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Duur K. Aanen - One of the best experts on this subject based on the ideXlab platform.
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farming termites determine the genetic population structure of termitomyces fungal symbionts
Molecular Ecology, 2011Co-Authors: Tânia Nobre, Cecilia Fernandes, Judith Korb, Jacobus J. Boomsma, Duur K. AanenAbstract:Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several fungal symbionts. However, even in the few termite lineages that secondarily adopted vertical symbiont transmission, the fungal symbionts are not monophyletic. We addressed this paradox by studying differential transmission of fungal symbionts by alate male and female reproductives, and the genetic population structure of Termitomyces fungus gardens across 74 colonies of Macrotermes bellicosus in four west and central African countries. We confirm earlier, more limited, studies showing that the Termitomyces symbionts of M. bellicosus are normally transmitted vertically and clonally by dispersing males. We also document that the symbionts associated with this termite species belong to three main lineages that do not constitute a monophyletic group. The most common lineage occurs over the entire geographical region that we studied, including west, central and southern Africa, where it is also associated with the alternative termite hosts Macrotermes subhyalinus and Macrotermes natalensis. While Termitomyces associated with these alternative hosts are horizontally transmitted and recombine freely, the genetic population structure of the same Termitomyces associated with M. bellicosus is consistent with predominantly clonal reproduction and only occasional recombination. This implies that the genetic population structure of Termitomyces is controlled by the termite host and not by the Termitomyces symbiont.
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presumptive horizontal symbiont transmission in the fungus growing termite Macrotermes natalensis
Molecular Ecology, 2006Co-Authors: H H De Fine Licht, Jacobus J. Boomsma, Duur K. AanenAbstract:All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be compatible with clonal vertical transmission, as is known to occur in Macrotermes bellicosus. We investigated this hypothesis by analysing DNA sequence polymorphisms as codominant SNP markers of four single-copy gene fragments of Termitomyces isolates from 31 colonies of M. natalensis. A signature of free recombination was found, indicative of frequent sexual horizontal transmission. First, all 31 strains had unique multilocus genotypes. Second, SNP markers (n = 55) were largely in Hardy–Weinberg equilibrium (90.9%) and almost all possible pairs of SNPs between genetically unlinked loci were in linkage equilibrium (96.7%). Finally, extensive intragenic recombination was found, especially in the EF1 fragment. Substantial genetic variation and a freely recombining population structure can only be explained by frequent horizontal and sexual transmission of Termitomyces. The apparent variation in symbiont transmission mode among Macrotermes species implies that vertical symbiont transmission can evolve rapidly. The unexpected finding of horizontal transmission makes the apparent absence of Termitomyces mushrooms on M. natalensis mounds puzzling. To our knowledge, this is the first detailed study of the genetic population structure of a single lineage of Termitomyces.
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Presumptive horizontal symbiont transmission in the fungus-growing termite Macrotermes natalensis
Molecular Ecology, 2006Co-Authors: H H De Fine Licht, Jacobus J. Boomsma, Duur K. AanenAbstract:All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be compatible with clonal vertical transmission, as is known to occur in Macrotermes bellicosus. We investigated this hypothesis by analysing DNA sequence polymorphisms as codominant SNP markers of four single-copy gene fragments of Termitomyces isolates from 31 colonies of M. natalensis. A signature of free recombination was found, indicative of frequent sexual horizontal transmission. First, all 31 strains had unique multilocus genotypes. Second, SNP markers (n = 55) were largely in Hardy-Weinberg equilibrium (90.9%) and almost all possible pairs of SNPs between genetically unlinked loci were in linkage equilibrium (96.7%). Finally, extensive intragenic recombination was found, especially in the EF1alpha fragment. Substantial genetic variation and a freely recombining population structure can only be explained by frequent horizontal and sexual transmission of Termitomyces. The apparent variation in symbiont transmission mode among Macrotermes species implies that vertical symbiont transmission can evolve rapidly. The unexpected finding of horizontal transmission makes the apparent absence of Termitomyces mushrooms on M. natalensis mounds puzzling. To our knowledge, this is the first detailed study of the genetic population structure of a single lineage of Termitomyces.
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the evolution of uniparental transmission of fungal symbionts in fungus growing termites macrotermitinae
Behavioral Ecology and Sociobiology, 2003Co-Authors: Judith Korb, Duur K. AanenAbstract:Mutualistic associations between different organisms are theoretically expected when the interests of independently reproducing units are aligned to form a single reproductive unit. This alignment does not come about easily, because models show that hosts and symbionts can be in conflict over the transmission of symbionts. Selection will favour hosts that are able to limit genetic variation of symbionts, for example by enforcing uniparental vertical transmission, while symbionts will be selected to disperse independently of the host. A crucial factor determining the evolution and elaboration of symbiotic relationships is therefore who controls the transmission of symbionts. In the fungus-growing termites (Macrotermintinae) horizontal transmission seems to be the rule as the termites normally acquire their cultivated fungus (Termitomyces) from the environment. In spite of this general pattern, uniparental, vertical transmission has evolved in two unrelated Macrotermitinae genera, where only one sex of the two primary reproductives carries asexual spores from the fungal comb of its parent colony to inoculate the new fungus comb. Remarkably, symbiont transmission is exclusively paternal in Macrotermes bellicosus, whereas symbionts are maternally inherited in all Microtermes species studied so far. Thus, in Macrotermitinae horizontal transmission is the ancestral state with two independent origins to uniparental, vertical transmission. This is in contrast to fungus-growing ants where uniparental, vertical transmission is the rule. Causes and consequences of this difference are further discussed. Despite this fundamental difference both groups evolved a similar symbiosis that is probably the key for their ecological success: the fungus-growing ants in the neotropics and the fungus-growing termites in the paleotropics.
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the evolution of fungus growing termites and their mutualistic fungal symbionts
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Duur K. Aanen, Paul Eggleton, Corinne Roulandlefevre, Tobias Guldbergfroslev, Soren Rosendahl, Jacobus J. BoomsmaAbstract:We have estimated phylogenies of fungus-growing termites and their associated mutualistic fungi of the genus Termitomyces using Bayesian analyses of DNA sequences. Our study shows that the symbiosis has a single African origin and that secondary domestication of other fungi or reversal of mutualistic fungi to a free-living state has not occurred. Host switching has been frequent, especially at the lower taxonomic levels, and nests of single termite species can have different symbionts. Data are consistent with horizontal transmission of fungal symbionts in both the ancestral state of the mutualism and most of the extant taxa. Clonal vertical transmission of fungi, previously shown to be common in the genus Microtermes (via females) and in the species Macrotermes bellicosus (via males) [Johnson, R. A., Thomas, R. J., Wood, T. G. & Swift, M. J. (1981) J. Nat. Hist. 15, 751–756], is derived with two independent origins. Despite repeated host switching, statistical tests taking phylogenetic uncertainty into account show a significant congruence between the termite and fungal phylogenies, because mutualistic interactions at higher taxonomic levels show considerable specificity. We identify common characteristics of fungus-farming evolution in termites and ants, which apply despite the major differences between these two insect agricultural systems. We hypothesize that biparental colony founding may have constrained the evolution of vertical symbiont transmission in termites but not in ants where males die after mating.
Jacobus J. Boomsma - One of the best experts on this subject based on the ideXlab platform.
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farming termites determine the genetic population structure of termitomyces fungal symbionts
Molecular Ecology, 2011Co-Authors: Tânia Nobre, Cecilia Fernandes, Judith Korb, Jacobus J. Boomsma, Duur K. AanenAbstract:Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several fungal symbionts. However, even in the few termite lineages that secondarily adopted vertical symbiont transmission, the fungal symbionts are not monophyletic. We addressed this paradox by studying differential transmission of fungal symbionts by alate male and female reproductives, and the genetic population structure of Termitomyces fungus gardens across 74 colonies of Macrotermes bellicosus in four west and central African countries. We confirm earlier, more limited, studies showing that the Termitomyces symbionts of M. bellicosus are normally transmitted vertically and clonally by dispersing males. We also document that the symbionts associated with this termite species belong to three main lineages that do not constitute a monophyletic group. The most common lineage occurs over the entire geographical region that we studied, including west, central and southern Africa, where it is also associated with the alternative termite hosts Macrotermes subhyalinus and Macrotermes natalensis. While Termitomyces associated with these alternative hosts are horizontally transmitted and recombine freely, the genetic population structure of the same Termitomyces associated with M. bellicosus is consistent with predominantly clonal reproduction and only occasional recombination. This implies that the genetic population structure of Termitomyces is controlled by the termite host and not by the Termitomyces symbiont.
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presumptive horizontal symbiont transmission in the fungus growing termite Macrotermes natalensis
Molecular Ecology, 2006Co-Authors: H H De Fine Licht, Jacobus J. Boomsma, Duur K. AanenAbstract:All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be compatible with clonal vertical transmission, as is known to occur in Macrotermes bellicosus. We investigated this hypothesis by analysing DNA sequence polymorphisms as codominant SNP markers of four single-copy gene fragments of Termitomyces isolates from 31 colonies of M. natalensis. A signature of free recombination was found, indicative of frequent sexual horizontal transmission. First, all 31 strains had unique multilocus genotypes. Second, SNP markers (n = 55) were largely in Hardy–Weinberg equilibrium (90.9%) and almost all possible pairs of SNPs between genetically unlinked loci were in linkage equilibrium (96.7%). Finally, extensive intragenic recombination was found, especially in the EF1 fragment. Substantial genetic variation and a freely recombining population structure can only be explained by frequent horizontal and sexual transmission of Termitomyces. The apparent variation in symbiont transmission mode among Macrotermes species implies that vertical symbiont transmission can evolve rapidly. The unexpected finding of horizontal transmission makes the apparent absence of Termitomyces mushrooms on M. natalensis mounds puzzling. To our knowledge, this is the first detailed study of the genetic population structure of a single lineage of Termitomyces.
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Presumptive horizontal symbiont transmission in the fungus-growing termite Macrotermes natalensis
Molecular Ecology, 2006Co-Authors: H H De Fine Licht, Jacobus J. Boomsma, Duur K. AanenAbstract:All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be compatible with clonal vertical transmission, as is known to occur in Macrotermes bellicosus. We investigated this hypothesis by analysing DNA sequence polymorphisms as codominant SNP markers of four single-copy gene fragments of Termitomyces isolates from 31 colonies of M. natalensis. A signature of free recombination was found, indicative of frequent sexual horizontal transmission. First, all 31 strains had unique multilocus genotypes. Second, SNP markers (n = 55) were largely in Hardy-Weinberg equilibrium (90.9%) and almost all possible pairs of SNPs between genetically unlinked loci were in linkage equilibrium (96.7%). Finally, extensive intragenic recombination was found, especially in the EF1alpha fragment. Substantial genetic variation and a freely recombining population structure can only be explained by frequent horizontal and sexual transmission of Termitomyces. The apparent variation in symbiont transmission mode among Macrotermes species implies that vertical symbiont transmission can evolve rapidly. The unexpected finding of horizontal transmission makes the apparent absence of Termitomyces mushrooms on M. natalensis mounds puzzling. To our knowledge, this is the first detailed study of the genetic population structure of a single lineage of Termitomyces.
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the evolution of fungus growing termites and their mutualistic fungal symbionts
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Duur K. Aanen, Paul Eggleton, Corinne Roulandlefevre, Tobias Guldbergfroslev, Soren Rosendahl, Jacobus J. BoomsmaAbstract:We have estimated phylogenies of fungus-growing termites and their associated mutualistic fungi of the genus Termitomyces using Bayesian analyses of DNA sequences. Our study shows that the symbiosis has a single African origin and that secondary domestication of other fungi or reversal of mutualistic fungi to a free-living state has not occurred. Host switching has been frequent, especially at the lower taxonomic levels, and nests of single termite species can have different symbionts. Data are consistent with horizontal transmission of fungal symbionts in both the ancestral state of the mutualism and most of the extant taxa. Clonal vertical transmission of fungi, previously shown to be common in the genus Microtermes (via females) and in the species Macrotermes bellicosus (via males) [Johnson, R. A., Thomas, R. J., Wood, T. G. & Swift, M. J. (1981) J. Nat. Hist. 15, 751–756], is derived with two independent origins. Despite repeated host switching, statistical tests taking phylogenetic uncertainty into account show a significant congruence between the termite and fungal phylogenies, because mutualistic interactions at higher taxonomic levels show considerable specificity. We identify common characteristics of fungus-farming evolution in termites and ants, which apply despite the major differences between these two insect agricultural systems. We hypothesize that biparental colony founding may have constrained the evolution of vertical symbiont transmission in termites but not in ants where males die after mating.
Judith Korb - One of the best experts on this subject based on the ideXlab platform.
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farming termites determine the genetic population structure of termitomyces fungal symbionts
Molecular Ecology, 2011Co-Authors: Tânia Nobre, Cecilia Fernandes, Judith Korb, Jacobus J. Boomsma, Duur K. AanenAbstract:Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several fungal symbionts. However, even in the few termite lineages that secondarily adopted vertical symbiont transmission, the fungal symbionts are not monophyletic. We addressed this paradox by studying differential transmission of fungal symbionts by alate male and female reproductives, and the genetic population structure of Termitomyces fungus gardens across 74 colonies of Macrotermes bellicosus in four west and central African countries. We confirm earlier, more limited, studies showing that the Termitomyces symbionts of M. bellicosus are normally transmitted vertically and clonally by dispersing males. We also document that the symbionts associated with this termite species belong to three main lineages that do not constitute a monophyletic group. The most common lineage occurs over the entire geographical region that we studied, including west, central and southern Africa, where it is also associated with the alternative termite hosts Macrotermes subhyalinus and Macrotermes natalensis. While Termitomyces associated with these alternative hosts are horizontally transmitted and recombine freely, the genetic population structure of the same Termitomyces associated with M. bellicosus is consistent with predominantly clonal reproduction and only occasional recombination. This implies that the genetic population structure of Termitomyces is controlled by the termite host and not by the Termitomyces symbiont.
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the evolution of uniparental transmission of fungal symbionts in fungus growing termites macrotermitinae
Behavioral Ecology and Sociobiology, 2003Co-Authors: Judith Korb, Duur K. AanenAbstract:Mutualistic associations between different organisms are theoretically expected when the interests of independently reproducing units are aligned to form a single reproductive unit. This alignment does not come about easily, because models show that hosts and symbionts can be in conflict over the transmission of symbionts. Selection will favour hosts that are able to limit genetic variation of symbionts, for example by enforcing uniparental vertical transmission, while symbionts will be selected to disperse independently of the host. A crucial factor determining the evolution and elaboration of symbiotic relationships is therefore who controls the transmission of symbionts. In the fungus-growing termites (Macrotermintinae) horizontal transmission seems to be the rule as the termites normally acquire their cultivated fungus (Termitomyces) from the environment. In spite of this general pattern, uniparental, vertical transmission has evolved in two unrelated Macrotermitinae genera, where only one sex of the two primary reproductives carries asexual spores from the fungal comb of its parent colony to inoculate the new fungus comb. Remarkably, symbiont transmission is exclusively paternal in Macrotermes bellicosus, whereas symbionts are maternally inherited in all Microtermes species studied so far. Thus, in Macrotermitinae horizontal transmission is the ancestral state with two independent origins to uniparental, vertical transmission. This is in contrast to fungus-growing ants where uniparental, vertical transmission is the rule. Causes and consequences of this difference are further discussed. Despite this fundamental difference both groups evolved a similar symbiosis that is probably the key for their ecological success: the fungus-growing ants in the neotropics and the fungus-growing termites in the paleotropics.
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resource availability and distribution patterns indicators of competition between Macrotermes bellicosus and other macro detritivores in the comoe national park cote d ivoire
African Journal of Ecology, 2001Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:Interspecific competition has rarely been demonstrated in field studies. For it to occur a resource must be in limited supply and potential competitors must be concurrently active in time and space. We studied the availability of plant litter during the course of the year and the activity and distribution of macro-detritivores (termites, diplopods and earthworms) in two habitats in a Guinea savanna (Cote d'Ivoire), to test whether interspecific competition might be important. Plant litter was limited during the rainy season in the savanna, but was never limited in the gallery forest. The termite Macrotermes bellicosus, the dominant macro-detritivore in this area, and other detritivorous termites (e.g. Microtermes spp., Ancistrotermes spp., Odontotermes spp.) were active all year round with a peak during the rainy season, when diplopods and earthworms were also active. In the savanna at the beginning of the rainy season when food became limiting, other detritivorous termite species were more active in the absence of M. bellicosus than in its presence. This complementary activity pattern of M. bellicosus and other termites indicates that interspecific competition among detritivorous termites may be occurring. However, the spatio-temporal distribution of diplopods and earthworms suggests that interspecific competition with M. bellicosus is of minor importance. Resume On a rarement montre la competition interspecifique lors d'etudes de terrain. Pour qu'elle apparaisse, il faut qu'une ressource n'existe qu'en quantites limitees et que les competiteurs potentiels soient actifs en meme temps et au meme endroit. Nous avons etudie la disponibilite de la litiere vegetale tout au long de l'annee ainsi que l'activite et la distribution des macro-detritivores (termites, diplopodes et vers de terre) dans deux habitats de la savane guineenne (en Cote d'Ivoire), pour voir si la competition interspecifique pouvait etre importante. La litiere vegetale etait limitee pendant la saison des pluies dans la savane, mais ne l'etait jamais dans la galerie forestiere. Le termite Macrotermes bellicosus, le macro-detritivore dominant dans cette zone, et les autres termites detritivores (ex. Microtermes spp., Ancistrotermes spp. et Odontotermes spp.) etaient actifs toute l'annee, avec un pic pendant la saison des pluies, lorsque les diplopodes et les vers de terre sont aussi en activite. Dans la savane, au debut de la saison des pluies, lorsque la nourriture devient un facteur limitant, les autres especes de termites detritivores sont plus actives en l'absence de M. bellicosus qu'en sa presence. Ce schema d'activite complementaire de M. bellicosus et des autres termites indique qu'il peut y avoir une competition interspecifique entre termites detritivores. Cependant, la distribution spatio-temporelle des diplopodes et des vers de terre suggere que la competition interspecifique avec M. bellicosus est de peu d'importance.
Chow-yang Lee - One of the best experts on this subject based on the ideXlab platform.
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Does lack of intraspecific aggression or absence of nymphs determine acceptance of foreign reproductives in Macrotermes
Insectes Sociaux, 2011Co-Authors: Kokboon Neoh, Y. Indiran, Michael Lenz, Chow-yang LeeAbstract:The rejection or acceptance of a foreign reproductive by an alien colony may not always be as straightforward as cue recognition between worker termites. This paper aims to determine whether adoption of foreign reproductives is caused simply by lack of intraspecific aggression or is contingent on the reproductive status of the host colony. In the fungus-culturing termites, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), major workers showed low intraspecific aggression towards non-nestmates irrespective of geographic distance between source colonies. Our results indicated that workers were hardly aggressive towards non-nestmates. In royal cell-swapping experiments, both species responded in a similar way: (1) in host colonies with nymphs present, the foreign reproductives were rejected; while (2) in host colonies without nymphs the foreign reproductives were either accepted and breeding resumed or the host colonies died eventually. Workers from the host colonies preferentially maintained offspring nymphs from which adultoid replacement reproductives develop rather than accepting foreign reproductives. There is no fitness gain for the queenless workers in accepting foreign reproductives; however, there is overall benefit to the newly born population.
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flight activity of two sympatric termite species Macrotermes gilvus and Macrotermes carbonarius termitidae macrotermitinae
Environmental Entomology, 2009Co-Authors: Kokboon Neoh, Chow-yang LeeAbstract:Flight activities of two sympatric termite species, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), were studied in Penang Island, Malaysia. Herein, we present the first documentation of chronological reproductive isolation of M. gilvus and M. carbonarius. Flights of M. gilvus were recorded over a remarkably long 7-mo period from March to September, whereas swarming of M. carbonarius took place from November to January. Swarming events of M. gilvus and M. carbonarius occurred under atmospheric pressures of 1,005-1,011 and 1,006-1,010 hPa, respectively. Most flights of M. gilvus occurred on days with rain, whereas M. carbonarius avoided rain. Flight activity of M. gilvus was correlated significantly with atmospheric pressure and rainfall. The threshold temperature and relative humidity of M. gilvus flights were between 23 and 26 degrees C and 83 and 98% RH, respectively; M. carbonarius swarmed between 25 and 30 degrees C and 72 and 83% RH, respectively. The flight activity of M. gilvus concentrated in the warmer and humid months with a monthly total rainfall of 228 mm. Both species swarmed at distinct times of day during the limited field observations: Flights of M. gilvus began between 0300 and 0430 hours (light intensity <1 Lx), and flights of M. carbonarius lasted for only 4-10 min between 1900 and 1910 hours (at dusk; light intensity: 20-200 Lx). Windless conditions were preferred for the flights of both species.
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Flight Activity of Two Sympatric Termite Species, Macrotermes gilvus and Macrotermes carbonarius (Termitidae: Macrotermitinae)
Environmental Entomology, 2009Co-Authors: Kokboon Neoh, Chow-yang LeeAbstract:Flight activities of two sympatric termite species, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), were studied in Penang Island, Malaysia. Herein, we present the first documentation of chronological reproductive isolation of M. gilvus and M. carbonarius. Flights of M. gilvus were recorded over a remarkably long 7-mo period from March to September, whereas swarming of M. carbonarius took place from November to January. Swarming events of M. gilvus and M. carbonarius occurred under atmospheric pressures of 1,005-1,011 and 1,006-1,010 hPa, respectively. Most flights of M. gilvus occurred on days with rain, whereas M. carbonarius avoided rain. Flight activity of M. gilvus was correlated significantly with atmospheric pressure and rainfall. The threshold temperature and relative humidity of M. gilvus flights were between 23 and 26 degrees C and 83 and 98% RH, respectively; M. carbonarius swarmed between 25 and 30 degrees C and 72 and 83% RH, respectively. The flight activity of M. gilvus concentrated in the warmer and humid months with a monthly total rainfall of 228 mm. Both species swarmed at distinct times of day during the limited field observations: Flights of M. gilvus began between 0300 and 0430 hours (light intensity
Kokboon Neoh - One of the best experts on this subject based on the ideXlab platform.
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Does lack of intraspecific aggression or absence of nymphs determine acceptance of foreign reproductives in Macrotermes
Insectes Sociaux, 2011Co-Authors: Kokboon Neoh, Y. Indiran, Michael Lenz, Chow-yang LeeAbstract:The rejection or acceptance of a foreign reproductive by an alien colony may not always be as straightforward as cue recognition between worker termites. This paper aims to determine whether adoption of foreign reproductives is caused simply by lack of intraspecific aggression or is contingent on the reproductive status of the host colony. In the fungus-culturing termites, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), major workers showed low intraspecific aggression towards non-nestmates irrespective of geographic distance between source colonies. Our results indicated that workers were hardly aggressive towards non-nestmates. In royal cell-swapping experiments, both species responded in a similar way: (1) in host colonies with nymphs present, the foreign reproductives were rejected; while (2) in host colonies without nymphs the foreign reproductives were either accepted and breeding resumed or the host colonies died eventually. Workers from the host colonies preferentially maintained offspring nymphs from which adultoid replacement reproductives develop rather than accepting foreign reproductives. There is no fitness gain for the queenless workers in accepting foreign reproductives; however, there is overall benefit to the newly born population.
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flight activity of two sympatric termite species Macrotermes gilvus and Macrotermes carbonarius termitidae macrotermitinae
Environmental Entomology, 2009Co-Authors: Kokboon Neoh, Chow-yang LeeAbstract:Flight activities of two sympatric termite species, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), were studied in Penang Island, Malaysia. Herein, we present the first documentation of chronological reproductive isolation of M. gilvus and M. carbonarius. Flights of M. gilvus were recorded over a remarkably long 7-mo period from March to September, whereas swarming of M. carbonarius took place from November to January. Swarming events of M. gilvus and M. carbonarius occurred under atmospheric pressures of 1,005-1,011 and 1,006-1,010 hPa, respectively. Most flights of M. gilvus occurred on days with rain, whereas M. carbonarius avoided rain. Flight activity of M. gilvus was correlated significantly with atmospheric pressure and rainfall. The threshold temperature and relative humidity of M. gilvus flights were between 23 and 26 degrees C and 83 and 98% RH, respectively; M. carbonarius swarmed between 25 and 30 degrees C and 72 and 83% RH, respectively. The flight activity of M. gilvus concentrated in the warmer and humid months with a monthly total rainfall of 228 mm. Both species swarmed at distinct times of day during the limited field observations: Flights of M. gilvus began between 0300 and 0430 hours (light intensity <1 Lx), and flights of M. carbonarius lasted for only 4-10 min between 1900 and 1910 hours (at dusk; light intensity: 20-200 Lx). Windless conditions were preferred for the flights of both species.
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Flight Activity of Two Sympatric Termite Species, Macrotermes gilvus and Macrotermes carbonarius (Termitidae: Macrotermitinae)
Environmental Entomology, 2009Co-Authors: Kokboon Neoh, Chow-yang LeeAbstract:Flight activities of two sympatric termite species, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), were studied in Penang Island, Malaysia. Herein, we present the first documentation of chronological reproductive isolation of M. gilvus and M. carbonarius. Flights of M. gilvus were recorded over a remarkably long 7-mo period from March to September, whereas swarming of M. carbonarius took place from November to January. Swarming events of M. gilvus and M. carbonarius occurred under atmospheric pressures of 1,005-1,011 and 1,006-1,010 hPa, respectively. Most flights of M. gilvus occurred on days with rain, whereas M. carbonarius avoided rain. Flight activity of M. gilvus was correlated significantly with atmospheric pressure and rainfall. The threshold temperature and relative humidity of M. gilvus flights were between 23 and 26 degrees C and 83 and 98% RH, respectively; M. carbonarius swarmed between 25 and 30 degrees C and 72 and 83% RH, respectively. The flight activity of M. gilvus concentrated in the warmer and humid months with a monthly total rainfall of 228 mm. Both species swarmed at distinct times of day during the limited field observations: Flights of M. gilvus began between 0300 and 0430 hours (light intensity
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developmental stages and castes of two sympatric subterranean termites Macrotermes gilvus and Macrotermes carbonarius blattodea termitidae
Annals of The Entomological Society of America, 2009Co-Authors: Kokboon NeohAbstract:The developmental stages and castes of two sympatric subterranean termites, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen) (Blattodea: Termitidae) were studied and biometric descriptors of each caste were developed for the identification of both species. Biometric descriptors revealed five well-defined groups of larval castes. After sex determination, three larval instars were detected in the development of minor and major worker castes. The first larval instars consist of both males and females which are homogenous in size. Size sexual dimorphism, in which females are smaller than males, occurs in the second larval instars, third larval instars, and worker castes. Minor and major soldiers are female sterile castes. Pictorial evidence of the fourth larval instar of M. carbonarius is presented herein; the individuals closely resemble minor workers but are poorly pigmented and have a distended abdomen, future presoldier-like mandibles, and a meso- and metanotum. In reproductive caste development, nymphs (derived from the first larval instars) undergo five moults from first to fifth instars before becoming winged termites.
