Absence Of Termites Research Articles

The Influence of Slope Gradient on Termite Assemblages and Soil Physico-Chemical Properties in Koudi Secondary Forest Patches of the Central Region of Cameroon

Soil is the Cameroon’s primary economic driver and an indispensable natural resource for agriculture. Various factors including physical, chemical and biological directly affect agricultural production by enhancing soil fertility. The influence of relief on termites’ diversity was extensively studied. However, the effect of the slope gradient on termite diversity and functional groups remains less studied. This study evaluated termite assemblages in relation to some edaphic parameters, with emphasis on gradual changes in soil slope. The study was conducted in Koudi, in the semi-deciduous forest zone of Southern Cameroon. The study aimed to evaluate the effect of slope gradient on termite diversity and some soil physico-chemical factors; the influence of some physico-chemical soil properties on termites. To achieve these, three slope gradients: gentle slope: A [0 - 15°]; moderate slope: B [15.1°- 31°]; and steeper slope: C [x > 31°[were chosen. The experimental design was composed of 66 rectangular quadrants of 5m x 2m in order to determine the presence or absence of termites. Two soil samples were taken per slope gradient for the determination of physico-chemical parameters. Termite community was characterized using species richness, Shannon diversity, Pielou Evenness and Simpson dominance indexes. Data obtained were subjected to Spearman correlation test and ANOVA followed by the Tukey HSD test at a threshold p = 0.05. Our findings suggested thirty-five(35) termite species belonging to eighteen (18) genders, six (6)subfamilies that were sampled and identified. Termites’ diversity and species richness decreased as slope gradient increased; slope gradient displayed a significant detrimental correlation with sand (%) and total organic (g/kg) content, with a positive significant correlation with clay (%) content, according to Spearman's test. It appeared that variations of slope at soil surface have been identified as one of the factors controlling nutrients and termite diversity.

Quantifying the factors affecting wood decomposition across a tropical forest disturbance gradient

Woody debris represents a substantial reservoir of carbon in forests. Disentangling the effects of factors affecting wood decomposition rates is therefore important. We examined the abiotic and biotic factors affecting wood decomposition across a disturbance gradient from mature forest to open land in a tropical montane site in Xishuangbanna, SW China. Wood logs (n = 280) of two native species with contrasting wood specific gravity (WSG), Castanopsis mekongensis (0.75) and Litsea cubeba (0.42), were exposed on the ground for three years. For each log, WSG was monitored at intervals by taking cores from top-half (up) and bottom-half (down) of the log. Mass loss was measured at the end of the experiment.WSG loss rates were similar across the disturbance gradient and the species effect varied with core position. For Castanopsis, which had higher initial WSG and wood N concentration and much thicker bark, up-cores had consistently higher WSG loss over the study period. This species also had substantially higher WSG loss for up-cores, but interspecific difference among down-cores was small.For mass loss, there was a complex interaction between species, habitat and the presence of termites. Litsea with low initial WSG experienced approximately two-fold higher mass loss in the absence of termites, but the difference between species was smaller in the presence of termites. Both species experienced higher mass loss in open habitats than in forests, but the termite effect was smaller in open habitats especially for Litsea. There was no interspecific difference in susceptibility to termite infestation, but infestation rates were higher in regenerating forests and open land than in mature forest. WSG loss explained 0% and 19% of mass loss variation in Listea and Castanopsis, respectively, in absence of termites and 0% for both in the presence of termites.Afterlife effects of wood functional traits interact with abiotic conditions and decomposition processes (microbial decomposition, macro-organisms (termites), photo-degradation) in a complex manner to determine wood decomposition rates. WSG loss is not a reliable predictor of mass loss. These results have important implications for understanding the carbon cycle in tropical landscapes that are undergoing anthropogenic disturbance.

CO2Emissions from Soil on Oklahoma's Tallgrass Prairie Preserve in the Presence or Absence of Termites (Isoptera: Rhinotermitidae)

Abstract CO2 flux from soil is a significant component of total atmospheric carbon, as well as an indicator of soil biological health, a useful tool for evaluating the impact of agricultural practices, and a key variable relevant to global climate change. A year-long study was conducted to evaluate subterranean termite contribution to soil CO2 flux on Oklahoma's Joseph H. Williams Tallgrass Prairie Preserve. Gas samples were extracted from metal flux chambers located within soil plots containing naturally occurring populations of foraging subterranean termites and from two different types of control plots without termites. Results indicate that CO2 flux during January, March, April, June, July, and December was similar among all three treatments. However, CO2 flux in control plots during May was significantly greater compared with termite-active plots. Overall CO2 flux from both termite-infested and termite-free plots was great enough to obscure CO2 contributions from subterranean termites alone. Therefor...

Relationship between wood-inhabiting fungi and Reticulitermes spp. in four forest habitats of northeastern Mississippi

Fungi from coarse woody debris samples containing or lacking termites were isolated, and identified from upland and bottomland hardwoods and pines in northeast Mississippi. Samples yielded 860 unique fungal isolates, with 59% identified to genus level. Four phyla, six classes, 10 orders, 14 families, and 50 genera were recovered. The fungal groups encountered by decreasing taxonomic diversity were Imperfect Fungi, Ascomycota, Zygomycota, Basidiomycota, and unknown fungi. The most frequently encountered fungi were Penicillium (81 occurrences), Nodulisporium (57), Cladosporium (37), Trichoderma (34), Xylaria (29), Talaromyces and Pestalotia (27 each), and Stachylidium (26). The true wood decay fungi only accounted for 0.9% of the fungi isolated. The only statistical interactions associated with termites were the genus Nodulisporium, the class Coelomycetes, and the order Xylariales which all correlated with the absence of termites. Of particular interest is the strong correlation of the Xylariales and absence of termites. These white rot ascomycetes may have inhibitory effects on termites. In addition, the correlation of the genus Nodulisporium may be related as many species of this genus are considered asexual stages of Xylaria and Hypoxylon. There were also a number of significant interactions between wood species, habitat and presence of certain fungi. Most prior research has found an attraction of termites to wood infested with different types of wood-associated fungi. This study, however, found no positive statistical correlations between the presence of termites and any given group of fungi. An increased understanding of these interactions may help locate and isolate biologically active compounds that may influence termite behavior.

Microbial community analysis in the termite gut and fungus comb of Odontotermes formosanus: the implication of Bacillus as mutualists

The microbial communities harbored in the gut and fungus comb of the fungus-growing termite Odontotermes formosanus were analyzed by both culture-dependent and culture-independent methods to better understand the community structure of their microflora. The microorganisms detected by denaturing gradient gel electrophoresis (DGGE), clonal selection, and culture-dependent methods were hypothesized to contribute to cellulose-hemicellulose hydrolysis, gut fermentation, nutrient production, the breakdown of the fungus comb and the initiation of the growth of the symbiotic fungus Termitomyces. The predominant bacterial cultivars isolated by the cultural approach belonged to the genus Bacillus (Phylum Firmicutes). Apart from their function in lignocellulosic degradation, the Bacillus isolates suppressed the growth of the microfungus Trichoderma harzianum (genus Hypocrea), which grew voraciously on the fungus comb in the absence of termites but grew in harmony with the symbiotic fungus Termitomyces. The in vitro studies suggested that the Bacillus sp. may function as mutualists in the termite-gut-fungus-comb microbial ecosystem.

Comparison of Localized Injections of Spinosad and Selected Insecticides for the Control of <I>Cryptotermes brevis</I> (Isoptera: Kalotermitidae) in Naturally Infested Structural Mesocosms

We investigated the efficacy of various chemical injections against Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) in hardwood shipping pallets. We had three principle interests: efficacy in whole structures, relative efficacy of the active ingredients, and whether acoustic evidence augmented treatment site selection. Infested pallets were delineated into boards with four monitoring sites each. Six chemical treatments were compared: chlorpyrifos aerosol, aqueous disodium octaborate tetrahydrate (DOT), resmethrin aerosol, distilled water (control), and two treatments of spinosad SC (one treatment applied based upon visual and the other treatment upon acoustic [AE] evidence). Individual boards were split apart; efficacy was determined by percentage mortality and pre- and posttreatment AE counts. Injections were constrained to a single point per board with the greatest level of termite activity. In whole pallets, mean percentage mortality ranged from 53.3 to 58.7% for the visual and AE spinosad treatments, respectively, whereas water averaged 6.8%. Remaining treatment mortalities were 33.2, 30.4, and 18.1% for chlorpyrifos, DOT, and resmethrin, respectively. Analysis of whole-pallet data indicated that none of the insecticides produced commercially acceptable mortality; localized injections of insecticides were not comparable with whole-structure treatments. We delineated independent groups of board sections (sectional aggregates; SA) that were connected by galleries. When treated SA were analyzed, spinosad and DOT treatments were significantly different from controls, whereas remaining treatments were not different from controls or spinosad and DOT. AE readings and visual termite evidence were compared with presence or absence of termites in SA, and it was determined that both AE and visual evidence were effective predictors of termite presence.

Dimensionally stable sensors for a continuous monitoring program to detect subterranean termite (Isoptera: Rhinotermitidae) activity.

A dimensionally stable sensor composed of a closed-cell polyethylene sheet on which a silver particle circuit was painted and sandwiched between two spruce stakes was tested for use in a monitoring program to detect subterranean termites. Sensors were connected to a datalogger for continuous monitoring of sensor circuit breakages over 12 mo, and were manually inspected monthly to assess sensor performance. The mean monthly sensor accuracy for three field test sites was 98.7%, with most false responses caused by early timing of the monthly inspection when termites entered the station before damaging the sensor circuits. Mean sensor longevity (the time for a sensor circuit to break in the absence of termites) of the dimensionally stable sensors was 11.7 mo; a substantial improvement over the 4.4-mo longevity recorded previously for wooden sensors.

A computerized system for remote monitoring of subterranean termites near structures.

Sensors comprising wooden stakes painted with conductive circuits of silver particle emulsion were inserted in Sentricon stations in soil near structures. Sensors were wired to a datalogger that was programmed to test for circuit breakage every 2 h and store the data in its memory. A host computer was programmed to access the datalogger through telephone communication lines for data download every 4 d. The computerized monitoring system was tested in three remote sites, and site visits were conducted monthly for 6 mo to examine system accuracy in detecting termite activity. The mean monthly accuracy for the system to correctly report the presence (true positive) or absence of termites (true negative) in the stations was 85%, but the accuracy at 6 mo after system installation ranged from 41 to 79%. Mean sensor longevity, defined as the time for a sensor circuit to break in the absence of termites, was approximately 4.4 mo.

Effects of termite exclusion on decay of heavy and light hardwood in a tropical rain forest of Peninsular Malaysia

Wood pieces of a heavy hardwood Neobalanocarpus heimii (King) P. S. Ashton and a light hardwood Shorea macroptera Dyer were used in decomposition experiments with termite-exclusion and control trays on the forest floor of the Pasoh Forest Reserve, West Malaysia to determine effects of wood quality on termite-mediated wood decay. Shorea macroptera had a significant loss of C in the presence of termites while Neobalanocarpus heimii showed no significant termite effect. Neobalanocarpus heimii and S. macroptera both accumulated N in the absence of termites, but S. macroptera lost it when termites were present. The C/N ratio decreased with and without termites as decay proceeded in both species. Neobalanocarpus heimii accumulated P, but S. macroptera lost it with and without termites. The C/P ratio decreased in N. heimii, but did not change in S. macroptera. Decomposition was considerably enhanced by termites in S. macroptera, but not in N. heimii, indicating that termite foraging activity was affected by the different wood qualities of the two trees. The qualities responsible for the differences and how different wood qualities affect nutrient cycling in the tropical rain forest ecosystem are discussed.

Transformation and mineralization of 14 C-labeled cellulose, peptidoglycan, and protein by the soil-feeding termite Cubitermes orthognathus

We performed feeding trials with the soil-feeding termite Cubitermes orthognathus using soil spiked by uniformly 14C-labeled preparations of cellulose, peptidoglycan, protein, and bacterial cells (Bacillus megaterium and Escherichia coli). When incubated in soil for 8 days in the absence of termites, cellulose and peptidoglycan showed low mineralization rates (0.5% and 0.2%, respectively). However, when termites were present, their mineralization rates strongly increased (21.6% and 30.6%, respectively). The mineralization rate of protein was 12.4% in the control soils and increased to 36.2% in the presence of termites. Mineralization of bacterial cells in control soils occurred in two phases (rapid mineralization during the first 4–5 days and stabilization thereafter). When termites were present, the rates of mineralization of bacterial cells increased and the stabilization phase was abolished. In all cases, radiolabel accumulated in the termites and the solubility of the labeled compounds located in the gut increased strongly. Mineralization was accompanied by transformation of residual carbon from the humic acid fraction to the fulvic acid fraction during gut passage. High-performance gel permeation chromatography demonstrated a strong shift in the size distribution of the residual carbon from high-molecular-weight towards low-molecular-weight molecules in the gut of termites and an accumulation of small molecules in the termite bodies. The present study provides strong evidence that structural polysaccharides of plants and bacteria and microbial biomass are carbon and energy sources for soil-feeding termites.

Use of Arboreal Termitaria by Nesting Birds in the Peruvian Amazon

Abstract I documented the use by nesting birds and availability of arboreal termite nests (termitaria) in the Peruvian Amazon. Birds occupy about 1% of the termitaria annually, suggesting that termitarium availability does not limit reproductive output. Birds choose termitaria that are larger and higher than average, and the three most common termitarium-nesting species differ in their use of termitaria. Two species of Brotogeris parakeets use termitaria with similar characteristics, but Tui Parakeets (B. sanctithomae) nest in young forests and edge habitats whereas Cobalt-winged Parakeets (B. cyanoptera) use mature forests. Termitaria used by Black-tailed Trogons (Trogon melanurus) are larger and lower than those used by the two Brotogeris species. The contention that birds usually nest in termitaria still occupied by termites was upheld, but the presence or absence of termites did not explain a significant proportion of the difference between used and available termitaria after removing the effects of height, volume, and substrate type. Birds choose to nest in termitaria inhabited by both termites and aggressive biting ants (Dolichoderus sp.). These ants may be protecting the birds' nests by attacking predators or by providing a sort of “olfactory camouflage.”

Use of Arboreal Termitaria by Nesting Birds in the Peruvian Amazon

I documented the use by nesting birds and availability of arboreal termite nests (termitaria) in the Peruvian Amazon. Birds occupy about 1% of the termitaria annually, suggesting that termitarium availability does not limit reproductive output. Birds choose termitaria that are larger and higher than average, and the three most common termitarium-nesting species differ in their use of termitaria. Two species of Brotogeris parakeets use termitaria with similar characteristics, but Tui Parakeets (B. sanctithomae) nest in young forests and edge habitats whereas Cobalt-winged Parakeets (B. cyanoptera) use mature forests. Termitaria used by Black-tailed Trogons (Trogon melanurus) are larger and lower than those used by the two Brotogeris species. The contention that birds usually nest in termitaria still occupied by termites was upheld, but the presence or absence of termites did not explain a significant proportion of the difference between used and available termitaria after removing the effects of height, volume, and substrate type. Birds choose to nest in termitaria inhabited by both termites and aggressive biting ants (Dolichoderus sp.). These ants may be protecting the birds' nests by attacking predators or by providing a sort of “olfactory camouflage.”

Transformation and mineralization of synthetic 14C-labeled humic model compounds by soil-feeding termites

The majority of termite species are considered to be humivorous, but the exact nature of their carbon and energy source, the mechanisms involved in digestion and the impact of this feeding habit on the humification of soil organic matter are largely obscure. We performed feeding trials with soil-feeding termites (Termitidae: Termitinae), using 14C-labeled humic model compounds as substrates. In the case of Cubitermes orthognathus, the components of chemically identical synthetic humic acids (HA), labeled either in their proteinaceous or aromatic building blocks, and synthetic fulvic acids (FA), labeled in the aromatic building blocks, all had similarly low mineralization rates (2.5, 2.2 and 2.7%, respectively) when incubated in soil for 10 days in the absence of termites. When termites were present, the mineralization rate of the aromatic component of HA and FA increased only slightly but significantly (2.4 and 3.1%, respectively; P < 0.05), whereas that of the proteinaceous component increased more than 10-fold (30.8%). Similar results were obtained when the protein was peptonized prior to polymerization (9.7 vs. 27.4% mineralization). Mineralization of HA was accompanied by a transformation of the residual peptide label to FA, whereas the aromatic label of HA and FA was partly transformed to humin during gut passage. High-performance gel permeation chromatography showed a strong shift in the size-class distribution of peptide label towards low-molecular-weight products, especially of the material ingested by the termites; the smallest molecules were recovered from the termite bodies. Similar results were obtained in feeding trials with Cubitermes umbratus and Thoracotermes macrothorax. Together with previous findings, the current results provide strong evidence that during gut passage, the combined action of extreme alkalinity in the anterior hindgut, autoxidative processes, and probably also proteolytic activities, renders a large reservoir of potential substrates accessible. While peptidic components of humic substances are selectively digested, aromatic components are apparently not an important food source for soil-feeding termites. These findings have important implications for the mobilization of organic nitrogen in tropical soils.

USE OF ARBOREAL TERMITARIA BY NESTING BIRDS IN THE PERUVIAN AMAZON

Abstract I documented the use by nesting birds and availability of arboreal termite nests (termitaria) in the Peruvian Amazon. Birds occupy about 1% of the termitaria annually, suggesting that termitarium availability does not limit reproductive output. Birds choose termitaria that are larger and higher than average, and the three most common termitarium-nesting species differ in their use of termitaria. Two species of Brotogeris parakeets use termitaria with similar characteristics, but Tui Parakeets (B. sanctithomae) nest in young forests and edge habitats whereas Cobalt-winged Parakeets (B. cyanoptera) use mature forests. Termitaria used by Black-tailed Trogons (Trogon melanurus) are larger and lower than those used by the two Brotogeris species. The contention that birds usually nest in termitaria still occupied by termites was upheld, but the presence or absence of termites did not explain a significant proportion of the difference between used and available termitaria after removing the effects of h...

Decomposition of cowpea and millet amendments to a sandy Alfisol in Niger

Current inputs of organic materials to cropped lands on sandy Alfisols and Entisols in Sahelian West Africa are insufficient to arrest soil organic matter (SOM) decline. Crop residues and green manures require proper management in order to maximize their contribution to nutrient supply and SOM maintenance. The objectives of this study were to quantify the rates of C and N mineralization from cowpea (Vigna unguiculata (L.) Walp.) green manure, cowpea residue, and millet (Pennisetum glaucum (L.) R.Br.) residue under field conditions in Niger and to determine the effect of these organic amendments on pearl millet yield. Millet was grown (1) as sole crop, (2) as intercrop with cowpea, (3) as intercrop with cowpea that was incorporated as green manure during the second half of the growing season, (4) with incorporated cowpea residue (2000 kg ha−1), (5) with millet residue mulch (3000 kg ha−1), and (6) with N fertilizer. Carbon loss as CO2 from soil with and without organic amendment was measured three times per week during the growing season. Nitrogen fertilizer increased millet yield only in a year with a favorable rainfall distribution. Cowpea grown in intercrop with millet during the first part of the growing season and subsequently incorporated as green manure between millet rows increased millet grain yield in a year with sufficient early rainfall, which could be attributed to the rapid rate of decomposition and nutrient release during the first 3 weeks after incorporation. In a year with limited early rainfall, however, densely planted green manure cowpeas competed for water and nutrients with the growing millet crop. Incorporated cowpea residue and millet residue mulch increased millet yield. Surface applied millet residue had high rates of decomposition only during the first 3 days after a rainfall event, with 34% of the millet residue C lost as CO2 in one rainy season. Recovery of undecomposed millet residue at the end of the rainy season was related to presence or absence of termites, but not to seasonal C loss. Millet residue mulch increased soil organic C content of this sandy Alfisol in Niger. Cowpea and millet residues had a greater effect on SOM and millet yield than cowpea green manure due to their greater rate of application and slower rate of decomposition.

A general model of litter decomposition in the northern Chihuahuan Desert

Numerous empirical studies have described the pathways of mass, C and N flows during decomposition, but there remains a paucity of data on underlying mechanisms in arid ecosystems. In the northern Chihuahuan Desert, termites remove large quantities of litter and act as carbon and nitrogen sinks, contributing to low soil fertility. In their absence, decomposition at the soil surface is primarily driven by abiotic weathering, but studies suggest buried litter decay occurs through microbiological activities. We develop a general, synthetic model to examine the interactions between buried litter, decomposer microorganisms, and C and N pools in this ecosystem. Our goal is to explore the mechanisms underlying observed patterns of decomposition in arid systems using a modelling approach that balances simplicity with enough detail to suggest the reasons for system behavior. To this end, we utilize elements of existing models, interfacing microbial physiology and population dynamics with empirical observations of C and N pool dynamics, litter mass loss and changing C:N ratios. Good agreement was achieved between simulated and observed patterns of mass loss and nitrogen concentrations once a time lag describing the microbial colonization of litter was included. Model results indicate nutrient availabilities may be determined by relatively short-term carbon dynamics mediated by microflora since soil organic matter and nitrogen content are low. Model behavior also suggests decomposer organisms immobilize nitrogen from surrounding soils, accounting for the elevated quantities observed within decaying materials. Past hypotheses have proposed that soil flora and fauna partially decouple decomposition processes from abiotic constraints in this system. This study indicates that the pattern of microbial activities, accounting for the decomposition of buried materials in the absence of termites, is primarily determined by climatic conditions.

Decomposition of Ocotillo (Fouquieria splendens) Wood in the Colorado Desert of California

The weight loss of stem sections of ocotillo (Fouquieria splendens) was determined for 11 years in the Colorado Desert of California. Weight of a stem section was a function of original weight, time in the field and presence or absence of termites. A section weighing 10 g is estimated to have a half-life of 29 years without termites and 17 years if termites find the section. Small sections of stem decayed slightly more rapidly than larger sections. INTRODUCTION Decomposition in desert ecosystems is considered to be a slow process and, because of this, there can be more dead than live aboveground biomass (Hadley and Szarek, 1981). There are few measurements of natural rates of decomposition in deserts; however, examples of such studies include Haverty and Nutting (1975), who measured loss in wood due to termites over a period of one year; Comanor and Staffeldt (1978), who documented loss of weight by creosote bush (Larrea tridentata) parts over 5 months, and Fowler and Whitford (1980), who examined L. tridentata litter in bags over a period of 1-2 months. The purpose of this note is to report results of a study of weight loss in pieces of ocotillo (Fouquieria splendens) stem over 11 years. The study was prompted by a question about the stability of ocotillo populations: dead ocotillos are common in the western Colorado Desert of California, but small living individuals are very rare. Either dead ocotillos take a very long time to decay and, hence, the rarity of small living individuals reflects stationary recruitment or the population in the Colorado Desert of California is in a state of decline, with high rates of death and decomposition and a low rate of recruitment. This work was conducted at the southern end of the Anza-Borrego State Park, California (33 N lat, 116 W long). The area is a bajada between the Coyote Mountains to the N and the Jacumba Mountains to the W. The substrate is recent alluvium made up of locally derived andesitic volcanic rock mixed with granite and sedimentary rocks from the surrounding hills. The area is finely dissected with a microtopography of small water courses. The elevation is 275 m above sea level. In addition to Fouquieria splendens, Larrea tridentata, Ambrosia dumosa, Opuntia echinocarpa, 0. bagelovii and Encelia farinosa are abundant. METHODS Stems of living ocotillo were collected in January 1971 at the study site, cut into sections ca. 8.5 cm long (range 8.0-9.5 cm), dried at 85 C for 2 weeks, and then weighed to the nearest milligram. Average weight of the dried sections was 15.1 g 4 7.8 SD (range 5.0-30.9 g, n = 22). A wire was fastened around 15 sections together with a numbered metal tag. In the field, wires were fastened to wooden stakes and sections were left on the soil surface. Two sections were collected in 1972, 1973, 1974, 1977 and 1978. Five sections were collected in 1982. All sections were randomly selected. Sand was brushed from the sections, they were dried at 85 C and then weighed to determine loss. Analysis is based on a simple model in which the final weight is related to original weight by an allometric function: