Isoptera Dotaz Zobrazit nápovědu
Ancistrotermes dimorphus is a common Macrotermitinae representative, facultative inquiline by its life-style, occurring in South-East China. Sex pheromone is used for couple formation and maintenance, and it is produced by and released from the female sternal gland and is highly attractive to males. Based on our combined behavioral, chemical and electrophysiological analyses, we identified (3Z,6Z)-dodeca-3,6-dien-1-ol as the female sex pheromone of A. dimorphus as it evoked the tandem behavior at short distance, and the active quantities ranged from 0.01ng to 10ng. Interestingly, GC-MS analyses of SPME extracts showed another compound specific to the female sternal gland, (3Z)-dodec-3-en-1-ol, which showed a clear GC-EAD response. However, this compound has no behavioral function in natural concentrations (0.1ng), while higher amounts (1ng) inhibit the attraction achieved by (3Z,6Z)-dodeca-3,6-dien-1-ol. The function of (3Z)-dodec-3-en-1-ol is not fully understood, but might be linked to recognition from sympatric species using the same major compound, enhancing the long-distance attraction, or informing about presence of other colonies using the compound as a trail-following pheromone. The sternal gland secretion of Ancistrotermes females contains additional candidate compounds, namely (3E,6Z)-dodeca-3,6-dien-1-ol and (6Z)-dodec-6-en-1-ol, which are not perceived by males' antennae in biologically relevant amounts.
- MeSH
- elektrofyziologické jevy účinky léků MeSH
- Isoptera chemie fyziologie MeSH
- sexuální chování zvířat účinky léků MeSH
- sexuální lákadla chemie izolace a purifikace farmakologie MeSH
- tykadla členovců fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Čína MeSH
Termites are major decomposers in terrestrial ecosystems and the second most diverse lineage of social insects. The Kalotermitidae form the second-largest termite family and are distributed across tropical and subtropical ecosystems, where they typically live in small colonies confined to single wood items inhabited by individuals with no foraging abilities. How the Kalotermitidae have acquired their global distribution patterns remains unresolved. Similarly, it is unclear whether foraging is ancestral to Kalotermitidae or was secondarily acquired in a few species. These questions can be addressed in a phylogenetic framework. We inferred time-calibrated phylogenetic trees of Kalotermitidae using mitochondrial genomes of ∼120 species, about 27% of kalotermitid diversity, including representatives of 21 of the 23 kalotermitid genera. Our mitochondrial genome phylogenetic trees were corroborated by phylogenies inferred from nuclear ultraconserved elements derived from a subset of 28 species. We found that extant kalotermitids shared a common ancestor 84 Ma (75-93 Ma 95% highest posterior density), indicating that a few disjunctions among early-diverging kalotermitid lineages may predate Gondwana breakup. However, most of the ∼40 disjunctions among biogeographic realms were dated at <50 Ma, indicating that transoceanic dispersals, and more recently human-mediated dispersals, have been the major drivers of the global distribution of Kalotermitidae. Our phylogeny also revealed that the capacity to forage is often found in early-diverging kalotermitid lineages, implying the ancestors of Kalotermitidae were able to forage among multiple wood pieces. Our phylogenetic estimates provide a platform for critical taxonomic revision and future comparative analyses of Kalotermitidae.
- MeSH
- buněčné jádro MeSH
- ekosystém MeSH
- fylogeneze MeSH
- genom mitochondriální * MeSH
- Isoptera * genetika MeSH
- lidé MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Social insects possess a rich set of exocrine organs producing diverse pheromones and defensive compounds. This is especially true for termite imagoes, which are equipped with several glands producing, among others, sex pheromones and defensive compounds protecting imagoes during the dispersal flight and colony foundation. Here, we describe the clypeal gland, a new termite exocrine organ occurring in the labro-clypeal region of imagoes of most Rhinotermitidae, Serritermitidae and Termitidae species. The clypeal gland of Coptotermes testaceus consists of class 1 (modified epidermal cell) and class 3 (bicellular gland unit) secretory cells. Ultrastructural features suggest that the gland secretes volatile compounds and proteins, probably after starting the reproduction. One peculiar feature of the gland is the presence of multiple secretory canals in a single canal cell, a feature never observed before in other insect glands. Although the function of the gland remains unknown, we hypothesize that it could produce secretion signalling the presence of functional reproductives or their need to be fed.
Labial glands are present in all castes and developmental stages of all termite species. In workers, their secretion contains a food-marking pheromone and digestive enzymes, while soldier secretion plays a defensive role. However, these functions were studied only in a limited set of species, and do not allow drawing general conclusions. Hence, we have investigated the chemical composition of the labial gland extracts from soldiers and workers in 15 termite species belonging to 6 families using an integrative approach based on proteomic and small-molecule profiling. We confirmed the presence of hydroquinone and cellulase in the labial glands of workers, and we identified new toxic compounds in soldiers and workers of several species. Our results highlight the dual role of labial gland secretion, i.e. the defensive role in soldiers and workers of several termite species, and the digestive function in workers.
- MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- exokrinní žlázy sekrece MeSH
- hmyzí proteiny chemie sekrece MeSH
- Isoptera fyziologie MeSH
- molekulární sekvence - údaje MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- sekvence aminokyselin MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Protection against predators and competitors is one of the main concerns of termite colonies, which developed a specialised defensive caste, the soldiers. However, soldiers are rare or even missing in several lineages of termites, while workers often develop new defence strategies especially in soil-feeding species. Here, we describe the morphology and ultrastructure of the autothysis-associated glands of Neocapritermes taracua workers and report their age-related changes in structure. The defensive glands of N. taracua workers consist of a pair of labial and a pair of crystal glands, whose secretions mix together through autothysis. Autothysis always occurs at the line of weakness connecting the anterior parts of the crystal-bearing pouches. The crystal glands consist of groups of bicellular secretory units (secretory and corresponding canal cells) which secrete the blue crystal material into external pouches. Their secretory activity is maximal in the middle of worker life, and is considerably lower in very young and old workers. The labial glands are composed of two types of secretory cells: the central and the parietal cells. While the central cells are developed similarly to other termites and secrete proteinaceous secretion into labial gland ducts, the parietal cells develop proteinaceous granules which may eventually bud off the cells. The secretory function of parietal cells is so far unique to N. taracua and differs from other termite species in which they are only responsible of water uptake by acini. The defensive device of N. taracua is truly exceptional as it involves a new gland and a previously undescribed function for parietal cells, being a remarkable example of evolution of morphological innovation.
- MeSH
- exokrinní žlázy růst a vývoj ultrastruktura MeSH
- Isoptera růst a vývoj ultrastruktura MeSH
- mikroskopie elektronová rastrovací MeSH
- transmisní elektronová mikroskopie MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Francouzská Guyana MeSH
Termites are the principal decomposers in tropical and subtropical ecosystems around the world. Time-calibrated molecular phylogenies show that some lineages of Neoisoptera diversified during the Oligocene and Miocene, and acquired their pantropical distribution through transoceanic dispersal events, probably by rafting in wood. In this paper, we intend to resolve the historical biogeography of one of the earliest branching lineages of Neoisoptera, the Rhinotermitinae. We used the mitochondrial genomes of 27 species of Rhinotermitinae to build two robust time-calibrated phylogenetic trees that we used to reconstruct the ancestral distribution of the group. Our analyses support the monophyly of Rhinotermitinae and all genera of Rhinotermitinae. Our molecular clock trees provided time estimations that diverged by up to 15.6 million years depending on whether or not 3rd codon positions were included. Rhinotermitinae arose 50.4-64.6 Ma (41.7-74.5 Ma 95% HPD). We detected four disjunctions among biogeographic realms, the earliest of which occurred 41.0-56.6 Ma (33.0-65.8 Ma 95% HPD), and the latest of which occurred 20.3-34.2 Ma (15.9-40.4 Ma 95% HPD). These results show that the Rhinotermitinae acquired their distribution through a combination of transoceanic dispersals and dispersals across land bridges.
- MeSH
- fylogeneze MeSH
- fylogeografie * MeSH
- genetická variace MeSH
- genom mitochondriální MeSH
- švábi klasifikace genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Trail-following behavior is a key to ecological success of termites, allowing them to orient themselves between the nesting and foraging sites. This behavior is controlled by specific trail-following pheromones produced by the abdominal sternal gland occurring in all termite species and developmental stages. Trail-following communication has been studied in a broad spectrum of species, but the "higher" termites (i.e. Termitidae) from the subfamily Syntermitinae remain surprisingly neglected. To fill this gap, we studied the trail-following pheromone in six genera and nine species of Syntermitinae. Our chemical and behavioral experiments showed that (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol is the single component of the pheromone of all the termite species studied, except for Silvestritermes euamignathus. This species produces both (3Z,6Z)-dodeca-3,6-dien-1-ol and neocembrene, but only (3Z,6Z)-dodeca-3,6-dien-1-ol elicits trail-following behavior. Our results indicate the importance of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol, the most widespread communication compound in termites, but also the repeated switches to other common pheromones as exemplified by S. euamignathus.
- MeSH
- feromony metabolismus MeSH
- Isoptera fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Effective defense is a common characteristic of insect societies. Indeed, the occurrence of specialized defenders, soldiers, has been the first step toward eusociality in several independent lineages, including termites. Among the multitude of defensive strategies used by termite soldiers, defense by chemicals plays a crucial role. It has evolved with complexity in advanced isopteran lineages, whose soldiers are equipped with a unique defensive organ, the frontal gland. Besides direct defense against predators, competitors, and pathogens, the chemicals emitted by soldiers from the frontal gland are used as signals of alarm. In this study, we investigated the chemical composition of the defensive secretion produced by soldiers of the termite Termitogeton planus (Isoptera: Rhinotermitidae), from West Papua, and the effects of this secretion on the behavior of termite groups. Detailed two-dimensional gas chromatography/mass spectrometry analyses of the soldier defensive secretion revealed the presence of four linear and nine monoterpene hydrocarbons. Soldier head extracts, as well as synthetic mixtures of the monoterpenes found in these extracts, elicited alarm behavior in both soldiers and pseudergates. Our results suggest that the alarm is not triggered by a single monoterpene from the defensive blend, but by a multi-component signal combining quantitatively major and minor compounds.
- MeSH
- exokrinní žlázy chemie MeSH
- feromony chemie MeSH
- Isoptera chemie fyziologie MeSH
- monoterpeny chemie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- sociální chování MeSH
- uhlovodíky chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
