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Jan Šobotník - One of the best experts on this subject based on the ideXlab platform.
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The trail-following pheromone of the termite Serritermes serrifer
Chemoecology, 2020Co-Authors: David Sillam-dussès, Thomas Bourguignon, Jaromír Hradecký, Petr Stiblik, Hélida Ferreira Cunha, Tiago F. Carrijo, Michael J. Lacey, Jan ŠobotníkAbstract:The Neotropical family Serritermitidae is a monophyletic group of termites including two genera, Serritermes and Glossotermes , with different way-of-life, the former being the sole obligatory inquiline among “lower” termites, while the latter is a single-site nester feeding on dry rotten red wood. Like the most advanced termite’s family, the Termitidae, the Serritermitidae is an inner group of the paraphyletic family “Rhinotermitidae”, but unlike the Termitidae, it has been poorly studied so far. In this study, we bring new insights into the chemical ecology of this key taxon. We studied the trail-following pheromone of Serritermes serrifer and we identified (10 Z ,13 Z )-nonadeca-10,13-dien-2-one as the only component of the trail-following pheromone of this termite species, as it is the case in Glossotermes , the other genus belonging to Serritermitidae. This result makes the family Serritermitidae clearly distinct from other Rhinotermitidae, such as the termites Psammotermes and Prorhinotermes , that use (3 Z ,6 Z ,8 E )-dodeca-3,6,8-trien-1-ol and/or neocembrene as trail-following pheromones.
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sphinganine like biogenesis of e 1 nitropentadec 1 ene in termite soldiers of the genus Prorhinotermes
ChemBioChem, 2014Co-Authors: Anna Jirosova, Pavel Jiroš, Jan Šobotník, Andrej Jancařik, Klara Dolejsova, Pavel Majer, Richard Tykva, Robert HanusAbstract:: In 1974, (E)-1-nitropentadec-1-ene, a strong lipophilic contact poison of soldiers of the termite genus Prorhinotermes, was the first-described insect-produced nitro compound. However, its biosynthesis remained unknown. In the present study, we tested the hypothesis that (E)-1-nitropentadec-1-ene biosynthesis originates with condensation of amino acids with tetradecanoic acid. By using in vivo experiments with radiolabeled and deuterium-labeled putative precursors, we show that (E)-1-nitropentadec-1-ene is synthesized by the soldiers from glycine or L-serine and tetradecanoic acid. We propose and discuss three possible biosynthetic pathways.
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SDS-PAGE of labial gland extracts of workers (W) or soldiers (S).
2012Co-Authors: David Sillam-dussès, Thomas Bourguignon, Jana Krasulová, Josef Cvačka, Vladimír Vrkoslav, Jana Pytelková, Kateřina Kutalová, Toru Miura, Jan ŠobotníkAbstract:Neotermes castaneus (Nc), Reticulitermes flavipes (Rf), Prorhinotermes simplex (Ps), Coptotermes formosanus (Cf). Controls made of a piece of abdomen were made for each species and caste. A black arrow indicates cellulase bands.
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Sex Pheromone and Trail Pheromone of the Sand Termite Psammotermes hybostoma
Journal of Chemical Ecology, 2011Co-Authors: David Sillam-dussès, Robert Hanus, Ashraf Oukasha Abd El-latif, Pavel Jiroš, Jana Krasulová, Blanka Kalinová, Irena Valterová, Jan ŠobotníkAbstract:Within the complex network of chemical signals used by termites, trail pheromones and sex pheromones are among the best known. Numerous recent papers map the chemical identity and glandular origin of these pheromones in nearly all major isopteran taxa. In this study, we aimed to describe the sex pheromone and the trail pheromone of a poorly known sand termite, Psammotermes hybostoma . We identified (3 Z ,6 Z ,8 E )-dodeca-3,6,8-trien-1-ol (dodecatrienol) as the sex pheromone released by tergal and sternal glands of female imagos and, at the same time, as the trail pheromone secreted from the sternal gland of workers. We conclude that chemical communication in Psammotermes does not differ from that of most other Rhinotermitidae, such as Reticulitermes , despite the presence of a diterpene as a major component of the trail pheromone of Prorhinotermes to which Psammotermes is presumed to be phylogenetically close. Our findings underline once again the conservative nature of chemical communication in termites, with dodecatrienol being a frequent component of pheromonal signals in trail following and sex attraction and, at the same time, a tight evolutionary relationship between the trail following of working castes and the sex attraction of imagos.
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Impact of a juvenile hormone analogue on the anatomy and the frontal gland secretion of Prorhinotermes simplex (Isoptera: Rhinotermitidae).
Journal of Insect Physiology, 2010Co-Authors: Jan Šobotník, Robert Hanus, Rafal Piskorski, Klára Urbanová, Zdeněk Wimmer, Frantisek Weyda, Blahoslava Vytisková, David Sillam-dussèsAbstract:Abstract In termites, juvenile hormone plays a key role in soldier differentiation. To better understand the evolutionary origin of the soldiers, we studied the external and inner morphology of pseudergate–soldier intercastes and neotenic–soldier intercastes formed artificially by the application of juvenile hormone analogue in Prorhinotermes simplex . A majority of these intercastes had a soldier phenotype, whereas the inner anatomy had an intermediary form between two castes or a form specific to intercastes. Our experiments showed that traits of neotenics and soldiers can be shared by the same individuals, although such individuals do not exist naturally in P. simplex , and they have not been reported in other species but in some Termopsidae. Our results reinforce the hypothesis that soldiers may have emerged from soldier neotenics during the evolution of termites.
Robert Hanus - One of the best experts on this subject based on the ideXlab platform.
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The detection and mapping of the spatial distribution of insect defense compounds by desorption atmospheric pressure photoionization Orbitrap mass spectrometry
Analytica chimica acta, 2015Co-Authors: Jan Rejšek, Robert Hanus, Vladimír Vrkoslav, Anu Vaikkinen, Markus Haapala, Tiina J. Kauppila, Risto Kostiainen, Josef CvačkaAbstract:Many insects use chemicals synthesized in exocrine glands and stored in reservoirs to protect themselves. Two chemically defended insects were used as models for the development of a new rapid analytical method based on desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). The distribution of defensive chemicals on the insect body surface was studied. Since these chemicals are predominantly nonpolar, DAPPI was a suitable analytical method. Repeatability of DAPPI-MS signals and effects related to non-planarity and roughness of samples were investigated using acrylic sheets uniformly covered with an analyte. After that, analytical figures of merit of the technique were determined. The spatial distribution of (E)-1-nitropentadec-1-ene, a toxic nitro compound synthesized by soldiers of the termite Prorhinotermes simplex, was investigated. Then, the spatial distribution of the unsaturated aldehydes (E)-hex-2-enal, (E)-4-oxohex-2-enal, (E)-oct-2-enal, (E,E)-deca-2,4-dienal and (E)-dec-2-enal was monitored in the stink bug Graphosoma lineatum. Chemicals present on the body surface were scanned along the median line of the insect from the head to the abdomen and vice versa, employing either the MS or MS2 mode. In this fast and simple way, the opening of the frontal gland on the frons of termite soldiers and the position of the frontal gland reservoir, extending deep into the abdominal cavity, were localized. In the stink bug, the opening of the metathoracic scent glands (ostiole) on the ventral side of the thorax as well as the gland reservoir in the median position under the ventral surface of the anterior abdomen were detected and localized. The developed method has future prospects in routine laboratory use in life sciences.
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sphinganine like biogenesis of e 1 nitropentadec 1 ene in termite soldiers of the genus Prorhinotermes
ChemBioChem, 2014Co-Authors: Anna Jirosova, Pavel Jiroš, Jan Šobotník, Andrej Jancařik, Klara Dolejsova, Pavel Majer, Richard Tykva, Robert HanusAbstract:: In 1974, (E)-1-nitropentadec-1-ene, a strong lipophilic contact poison of soldiers of the termite genus Prorhinotermes, was the first-described insect-produced nitro compound. However, its biosynthesis remained unknown. In the present study, we tested the hypothesis that (E)-1-nitropentadec-1-ene biosynthesis originates with condensation of amino acids with tetradecanoic acid. By using in vivo experiments with radiolabeled and deuterium-labeled putative precursors, we show that (E)-1-nitropentadec-1-ene is synthesized by the soldiers from glycine or L-serine and tetradecanoic acid. We propose and discuss three possible biosynthetic pathways.
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Sex Pheromone and Trail Pheromone of the Sand Termite Psammotermes hybostoma
Journal of Chemical Ecology, 2011Co-Authors: David Sillam-dussès, Robert Hanus, Ashraf Oukasha Abd El-latif, Pavel Jiroš, Jana Krasulová, Blanka Kalinová, Irena Valterová, Jan ŠobotníkAbstract:Within the complex network of chemical signals used by termites, trail pheromones and sex pheromones are among the best known. Numerous recent papers map the chemical identity and glandular origin of these pheromones in nearly all major isopteran taxa. In this study, we aimed to describe the sex pheromone and the trail pheromone of a poorly known sand termite, Psammotermes hybostoma . We identified (3 Z ,6 Z ,8 E )-dodeca-3,6,8-trien-1-ol (dodecatrienol) as the sex pheromone released by tergal and sternal glands of female imagos and, at the same time, as the trail pheromone secreted from the sternal gland of workers. We conclude that chemical communication in Psammotermes does not differ from that of most other Rhinotermitidae, such as Reticulitermes , despite the presence of a diterpene as a major component of the trail pheromone of Prorhinotermes to which Psammotermes is presumed to be phylogenetically close. Our findings underline once again the conservative nature of chemical communication in termites, with dodecatrienol being a frequent component of pheromonal signals in trail following and sex attraction and, at the same time, a tight evolutionary relationship between the trail following of working castes and the sex attraction of imagos.
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Impact of a juvenile hormone analogue on the anatomy and the frontal gland secretion of Prorhinotermes simplex (Isoptera: Rhinotermitidae).
Journal of Insect Physiology, 2010Co-Authors: Jan Šobotník, Robert Hanus, Rafal Piskorski, Klára Urbanová, Zdeněk Wimmer, Frantisek Weyda, Blahoslava Vytisková, David Sillam-dussèsAbstract:Abstract In termites, juvenile hormone plays a key role in soldier differentiation. To better understand the evolutionary origin of the soldiers, we studied the external and inner morphology of pseudergate–soldier intercastes and neotenic–soldier intercastes formed artificially by the application of juvenile hormone analogue in Prorhinotermes simplex . A majority of these intercastes had a soldier phenotype, whereas the inner anatomy had an intermediary form between two castes or a form specific to intercastes. Our experiments showed that traits of neotenics and soldiers can be shared by the same individuals, although such individuals do not exist naturally in P. simplex , and they have not been reported in other species but in some Termopsidae. Our results reinforce the hypothesis that soldiers may have emerged from soldier neotenics during the evolution of termites.
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Beyond cuticular hydrocarbons: evidence of proteinaceous secretion specific to termite kings and queens
Proceedings. Biological sciences, 2009Co-Authors: Robert Hanus, Ivan Hrdý, Josef Cvačka, Vladimír Vrkoslav, Jan ŠobotníkAbstract:In 1959, P. Karlson and M. Luscher introduced the term ‘pheromone’, broadly used nowadays for various chemicals involved in intraspecific communication. To demonstrate the term, they depicted the situation in termite societies, where king and queen inhibit the reproduction of nest-mates by an unknown chemical substance. Paradoxically, half a century later, neither the source nor the chemical identity of this ‘royal’ pheromone is known. In this study, we report for the first time the secretion of polar compounds of proteinaceous origin by functional reproductives in three termite species, Prorhinotermes simplex, Reticulitermes santonensis and Kalotermes flavicollis. Aqueous washes of functional reproductives contained sex-specific proteinaceous compounds, virtually absent in non-reproducing stages. Moreover, the presence of these compounds was clearly correlated with the age of reproductives and their reproductive status. We discuss the putative function of these substances in termite caste recognition and regulation.
Irena Valterová - One of the best experts on this subject based on the ideXlab platform.
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Sex Pheromone and Trail Pheromone of the Sand Termite Psammotermes hybostoma
Journal of Chemical Ecology, 2011Co-Authors: David Sillam-dussès, Robert Hanus, Ashraf Oukasha Abd El-latif, Pavel Jiroš, Jana Krasulová, Blanka Kalinová, Irena Valterová, Jan ŠobotníkAbstract:Within the complex network of chemical signals used by termites, trail pheromones and sex pheromones are among the best known. Numerous recent papers map the chemical identity and glandular origin of these pheromones in nearly all major isopteran taxa. In this study, we aimed to describe the sex pheromone and the trail pheromone of a poorly known sand termite, Psammotermes hybostoma . We identified (3 Z ,6 Z ,8 E )-dodeca-3,6,8-trien-1-ol (dodecatrienol) as the sex pheromone released by tergal and sternal glands of female imagos and, at the same time, as the trail pheromone secreted from the sternal gland of workers. We conclude that chemical communication in Psammotermes does not differ from that of most other Rhinotermitidae, such as Reticulitermes , despite the presence of a diterpene as a major component of the trail pheromone of Prorhinotermes to which Psammotermes is presumed to be phylogenetically close. Our findings underline once again the conservative nature of chemical communication in termites, with dodecatrienol being a frequent component of pheromonal signals in trail following and sex attraction and, at the same time, a tight evolutionary relationship between the trail following of working castes and the sex attraction of imagos.
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Temporal and geographic variations in the morphology and chemical composition of the frontal gland in imagoes of Prorhinotermes species (Isoptera: Rhinotermitidae)
Biological Journal of the Linnean Society, 2009Co-Authors: Rafal Piskorski, Thomas Bourguignon, Yves Roisin, Robert Hanus, Blanka Kalinová, Irena Valterová, Jan Křeček, Jan ŠobotníkAbstract:Although the frontal gland has long been known as a prominent defensive device for termite soldiers in many Rhinotermitidae and Termitidae, almost nothing is known about its function in imagoes. In the present study, we show that the frontal gland of imagoes in Prorhinotermes species is well developed at the time of the nuptial flight, and is filled with a complex mixture of sesquiterpene hydrocarbons and nitroalkenes. The sesquiterpene composition varies between Prorhinotermes simplex and Prorhinotermes canalifrons, between geographically distant colonies of P. simplex (Cuba versus Florida), and even between different flights of closely-related subcolonies. The ratio between (E)-1-nitropentadec-1-ene and sesquiterpenes is sex-specific. The volume of secretory cells decreases in functional kings and queens after colony foundation, and the subcellular organization changes into a form resembling unmodified epidermal cells. Dealate reproductives lose the ability for biosynthesis, and their frontal gland is devoid of volatile compounds found in swarming imagoes. The results obtained in the present study clearly show that the frontal gland is only temporarily active at the time of the dispersal flight. The most likely function of this gland is defence by the toxic nitroalkenes. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 384–392.
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Identification by GC-EAD of the two-component trail-following pheromone of Prorhinotermes simplex (Isoptera, Rhinotermitidae, Prorhinotermitinae)
Journal of insect physiology, 2009Co-Authors: David Sillam-dussès, Christian Bordereau, Robert Hanus, Pavel Jiroš, Blanka Kalinová, Jan Šobotník, Josef Cvačka, Anna Brezinová, Irena ValterováAbstract:GC/MS analysis confirmed that neocembrene is the major component of the trail pheromone in the three species of the termite genus Prorhinotermes (P. simplex, P. canalifrons, P. inopinatus). In addition, EAG and GC-EAD experiments with P. simplex strongly suggest that dodecatrienol is a quantitatively minor component but a qualitatively important component of this trail pheromone. Trail-following bioassays confirmed the two-component nature of the trail pheromone. This is the first report of the use of the GC-EAD for the identification of trail pheromone in termites. These original results underline once again the special phylogenetic status of the Prorhinotermitinae among Rhinotermitidae.
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Nitroalkenes and Sesquiterpene Hydrocarbons from the Frontal Gland of Three Prorhinotermes Termite Species
Journal of Chemical Ecology, 2007Co-Authors: Rafal Piskorski, Robert Hanus, Jan Šobotník, Josef Cvačka, Soňa Vašíčková, Aleš Svatoš, Irena ValterováAbstract:Frontal gland contents of soldiers of three Prorhinotermes species, Prorhinotermes canalifrons , Prorhinotermes inopinatus , and Prorhinotermes simplex , consisted of two groups of compounds: nitroalkenes and sesquiterpene hydrocarbons. Analysis by gas chromatography-mass spectrometry revealed ( E )-1-nitropentadec-1-ene as the major component of the glands with mean values of 152, 207, and 293 μg/individual for P. canalifrons , P. inopinatus , and P. simplex , respectively. Four other 1-nitroalkenes (C13, C14, C16, and C17), and two nitrodienes (C15 and C17) were also detected in the three species. The C17:1 nitroalkene was identified as ( E )-1-nitroheptadec-1-ene. The sesquiterpene composition of the gland was species-specific: P. simplex contained (3 Z ,6 E )-α-farnesene (mean of 39 μg/individual), while P. canalifrons and P. inopinatus contained the same compound (means of 0.5 and 1.5 μg/individual, respectively) as well as the (3 E ,6 E ) isomer (means of 1.8 and 0.7 μg/individual, respectively). Two other sesquiterpenes, trans -β-bergamotene and ( Z )-γ-bisabolene, were also found in low quantities in the frontal gland of P. canalifrons .
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Computer‐assisted interpretation of atmospheric pressure chemical ionization mass spectra of triacylglycerols
Rapid communications in mass spectrometry : RCM, 2006Co-Authors: Josef Cvačka, Pavel Jiroš, Edita Krafková, Irena ValterováAbstract:Current lipidomics approaches require simple and rapid algorithms enabling the interpretation of mass spectra of lipids. Most lipids are complex mixtures of related components in which the composition of the aliphatic fatty acid chains varies from one molecule to the next. Triacylglycerols (TAGs) are an example of such a lipid class. Fatty acid chains are the only parts of the molecule to change from one species to another. Fatty acids, and consequently also TAGs, can be characterized by two parameters; the number of carbon atoms and the number of double bonds. All calculations reflecting relations among ions in the spectra can be easily made using these parameters. An algorithm for the automated interpretation of TAGs from atmospheric pressure chemical ionization mass spectra (TriglyAPCI) is presented in this paper. The algorithm first identifies diacylglycerol fragments and molecular adducts. In the next step, relations among the ions are searched and possible TAG structures are suggested. Individual features of the algorithm are described in detail and the software performance is demonstrated for the liquid chromatography/mass spectrometric (LC/MS) analysis of TAGs isolated from the termite Prorhinotermes canalifrons.
Yves Roisin - One of the best experts on this subject based on the ideXlab platform.
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Social organisation and the status of workers in termites
Biology of Termites: a Modern Synthesis, 2010Co-Authors: Yves Roisin, Judith KorbAbstract:Whereas the soldier caste is clearly ancestral to all extant termite lineages and constitutes the hallmark of termite eusociality, the origin and evolution of workers is much more difficult to comprehend. Here, we first review the status of working individuals throughout the Isoptera, insisting on the need for a consistent terminology. Pseudergates sensu stricto are defined ontogenetically as individuals stepping aside the straight egg-to-alate pathway, through regressive or stationary moults. They reveal an ancestral developmental flexibility, since they are common in small-colony wood-dwelling termites, but may also occur in large-colony Rhinotermitidae or Termitidae. They may participate in social tasks but never constitute a functional category by themselves. Pseudergates sensu lato, or false workers, are defined as a functional category of individuals performing work, while remaining developmentally flexible. This latter property distinguishes them from true workers, which result from an early and irreversible developmental bifurcation, and have lost the possibility to resume alate development. We emphasize three major kinds of social organisation, with respect to the worker caste. In the drywood-dwelling Cryptotermes (Kalotermitidae), all immatures (pseudergates sensu lato) participate in colony work in a cooperative rather than altruistic manner, with very little if any direct fitness loss. In Prorhinotermes (Rhinotermitidae) and Glossotermes (Serritermitidae), wing bud development is postponed until the last pre-alate nymph instar and the preceding instars form a large functional caste of pseudergates (sensu lato), performing partially altruistic colony work. In the Termitidae, tasks are done by a specialized, altruistic true worker caste. After reviewing the proximate developmental and regulatory mechanisms determining the fate of termite immatures, we discuss the ultimate causes of worker evolution. The potential role of kin-selected benefits of helping versus direct benefits of inheritance is examined in detail. Both approaches still face some difficulties and it is probably a combination of both that explains the early social evolution of termites. We stress the need for new theoretical models as well as broader comparative data on life history and social behaviour.
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Temporal and geographic variations in the morphology and chemical composition of the frontal gland in imagoes of Prorhinotermes species (Isoptera: Rhinotermitidae)
Biological Journal of the Linnean Society, 2009Co-Authors: Rafal Piskorski, Thomas Bourguignon, Yves Roisin, Robert Hanus, Blanka Kalinová, Irena Valterová, Jan Křeček, Jan ŠobotníkAbstract:Although the frontal gland has long been known as a prominent defensive device for termite soldiers in many Rhinotermitidae and Termitidae, almost nothing is known about its function in imagoes. In the present study, we show that the frontal gland of imagoes in Prorhinotermes species is well developed at the time of the nuptial flight, and is filled with a complex mixture of sesquiterpene hydrocarbons and nitroalkenes. The sesquiterpene composition varies between Prorhinotermes simplex and Prorhinotermes canalifrons, between geographically distant colonies of P. simplex (Cuba versus Florida), and even between different flights of closely-related subcolonies. The ratio between (E)-1-nitropentadec-1-ene and sesquiterpenes is sex-specific. The volume of secretory cells decreases in functional kings and queens after colony foundation, and the subcellular organization changes into a form resembling unmodified epidermal cells. Dealate reproductives lose the ability for biosynthesis, and their frontal gland is devoid of volatile compounds found in swarming imagoes. The results obtained in the present study clearly show that the frontal gland is only temporarily active at the time of the dispersal flight. The most likely function of this gland is defence by the toxic nitroalkenes. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 384–392.
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agonistic behavior of the termite Prorhinotermes canalifrons isoptera rhinotermitidae
Journal of Insect Behavior, 2008Co-Authors: Jan Šobotník, Robert Hanus, Yves RoisinAbstract:While intercolonial and interspecific agonism has been broadly documented in termites, detailed studies of individual behavior and its differentiation among castes are scarce. We studied the responses of non-reproductive castes of Prorhinotermes canalifrons (pseudergates, presoldiers, soldiers of different age and artificial intercastes) to conspecific and heterospecific aliens. Each caste displayed a specific behavioral repertoire. Soldiers, but to a lesser extent pseudergates as well, are responsible for colony defense. The behavioral repertoire of the soldier appears on the second day after exuviation and becomes complete on the third day, well before its defensive secretion is present. The behavior of artificial intercastes induced by a JH analog is intermediate between that of pseudergates and soldiers. Reactions to heterospecific aliens were much quicker and more violent than reactions to conspecifics, which suggests that individuals experience difficulties in identifying conspecific aliens.
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Coming out of the woods: do termites need a specialized worker caste to search for new food sources?
Naturwissenschaften, 2008Co-Authors: Thomas Rupf, Yves RoisinAbstract:Most small-colony termites live confined within a single piece of wood on which they feed and do not possess permanent workers: Tasks are done by developmentally flexible immatures (pseudergates). By contrast, large-colony termites possess a specialized (true) worker caste and forage outside their nest for food. To shed light on possible transitional steps between these contrasting patterns of social organization, we studied an atypical Rhinotermitidae, Prorhinotermes inopinatus . In this species, despite the absence of a true worker caste, soldiers, pseudergates, and neotenic reproductives may leave the nest and explore their surroundings. Although evidence presented in this study indicates that termites recognize unknown areas, there is no directional recruitment toward them. The discovery of a food source, i.e., a piece of wood, is followed by the establishment of a long-lasting trail between the nest and the food source. A large fraction of the colony, including neotenic reproductives, ultimately migrates into the piece of wood. Our results thus demonstrate that multiple features of external foraging behavior can evolve independently of the existence of a true worker caste in termites. We suggest that large colonies with true workers, like those of most Rhinotermitidae, may easily have evolved from a Prorhinotermes -like pattern if submitted to increasing selective pressures for worker efficiency in a stable environment.
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Caste morphology and development in Termitogeton nr. planus (Insecta, Isoptera, Rhinotermitidae).
Journal of Morphology, 2003Co-Authors: Dominique Parmentier, Yves RoisinAbstract: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 103 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. J. Morphol. 255:69–79, 2003. © 2002 Wiley-Liss, Inc.
Josef Cvačka - One of the best experts on this subject based on the ideXlab platform.
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The detection and mapping of the spatial distribution of insect defense compounds by desorption atmospheric pressure photoionization Orbitrap mass spectrometry
Analytica chimica acta, 2015Co-Authors: Jan Rejšek, Robert Hanus, Vladimír Vrkoslav, Anu Vaikkinen, Markus Haapala, Tiina J. Kauppila, Risto Kostiainen, Josef CvačkaAbstract:Many insects use chemicals synthesized in exocrine glands and stored in reservoirs to protect themselves. Two chemically defended insects were used as models for the development of a new rapid analytical method based on desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). The distribution of defensive chemicals on the insect body surface was studied. Since these chemicals are predominantly nonpolar, DAPPI was a suitable analytical method. Repeatability of DAPPI-MS signals and effects related to non-planarity and roughness of samples were investigated using acrylic sheets uniformly covered with an analyte. After that, analytical figures of merit of the technique were determined. The spatial distribution of (E)-1-nitropentadec-1-ene, a toxic nitro compound synthesized by soldiers of the termite Prorhinotermes simplex, was investigated. Then, the spatial distribution of the unsaturated aldehydes (E)-hex-2-enal, (E)-4-oxohex-2-enal, (E)-oct-2-enal, (E,E)-deca-2,4-dienal and (E)-dec-2-enal was monitored in the stink bug Graphosoma lineatum. Chemicals present on the body surface were scanned along the median line of the insect from the head to the abdomen and vice versa, employing either the MS or MS2 mode. In this fast and simple way, the opening of the frontal gland on the frons of termite soldiers and the position of the frontal gland reservoir, extending deep into the abdominal cavity, were localized. In the stink bug, the opening of the metathoracic scent glands (ostiole) on the ventral side of the thorax as well as the gland reservoir in the median position under the ventral surface of the anterior abdomen were detected and localized. The developed method has future prospects in routine laboratory use in life sciences.
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SDS-PAGE of labial gland extracts of workers (W) or soldiers (S).
2012Co-Authors: David Sillam-dussès, Thomas Bourguignon, Jana Krasulová, Josef Cvačka, Vladimír Vrkoslav, Jana Pytelková, Kateřina Kutalová, Toru Miura, Jan ŠobotníkAbstract:Neotermes castaneus (Nc), Reticulitermes flavipes (Rf), Prorhinotermes simplex (Ps), Coptotermes formosanus (Cf). Controls made of a piece of abdomen were made for each species and caste. A black arrow indicates cellulase bands.
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Beyond cuticular hydrocarbons: evidence of proteinaceous secretion specific to termite kings and queens
Proceedings. Biological sciences, 2009Co-Authors: Robert Hanus, Ivan Hrdý, Josef Cvačka, Vladimír Vrkoslav, Jan ŠobotníkAbstract:In 1959, P. Karlson and M. Luscher introduced the term ‘pheromone’, broadly used nowadays for various chemicals involved in intraspecific communication. To demonstrate the term, they depicted the situation in termite societies, where king and queen inhibit the reproduction of nest-mates by an unknown chemical substance. Paradoxically, half a century later, neither the source nor the chemical identity of this ‘royal’ pheromone is known. In this study, we report for the first time the secretion of polar compounds of proteinaceous origin by functional reproductives in three termite species, Prorhinotermes simplex, Reticulitermes santonensis and Kalotermes flavicollis. Aqueous washes of functional reproductives contained sex-specific proteinaceous compounds, virtually absent in non-reproducing stages. Moreover, the presence of these compounds was clearly correlated with the age of reproductives and their reproductive status. We discuss the putative function of these substances in termite caste recognition and regulation.
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Identification by GC-EAD of the two-component trail-following pheromone of Prorhinotermes simplex (Isoptera, Rhinotermitidae, Prorhinotermitinae)
Journal of insect physiology, 2009Co-Authors: David Sillam-dussès, Christian Bordereau, Robert Hanus, Pavel Jiroš, Blanka Kalinová, Jan Šobotník, Josef Cvačka, Anna Brezinová, Irena ValterováAbstract:GC/MS analysis confirmed that neocembrene is the major component of the trail pheromone in the three species of the termite genus Prorhinotermes (P. simplex, P. canalifrons, P. inopinatus). In addition, EAG and GC-EAD experiments with P. simplex strongly suggest that dodecatrienol is a quantitatively minor component but a qualitatively important component of this trail pheromone. Trail-following bioassays confirmed the two-component nature of the trail pheromone. This is the first report of the use of the GC-EAD for the identification of trail pheromone in termites. These original results underline once again the special phylogenetic status of the Prorhinotermitinae among Rhinotermitidae.
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e e α farnesene an alarm pheromone of the termite Prorhinotermes canalifrons
Journal of Chemical Ecology, 2008Co-Authors: Jan Šobotník, Robe Hanus, Lanka Kalinova, Rafal Piskorski, Thomas Ourguigno, Josef Cvačka, Yves RoisiAbstract:The behavioral and electroantennographic responses of Prorhinotermes canalifrons to its soldier frontal gland secretion, and two separated major components of the secretion, (E)-1-nitropentadec-1-ene and (E,E)-α-farnesene, were studied in laboratory experiments. Behavioral experiments showed that both the frontal gland secretion and (E,E)-α-farnesene triggered alarm reactions in P. canalifrons, whereas (E)-1-nitropentadec-1-ene did not affect the behavior of termite groups. The alarm reactions were characterized by rapid walking of activated termites and efforts to alert and activate other members of the group. Behavioral responses to alarm pheromone differed between homogeneous and mixed groups, suggesting complex interactions. Antennae of both soldiers and pseudergates were sensitive to the frontal gland secretion and to (E,E)-α-farnesene, but soldiers showed stronger responses. The dose responses to (E,E)-α-farnesene were identical for both soldiers and pseudergates, suggesting that both castes use similar receptors to perceive (E,E)-α-farnesene. Our data confirm (E,E)-α-farnesene as an alarm pheromone of P. canalifrons.
