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Karen Nieber - One of the best experts on this subject based on the ideXlab platform.
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Chemical Profile and Antimicrobial Activity of the Fungus-Growing Termite Strain Macrotermes Bellicosus Used in Traditional Medicine in the Republic of Benin
Molecules, 2020Co-Authors: Dima Hammoud Mahdi, Jane Hubert, Jean-hugues Renault, Agathe Martinez, Andreas Schubert, Kathrin Monika Engel, Blaise Koudogbo, Zacharie Vissiennon, Virgile Ahyi, Karen NieberAbstract:The fungus growing termite species Macrotermes Bellicosus (M. Bellicosus) is used in nutrition and traditional medicine in the Republic of Benin for the treatment of infectious and inflammatory diseases. Previous findings demonstrated evidence of anti-inflammatory and spasmolytic properties of M. Bellicosus. The aim of the present study was to evaluate the antimicrobial potential of different extracts of M. Bellicosus samples and determine the chemical profile of an ethanolic M. Bellicosus extract. Chemical profiling was conducted using centrifugal partition chromatography and 13C-NMR, followed by MALDI-TOF MS. Major identified compounds include hydroquinone (HQ), methylhydroquinone (MHQ), 3,4-dihydroxyphenethyl glycol (DHPG), N-acetyldopamine (NADA) and niacinamide. The fatty acid mixture of the extract was mainly composed of linoleic and oleic acid and highlights the nutritional purpose of M. Bellicosus. Using the Kirby–Bauer disc diffusion and broth microdilution assay, an antibacterial activity of M. Bellicosus samples was observed against various clinical strains with a highest growth inhibition of S. aureus. In addition, HQ and MHQ as well as fractions containing DHPG, niacinamide and NADA inhibited S. aureus growth. The reported antimicrobial activity of M. Bellicosus and identified active substances provide a rationale for the traditional medicinal use of M. Bellicosus.
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ethnomedicinal survey and in vitro confirmation of anti inflammatory and antispasmodic properties of the termite strain Macrotermes Bellicosus used in traditional medicine in the republic of benin
Journal of Ethnopharmacology, 2020Co-Authors: Zacharie Vissiennon, Virgile Ahyi, Karen Nieber, Dima Hammoud Mahdi, Dirk K Wissenbach, Martin Von Bergen, Daniel Chougourou, C VissiennonAbstract:Abstract Ethnopharmacological relevance Insects and insect-derived products play a vital role in traditional medicine in many parts of the world since ancient times. Among these insects, fungus-growing termites like Macrotermes Bellicosus (M. Bellicosus) are widely used in nutrition and traditional medicine in various societies of sub-Saharan Africa. Aim of the study Aim of the present study was to explore the traditional applications of M. Bellicosus and subsequently investigate the anti-inflammatory and spasmolytic activity of samples collected in Benin. Material and methods An ethnomedicinal survey with thirty active healers in Benin was conducted and the anti-inflammatory activity of an ethanolic extract of M. Bellicosus was investigated. Thus, LPS-induced TNFα release from differentiated human macrophages (THP-1) and IL-8 release from cytokine (IL-1β/TNFα/IFNγ)-challenged human intestinal epithelial cells (Caco-2) was measured by enzyme-linked immunosorbent assay. Furthermore, the influence of M. Bellicosus extract on basal tone and induced contractions in isolated rat small intestinal preparations was determined to examine the influence on intestinal motility. Results The survey of 30 active healers demonstrated that M. Bellicosus and its products (termites’ mound and fungus comb) are used in Benin for therapeutic purposes mainly to treat infectious and inflammatory diseases including digestive disorders, snake bites and diarrhea. It was found that M. Bellicosus extract inhibited both LPS-induced TNFα release from human macrophages and cytokine-induced IL-8 release from intestinal epithelial cells comparable to budesonide. In addition, isometric contraction measurement with isolated rat small intestinal preparations demonstrated a mild spasmolytic effect of the termite extract in higher concentrations with a suppression of induced contractions and relaxation of basal tone. Conclusion M. Bellicosus which is used in traditional medicine in Benin to treat infectious and inflammatory diseases showed anti-inflammatory activity by inhibiting pro-inflammatory cytokine release and a moderate influence on intestinal motility.
Karl Eduard Linsenmair - One of the best experts on this subject based on the ideXlab platform.
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evaluation of predation risk in the collectively foraging termite Macrotermes Bellicosus
Insectes Sociaux, 2002Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:Few studies have investigated foraging decisions in collectively foraging social insects with no studies in termites. In termites predation is assumed to be a key mortality factor. Therefore, we experimentally investigated the role of predation pressure in foraging decisions of the fungus cultivating, mound building termite Macrotermes Bellicosus in two habitats of the Comoe National Park (Ivory Coast). We used the indirect approach of measuring the Giving up Density (GUD), which is the amount of food left when individuals stop foraging in a food patch, whilst experimentally varying predation pressure. Three different conditions were examined: (a) natural predation, (b) no predation, and (c) experimental predation through artificial removal of termites. In the shrub savanna, foraging termites responded to increasing predation with increasing GUDs. By contrast, in the gallery forest, there was no gradual response. Instead termites abandoned a food patch immediately after an attack by predators. Without predation GUDs were lower in the savanna than in the gallery forest indicating that food had a higher value in the former habitat. This, together with the differential behavioral responses to predation, was in accordance with high availability of food in the gallery forest and a limited supply of food in the savanna. Thus, according to our results termites traded off predation pressure differently, according to the availability of food in both habitats.
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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.
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ventilation of termite mounds new results require a new model
Behavioral Ecology, 2000Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:In 1955, Luscher proposed a ventilation mechanism for cathedral-shaped termite mounds to exchange respiratory gases. This mechanism was generally accepted, although it had never been tested critically. We tested this mechanism by investigating temperatures, CO2 concentrations, and air currents in and around two types of Macrotermes Bellicosus mounds: cathedral-shaped mounds with many ridges and thin walls located in the savanna and dome-shaped mounds without ridges and with thick walls in the forest. These two mound shapes have two different mechanisms of ventilation, depending on the environmental tem- perature. In the savanna during the day, sun heats the air in the peripheral air channels inside the ridges of the mound above the central nest temperatures and produces a temperature gradient in the peripheral air channels with decreased temperatures at the top of the mound. This temperature gradient leads to convection currents with air rising inside the air channels of the ridges to the top of the mound, meanwhile exchanging CO2. In contrast, in the savanna during the night and generally in the forest, the temperatures inside the air channels are lower than those of the central nest, and no air currents rising upward inside the air channels were detected. The CO2 concentrations in the air channels of savanna mounds at night and forest mounds in general were higher than during the day in the savanna. Therefore, our data do not support Luscher's proposed mechanism. Key words: carbon dioxide, gas exchange, Ivory Coast, Macrotermes Bellicosus, metabolism, termite mounds, ther- moregulation. (Behav Ecol 11:486-494 (2000))
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reproductive success of Macrotermes Bellicosus isoptera macrotermitinae in two neighbouring habitats
Oecologia, 1999Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:The fungus-cultivating, mound-building termite Macrotermes Bellicosus can reach high densities in African savannah habitats, whereas in forests it is comparatively rare and is only found in relatively open areas. Earlier studies in the Comoe National Park (Cote d'Ivoire, West Africa) suggested that this might be because ambient temperatures are lower in the forest than the savannah. Therefore, forests seem to be suboptimal habitats. During 3 consecutive years we measured relevant fitness parameters in both habitats to test this hypothesis. Colonies in the savannah had higher reproductive outputs. They reproduced annually, producing high numbers of offspring (alates), whereas forest colonies reproduced on average only once every 3 years and even then only low numbers of alates were produced. Annual growth of mound height, which can be regarded as an indicator of colony growth, varied considerably between individual colonies and years. Nevertheless, in two years the growth rate of mounds in the shrub savannah was higher than that of mounds in the gallery forest. Unexpectedly, survival probability as calculated by Kaplan Meier analysis was much lower for colonies in the shrub savannah than for colonies in the gallery forest. Using these data in a computer simulation we calculated lifetime reproductive success (LRS) for an average colony in both habitats. As LRS was much higher for colonies in the shrub savannah than in the gallery forest, these results confirmed our suggestion that the forest is a suboptimal habitat for M. Bellicosus.
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experimental heating of Macrotermes Bellicosus isoptera macrotermitinae mounds what role does microclimate play in influencing mound architecture
Insectes Sociaux, 1998Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:Mounds of the fungus-cultivating termite Macrotermes Bellicosus (Smeathman) in the Comoe-National Park (Ivory Coast, West Africa) differ in architecture between habitats. Mounds in the cooler, but thermally more stable gallery forest have been shown to be dome-shaped with thick walls, whereas mounds in the shrub savanna are more complex with many ridges and thin walls. In this investigation, we performed heating experiments to determine the thermal properties of the mounds in both habitats in order to test the hypothesis of a thermoregulatory significance of mound architecture. These experiments revealed that each mound had its characteristic individual heating up behavior that depends on its dimensions (height, surface, volume). In addition, habitat-specific traits were demonstrated: mounds of the gallery forest had higher thermal inertia, measured by the thermal capacity, than mounds of the shrub savanna. Thus, the dome-shaped mounds with thick walls in the gallery forest, with its suboptimal low temperatures, reduce loss of heat to the environment.
Dima Hammoud Mahdi - One of the best experts on this subject based on the ideXlab platform.
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ethnomedicinal survey and in vitro confirmation of anti inflammatory and antispasmodic properties of the termite strain Macrotermes Bellicosus used in traditional medicine in the republic of benin
Journal of Ethnopharmacology, 2020Co-Authors: Zacharie Vissiennon, Virgile Ahyi, Karen Nieber, Dima Hammoud Mahdi, Dirk K Wissenbach, Martin Von Bergen, Daniel Chougourou, C VissiennonAbstract:Abstract Ethnopharmacological relevance Insects and insect-derived products play a vital role in traditional medicine in many parts of the world since ancient times. Among these insects, fungus-growing termites like Macrotermes Bellicosus (M. Bellicosus) are widely used in nutrition and traditional medicine in various societies of sub-Saharan Africa. Aim of the study Aim of the present study was to explore the traditional applications of M. Bellicosus and subsequently investigate the anti-inflammatory and spasmolytic activity of samples collected in Benin. Material and methods An ethnomedicinal survey with thirty active healers in Benin was conducted and the anti-inflammatory activity of an ethanolic extract of M. Bellicosus was investigated. Thus, LPS-induced TNFα release from differentiated human macrophages (THP-1) and IL-8 release from cytokine (IL-1β/TNFα/IFNγ)-challenged human intestinal epithelial cells (Caco-2) was measured by enzyme-linked immunosorbent assay. Furthermore, the influence of M. Bellicosus extract on basal tone and induced contractions in isolated rat small intestinal preparations was determined to examine the influence on intestinal motility. Results The survey of 30 active healers demonstrated that M. Bellicosus and its products (termites’ mound and fungus comb) are used in Benin for therapeutic purposes mainly to treat infectious and inflammatory diseases including digestive disorders, snake bites and diarrhea. It was found that M. Bellicosus extract inhibited both LPS-induced TNFα release from human macrophages and cytokine-induced IL-8 release from intestinal epithelial cells comparable to budesonide. In addition, isometric contraction measurement with isolated rat small intestinal preparations demonstrated a mild spasmolytic effect of the termite extract in higher concentrations with a suppression of induced contractions and relaxation of basal tone. Conclusion M. Bellicosus which is used in traditional medicine in Benin to treat infectious and inflammatory diseases showed anti-inflammatory activity by inhibiting pro-inflammatory cytokine release and a moderate influence on intestinal motility.
Judith Korb - One of the best experts on this subject based on the ideXlab platform.
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Developmental pathways in termites.
2019Co-Authors: José Manuel Monroy Kuhn, Karen Meusemann, Judith KorbAbstract:Developmental pathways in termites with different degrees of sociality. (A) Typical developmental pathway for a termite with high degree of sociality, e.g. Macrotermes Bellicosus (foraging termites). The development is less flexible and the immature workers are not totipotent. Early on during development (here in the egg stage) caste fate is determined. Individuals can either develop along the apterous line into workers and soldiers or along the nymphal line into primary reproductives. Arrows indicate the transition of one stage to another; in white: the default nymphal line which occurs in all insects, in black: deviations from these trajectories, specific to termites. (B) Typical developmental pathway for a termite with low degree of sociality, e.g. Cryptotermes secundus (wood-dwelling termites). Termite workers are totipotent immatures that can develop into soldiers or two kinds of reproductives, primary or neotenic reproductives. They also can molt regressively (arrow pointing backwards).
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evaluation of predation risk in the collectively foraging termite Macrotermes Bellicosus
Insectes Sociaux, 2002Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:Few studies have investigated foraging decisions in collectively foraging social insects with no studies in termites. In termites predation is assumed to be a key mortality factor. Therefore, we experimentally investigated the role of predation pressure in foraging decisions of the fungus cultivating, mound building termite Macrotermes Bellicosus in two habitats of the Comoe National Park (Ivory Coast). We used the indirect approach of measuring the Giving up Density (GUD), which is the amount of food left when individuals stop foraging in a food patch, whilst experimentally varying predation pressure. Three different conditions were examined: (a) natural predation, (b) no predation, and (c) experimental predation through artificial removal of termites. In the shrub savanna, foraging termites responded to increasing predation with increasing GUDs. By contrast, in the gallery forest, there was no gradual response. Instead termites abandoned a food patch immediately after an attack by predators. Without predation GUDs were lower in the savanna than in the gallery forest indicating that food had a higher value in the former habitat. This, together with the differential behavioral responses to predation, was in accordance with high availability of food in the gallery forest and a limited supply of food in the savanna. Thus, according to our results termites traded off predation pressure differently, according to the availability of food in both habitats.
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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.
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ventilation of termite mounds new results require a new model
Behavioral Ecology, 2000Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:In 1955, Luscher proposed a ventilation mechanism for cathedral-shaped termite mounds to exchange respiratory gases. This mechanism was generally accepted, although it had never been tested critically. We tested this mechanism by investigating temperatures, CO2 concentrations, and air currents in and around two types of Macrotermes Bellicosus mounds: cathedral-shaped mounds with many ridges and thin walls located in the savanna and dome-shaped mounds without ridges and with thick walls in the forest. These two mound shapes have two different mechanisms of ventilation, depending on the environmental tem- perature. In the savanna during the day, sun heats the air in the peripheral air channels inside the ridges of the mound above the central nest temperatures and produces a temperature gradient in the peripheral air channels with decreased temperatures at the top of the mound. This temperature gradient leads to convection currents with air rising inside the air channels of the ridges to the top of the mound, meanwhile exchanging CO2. In contrast, in the savanna during the night and generally in the forest, the temperatures inside the air channels are lower than those of the central nest, and no air currents rising upward inside the air channels were detected. The CO2 concentrations in the air channels of savanna mounds at night and forest mounds in general were higher than during the day in the savanna. Therefore, our data do not support Luscher's proposed mechanism. Key words: carbon dioxide, gas exchange, Ivory Coast, Macrotermes Bellicosus, metabolism, termite mounds, ther- moregulation. (Behav Ecol 11:486-494 (2000))
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reproductive success of Macrotermes Bellicosus isoptera macrotermitinae in two neighbouring habitats
Oecologia, 1999Co-Authors: Judith Korb, Karl Eduard LinsenmairAbstract:The fungus-cultivating, mound-building termite Macrotermes Bellicosus can reach high densities in African savannah habitats, whereas in forests it is comparatively rare and is only found in relatively open areas. Earlier studies in the Comoe National Park (Cote d'Ivoire, West Africa) suggested that this might be because ambient temperatures are lower in the forest than the savannah. Therefore, forests seem to be suboptimal habitats. During 3 consecutive years we measured relevant fitness parameters in both habitats to test this hypothesis. Colonies in the savannah had higher reproductive outputs. They reproduced annually, producing high numbers of offspring (alates), whereas forest colonies reproduced on average only once every 3 years and even then only low numbers of alates were produced. Annual growth of mound height, which can be regarded as an indicator of colony growth, varied considerably between individual colonies and years. Nevertheless, in two years the growth rate of mounds in the shrub savannah was higher than that of mounds in the gallery forest. Unexpectedly, survival probability as calculated by Kaplan Meier analysis was much lower for colonies in the shrub savannah than for colonies in the gallery forest. Using these data in a computer simulation we calculated lifetime reproductive success (LRS) for an average colony in both habitats. As LRS was much higher for colonies in the shrub savannah than in the gallery forest, these results confirmed our suggestion that the forest is a suboptimal habitat for M. Bellicosus.
Susumu S Abe - One of the best experts on this subject based on the ideXlab platform.
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Accumulation of free oxyhydroxides in termite (Macrotermes Bellicosus (Smeathman)) mounds and the implications for their dynamics in an African savannah Ultisol
Soil Science and Plant Nutrition, 2016Co-Authors: Susumu S AbeAbstract:ABSTRACTThe present study aimed to assess the dynamics of oxyhydroxides via termite mounds in a tropical savannah of Central Nigeria, where the soils often contain oxyhydroxides as a major component of soil minerals. To this end, the quantities of oxyhydroxides stored in mounds built by Macrotermes Bellicosus (Smeathman) were compared to those stored in surface (Ap1) soils, and their turnover rates were estimated. Both the mound wall and nest of M. Bellicosus were enriched two- to 10-fold with acidified ammonium oxalate soluble iron (Feo) and aluminum (Alo) and dithionite-citrate-bicarbonate (DCB) soluble iron (Fed) and aluminum (Ald) relative to the adjacent surface soil horizon. These oxyhydroxide contents were positively correlated with the clay content (P
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accumulation of free oxyhydroxides in termite Macrotermes Bellicosus smeathman mounds and the implications for their dynamics in an african savannah ultisol
Soil Science and Plant Nutrition, 2016Co-Authors: Susumu S AbeAbstract:ABSTRACTThe present study aimed to assess the dynamics of oxyhydroxides via termite mounds in a tropical savannah of Central Nigeria, where the soils often contain oxyhydroxides as a major component of soil minerals. To this end, the quantities of oxyhydroxides stored in mounds built by Macrotermes Bellicosus (Smeathman) were compared to those stored in surface (Ap1) soils, and their turnover rates were estimated. Both the mound wall and nest of M. Bellicosus were enriched two- to 10-fold with acidified ammonium oxalate soluble iron (Feo) and aluminum (Alo) and dithionite-citrate-bicarbonate (DCB) soluble iron (Fed) and aluminum (Ald) relative to the adjacent surface soil horizon. These oxyhydroxide contents were positively correlated with the clay content (P < 0.05), suggesting that M. Bellicosus preferentially used silicate clay-associated oxyhydroxides for mound construction. The Fed, Ald and DCB-soluble manganese (Mnd) preserved in the M. Bellicosus mounds ran up to 112 ± 25.6, 5.72 ± 1.41 and 2.17 ± ...
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soil particle accumulation in termite Macrotermes Bellicosus mounds and the implications for soil particle dynamics in a tropical savanna ultisol
Ecological Research, 2012Co-Authors: Susumu S Abe, Yoshinori Watanabe, Taisuke Onishi, Takashi Kotegawa, Toshiyuki WakatsukiAbstract:This study investigated the influence of mound-building termites on soil particle dynamics on the land surface and in soil-forming processes by examining the amount of soil particles in mound structures of Macrotermes Bellicosus in a highly weathered Ultisol of tropical savanna. Soil particle turnover via the mounds was estimated using particle stock data and soil turnover data from previous studies. A 4-ha study plot with six mounds of relatively uniform shape and size was investigated. Soil mass constituting the mounds was 6,166 ± 1,581 kg mound−1 within which the mound wall and nest body accounted for 5,002 ± 1,289 and 1,164 ± 293 kg, respectively. The mound wall contained a significantly larger amount of clay (252 ± 9.97 g kg−1) balanced with a lower sand content (676 ± 26.5 g kg−1) than in the adjacent surface (Ap1) horizon, (46.4 ± 12.8 g clay kg−1; 866 ± 83.2 g sand kg−1); the nest body had much higher clay content (559 ± 51.0 g kg−1) but less sand (285 ± 79.2 g kg−1) than the mound wall. As a result, the mounds of M. Bellicosus accumulated clay of 2,874 ± 781 kg ha−1 (corresponding to 2.52% of clay stock in the Ap1 horizon) along with an estimated clay turnover rate of 169 kg ha−1 year−1. These findings suggest a positive feedback effect from termite mound-building activity on soil particle dynamics in tropical savanna ecosystems: M. Bellicosus preferentially use subsoil material for mound construction, resulting in relocation of illuvial clay in the subsoil to the land surface where clay eluviation from the surface soil and its illuviation in the subsoil are major soil-forming processes.
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nutrient storage in termite Macrotermes Bellicosus mounds and the implications for nutrient dynamics in a tropical savanna ultisol
Soil Science and Plant Nutrition, 2011Co-Authors: Susumu S Abe, Yoshinori Watanabe, Taisuke Onishi, Takashi Kotegawa, Toshiyuki WakatsukiAbstract:The role of mounds of the fungus-growing termite Macrotermes Bellicosus (Smeathman) in nutrient recycling in a highly weathered and nutrient-depleted tropical red earth (Ultisol) of the Nigerian savanna was examined by measuring stored amounts of selected nutrients and estimating their rates of turnover via the mounds. A study plot (4 ha) with a representative termite population density (1.5 mounds ha−1) and size (3.7 ± 0.4 m in height, 2.4 ± 0.2 m in basal diameter) of M. Bellicosus mounds was selected. The mounds were found to contain soil mass of 9249 ± 2371 kg ha−1, composed of 7502 ± 1934 kg ha−1 of mound wall and 1747 ± 440 kg ha−1 of nest body. Significant nutrient enrichment, compared to the neighboring topmost soil (Ap1 horizon: 0–16 cm), was observed in the nest body for total nitrogen (N) and exchangeable calcium (Ca), magnesium (Mg) and potassium (K), and in the mound wall for exchangeable K only. In contrast, available (Bray-1) phosphorus (P) content was found to be lower in both the mound wa...
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possible influence of termites Macrotermes Bellicosus on forms and composition of free sesquioxides in tropical soils
Pedobiologia, 2010Co-Authors: Susumu S Abe, Toshiyuki WakatsukiAbstract:Abstract There has been less concern about soil mineralogical alteration than about soil physical, chemical and biological changes induced by termite nest-building activity. Furthermore, much less attention has been paid to free sesquioxides than to phyllosilicate minerals. In the present study, we conducted field morphological observations and selective dissolution analysis to characterize free sesquioxides in termite ( Macrotermes Bellicosus ) mounds as compared with surrounding pedons in different toposequence positions, i.e., seasonally flooded valley bottom, hydromorphic fringe and well-drained upland sites. Distinctive redoximorphic features, such as surface yellowish layers on mound structures from the fringe site, indicate possible alteration of iron sesquioxide forms in the mounds due to the transportation of soil from reductive (aquic subsoil) to oxidative (epigeal mound) environments by the nest-building activity of M. Bellicosus . On the other hand, the iron-soluble content in the dithionite–citrate–bicarbonate (DCB) system (Fe d ) was generally higher in the mound structures than at the adjacent sub-surface (Ap2) horizon at each toposequence position, while there was less difference in the content of acid ammonium oxalate (AAO) extractable iron (Fe o ) as compared to Fe d . As a consequence, the iron activity index (Fe d /Fe o ratio) was found for the most part to be lower in the mound structures than in the neighboring Ap2 horizon. In addition, the content of Fe d , AAO-soluble Al (Al o ) and DCB-extractable Al (Al d ) was significantly correlated with clay content in these soils. These findings suggest that M. Bellicosus preferentially collects clay particles, probably from the clay-rich subsoils, such as the argillic horizon, which has been formed by the co-migration of phyllosilicate minerals and relatively crystalline sesquioxides. The species then likely incorporates them into the mounds, which induces an increase in the Fe d content relative to that of Fe o , resulting in a decreased iron activity index in the mound structures.
