the size of the population of phytophages. This represents an index of 1, to 5, times higher than average. Through the few resources we have it is impossible to study all groups to know their biodiversity. We need to choose important groups or habitats to be studied with priority. Insects constitute the group of invertebrates best represented on the planet, constituting half of the living organisms described , species and making the greatest impact on terrestrial ecosystems.
They keep the various trophic levels united; are millions of herbivores consuming plants and also millions of consumers by others who are predators or parasitoids.
Not all species have the same influence on ecosystems and according to Solbrig there are 3 categories of "key species": natural enemies predators, parasitoids, herbivores and pathogens ; and species that are a source for the survival of other decomcomposers.
Lepidoptera and Hymenoptera Parasitica mainly Chalcidoidea and Ichneumonoidea participate in many trophic chains of tropical ecosystems involving plants, herbivore insects and parasitoids. Without the controlling action of the parasitoids there would be an explosion in the herbivorous populations which would lead to a greater degradation of the plant species consumed by them; therefore, parasitoids, herbivores and plants must be kept in balance so that their diversity is not altered.
Successful groups such as Lepidoptera and Hymenoptera become fragile in the face of environmental degradation, prone to extinction. The Hymenoptera Parasitica are the most important natural regulators responsible for most of the economic and environmental benefits produced by biological control programs and can provide subsidies for biology and conservation studies.
As biological control agents they react to the size of populations of their hosts. Its mortality action increases with the increase in the population of its hosts and decreases with the decrease of it. The two linked populations float each other in order to prevent both the mass increase and extinction of the host population.
Interest in biological control has grown in several countries, in part, in response to the adverse effects of chemical pesticides on the environment and biodiversity, and also due to the new international segmentation of agricultural production through the use of alternative means to the environment in order to promote the conservation and sustainable use of biodiversity.
Brazil is one of the few countries in the world that hold the so-called biological megadiversity, that is, important ecosystems, still healthy.
This biodiversity can offer unique opportunity for pest control in both Brazil and other countries, due to the identification of new organisms with potential to be used in biological control.
For many agroecosystems in our country, little is known about the biodiversity and identity of species of natural enemies with the function of sustaining crop production. As a key component of global biodiversity and as a key determinant of sustainable agriculture, natural enemies should be better understood to be protected.
Currently, Brazil has many laboratories that work with biological control contributing to several programs of great success, mainly in the control of insect pests. Several recent works have questioned the safety of classical biological control and, specifically, the use of generalist natural enemies. There are many examples of introductions that have resulted in severe impacts on untargeted organisms, extinctions, biodiversity loss and imbalance of native communities.
The great difficulty is to decide what is necessary to preserve biodiversity, since it is unfeasible to study all existing species. The natural parasitoids of a plague are not only important to it, because the number of natural enemies found in any project can be important to the success of the program. If different species are more effective at different times of the year or on different host plants or different population densities or at the same time at different stages of hosts, then diversity is important.
Problems of animal ecology. Press, Oxford. Brown, W. In Parker, S. Synopsis and classification of living organisms. New York. Greathead, D. Parasitoids in classical biological control. Insects Parasitoids, pp. Academic Press, London. Hanson, P. The Hymenoptera of Costa Rica. Oxford University Press, Oxford. Hawkins, B. Species richness for parasitoids of Britain phytophagous insects. Nature, La Salle, J. Parasitic Hymenoptera and biodiversity crisis. Redia, Laroca, S. Notuerva, P. Synanthropy of blowflies Diptera.
Price, P. Evolutionary biology of parasites. Princeton University Press, Princeton. Reid, W. Miller, K. Keeping options Alive: the scientific basis for conserving by biodiversity.
World Research Institute, Washington, D. Solbrig, O. Biodiversity: scientific issues and collaborative research proposals. MAB Digest 9. Strong, D. Insects on plants. Blackwell Scientific Oxford, Oxford.
Characteristics of Hymenoptera Parasitica (Insecta: Hymenoptera).
HYMENOPTERA PARASITICA PDF
Parasitica - (all Apocrita except for the Aculeata)
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