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At least 145 records · Page 8Linked to original sources
PubMed2003

Repellent effects of isoborneol on subterranean termites (Isoptera: Rhinotermitidae) in soils of different composition.

The repellence of the plant-derived bicyclic monoterpenoid isoborneol on subterranean termites was assessed in short-term laboratory bioassays. Depending on concentration, application of isoborneol to different soil types was efficient in creating repellent soil barriers, which were not penetrated by workers of Reticulitermes santonensis De Feytaud or R. flavipes Kollar within 2 wk after adding the substance to the substrate. Isoborneol-treated barriers did not affect termite survival. The bioavailability of the active ingredient decreased with increasing clay content of the soil. Evaporation of isoborneol from treated soil increased with increasing particle size of the substrate and could be reduced by covering the soil surface.

Animals↗
PubMed2006

Intraspecific molecular phylogeny, genetic variation and phylogeography of Reticulitermes speratus (Isoptera: Rhinotermitidae).

Population structure was investigated in Reticulitermes speratus populations in the Korean Peninsula and the Japanese Archipelago. All trees derived from analyses of the combined sequence dataset of two mitochondrial genes, COII and COIII, showed that R. speratus populations cluster into two major clades comprising the Korean/southern Japanese populations and the north-ern Japanese populations. Analysis of population ge-netic structure showed strong genetic partitioning between populations of the two clades. To understand historical migration routes and current distributions, the phylogeographic history of R. speratus was inferred from intra-/interspecific phylogeny and diver-gence times estimated between the clades of the phylogenetic tree. The estimated migration route and divergence time of ancestral R. speratus are congruent with recent paleogeographic hypotheses involving land-bridge connections between the Asian continent and the Japanese Archipelago. We suggest that ancestral R. speratus separated into northern and southern Japanese populations after its migration into the Japanese main islands from East China during the early Pleistocene via the East China Sea basin, which may have been exposed during that period. The Korean populations seem to have diverged recently from southern Japanese populations; this may explain the current distribution of R. speratus in the Japanese Arachipelago, and account for why it is restricted to northern areas of the Tokara Strait.

Animals↗
PubMed2006

Phylogeny of Australian Coptotermes (Isoptera: Rhinotermitidae) species inferred from mitochondrial COII sequences.

Six Australian species of Coptotermes are traditionally recognized, but recent cuticular hydrocarbon studies suggest that some of these may represent more than one species. An understanding of the phylogenetic diversity of Australian Coptotermes, particularly the pest species, is likely to be important for the improvement of termite management strategies. A study of phylogenetic relationships among species of this genus was performed, based on the mitochondrial cytochrome oxidase (COII) gene, comparing the data with recent data from Asian species. Representatives of the species C. lacteus (Froggatt), C. frenchi Hill and C. michaelseni Silvestri were each found to form closely related monophyletic groups, however representatives of C. acinaciformis (Froggatt) were not. For C. acinaciformis, representatives from northern mound-building populations were found to form a distinct group to southern, tree-nesting forms. Among southern C. acinaciformis, two Western Australian representatives were found to be divergent from other populations. The results suggest that C. acinaciformis probably represents a complex of species rather than one, as has been suggested previously. One unidentified Coptotermes sp. taxon from Melbourne was found to be divergent from other taxa. Notably, some Australian species were more closely related to Asian species than other Australian species.

Animals↗
PubMed1975

The labrum of Schedorhinotermes minor soldier (Isoptera, Rhinotermitidae): morphology, innervation and fine-structure.

The labrum of Schedorhiontermes minor soldier was examined to determine the distribution, types and structures of sense organs present with both light microscopy and scanning and transmission electron microscopy. Three types of sensilla were recognized: companiform sensillae and two types of sensillae trichodea, the short bristles and the long bristles. The companiform sensillae are singly-innervated receptors distributed in large numbers on the anterolateral margins of the labrum. The short and long bristles are multi-innervated; the former are found all over the surface, the latter are much more scarce and are found only at the front of the labrum. Both are at the same time chemo- and mechanoreceptors. The labrum is strewn with many glandular pits and exhibits at its apex a brush of cuticular not innervated spines. On the basis of ultrastructural evidence and of what we know of the defense mechanisms of the soldier, a functional interpretation is attempted.

Animals↗
PubMed1983

Ecdysteroid levels associated with epidermal events during worker and soldier differentiation in Macrotermes michaelseni (Isoptera: Macrotermitinae).

Radioimmunoassay of ecdysteroid levels coupled with morphological and histological studies have revealed a close association between hormonal titers and epidermal events during worker and soldier differentiation from lighter and heavier third instars of Macrotermes michaelseni, respectively. Two main peaks of ecdysteroid levels were found during the development of these larvae. The first low one occurred on Day 4 in both cases, although that of lighter larvae was short lived (only 1 day) while that of the heavier larvae continued for another day. Epidermal detachment (apolysis) was shown to start earlier in the heavier larvae (Day 4) than in the lighter ones (Day 6), indicating a differential influence of the first ecdysteroid peak on the epidermis (probably modulated by differing levels of juvenile hormones in the two types of larvae). It was also at this time that morphological differentiation of presoldier mandibles was observed. From this interval onward, hormonal levels remained higher and achieved a second peak in the heavier larvae earlier (Day 9-10) than in the lighter ones (Day 11-12). Epidermal events, i.e., complete apolysis, increased cellular growth, new cuticle deposition, and ecdysis, correlated well with the hormonal level increases, those of the lighter larvae always lagging behind by about 2 days. During presoldier-soldier transformation two distinct ecdysteroid peaks were demonstrated, one occurring on Day 2 (low) and the other on Day 9 (high). The third one was transient and not very distinct from the second peak. The significance of these peaks is discussed in the context of differentiation.

Animals↗
PubMed1997

On the respiratory quotient (RQ) of termites (Insecta: Isoptera).

The respiratory quotient (RQ) at 28 degrees C was determined by Warburg manometry in 23 species of termites from the Mbalmayo Forest Reserve (Cameroon) and three sub-tropical species cultured under laboratory conditions in the U.K. or freshly collected in Australia. The data are tabulated with other recently reported RQs (determined by manometry or GC) and with measured CH(4) emission rates to provide a survey of 29 species covering both lower and higher termites in all major trophic (functional) categories. In all species, except the wood-feeding Coptotermes acinaciformis and the soil-feeding Cubitermes fungifaber, the observed mean values (with manometry corrected for known fluxes of H(2) and CH(4)) were at or well above 1.00. Soil-feeding forms (except C. fungifaber) generally showed a high apparent RQ (not corrected for H(2)), with nine species (out of 13) above 1.20 and six species above 1.30. Well-replicated laboratory experiments with Reticulitermes lucifugus showed that there was a tendency for RQ to fall with time over a 4-h incubation, although remaining greater than 1.00.The observed RQs are consistent with carbohydrate being the principal substrate supporting respiration in all trophic and taxonomic categories, with little or no contribution from the degradation of lignin or other polyaromatic materials. However, in many species (especially soil-feeders), the observed RQ is greater than that expected from known fluxes of O(2), CO(2) and CH(4) on the assumption that carbohydrate is the respiratory substrate. This presupposes that there is a large hydrogen sink (additional to CH(4) production), possibly the emission of H(2) gas, and/or the existence of unresolved digestive mechanisms or electron routings. Uncertainties in the use of manometry with termites are discussed.

Journal Article↗
PubMed1967

Alarm, defense, and construction behavior relationships in termites (Isoptera).

Evidence indicates that building behavior in termites is a direct consequence of low-level alarm stimuli and that its immediate function is defense. As in other forms of termite defense behavior, recruitment of nymphs and workers is accomplished by trail laying in conjuction with transmission of the alarm. The number recruited is related to the intensity of the input stimulus. Primary construction ceases when the original causal stimulus is eliminated by the effects of the actual building.

Animals↗