Heterotermes Tenuis Research Articles

Coevolution of symbiotic spirochete diversity in lower termites.

The phylogenetic relationships of symbiotic spirochetes from five dry-wood feeding lower termites (Cryptotermes cavifrons, Heterotermes tenuis, Kalotermes flavicollis, Neotermes mona, and Reticulitermes grassei) was compared to those described in previous reports. The 16S rDNA bacterial genes were PCR-amplified from DNA isolated from intestinal samples using a spirochete-selective primer, and the 16S amplicons were cloned into Escherichia coli. Sequences of the cloned inserts were then used to determine closest relatives by comparison with published sequences. Clones sharing more than 97% sequence identity were grouped into the same phylotype. Forty-three new phylotypes were identified. These termite whole-gut-spirochetes fell into two previous defined clusters, designated as Treponema Clusters I and II, and one new Cluster III. Thirty-seven phylotypes were grouped in Cluster I. Cluster II comprised three phylotypes, two from Reticulitermes grassei (LJ029 and LJ012) and one from Heterotermes tenuis (LQ016). Three phylotypes, LK057, LK050 and LK028, were affiliated to Cluster III. Members of Cluster I showed the following characteristics: (i) spirochete phylotypes from a particular species of termite were more closely related to each other than to phylotypes of other termite species; (ii) spirochetes obtained from different genera of the same family, such as Cryptotermes sp., Kalotermes sp., and Neotermes sp., all from the family Kalotermitidae, were also related to each other. It was therefore concluded that spirochetes are specific symbionts that have coevolved with their respective species of termites, are stably harbored, and are closely related to members of the same termite family.

Foraging activity and demographic patterns of two termite species (Isoptera: Rhinotermitidae) living in urban landscapes in southeastern Brazil

Coptotermes gestroi and Heterotermes tenuis (Isoptera: Rhinotermitidae) are important pests in southeastern Brazil causing serious economic damage. In this study we determined the demographic patterns and foraging activity of these species using mark-release-recapture and the consumption of wooden stakes. Using both the weighted mean and Lincoln index methods, popula- tion estimates ranged from | 0.57 to 1.99 million individuals for C. gestroi and from | 0.20 to 1.37 million for H. tenuis. Territory size of the colonies ranged from 172.5 to 5235 m 2 for C. gestroi and from 16 to 40 m 2 for H. tenuis. Our results also indicate that for- aging activity was dependent on the minimum temperature; however, the existence of a compensation strategy in the foraging activi- ties may permit foragers to exploit food sources under different environmental conditions.

Electroantennographic responses of Heterotermes tenuis (Isoptera: Rhinotermitidae) to synthetic (3Z,6Z,8E)-Dodecatrien-1-ol

The subterranean termite Heterotermes tenuis (Isoptera: Rhinotermitidae) is a pest of great importance for the Brazilian economy as it causes serious damages in commercial reforestations of Eucalyptus spp. and sugarcane cultures. (3Z,6Z,8E)-Dodecatrien-1-ol has been identified as a pheromone of some species of subterranean termites. The objective of this research was to synthesize (3Z,6Z,8E)-dodecatrien-1-ol and determine by electroantennographic (EAG) bioassays the selectivity and sensitivity of H. tenius antennae to its whole worker extract and to the synthetic triene alcohol.

Molecular Phylogeny and Biogeography of <I>Heterotermes</I> (Isoptera: Rhinotermitidae) in the West Indies

A phylogenetic analysis of Heterotermes from 63 locations in the West Indies and associated mainland is presented based on the DNA sequence of a portion of the mitochondrial 16S rRNA gene. Maximum parsimony analysis of the aligned Heterotermes species and the outgroup taxa resulted in a consensus tree with five distinct West Indian groups. Morphological characters and geographical distribution supported the resulting clades, which were given the following taxonomic assignments: Heterotermes cardini (Bahamas and Cuba); Heterotermes sp. (Bonaire, FL; Grand Cayman; Grand Turk; Jamaica; and St. Barthelemy), Heterotermes convexinotatus (Antigua, Barbados, Curacao, Dominican Republic, Martinique, Puerto Rico, St. Kitts, St. Maarten, Venezuela, and Virgin Island), and Heterotermes tenuis (Lesser Antilles except Barbados and Martinique, Ecuador, and Suriname). The Florida Heterotermes sp. is a known nonendemic population, whereas those on Barbados, Grand Cayman, Grand Turk, Martinique, St. Barthelemy, and elsewhere may harbor or consist solely of nonendemic populations.

Cuticular hydrocarbons of Heterotermes tenuis (Isoptera: Rhinotermitidae): analyses and electrophysiological studies.

Termites have become an important pest of Eucalyptus and Pinus reforestations, sugarcane and other cultures. An alternative for the control of this pest would be the use of attractive traps that take in account the social behavior of these insects. Diverse factors are important for the insects in the localization of the habitat and the choice of the food and specific odors can facilitate this. Studies referring to Heterotermes tenuis (Isoptera: Rhinotermitidae) are scarce. The objective of this work was to analyze the tergal cuticular extract of H. tenuis and determine the selectivity and sensitivity of its antennae to the components of this extract by electroantennography (EAG). The composition of the cuticular extract was determined by GC-MS analysis. The hydrocarbons found were restricted to linear alkanes, being most abundant C24 to C27 that comprises ca. 65% of the total. Olefins were not detected. EAG and behavioral test responses to the cuticular hydrocarbons were greater and significantly different from the control and the high selectivity of the antennae to the extract indicates its potential as chemical messenger. Cuticular hydrocarbons mixture is species-specific and can be used to identify a given taxon without the diagnostic castes, soldiers or imagoes Difference in the composition appears to relate with the type of habitat of specie.

População e território de forrageamento de uma colônia de Heterotermes tenuis (Hagen) (Isoptera, Rhinotermitidae)

Heterotermes tenuis (Hagen, 1858) is a subterranean termite that cause damage in forests, crops and urban areas. The population and foraging territory of an urban colony were determined using triple mark-release-recapture technique. Foraging population was estimated in 134,583 ± 5,803 individuals. The foraging territory encompassed an area of 175,5 m2 and the maxim linear foraging distance was 36 m.

External development of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae in the subterranean termite Heterotermes tenuis

The subterranean termite Heterotermes tenuis is one of the main pests of sugarcane and eucalyptus in Brazil, and the use of entomopathogenic fungi, alone or associated to chemicals, is an efficient and environmentally favorable method for its control. Studies related to the fungal development on these insects are important due to the effect of insect behavior on entomopathogens. The objective of this work was to describe the external development of Beauveria bassiana and Metarhizium anisopliae on H. tenuis using Scanning Electron Microscopy (SEM), determining the duration of the different phases of fungal infection. Two fixation techniques for preparing SEM samples were also evaluated. Worker specimens of H. tenuis were inoculated with a 1 x 10(9) conidia mL-1 suspension of the fungi and maintained at 25±1ºC and 70±10% relative humidity. Insects were collected from 0 to 144 hours after inoculation and prepared on SEM stubs for each of the two fixation techniques. The results obtained with the two techniques were compared and duration of the different phases of the infection process were estimated from SEM observations and compared for three fungal isolates. B. bassiana and M. anisopliae have similar development cycles on the termite, but some important differences exist. The penetration, colonization and conidiogenesis phases are relatively faster for M. anisopliae than for B. bassiana, which results in a faster rate of insect mortality. The fixation technique with OsO4 vapor is suitable for preparation of insects to be used in SEM observation of the developmental stages of entomopathogenic fungi.

Morfologia do tubo digestivo nos cupins Heterotermes tenuis (Hagen) e Coptotermes havilandi Holmgren (Isoptera, Rhinotermitidae)

The digestive tube of workers of Heterotermes tenuis (Hagen, 1858) e Coptotermes havilandi Holmgren, 1911 was analysed under the anatomical view. The digestive tube of both species did not show conspicuous diferences in relation to the morphology, morphometry and the configuration of the digestive tube that were the aspects studied. The general organization of the digestive tube of these species show several similarity with other lower termites previously analysed.

TAMANHO DA ÁREA DE FORRAGEAMENTO DO CUPIM SUBTERRÂNEO Heterotermes tenuis (ISOPTERA; RHINOTERMITIDAE) EM CANA-DE-AÇÚCAR

Estudou-se a área de forrageamento do cupim Heterotermes tenuis utilizando-se a isca Termitrap® marcada com o radioisótopo 32P. O experimento foi conduzido numa área com cana-de-açúcar, em Piracicaba-SP. Foram localizados 20 focos de H. tenuis, com iscas. Em cada um desses focos aplicou-se uma isca Termitrap® impregnada com 18,5 MBb (500 mCi) 32P na forma de fosfato de sódio diluído em 15 ml de água destilada. Ao redor das iscas marcadas, foram instaladas iscas sem marcador em quatro pontos: Norte, Sul, Leste e Oeste, eqüidistantes de 1, 5, 10 e 20 metros. Cada tratamento foi representado por um foco previamente determinado e marcado e uma das distâncias estipuladas para a isca de monitoramento, sendo repetido de 4 a 6 vezes. Após 15 dias da marcação, procedeu-se a avaliação coletando-se 15 indivíduos de H. tenuis de cada isca de monitoramento infestada, acondicionando-os em frascos de vidro com água destilada, que foram analisados em cintilador líquido, pelo teste de Cerenkov. Verificou-se que em apenas 20% das iscas de monitoramento coletaram-se cupins e 11,3% estavam marcadas com o radioisótopo. Constatou-se que ocorrem diversas colônias forrageando numa mesma área. A área de forrageamento de H. tenuis em cana-de-açúcar pode variar de 3 a 1.250 m2.

Controle do cupim subterrâneo Heterotermes tenuis (Hagen) com iscas termitrap impregnadas com inseticidas e associadas ao fungo entomopatogênico Beauveria bassiana (Bals.) Vuill.

Avaliou-se o controle do cupim Heterotermes tenuis (Hagen) (Isoptera: Rhinotermitidae) utilizando-se a isca Termitrap impregnada com inseticidas em baixas concentrações e associados ou não ao fungo Beauveria bassiana (Bals.) Vuill., isolado 634 (obtido de Solenopsis invicta F. Smith) em cana-de-açúcar (híbridos de Saccharum officinarum L.). O experimento foi conduzido num canavial da Fazenda São José, no município de Rio Claro-SP, com alta infestação de cupins. Os tratamentos foram os seguintes: imidacloprid 0,01%; imidacloprid 0,01% + B. bassiana; WG 0,003%; WG 0,003% + B. bassiana; B. bassiana; e Testemunha (sem tratamento). Cada tratamento foi repetido cinco vezes. As iscas foram impregnadas com os inseticidas por imersão em água, sendo suas concentrações calculadas de acordo com o peso da isca, sendo B. bassiana aplicado em conídios puros (10(9) conídios/isca). As avaliações foram realizadas após 15, 30, 41, 63, 86 e 136 dias, aplicando-se notas para as populações encontradas. O trabalho foi conduzido entre os meses de novembro de 1996 a abril de 1997. Foi possível observar que o imidacloprid 0,01% causou a diminuição da população de H. tenuis de forma mais lenta, pois essa população somente chegou a zero na avaliação aos 30 dias. Quando fungo foi aplicado isoladamente, o decréscimo da população foi mais lento do que nos tratamentos imidacloprid 0,01% e WG 0,003%. Os tratamentos com imidacloprid e WG, associados ao fungo B. bassiana foram os mais eficientes no controle dessa espécie de cupim em cana-de-açúcar. Os cupins visitaram e se alimentaram das iscas normalmente, demonstrando não haver repelência dos tratamentos a esses insetos.

Efeito de imidacloprid e fipronil sobre Beauveria bassiana (Bals.) Vuill. e Metarhizium anisopliae (Metsch.) Sorok. e no comportamento de limpeza de Heterotermes tenuis (Hagen)

Avaliou-se o efeito fungitóxico dos inseticidas imidacloprid e fipronil sobre os fungos entomopatogênicos Beauveria bassiana (Bals.) Vuill. e Metarhizium anisopliae (Metsch.) Sorok., por meio da medição do diâmetro de colônias e contagem do número de conídios produzidos por colônia que cresceu em meio de cultura contendo esses inseticidas. O imidacloprid foi menos tóxico para B. bassiana e M. anisopliae que o fipronil, sendo que M. anisopliae mostrou-se menos suscetível que B. bassiana aos dois produtos. Também foi avaliada a alteração no comportamento de limpeza de operários de Heterotermes tenuis (Hagen) sob a ação dos dois produtos. Para isso foram observados, com o auxílio da microscopia eletrônica de varredura, os conídios dos dois entomopatógenos presentes na superfície do tegumento dos insetos em diferentes horários após a inoculação. O produto imidacloprid em concentrações subletais alterou o comportamento de limpeza dos operários de H. tenuis, enquanto fipronil não provocou alteração nesse comportamento.

Seleção de iscas celulósicas para o cupim Heterotermes tenuis (isoptera: rhinotermitidae) em cultura de cana-de-açúcar

Estudou-se em condições de campo a atratividade ao cupim subterrâneo Heterotermes tenuis (H.,1858), importante praga da cana-de-açúcar no Brasil, de dezessete produtos com alto teor celulósico (bagaço de cana-de-açúcar "in natura"-T1; bagaço de cana + papelão ondulado picado-T2; bagaço de cana + açúcar refinado-T3; bagaço de cana + açúcar refinado + papelão picado-T4; bagaço de cana-de-açúcar decomposto-T5; bagaço decomposto + papelão picado-T6; bagaço decomposto + açúcar refinado-T7; bagaço decomposto + papelão picado + açúcar refinado-T8; torta de filtro "in natura"-T9; torta de filtro decomposta-T10; rolão de milho-T11; fezes frescas e secas de bovino-T12; papelão ondulado picado-T13; papel toalha picado-T14; serragem de pinus-T15; papelão ondulado usado picado-T16; celulose picada-T17). Usando-se a isca TermitrapR localizaram-se os focos do inseto no campo e, através de uma escala de notas, de zero a três, para a quantidade de cupins encontrados nas iscas, selecionaram-se os produtos mais atrativos, que foram em ordem decrescente: T12, T11, T1, T6, T3, T16, e T17.

Native, Introduced, and Structure-Infesting Termites of the Turks and Caicos Islands, B.W.I. (Isoptera: Kalotermitidae, Rhinotermitidae, Termitidae)

A survey of termites (Isoptera) from Providenciales and Grand Turk, Turks and Caicos Islands, British West Indies, yielded twelve species from three families. The Kalotermitidae included Incisitermes snyderi (Light), Incisitermes sp. nr. bequaerti (Snyder), Incisitermes sp. nr. milleri (Emerson), Neotermes sp. nr. mona (Banks), N. castaneus (Burmeister), N. jouteli (Banks), Procryptotermes corniceps (Snyder), and the introduced Cryptotermes brevis (Walker). Rhinotermitidae collected were Heterotermes tenuis (Hagen) and the introduced Coptotermes havilandi Holmgren, and the Termitidae included Nasutitermes nigriceps (Haldeman) and N. costalis (Holmgren).