12 resultados para Syntermes wheeleri


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The trawl fishery for pelagic annorhead, Pseuaopentaceros wheeleri(fonnerly referred to as Pentaceros richardsoni), and alfonsin, Beryx splendens, over the central North Pacific seamounts has a relatively short history. Before 1967, fishery scientists were generally unaware of the resources on seamounts; however, the discovery of commercial concentrations of pelagic armorhead on seamounts in the southern Emperor Seamounts by a Russian commercial trawler in November 1967 led to almost immediate exploitation of the species by the Soviets. Unconfinned reports indicated that the schools of pelagic annorhead on the seamounts averaged 30 m thick and catches averaged from 3 to 50 metric tons on 10-20 min hauls (Sakiura 1972). Japanese trawlers entered the fishery in 1969. To assist in the development of this tishery, Japanese research vessels conducted extensive surveys in 1972 on the distribution and potential for development ofthe pelagic armorhead and alfonsin resources. The results of their surveys to the central North Pacific and mid-Pacific seamounts showed that many had summits that were too deep for trawling. Those found suitable were concentrated in the southern Emperor-northern Hawaiian Ridge. (PDF file contains 113 pages.)

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Cupins-de-montículo predominam em áreas menos sujeitas à mecanização, como as pastagens. Dessa forma, quando não controlados, pastagens mais velhas podem apresentar níveis de infestação mais elevados. Em verdade, altas infestações desses cupins são, em muitos casos, indicadores de pastagens degradadas. As espécies mais comuns em pastagens pertencem ao gênero Cornitermes, destacando-se C. cumulans, C. bequaerti e C. silvestrii. Não há confirmação de danos diretos ocasionados por esses insetos em pastagens, assim como, contesta-se sobre a possível redução de área útil, normalmente associada aos cupinzeiros. Podem, sim, dificultar a movimentação de máquinas e implementos, assim como abrigar animais peçonhentos. Embora a importância desses cupins como pragas de pastagem seja discutível, tem sido generalizada a demanda por controle; que, predominantemente, tem sido feito através de inseticidas químicos. Ressalta-se que em pastagens altamente infestadas, muitas vezes velhas e degradadas, ocorre a morte natural de colônias, e o percentual de cupinzeiros já abandonados na área pode ser alto. Como essas áreas são passíveis de serem reformadas, não se recomenda o controle prévio dos cupinzeiros dessas espécies, e sim, que sejam implementadas as práticas previstas e recomendadas na reforma da pastagem. Estas práticas por si só controlam a maioria, se não todas, as colônias presentes na área. Alerta-se, no entanto, que alguns cupins pertencentes ao gênero Syntermes que, por vezes, também constroem montículos em pastagens, têm a característica de forragear na superfície, coletando folhas secas e verdes. Embora se admita que ocorram em menor freqüência, se comparado a outras espécies de cupins-de-montículo em pastagens, os mesmos representam uma ameaça em potencial.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)National Science Foundation (NSF)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Meiosis and (or) mitosis of males and females of Cryptotermes brevis, Eucryptotermes wheeleri, and Neotermes fulvescens, all of them from the neotropical region, were analyzed. Cryptotermes brevis showed a similar karyotype to that obtained by other authors for specimens of the neartic and Australian regions (2n = 36 for females and 2n = 37 for males, with XX and XYY sex mechanisms, respectively). Eucryptotermes wheeleri, the only species that has been described in this genus, showed the lowest number of chromosomes reported for Isoptera (2n = 22) until now. The male meiosis of this species presents a linear chain of six sex chromosomes, three of them being X and three of them Y chromosomes. Neotermes fulvescens showed a diploid number of 40 for males and 42 for females and, in the first male meiosis, two linear chains of chromosomes, both related to sex. One of the chains, named A, presented nine chromosomes and the other, named B, seven chromosomes. Hypotheses to explain these mechanisms are formulated in this paper and putative ancestral relationships with other species of Kalotermitidae are presented.

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is a predominant characteristic, conditioned by the presence of castes with different morphology, ontogeny, and development. The soldier caste is unique among social insects and it is responsible for colony defense. Soldiers belonging to the Nasutitermitinae subfamily are very peculiar, since they may be polymorphic and present a nasus in addition to either developed or vestigial mandibles. The defensive secretions of soldiers of the neotropical Nasutitermitinae have been the aim of several chemical studies, but few data exist concerning the anatomy and histology of the exocrine glands. This article presents a comparative study on the anatomy of the frontal gland of soldiers of several Nasutitermitinae species: Syntermes dirus (Burmeister), Syntermes nanus (Constantino), Constrictotermes cyphergaster (Silvestri), Nasutitermes corniger (Motschulsky) and Velocitermes heteropterus (Silvestri), with emphasis on the ultramorphology and ultrastructure of the frontal tube.

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Eucryptotermes breviceps, new species, is described from central Amazonia. Both imagoes and soldiers of this new species have only two apical spurs on the foretibia, a condition previously unknown for Kalotermitidae. The soldier of E. breviceps has a peculiar and extremely phragmotic head. The geographical distribution of E. wheeleri is expanded with new records, and measurements of soldiers and imagoes of this species are presented for the first time. E. wheeleri is a native of the Atlantic forest of southeastern Brazil, from Santa Catarina to Rio de Janeiro, but it has been recorded in urban areas and may be an occasional minor pest.

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The termite problem in eucalyptus forest plantations in Brazil has been registered since 1908. The main termite pests can be separated in four groups: a) seedling/sapling termites; b) heartwood termites; c) bark termites and d) wood termites. The termites in the first group attack root and stalk bases of young eucalyptus plants. The most common species are Syntermes spp. and Cornitermes spp. and they are a serious obstacle to early eucalyptus developing. The heartwood termites attack formed trees destroying eucalyptus heartwood. Coptotermes testaceus is the most cited species in reports, but more species probably occur. Plant mortality caused by seedling/sapling termites vary of 10-70 %. There are not effective control methods to heartwood termites. The main seedling/sapling termite control strategy is the chemical barrier around root systems of plants. Nowadays, studies are being carried out to determine monitoring systems to termite infestations. Early results indicate that proportionally, few areas really need insecticide application, due to spatial distribution of termites to be aggregated. Therefore, it is necessary to develope techniques rationalizing insecticide utilization in eucalyptus plantations, to keep production systems feasible and to be suitable for environmental exigencies.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

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This is a taxonomic revision of the Neotropical genus Orthognathotermes Holmgren, 1910 (Termitidae, Termitinae), previously with nine species: O. aduncus, O. brevipilosus, O. gibberorum, O. heberi, O. humilis, O. insignis, O. macrocephalus, O. orthognathus and O. wheeleri. We redescribe these species and describe six new species: O. longilamina sp. nov., O. mirim sp. nov., O. okeyma sp. nov., O. pilosus sp. nov., O. tubesauassu sp. nov., and O. uncimandibularis sp. nov., based on soldiers and, when possible, imago castes along with the first description of imagos of O. wheeleri and O. heberi. We present a key for soldier identification and distribution maps for all species.