Search results for "Termiti"

Inhibition of Metarhizium anisopliae in the alimentary tract of the eastern subterranean termite Reticulitermes flavipes

2009

Reticulitermes flavipes workers were individually inoculated with 10,000 conidia of the entomopathogenic fungus Metarhizium anisopliae. After being kept in groups of 20 individuals for 1–6 d, histopathological approach showed that most of the inoculated conidia were groomed from the surface of the cuticle by nestmates within 24 h, and that a large number of conidia was subsequently found in different parts of the gut of the groomers. Our observations showed that, among thousands of conidia found in the termite's gut, conidial germination never occurred in all inspected specimens, even when the conidia had the chance to bind to the surface of the cuticular lining of the gut. In addition, whe…

Sex-pairing pheromones and reproductive isolation in three sympatric Cornitermes species (Isoptera, Termitidae, Syntermitinae)

2011

International audience; The species-specificity of pairing has been studied in three sympatric Neotropical termites: Cornitermes bequaerti, Cornitermes cumulans and Cornitermes silvestrii (Termitidae, Syntermitinae). Bioassays showed that sex attraction was highly species-specific between C. bequaerti and C cumulans but not between C. cumulans and C. silvestrii. The sex-pairing pheromone of the three species is secreted by the tergal glands of female alates. It consists of a common compound (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. In C. bequaerti, this polyunsaturated alcohol is the only compound of the sex-pairing pheromone, whereas it is associated with the oxygenated sesquiterpene (E)-nerolid…

RESISTENZA NATURALE DI DIVERSE SPECIE LEGNOSE AGLI ATTACCHI DI RETICULITERMES LUCIFUGUS (ISOPTERA, RHINOTERMITIDAE)

2009

Cellular encapsulation in the eastern subterranean termite, Reticulitermes flavipes (Isoptera), against infection by the entomopathogenic fungus Meta…

2009

Reticulitermes flavipes workers were topically inoculated with approximately 10,000 conidia of the entomopathogenic fungus Metarhizium anisopliae. After being kept in groups of 20 individuals for 1-9 d, histopathological examination showed that termites had an individual immune reaction. The nodule formation at the point of entrance of the fungal hyphae was identified as a cellular encapsulation and the different steps in the nodule formation are described. The relative number of hemocytes per termite increased 24h after fungal exposure and remained high in the hemolymph for at least 3 d before decreasing back to pre-exposure levels. The role of an individual immune cellular reaction in soc…

Sex pheromones and trail-following pheromone in the basal termites Zootermopsis nevadensis (Hagen) and Z. angusticollis (Hagen) (Isoptera: Termopsida…

2010

In the context of an evolutionary study of the chemical communication in termites, sex pheromones and trail-following pheromones were investigated in two Termopsidae, Zootermopsis nevadensis and Z. angusticollis. In these species, in which the presence of sex-specific pheromones has been demonstrated previously, the chemical structure of the female sex pheromone has now been identified as (5E)-2,6,10-trimethylundeca-5,9-dienal and the male sex pheromone as (+)- or (-)-syn-4,6-dimethyldodecanal. The amount of sex pheromone was estimated at 5-10 ng per individual in females and 2-5 ng in males. Because these two sympatric species do not differ in their pheromonal chemical composition, reprodu…

The phylogeny of termites (Dictyoptera : Isoptera) based on mitochondrial and nuclear markers : implications for the evolution of the worker and pseu…

2008

A phylogenetic hypothesis of termite relationships was inferred from DNA sequence data. Seven gene fragments (12S rDNA, 16S rDNA, 18S rDNA, 28S rDNA, cytochrome oxidase I, cytochrome oxidase II and cytochrome b) were sequenced for 40 termite exemplars, representing all termite families and 14 outgroups. Termites were found to be monophyletic with Mastotermes darwiniensis (Mastotermitidae) as sister group to the remainder of the termites. In this remainder, the family Kalotermitidae was sister group to other families. The families Kalotermitidae, Hodotermitidae and Termitidae were retrieved as monophyletic whereas the Termopsidae and Rhinotermitidae appeared paraphyletic. All of these result…

The Intestinal Yeasts

2005

Yeast isolates were obtained from the hindgut of the lower termites Mastotermis darwiniensis (Mastotermitidae), Zootermopsis angusticollis, Zootermopsis nevadensis (Hodotermitidae), Neotermes jouteli (Kalotermitidae), Reticulitermes santonensis, Heterotermes indicola (Rhinotermitidae) and the roach Cryptocercus punctulatus (Prillinger et al. 1996). The monosaccharide composition of the cell wall, the ubiquinone system, partial sequencing of 18S ribosomal DNA and the ultrastructure of septal pores indicate that most yeast species belonged to the Endomycetales. They were assigned to the genera Candida, Debaryomyces, Pichia and Sporothrix. Other species showed affinities to the Basidiomycetes …

The fine structure of colleterial glands in two cockroaches and three termites, including a detailed study of Cryptocercus punctulatus (Blattaria, Cr…

2007

1873-5495 (Electronic) Journal Article Research Support, U.S. Gov't, Non-P.H.S.; The colleterial glands of insects are organs associated with the female genital apparatus. In cockroaches, these glands produce secretions that cover two parallel rows of eggs during oviposition, and in oviparous species, these secretions become the tanned, sculpted, rigid outer casing of the ootheca. The goal of this study was to compare the gross anatomy of the colleterial glands and the ultrastructure of their component tubules in the phylogenetically significant genera Cryptocercus (Blattaria) and Mastotermes (Isoptera). Recent studies indicate that cockroaches in the genus Cryptocercus are the sister group…

Dispersal flight and colony development in the fungus-growing termites Pseudacanthotermes spiniger and P. militaris

2012

International audience; Pseudacanthotermes spiniger and P. militaris are two African fungus-growing termites (Termitidae, Macrotermitinae) which may become pests in disturbed agrosystems where they often live in sympatry. To study their development and their reproductive strategies, colonies of both species were reared in the laboratory for 20 and 17 years, respectively, after their foundation from reproductive pairs. The first steps of development were in great part similar in both species, although P. spiniger favoured the defence during the juvenile period, while P. militaris tended to favour a rapid development. While P. spiniger colonies did not produce alates until year 7 of colony li…

Termite Nests: Architecture, Regulation and Defence

2000

Termite nest architecture evolved along with changes in lifestyle, the basic building behaviour being transmitted through the genes of reproductives. The main selective pressure is thought to have been defence against predators. In more advanced termites the maintenance of homeostasis in temperature and humidity may appear to dominate nest architecture. Nest defence involves nest structures in combination with the morphology and behaviour of the sterile castes. The soldier caste, characteristic of termites, is specialized for defence, with a variety of mechanical and chemical weapons, but this caste was lost in some advanced genera, especially the Apicotermitinae. Workers are always involve…