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At least 19 recordsLinked to original sources

PubMed2000

Phylogenetic analysis and trait evolution in Australian lineages of drywood termites (Isoptera, Kalotermitidae).

A phylogenetic analysis of Australian drywood termites (Isoptera, Kalotermitidae) based on partial sequence from the cytochrome oxidase II (COII) and cytochrome b genes is presented. In addition to providing new information on the evolutionary relationships among 25 species from seven genera, we evaluate the relative likelihoods of alternative topological hypotheses, including those derived from morphology-based classifications. We also test the applicability of a molecular clock for estimating the age of the Kalotermitidae and infer the evolution of species-specific variation for habitat type and soldier caste phragmosis by mapping this information onto the independently derived phylogeny. Maximum-likelihood analysis of both nucleotide and protein sequences from a multigene data set jointly support a single topology, which is shown to be the best estimate of the true phylogeny among the alternatives tested. Our results support the monophyly of all genera but question the discrimination between Procryptotermes and Cryptotermes. A basal dichotomy among generic groups suggests two principle lines of divergence within the family. Intergeneric relationships show mixed congruence to previous proposals, resulting in one morphology-based classification being rejected. A molecular clock hypothesis is not supported due to significant among-lineage rate heterogeneity in the COII gene. Patterns revealed through trait mapping suggest that the most recently diverged taxa tend to occupy the driest habitats and that these same taxa reflect a defensive transition away from large mandibulate soldiers toward small phragmotic soldiers. The association between habitat and defensibility supports the hypothesis that these two characters have been tightly linked throughout the social diversification of termites.

Animals↗

PubMed2003

The life cycle of Reticulitermes spp (Isoptera: Rhinotermitidae): what do we know?

The subterranean termites in the genus Reticulitermes have a complex and plastic life cycle, which has been the subject of a number of publications over the past century. Given the inherent difficulties in studying such cryptic, eusocial organisms it is not perhaps surprising that the literature on their biology has failed to reach a consensus. An overview of the literature is given, which is followed by a discussion of the various theories on the life cycle of Reticulitermes spp. A substantial proportion of the review focuses on the French literature, which constitutes the majority of the primary sources and can be difficult to access. There are many discrepancies in the literature in terms of the number of instars, the definition of workers and the question of whether they should be termed pseudergates or, potentially, an additional terminology used to differentiate between pseudergates and the true workers seen in the higher termites (Isoptera: Termitidae). It remains very difficult to compare publications as there is little conformity; a problem that is aggravated by a general absence of drawings of the relevant instars. Further work on the biology of Reticulitermes is clearly required. There is also a need for researchers to agree on a standard terminology for this genus. A glossary is provided for the various synonyms and definitions.

Animals↗

PubMed2000

The ootheca of Mastotermes darwiniensis Froggatt (Isoptera: Mastotermitidae): homology with cockroach oothecae.

The basal termite Mastotermes darwiniensis produces an egg mass, the nature of which is controversial. The debate centres on whether it is homologous with the oothecae of mantids and cockroaches and, if so, whether its simple structure is plesiomorphic or apomorphic within the Dictyoptera. To help resolve these issues we observed primary reproductives of M. darwiniensis during oviposition and examined the morphology of the reproductive product. Oviposition is cockroach-like in that the egg mass is assembled within the vestibulum and the eggs are issued externally in pairs. The reproductive product is an ootheca of the blattarian type. A distinct, tanned outer covering is stretched over the two parallel rows of eggs. No keel is present and no calcium oxalate crystals were apparent in the outer covering. We cannot rule out the possibility that the simple structure of the ootheca is plesiomorphic within Dictyoptera. However, based on (i) apomorphies shared by Mastotermes and Blattaria, and (ii) the life habits of Isoptera, a secondary reduction is the more plausible explanation.

Animals↗

PubMed2003

Nutritional ecology of the Formosan subterranean termite (Isoptera: Rhinotermitidae): growth and survival of incipient colonies feeding on preferred wood species.

The wood of 11 plant species was evaluated as a food source significantly impacting the growth and survival of incipient colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Colonies of C. formosanus feeding on pecan, Carya illinoensis (Wangenh.), and red gum, Liquidambar styraciflua L., produced significantly more progeny than colonies feeding on other wood species tested. Progeny of colonies feeding on pecan and American ash, Fraxinus americana L., had significantly greater survival than progeny of colonies feeding on other wood species. Colonies feeding on a nutritionally supplemented cellulose based matrix showed similar fitness characteristics as colonies feeding on the best wood treatments. These results indicate that differences observed in colony fitness can be partially explained by nutritional value of the food treatment, raising the possibility that wood from different tree species have different nutritional values to the Formosan subterranean termites. Colonies feeding on loblolly pine, Pinus taeda L., and ponderosa pine, Pinus ponderosa Laws., had significantly lower survival and produced significantly fewer workers and soldiers than colonies feeding on other wood species. Colony survival from 90 to 180 d of age and from 90 to 360 d of age was significantly correlated with the number of workers present at 90 d of colony age, indicating that colony survival depends on the presence of workers. Wood consumption in a multiple-choice study was significantly correlated with colony fitness value. This suggests that feeding preference of C. formosanus is at least partially influenced by the nutritional value of the food source.

Animal Nutritional Physiological Phenomena↗

PubMed2002

Population structure and genetic diversity in insular populations of Nasutitermes takasagoensis (Isoptera: Termitidae) analyzed by AFLP markers.

Dispersal ability and degree of inbreeding in a population can indirectly be assessed using genetic markers. In general, it was suggested that winged termites are not able to fly distances greater than several hundred meters. Here, amplified fragment length polymorphism (AFLP) was used to analyze genetic diversity, population substructure, and gene flow among insular populations of the termite Nasutitermes takasagoensis (Isoptera: Termitidae) in the Yaeyama Islands, Okinawa, Japan. Samples were collected from 77 nests on seven islands of the Yaeyama Group. Using three primer combinations a total of 155 bands were generated with 78 (50%) polymorphic bands. Genetic distance and G(st) values among insular populations were calculated. Relatively high genetic diversity and low values of G (st), suggest there is moderate subpopulation structure. Based on these results, we discussed two possibilities; first, winged termites are able to fly over distances of several kilometers, and second, these results were obtained because insular populations share a recent common origin.

Animals↗

PubMed1998

Some aspects of intracellular symbiosis during embryo development of Mastotermes darwiniensis (Isoptera: Mastotermitidae).

All examined species of cockroaches have been shown to harbour intracellular bacteria in specialized cells (bacteriocytes) of the fat body. In termites, bacteria in specialized cells have been observed only in Mastotermes darwiniensis (Isoptera: Mastotermitidae). All of these bacteria have been assigned to the same eubacterial lineage, with the bacteria of M. darwiniensis as the sister group to the cockroach bacteria. While the main steps of the life cycle of cockroach bacteria have been described, little is known about the bacteria of M. darwiniensis. More specifically, no data are available on their behaviour during the development of this termite. Using both optical and electron microscopy methods, we examined embryos of M. darwiniensis at different developmental stages. Our results show that the integration of bacteria during the development of M. darwiniensis is implemented in the same way as in cockroaches. In particular, we observed the aggregation of a large amount of bacteria in a single mass in the yolk sac, with vitellophage-associated bacterial lysis. In cockroaches, a similar process has been described in detail for Periplaneta americana (Blattaria: Blattidae), where the bacterial mass is referred to as the transitory mycetome. The formation of a transitory mycetome could thus be regarded as an ancestral condition for cockroaches and termites.

Animals↗

PubMed2003

Caste morphology and development in Termitogeton nr. planus (Insecta, Isoptera, Rhinotermitidae).

The termite family Rhinotermitidae displays a wide diversity in its patterns of social organization in castes. The genus Termitogeton probably branched off early in the evolution of this family. We studied the developmental pathways of a putative undescribed species from New Guinea, Termitogeton nr planus. The development begins with two white inactive instars (larvae), the second of which possesses small wing buds. These are followed by a relatively homogenous group of active immature stages (pseudergates) among which a biometric study revealed the presence of four instars. The first of these instars possesses wing buds that regress at subsequent molts. The external morphology of older instars resembles that of higher termite workers. Older pseudergates can differentiate into presoldiers and then into soldiers, but they are also able to molt into a unique stage with long wing pads (nymph), preceding the imago. Colony maturity can be reached with about 10(3) individuals. The sex ratio is near 1:1 in all castes except soldiers, among which females are more numerous than males. The caste pattern of T. nr. planus is reminiscent of those of the Kalotermitidae and Termopsidae, and of Prorhinotermes among the Rhinotermitidae. None of these taxa possess a true worker caste, permanently diverted from imaginal development: social tasks are done by unspecialized immatures that retain a full array of developmental options, including that of proceeding to the imago. The most remarkable trait of T. nr. planus is the presence in all second-instar individuals of wing buds that later regress to reappear in the single nymphal stage. We suggest that the traditional definitions of the terms larvae, nymphs, and pseudergates should be revised because they cannot be satisfactorily applied to the castes of Termitogeton.

Animals↗

PubMedDate not supplied

United States Department of Agriculture-Agriculture Research Service research on targeted management of the Formosan subterranean termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae).

The Formosan subterranean termite, Coptotermes formosanus Shiraki is currently one of the most destructive pests in the USA. It is estimated to cost consumers over US dollars 1 billion annually for preventative and remedial treatment and to repair damage caused by this insect. The mission of the Formosan Subterranean Termite Research Unit of the Agricultural Research Service is to demonstrate the most effective existing termite management technologies, integrate them into effective management systems, and provide fundamental problem-solving research for long-term, safe, effective and environmentally friendly new technologies. This article describes the epidemiology of the pest and highlights the research accomplished by the Agricultural Research Service on area-wide management of the termite and fundamental research on its biology that might provide the basis for future management technologies. Fundamental areas that are receiving attention are termite detection, termite colony development, nutrition and foraging, and the search for biological control agents. Other fertile areas include understanding termite symbionts that may provide an additional target for control. Area-wide management of the termite by using population suppression rather than protection of individual structures has been successful; however, much remains to be done to provide long-term sustainable population control. An educational component of the program has provided reliable information to homeowners and pest-control operators that should help slow the spread of this organism and allow rapid intervention in those areas which it infests.

Agriculture↗

PubMed2000

Molecular phylogeny and biogeography of the nasute termite genus Nasutitermes (Isoptera: Termitidae) in the pacific tropics.

The nasute termite genus Nasutitermes is widely distributed over all tropical regions. The phylogenetic relationships among 17 Nasutitermes species from the Pacific tropics were inferred from sequences of mitochondrial cytochrome oxidase II and 16S ribosomal RNA genes. Several methods of analysis yielded phylogenetic trees showing almost the same topology and in good agreement with reconstructions based on morphological or behavioral characters. Neotropical and Australian species came out as separate, apical clades. Asian species split between an apical branch, appearing as sister group to the neotropical clade, and basal taxa. New Guinean species were spread among several clades, suggesting a derivation from multiple origins. A well-supported clade includes the neotropical, Australian, and New Guinean species, with the southeast Asian N. takasagoensis and N. matangensis. It excludes the Asian species N. regularis, N. parvonasutus, and N. longinasus, which might deserve to be removed from Nasutitermes, as well as the long-legged Asian genera Hospitalitermes and Longipeditermes. A Gondwanan origin is proposed for the former clade, although an Old World origin of Nasutitermes followed by dispersal to Australia and South America cannot be excluded.

Animals↗

PubMed2001

Phylogenetic analyses of two mitochondrial genes and one nuclear intron region illuminate European subterranean termite (Isoptera: Rhinotermitidae) gene flow, taxonomy, and introduction dynamics.

Phylogenetic analyses of multiple DNA sequences were conducted to elucidate gene flow, evolutionary patterns, taxonomy, and the dynamics of two accidental introductions: Reticulitermes lucifugus grassei into Devon, United Kingdom and R. flavipes into Europe. Two mitochondrial DNA genes totaling 1495 bp and a 380-bp ribosomal intergenic transcribed spacer were sequenced. Neighbor-joining and parsimony analyses revealed that multiple female lineages of R. lucifugus grassei were introduced into Devon possibly from southwestern France, where the species was indigenous. The taxonomic status of the European R. santonensis as a species separate from the North American R. flavipes has been questioned since it was described in 1924. Phylogenetic analyses revealed a close genetic relationship between R. flavipes from the United States and R. santonensis from France. These analyses, coupled with morphological and chemotaxonomic data, provide strong support for R. santonensis and R. flavipes being the same species. They also suggested that R. santonensis infestations likely resulted from R. flavipes being introduced into Europe.

Animals↗

PubMed2002

Molecular relationships among European samples of Reticulitermes (Isoptera, Rhinotermitidae).

Taxonomy and phyletic relationships of the European termites of the holarctic genus Reticulitermes are highly debated and poorly known. Sequencing analyses of the complete cytochrome oxidase subunit II and of a fragment of 16S rDNA mitochondrial genes were performed on 21 Italian and French populations. Distance, parsimony, and maximum-likelihood evaluations on single and combined data sets confirm the presence in central peninsular Italy of R. lucifugus lucifugus, but demonstrate that a coastal Tuscan population and the Sardinian ones pertain to the Corsican subspecies R. lucifugus corsicus, whose distribution appears therefore transtyrrenian. Northeastern Italian samples are highly differentiated from presently analyzed R. lucifugus and constitute a new entity, possibly more related to the Japanese R. speratus. Finally, the French R. santonensis and the North American R. flavipes appear strongly related, so that the supposed synonymy between the two taxa must be accepted.

Animals↗

PubMed2003

Mandibular morphogenesis during soldier differentiation in the damp-wood termite Hodotermopsis sjoestedti (Isoptera: Termopsidae).

The conspicuous morphogenesis during termite soldier differentiation is one of the most remarkable examples of specialized caste development in social insects. To clarify the mechanism of morphological changes during soldier differentiation, mandibular morphogenesis prior to the presoldier moult was examined in the damp-wood termite Hodotermopsis sjoestedti. Using experimental induction of presoldier differentiation from pseudergates (7th or later instar larvae) by the application of juvenile hormone analogue (JHA), we compared mandibular morphogenesis in a presoldier moult (from pseudergate to presoldier) with that of a stationary moult (from pseudergate to pseudergate). Future presoldier mandibles were formed under the old mandibular cuticle of the pseudergates just prior to the presoldier moult. Multiple folds of both epidermis and new cuticle were observed in the developing mandible, and large concavities between teeth were formed on the mandibular surface. While in the stationary moult, the future mandibles were formed with a smooth surface. The process of the mandibular morphogenesis in soldier differentiation explains the allometry of soldier mandibles. The morphological differences in mouth parts between castes arise from a switching mechanism that triggers caste-specific mandibular epithelial growth during development.

Animals↗

PubMed1999

Energy consumption of termite colonies of Nasutitermes ephratae (Isoptera: Termitidae).

Measurements of CO2 production of whole termite colonies showed that respiration intensity varies slightly during the daily cycle, that the relation between standard metabolism and colony size is best described with a negative exponential, taking into account the proportion of the various castes. Larger colonies were more efficient in their energy use, suggesting that energetic considerations may contribute in explaining the maintenance in evolution of complex societies.

Adaptation, Biological↗

PubMed2001

Cyclic CO(2) release in Cryptotermes cavifrons Banks, Incisitermes tabogae (Snyder) and I. minor (Hagen) (Isoptera: Kalotermitidae).

CO(2) release patterns of three drywood termite species were investigated using flow-through respirometry techniques. Eight hours of real-time CO(2) release data were recorded for pseudergates of Cryptotermes cavifrons Banks, Incisitermes minor (Hagen), and I. tabogae (Snyder) at 20-40 degrees C. Cyclic release of CO(2) was observed in 20-90% of C. cavifrons, 70-100% of I. tabogae, and 87-100% of I. minor pseudergates. Variability of the recordings (calculated as the coefficient of variability or CV) was used to estimate the level of cycling in each recording. CV ranged from 14.53+/-2.57 (40 degrees C) to 32.33+/-1.12% (30 degrees C) in C. cavifrons, 20.24+/-2.44 (35 degrees C) to 67.3+/-10.3% (20 degrees C) in I. minor, and 15.9+/-1.46 (35 degrees C) to 34.15+/-6.18% (20 degrees C) in I. tabogae. The relationship between temperature and CV for each species was modeled using non-linear regression. CV of both Incisitermes spp. decreased exponentially with temperature, while C. cavifrons CV followed a Gaussian model, indicating an optimal cycling temperature of approximately 30 degrees C. Mean V.CO(2) values were determined for each species as a function of temperature, and ranged from 0.1 ml CO(2) g(-1) h(-1) (I. minor at 20 degrees C) to 0.8 ml CO(2) g(-1) h(-1) (C. cavifrons at 40 degrees C). For all three species, V.CO(2) significantly increased linearly with temperature. Colinearity tests indicated that different models described the V.CO(2) relationship with temperature for both genera. Q(10) values for V.CO(2) over the range of 20-40 degrees C were 1.92 for I. minor, 1.66 for I. tabogae, and 1.62 for C. cavifrons pseudergates.

Adaptation, Physiological↗

PubMed2003

Cuticular permeability of two species of Coptotermes Wasmann (Isoptera: Rhinotermitidae).

Cuticular permeability (CP) values of worker and soldier castes of Coptotermes formosanus Shiraki and Coptotermes vastator Light were determined using gravimetric techniques. Comparisons were made between castes, species, and between colonies of C. formosanus and C. vastator. CP values did not differ among either species or colony, however they did differ between castes. Data reported here and that of established data in the literature for C. formosanus are inconsistent, with the current report having values as small as half that of previously published data. Examining mean CP data by colony indicated that there is a range for Coptotermes spp. termites, from 6.84+/-1.2 to 25.61+/-1.49 microg H(2)Ocm(-2)mmHg(-1)h(-1) dependent upon caste. A novel method of examining intercaste CP variability is the use of worker:soldier CP ratios. Ratios for C. formosanus were consistent between the current study and previous reports. Mean percentage total body water (%TBW) lost at the time of death was 33.75+/-1.15% (soldiers) and 54.24+/-1.43% (workers) for C. formosanus, and 37.69+/-3.31% (soldiers) and 52.87+/-3.65% (workers) for C. vastator. Consistently, %TBW (and fresh mass) was greater in worker than in soldier castes. These data suggest the use of water storage mechanisms in worker termites, as shown for other rhinotermitids.

Animals↗

PubMed2002

Cuticular hydrocarbons suggest three lineages in Reticulitermes (Isoptera: Rhinotermitidae) from North America.

Cuticular hydrocarbon mixtures can be used to discriminate insect taxa. They have utility for determining phylogenetic relationships where they are independent characters with discrete states and represent a hierarchical distribution of shared, derived characters. We report inferred degrees of relatedness among the chemical phenotypes of Reticulitermes from PAUP (phylogenetic analysis using parsimony) analyses of cuticular hydrocarbon characters. One hundred and forty-one Reticulitermes colonies collected from California, Georgia, New Mexico, Arizona and Nevada were used. Initial maximum parsimony analyses sorted the 141 colonies into 26 chemical phenotypes. Subsequent analyses, using the ancestral species Coptotermes formosanus and Heterotermes sp. as outgroups, sorted Reticulitermes taxa into three major lineages, each characterized by a different set of dominant methyl-branched or unsaturated hydrocarbon components. Reticulitermes in lineage I have cuticular hydrocarbon mixtures with a preponderance of internally branched monomethylalkanes and 11,15-dimethylalkanes. Those in lineage II are defined by a preponderance of 5-methylalkanes and 5,17-dimethylalkanes. Taxa in lineage III are characterized by the predominance of olefins and a relative paucity of n-alkanes and methyl-branched alkanes. Bootstrap analyses and decay indices provided statistical support and robustness for these chemical-based relationships.

Animals↗

PubMed2001

Food exploitation in termites: indication for a general feeding-stimulating signal in labial gland secretion of isoptera.

The paired labial glands are located in all termite species in the thorax. During food exploitation workers of the French termite Reticulitermes santonensis and the African termite Schedorhinotermes lamanianus release the secretion of their labial glands directly onto the food. The secretion carries a water-soluble, heat-resistant, nonvolatile signal that stimulates gnawing and feeding and leads to aggregations of feeding workers. In a feeding bioassay, extracts of the labial glands of 11 termite species from five families all proved to have this feeding-stimulating effect both on R. santonensis and S. lamanianus. The heat resistance of the feeding-stimulating signal also could be shown for selected species from all termite families tested. A combined thin layer chromatography-feeding bioassay on cellulose TLC plates showed that after chromatography of labial gland secretion, the feeding-stimulating signal is located in all 11 species in the same area from Rf 0.46 to 0.88. An extract of labial glands of cockroaches stimulated feeding in R. santonensis and S. lamanianus as well, but was not active after heat treatment and after TLC. This points towards a general feeding-stimulating signal having evolved only in the labial gland secretion of termites.

Animals↗

PubMed2000

Characterization of Nasutitermes globiceps (Isoptera: Termitidae) esterases.

Esterases of Nasutitermes globiceps termites which occur on the Upper Paraná River floodplain (Brazil) were characterized. The electrophoretic pattern of the termite esterases Nasutitermes globiceps was obtained by starch gel electrophoresis. Six esterase activity zones were obtained and numbered, with esterase-1 being the most anodall one and esterase-6 the most cathodal one. Esterase-2 was detected only with substrates derived from the 4-methylumbelliferyl radical. The esterases of N. globiceps present wide substrate specificity, having been observed with substrates derived from alpha-naphthyl (acetate, propionate, and butyrate) and beta-naphthyl (acetate, butyrate) and from 4-methylumbelliferyl (acetate, propionate and butyrate). Esterase-6 is a caste-specific enzyme detected in soldiers. Only esterases 1, 3 and 5 were detected in nymphs. No genetic polymorphism has been detected thus far in the esterases of Nasutitermes globiceps. This study suggests that allozyme variation can be explored to understand Nasutitermes social structure.

Animals↗