The biological control of subterranean termites (Isoptera: Rhinotermitidae; Termitidae) using entomopathogenic nematodes (Nematoda: Steinernematidae; Heterorhabditidae) (EPN) was investigated. The desert subterranean termite Heterotermes aureus Snyder was found to be very susceptible to Steinernema riobrave Cabanillas, Poinar and Raulston. In laboratory bioassays S. riobrave (355, TP, 3-8b and 7-12 strains), S. carpocapsae Weiser (Mexican 33 strain), S. feltiae Filipjev (UK76 strain), and Heterorhabditis bacteriophora Poinar (HP88 strain) were all capable of infecting and killing H. aureus, Reticulitermes flavipes Kollar, R. virginicus Banks, Coptotermes formosanus Shiraki and Gnathamitermes perplexus Banks. In sand assays, S. riobrave caused > 90% H. aureus mortality in 3 days and 100% mortality by day 5 at 22 °C. TP strain of S. riobrave caused 75% R. flavipes mortality and 90.91% C. formosanus mortality in 7 days. EPNs utilizing termites as hosts produced smaller sized offspring, with the exception of S. feltiae. Stunted females of S. feltiae were frequently found in termite cadavers, but no progeny. Small IJs of S. carpocapsae, S. riobrave and H. bacteriophora infect, reproduce and form normal size IJs after subsequent infection in Galleria mellonella L. The progeny of small IJs were as effective as the normal size IJs, with regard to subsequent induced mortality, under the conditions tested. In laboratory two-container choice experiments, H. aureus were repelled by EPN treated areas for up to 10 days at 10,000 IJs per device. The repellency threshold was found to vary among nematodes species. We hypothesis that it is the physical movement of the nematodes that repels the termites. Temperature is a key factor affecting nematode pathogenicity. Temperature tolerance of the nematodes varied between species. After a gradual heat adaptation process, S. riobrave and H. bacteriophora caused significantly higher H. aureus mortality at 32 °C compared with original laboratory cultured strains. Further work may result in the contribution of commercially available strains with enhanced heat tolerance. Preliminary field studies confirmed EPN protection of a structure, however, termites began to reinfest 4 weeks after the application. Additional tests are necessary to provide more evidence before we can conclude nematodes as useful in the field.

Made available in DSpace on 2014-06-11T19:35:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-27Bitstream added on 2014-06-13T20:46:52Z : No. of bitstreams: 1 lima_jt_dr_rcla.pdf: 1902367 bytes, checksum: 643e995723baa05601e16df2db548e28 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Coptotermes gestroi e Heterotermes tenuis são espécies de cupins pertencentes à família Rhinotermitidae consideradas importantes pragas urbanas no Brasil, sendo que a segunda também é encontrada em ambientes agrícolas. No ambiente urbano, tais espécies são encontradas consumindo várias fontes celulósicas, algumas até aparentemente similares. O processo de forrageamento dos cupins subterrâneos é dinâmico e muda ao longo do tempo. Contudo, devido aos seus hábitos crípticos, existem alguns pontos polêmicos que precisam ser esclarecidos, principalmente visando melhorar e embasar as novas estratégias de manejo, tais como a tecnologia de isca. Em vista do exposto, a presente pesquisa propôs analisar e comparar, por meio de bioensaios, as respostas comportamentais de C. gestroi e H. tenuis considerando diferentes formas de apresentação do alimento e frente a recursos alimentares equivalentes. Uma vez que uma colônia pode utilizar várias fontes alimentares, também foi observado o comportamento de busca por novos alimentos, verificando o forrageamento desses insetos frente a recursos alimentares previamente visitados por outros cupins. Para esses bioensaios foram utilizados diferentes tipos de arenas experimentais compostas por câmaras “ninho” e câmaras alimentares. Adicionalmente, foi observado o comportamento de tunelamento dos forrageiros em solos heterogêneos, acrescidos de pistas físicas, químicas e biológicas, simulando aqueles presentes em áreas urbanas. Para tanto, foram utilizadas arenas bidimensionais compostas por duas placas de vidro separadas por uma moldura, a qual delimitava a área de tunelamento disponível para os indivíduos. Todos os dados obtidos foram analisados gráfica e estatisticamente, sendo que o nível de significância (a) adotado foi igual a 0,05. De acordo com os resultados obtidos nos experimentos com diferentes formas de apresentação... / Coptotermes gestroi and Heterotermes tenuis, termites of the Rhinotermitidae family, are considered important urban pests in Brazil. The latter is also found in rural areas. In urban environments, these species consume many cellulose sources, some apparently similar. The foraging behavior of subterranean termites is dynamic and changes throughout time. However, due to their cryptic behavior, some questions still remain, especially regarding the construction of a framework and the improvement of new control strategies involving baits. The present study was aimed at analyzing and comparing the behavioral responses of C. gestroi and H. tenuis using bioassays involving different food presentations and equivalent food resources. Since a colony can feed on many food sources, the searching behavior of new food items was examined as well as foraging of food items previously visited by other termites. Bioassays consisted of different types of arenas with a “nest” and feeding chambers were carried out. Also, the tunneling behavior of foragers in heterogeneous soils and physical, chemical, and biological cues was examined, simulating those present in urban areas. Bioassyas consisted of two glass plates separated by a frame delimitating the tunneling area available for the termites were carried out. The results were analyzed and significance level was set at p = 0.05. Based on the results obtained in the experiments with different forms of presentation of the food item, both species had similar behavioral patterns, showing a bias toward food items completely buried in the substrate. Regarding the exploitation of equivalent food sources, no differences were observed between consumption and recruiting for the first food sources visited compared to other sources available. Thus, C. gestroi and H. tenuis did not concentrate their efforts in the consumption of the first food item found. In tenacity... (Complete abstract click electronic access below)