Papers by Maria Bezerra Gusmao
Termite nests are microenvironments rich in organic matter and fauna, and are home to several gro... more Termite nests are microenvironments rich in organic matter and fauna, and are home to several groups of organisms such as lichens and fungi. Termite species from the genus Inquilinitermes live in the nests of Constrictotermes cyphergaster and feed on the feces of their host, which is a dark material (black mass) rich in lignin and cellulose. This study assessed the richness of lignocellulosic fungi associated with the black mass from the nests and the food content of C. cyphergaster and the inquilinous Inquilinitermes fur. The black mass of the nests and their adjacent soils, in addition to the food content from 100 workers of each termite species, were submitted to serial dilutions of up to 10 À4 g ml À1. Ten species of fungi were recorded. The analysis of similarity revealed two groups (soil and black mass versus food content of termites) that were 84% dissimilar. For I. fur, fungal richness was higher in the paunch, while for C. cyphergaster, the richness was higher in the crop. The mycobiota consisted of ascomycetes known for their potential to decompose cellulose and lignin.
Termites play an important role in the carbon cycling of several ecosystems. Part of this C is di... more Termites play an important role in the carbon cycling of several ecosystems. Part of this C is directed to the formation of nests or mounds, but few published estimations have been made of the proportions of this C in relation to those in the vegetation and/or in the litter. The dynamics of C of Constrictotermes cyphergaster nests, in the driest part of caatinga, in semiarid northeast Brazil, was calculated considering all present, formed and abandoned nests in 1 ha, for two years. Carbon concentrations were determined from samples taken from the core and the external layer of nests. Total aboveground biomasses of trees and shrubs in the 1 ha were estimated by allometric equations. C concentrations were lower in the external layer (24–33 g kg−1) than in the nest cores (38–76 g kg−1). The stock of C in the nests of the sampled ha was 61.5 kg, which represents about 0.6% of that in the plant aboveground biomass (10.25 Mg C ha−1). The C in the annual formation and abandonment of nests (10.2 kg ha−1 year−1) corresponded to 16% of the stock of C in the nests, 1.1% of the carbon in the annual litter production (925 kg C ha−1 year−1) and 3.1% of the non-leaf litter. Although lower than the few values reported for more humid areas, these proportions indicate that C. cyphergaster nest formation contributes to C cycling in this very dry semiarid caatinga site.
The termite assemblages of three sites of Caatinga under different levels of anthropogenic distur... more The termite assemblages of three sites of Caatinga under different levels of anthropogenic disturbance in the semi-arid region of northeastern Brazil were sampled using 65 Â 2 m transects. A total of 26 species of termites were present in the three sites, and 196 encounters were recorded in the transects. The termite assemblages were considerably different among sites, with a conspicuous reduction in both diversity and abundance with increased disturbance, related to the reduction of tree density and soil cover, and with the intensity of trampling by cattle and goats. The wood-feeders were the most severely affected feeding group.
The fauna of termites was investigated in a fragment of cerrado (an open tree-dominated savannah-... more The fauna of termites was investigated in a fragment of cerrado (an open tree-dominated savannah-like vegetation) in a preservation area of the Reserva Biológica Guaribas (RBG), in the municipality of Mamanguape, State of Paraíba. A standardized sampling protocol was applied, made up of six transects of 65 m x 2 m, each one with five plots of 5 m x 2 m, with a distance of 10 m between each other, totalling 30 plots in an overall study area of 300 m 2 . Fourteen species of termites were found in the transects and six additional species were collected by chance, all of them belonging to the family Termitidae. The conspicuous nest builders species found were Constrictotermes cyphergaster and Nasutitermes coxipoensis. The majority of the species were wood feeders, but humus feeders were the most frequent in the transects. The species richness here determined was the lowest ever reported in a Brazilian cerrado vegetation and one of the lowest reported in a Neotropical region. The size and the isolation time of the fragment and its distance from larger cerrado areas in the central region of Brazil may explain the low species richness. The taxonomic structure of the termite fauna was made up of species often found in other Brazilian biomes, like in the caatinga and in the Amazonian and Atlantic forests; however, five species seem to be endemic to areas of cerrado.
Termites play an important role in the carbon cycling of several ecosystems. Part of this C is di... more Termites play an important role in the carbon cycling of several ecosystems. Part of this C is directed to the
formation of nests or mounds, but few published estimations have been made of the proportions of this C
in relation to those in the vegetation and/or in the litter. The dynamics of C of Constrictotermes cyphergaster
nests, in the driest part of caatinga, in semiarid northeast Brazil, was calculated considering all present,
formed and abandoned nests in 1 ha, for two years. Carbon concentrations were determined from samples
taken from the core and the external layer of nests. Total aboveground biomasses of trees and shrubs
in the 1 ha were estimated by allometric equations. C concentrations were lower in the external layer
(24–33 g kg−1) than in the nest cores (38–76 g kg−1). The stock of C in the nests of the sampled ha was
61.5 kg, which represents about 0.6% of that in the plant aboveground biomass (10.25MgC ha−1). The C in
the annual formation and abandonment of nests (10.2 kg ha−1 year−1) corresponded to 16% of the stock
of C in the nests, 1.1% of the carbon in the annual litter production (925 kg C ha−1 year−1) and 3.1% of the
non-leaf litter. Although lower than the few values reported for more humid areas, these proportions
indicate that C. cyphergaster nest formation contributes to C cycling in this very dry semiarid caatinga
site.
We evaluated growth, abandonment, decay and emergence of new nests of the Neotropical termite
Co... more We evaluated growth, abandonment, decay and emergence of new nests of the Neotropical termite
Constrictotermes cyphergaster (Termitidae) and its association with the supporting vegetation in an area
of caatinga (arid thorn scrub in the state of Paraíba, northeastern Brazil). In an area of 1 ha, a total of 272
nests were observed monthly, from March 2005 to March 2007. Of these, 245 nests were small, 9 were of
medium size, and 18 were large nests. During the rainy season (from June to February), nests grew 94.2 L,
whereas during the dry season (MarcheMay), their total growth was 23 L. The number of abandoned
nests was positively correlated with rainfall. Decomposition of nests was greater during the rainy
season. The pattern of nest distribution was associated with the distribution of the primary
supporting plants. Rainfall appears to be one of the most important factors in the dynamics of growth
of nests of C. cyphergaster in the caatinga.
Insectes sociaux, Jan 1, 2006
While recent results have provided strong evidence for the presence of a stable gut microbiota am... more While recent results have provided strong evidence for the presence of a stable gut microbiota among several termite species, little is known about variations at the colony or individual level. Using a cultivation-independent approach, we investigated the structure of the bacterial community in the gut of termites from four different colonies of Hodotermes mossambicus. 16S rRNA-based terminal restriction fragment length polymorphism (T-RFLP) analysis of the bacterial gut microbiota revealed (1) a high consistency of the gut microbiota among nestmates and (2) subtle but distinct differences in community structure between individuals from different colonies. Since products of bacterial metabolism may contribute to a colony odor that can be used as discriminatory signal, the presence of a colony-specific bacterial community adds support to the hypothesis that the gut microbiota of termites is involved in nestmate recognition.
Biology and Fertility of …, Jan 1, 2007
Nest structures of two termite species (Trinervitermes spp.) with epigeal (above-ground) mounds w... more Nest structures of two termite species (Trinervitermes spp.) with epigeal (above-ground) mounds were analyzed to compare their nutrient status with that of adjacent soils. To take into account soil variability, the observations and samplings were made in three toposequences of different and representative West African savanna soils. The data showed the high degree of adaptation of these termite species to a large range of soil types and environments. Mounds of Trinervitermes geminatus and Trinervitermes trinervius, both grass-feeders, contained more clay, organic matter (OM), and exchangeable cations than the surrounding surface layer soil. The storage of OM and exchangeable cations was determined for T. geminatus nests and compared to the surrounding soil. Despite substantial nutrient storage in mounds, its total weight appeared low when compared to the nutrient storage in the surrounding 0-15 cm of soil surface layer. This illustrates how contradictory points of view on the use of termite mounds in agriculture need to be clarified using a classical approach that takes into account data by species; and this also evaluates the contribution of different termite mounds to nutrient fluxes and storage and the exact stocking rate of living mounds.
Insectes Sociaux, Jan 1, 1975
... Both nest building and foraging by termites use energy, with additional losses from predation... more ... Both nest building and foraging by termites use energy, with additional losses from predation whilst so exposed. ... Ser. Tocklai Expt. Stn., 182, 1-3. -- 1971. Dynamics of termite populations - some theoretical considerations. Ins. Soe., 18, 21-28. ...
Journal of theoretical biology, Jan 1, 2004
The role of disease in the organization of insect colonies has become an important focus of resea... more The role of disease in the organization of insect colonies has become an important focus of research in evolutionary pathobiology, in which the relationship of sociality and disease transmission can be comparatively and experimentally analysed. In this paper we use an individual-based model of disease transmission to assess how an epidemic is influenced by worker density and activity level, the probability of disease transmission, and the structural organization of the nest. First, we observed in our model a nonlinear interaction between worker density and the probability of disease transmission: high levels of both factors interact to enhance the likelihood of an epidemic. Additionally, when we incorporated in our model the empirical observation that only a fraction of the worker population in social insect colonies is active at any given point in time, results suggested that relatively low levels of worker movement can have a significant impact on the spread of disease, slowing its transmission through the colony. Finally, we found that nests having even a simple spatial separation of chambers could delay the spread of infection and diminish the severity of an outbreak. The effect of nest structure in delaying infection spread became more pronounced as nest architecture became increasingly unidimensional, as in the case of simple gallery nests. Therefore, nest architecture and worker activity patterns might indeed exert considerable influence on the dynamics of epidemics in social insects and should be incorporated into models of disease transmission. r
Termites evolution sociality symbioses …, Jan 1, 2000
... colonies are one of the major factors regulating nest density. Functional group assemblages a... more ... colonies are one of the major factors regulating nest density. Functional group assemblages and the territoriality of termite nests could explain their spatial pattems. Intraspecific competition, together with predation are major constraints in the population dynamics of termites. ...
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Papers by Maria Bezerra Gusmao
formation of nests or mounds, but few published estimations have been made of the proportions of this C
in relation to those in the vegetation and/or in the litter. The dynamics of C of Constrictotermes cyphergaster
nests, in the driest part of caatinga, in semiarid northeast Brazil, was calculated considering all present,
formed and abandoned nests in 1 ha, for two years. Carbon concentrations were determined from samples
taken from the core and the external layer of nests. Total aboveground biomasses of trees and shrubs
in the 1 ha were estimated by allometric equations. C concentrations were lower in the external layer
(24–33 g kg−1) than in the nest cores (38–76 g kg−1). The stock of C in the nests of the sampled ha was
61.5 kg, which represents about 0.6% of that in the plant aboveground biomass (10.25MgC ha−1). The C in
the annual formation and abandonment of nests (10.2 kg ha−1 year−1) corresponded to 16% of the stock
of C in the nests, 1.1% of the carbon in the annual litter production (925 kg C ha−1 year−1) and 3.1% of the
non-leaf litter. Although lower than the few values reported for more humid areas, these proportions
indicate that C. cyphergaster nest formation contributes to C cycling in this very dry semiarid caatinga
site.
Constrictotermes cyphergaster (Termitidae) and its association with the supporting vegetation in an area
of caatinga (arid thorn scrub in the state of Paraíba, northeastern Brazil). In an area of 1 ha, a total of 272
nests were observed monthly, from March 2005 to March 2007. Of these, 245 nests were small, 9 were of
medium size, and 18 were large nests. During the rainy season (from June to February), nests grew 94.2 L,
whereas during the dry season (MarcheMay), their total growth was 23 L. The number of abandoned
nests was positively correlated with rainfall. Decomposition of nests was greater during the rainy
season. The pattern of nest distribution was associated with the distribution of the primary
supporting plants. Rainfall appears to be one of the most important factors in the dynamics of growth
of nests of C. cyphergaster in the caatinga.
formation of nests or mounds, but few published estimations have been made of the proportions of this C
in relation to those in the vegetation and/or in the litter. The dynamics of C of Constrictotermes cyphergaster
nests, in the driest part of caatinga, in semiarid northeast Brazil, was calculated considering all present,
formed and abandoned nests in 1 ha, for two years. Carbon concentrations were determined from samples
taken from the core and the external layer of nests. Total aboveground biomasses of trees and shrubs
in the 1 ha were estimated by allometric equations. C concentrations were lower in the external layer
(24–33 g kg−1) than in the nest cores (38–76 g kg−1). The stock of C in the nests of the sampled ha was
61.5 kg, which represents about 0.6% of that in the plant aboveground biomass (10.25MgC ha−1). The C in
the annual formation and abandonment of nests (10.2 kg ha−1 year−1) corresponded to 16% of the stock
of C in the nests, 1.1% of the carbon in the annual litter production (925 kg C ha−1 year−1) and 3.1% of the
non-leaf litter. Although lower than the few values reported for more humid areas, these proportions
indicate that C. cyphergaster nest formation contributes to C cycling in this very dry semiarid caatinga
site.
Constrictotermes cyphergaster (Termitidae) and its association with the supporting vegetation in an area
of caatinga (arid thorn scrub in the state of Paraíba, northeastern Brazil). In an area of 1 ha, a total of 272
nests were observed monthly, from March 2005 to March 2007. Of these, 245 nests were small, 9 were of
medium size, and 18 were large nests. During the rainy season (from June to February), nests grew 94.2 L,
whereas during the dry season (MarcheMay), their total growth was 23 L. The number of abandoned
nests was positively correlated with rainfall. Decomposition of nests was greater during the rainy
season. The pattern of nest distribution was associated with the distribution of the primary
supporting plants. Rainfall appears to be one of the most important factors in the dynamics of growth
of nests of C. cyphergaster in the caatinga.