Termite Feeding Research Articles

Reduction in Toxicity of Tectoquinone against Reticulitermes speratus Kolbe termites

The cause of low toxicity against Reticulitermes speratusKolbe termite species of teakwood under natural condition was investigated. Anti-termite test was conducted to evaluate the effectivity of four major components (tectoquinone, deoxylapachol, tecomaquinone, and squalene) of ethanol-benzene extracts in the teak heartwood. Tectoquinone exhibited both strong toxicity and antifeedancy as well as it was far superior to other components. The strength reduction of tectoquinone bioactivity is assumed due to interaction with other major components. As squalene was found in considerable amounts or 1.8 to 13.1 times as high as the tectoquinone concentration in woods, termite feeding was set to the mixtures of tectoquinone and squalene in various ratios (1:1, 1:5, 1:10, and 1:20). It was revealed that squalene addition could decrease the termite mortality 15% to 44% from its initial value (tectoquinone only). On the other hand, the mixtures reduced mass loss due to termite attacks only to a small degree.

Importance of fungus in feeding termites with sunflower plants

Fungal species were isolated from samples of damaged sunflower. The strains selected on the basis of cultural and morphological characteristics belonged to the species Alternaria alternata, Alternaria tennus and Fusarium oxysporum, Fusarium solan, and fungal strains were identified, as well as fungal strains, and fungal strains 67, termites, termarium, oxolbate 10, oxoliban 10 - to termites, oxolbate 10 - to termites, oxolbate 10.9%.

Island size affects wood decomposition by changing decomposer distribution

Island biogeography theory describes the relationship between island size, isolation and biodiversity, but it does not address the effects on ecosystem processes such as wood decomposition. Wood decomposition rates can be expected to increase with decomposer diversity, which increases with island size and decreases with increasing island isolation. However, island size and isolation effects on wood decomposition may also act by impacting substrate composition, forest composition and biotic interactions among decomposers. In this study, branch‐wood decomposition rates of three locally dominant tree species deployed at 154 plots on 15 islands in Thousand Island Lake, China, were measured over one year. The results showed that decomposition rates in coarse‐mesh bags where both termites and fungi were allowed access increased with island size for the two tree species preferred by the termites. By contrast, decomposition rates in fine‐mesh bags which only fungi could access decreased with island size for the two tree species preferred by fungi. The positive effects of island size on termite feeding activity were mediated by a higher deadwood diversity, a more diverse forest composition and a higher soil moisture content, with forest composition shaping soil moisture. For fungal diversity, the negative effects of island size were attributable to a higher soil moisture content and termite feeding activity. Island isolation decreased fungal diversity but increased wood decomposition rates. Our study indicates that island size affects wood decomposition by altering the distribution of decomposers and their relative contributions to wood decomposition. Size–decomposition relationship further depends on the affinity between substrates and decomposer taxa. In general, our results show that ecosystem processes may be affected by island size and isolation, but the patterns are more complex than expected from the island biogeography theory. This discrepancy is largely due to the different responses and trade‐offs among different functional groups.

Correction to: Toxicity and repellent effects of wood extractives of five Malaysian wood species on Asian subterranean termite Coptotermes gestroi Wasmann

Antitermitic potential of heartwood extractives of five Malaysian wood species against the subterranean termite, Coptotermes gestroi was investigated in laboratory experiments. Heartwood extractives of the wood species, Cinnamomum sp., Canarium littorale Blume, Cynometra malaccensis Meeuwen, Eugenia griffithii Duthie and Scorodocarpus borneensis (Baill.) Becc. were removed from wood sawdust using the four solvents, methanol (MeOH), ethanol (EtOH), acetone and toluene:industrial methylated spirit (Tol:IMS). Extraction was done using a Soxhlet extractor. Two different tests, toxicity and repellency, were conducted on filter paper treated with different concentrations (0.5, 1, 2, 3 and 4%) of each wood extract to observe the repellents, feeding response and mortality of termites. No-choice bioassay using Hevea brasiliensis test blocks treated with the same concentrations of each wood extract was also carried out to compare the results with the termiticidal activity of extractives. Termite feeding, repellents, and mortality followed a concentration-dependent response. The highest termite mortality occurred at an extractive concentration of 4% of each wood species. Extractive of each wood species prepared using MeOH showed higher termite mortality, feeding inhibition and lower filter paper consumption when treated with 4% of concentration. Extractive of C. littorale prepared using EtOH as a solvent was least toxic to termite. Acetone extractive of S. borneensis showed significantly higher repellent activity against C. gestroi at 2, 3 and 4% of concentrations compared to the rest of treatments. Further characterization of the extractive content is needed to find out which compounds are responsible for termiticidal and antifeedant activity, either singly or jointly.

Termiticidal Activity and Chemical Components of Bamboo Vinegar against Subterranean Termites under Different Pyrolysis Temperatures

In this study, the chemical components and termiticidal activities of bamboo vinegar against subterranean termite were evaluated. Bamboo vinegar used in this study were produced from Mayan (Gigantochloa robusta Kurz.), Balcoa (Bambusa balcooa Roxb.), and Taiwan (Dendrocalamus latiflorus Munro). It was analyzed by gravimetric methods. Rubberwood (Hevea brasiliensis) was soaked for 24 h and tested against Coptotermes curvignathus Holmgren according to the Indonesian National Standard (SNI 7207-2014). The bamboo vinegar demonstrated antitermite activities against subterranean termite. Vinegar of 400°C recorded higher total phenol and acid than that of 300°C. Results from this study suggest that the phenolic and acidic component of the bamboo vinegar contributed to 100% mortality rate of the termite, some wood weight loss, and a decrease in the termite feeding rate. These results strongly recommend that bamboo vinegar from D. latiflorus Munro is a potential environmentally friendly preservative.

Termite functional diversity along an elevational gradient in the Cerrado of Mato Grosso do Sul

Termites are dominant invertebrates in tropical environments and are important intermediate species of decomposition in terrestrial ecosystems. The study aimed to characterize how termite richness and feeding group diversity vary along an elevational gradient in the Brazilian savanna. Termites were sampled within a standardized 100 × 2 m transect at undisturbed Cerrado sites along an elevational gradient from 210 to 600 m asl. Termite diversity declined with the increase in elevation in the Serra de Maracaju, with an elevation range of 400 m and strong undulated relief. Higher elevations cause a significant decrease in the number of grass-litter-feeding species and Syntermitinae species, associated with more acidic soils with lower saturation by exchangeable bases. Beta and, especially, alpha diversity at plot level were responsible for the observed diversity of almost all groups, except for wood-feeders. Our results suggest a greater change in termite taxonomic and functional diversities at a lower elevational gradient than at high elevations. Finally, this study gives some insights that even in a rockier physiognomy, probably with fewer resources to be explored the termite diversities was still higher than in a pasture area at lower elevations.

Termite resistance of pine wood treated with nano metal fluorides

Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect wood from termite attack.

Anti-fungal and anti-termite activity of extractives compounds from thermally modified ash woods

Thermal modification of wood is a promising alternative to chemical and biocidal modification processes, increasing the biological durability and dimensional stability of wood. However, the wood-decay resistance properties of heat-treated wood are still not well known. The main objective of this study was to determine the biological resistance of heat-treated ash wood, and assess the antifungal and anti-termite activity of extractive compounds from heat-treated ash woods, depending on the intensity of the modification process (2 hours at 170, 200, 215, 228 (°C) - steam pressure). Untreated and heat-treated wood samples were extracted with water or acetone. The extracts were then used to determine inhibition effectiveness against white-rot (Trametes versicolor) and brown-rot (Rhodonia placenta) fungi. Whatman papers impregnated with extractives were used to evaluate the inhibition of termite feeding. Lastly, the extractives were analyzed by Gas Chromatography - Mass Spectrometry (GC-MS) and compared for their level of anti-termite and antifungal activity. The results showed that the degree of antifungal activity of these extracts depended on the solvent used during the extraction process and varied depending on heat treatment intensity. The extracts were more effective against brown-rot than white-rot fungi. However, the anti-termite activity of heat-treated ash wood extracts was not really significant. A GC-MS analysis showed that the main share of the extractives in untreated wood was removed. In addition, new chemical elements were generated by the thermal degradation of wood polymers (lignin and hemicelluloses), including aliphatic acids, monosaccharides and other products resulting from their dehydration reaction. The most abundant element was syringaldehyde, from lignin derived compounds, which might explain the antifungal activities of thermally treated ash wood extracts.

Synergistic effect of heartwood extracts in combination with linseed oil as wood preservatives against subterranean termite Heterotermes indicola (Blattodea: Rhinotermitidae).

This study evaluated the effect of wood extracts from Tectona grandis, Dalbergia sissoo, Cedrus deodara, and Pinus roxburghii combined with linseed oil as protectants of two non-durable wood species against the termite, Heterotermes indicola. Heartwood blocks (19 × 19 × 19mm) and wood shavings were extracted using an ethanol/toluene (2:1) solvent system. Results of choice and no-choice tests with solvent-extracted and non-extracted heartwood blocks showed greater wood mass loss from termite feeding on solvent-extracted blocks compared with non-extracted blocks for all wood species. Significantly higher termite mortality was observed after termite exposure to non-extracted blocks compared with extracted blocks for all durable species. Sapwood blocks of two non-durable wood species (southern pine and cottonwood) were vacuum/pressure impregnated separately with each of the four types of extract at a concentration of 7.5mgml-1, linseed oil (20%) and a mixture of oil (20%) and extracts (4.25mgml-1) for the laboratory and field tests. Results showed that extract-oil mixture imparted significantly higher termite resistance compared with linseed or extracts alone under laboratory conditions. This apparent synergistic effect was clearly noted when linseed oil was combined with extracts from T. grandis or D. sissoo followed by an extract-oil mixture using C. deodara. These extract oil mixtures showed significantly less weight loss for the treated non-durable wood species and higher termite mortality (83-100%) compared with the control treatments and other extract-linseed oil mixtures tested. Treatment of both non-durable wood species with T. grandis + oil and D. sissoo + oil prevented termite damage compared with other treatments when blocks and stakes were exposed in the field for a period of 2years. Results of the current study indicated that a mixture of a particular heartwood extract with linseed oil has potential to be used as environmentally friendly wood protectants.

Diversity of Ants and Termites of the Botanical Garden of the University of Lomé, Togo.

Ants and termites are used as bioindicators in many ecosystems. Little knowledge is available about them in Togo, especially ants. This study aimed to find out how ants and termites could be used to assess the restoration of former agricultural land. These insect groups were sampled within six transects of 50 × 2 m2 (using pitfall traps, monoliths, baits for ants and hand sampling for termites) in two consecutive habitats: open area (grassland) and covered area (an artificial forest). Seventeen termite species and 43 ant species were collected. Seven ant species were specific to the covered area against four for the open area, while four unshared species of termite were found in the open area against three in the covered area. The presence of unshared species was linked to vegetation, as Trinervitermes (Holmgren, 1912), a grass feeding termite, was solely found in open area. Also, for some ant species like Cataulacus traegaordhi (Santschi, 1914), Crematogaster (Lund, 1831) species, Oecophylla longinoda (Latreille, 1802) and Tetraponera mocquerysi (Brown, 1960), all arboreal species, vegetation was a determining factor for their presence. The occurrence of these species together with Basidentitermes mactus (Sjöstedt, 1911), Strumigenys bernardi (Brown, 1960) and S. sistrura (Bolton, 1983), suggest a more advanced level of restoration of the covered area.

Virtual micromorphology: The application of micro-CT scanning for the identification of termite mounds in archaeological sediments

X-ray micro-computed tomography (micro-CT) scans were conducted on impregnated sediment blocks from the early Holocene rockshelter site of Lapa do Santo, East-Central Brazil. The analysis was designed to investigate the presence of termite mound fragments in the archaeological sediments and test the value of complementary techniques in micromorphological studies. Soil feeding termites have been common in the tropical soils of Central Brazil since the Paleogene/Neogene and exist in high concentrations in the surroundings of Lapa do Santo. The micro-CT scans revealed a distinctive spongy microstructure inside some of the clay aggregates in the sediments that are not visible in thin section, matching the spongy microstructure inside termite mound fragments. The microstructure consists of a mix of clay and organic material (feces, saliva and other body fluids) produced by termites to cement the mounds' matrix. The cements are undistinguishable from the matrix under the microscope, but clearly visible in the micro-CT scans given the low attenuation coefficient of organo-mineral matter. The termite mound fragments appear dispersed within the ashy matrix (made of intact and reworked combustion features), suggesting their possible use in earth ovens. The combination of combustion features and reworked earth ovens attests to the complex input of anthropogenic sediments in the formation of Lapa do Santo. This study demonstrates that micro-CT can potentially disclose materials not visible in thin section and can be utilized as a complementary technique to micromorphology.

Linking Termite Feeding Preferences and Soil Physical Functioning in Southern-Indian Woodlands.

Termites are undoubtedly amongst the most important soil macroinvertebrate decomposers in semi-arid environments in India. However, in this specific type of environment, the influence of termite foraging activity on soil functioning remains unexplored. Therefore, this study examines the link between the quality of litter and the functional impact of termite feeding preferences on soil properties and soil hydraulic conductivity in a deciduous forest in southern India. Different organic resources (elephant dung: “ED”, elephant grass: “EG”, acacia leaves: “AL” and layers of cardboard: “CB”) were applied on repacked soil cores. ED appeared to be the most attractive resource to Odontotermes obesus, leading to a larger amount of soil sheeting (i.e., the soil used by termites for covering the litter they consume), more numerous and larger holes in the ground and a lower soil bulk density. As a consequence, ED increased the soil hydraulic conductivity (4-fold) compared with the control soil. Thus, this study highlights that the more O. obesus prefers a substrate, the more this species impacts soil dynamics and water infiltration in the soil. This study also shows that ED can be used as an efficient substrate for accelerating the infiltration of water in southern-Indian soils, mainly through the production of galleries that are open on the soil surface, offering new perspectives on termite management in this environment.

Toxicity potential of heartwood extractives from two mulberry species against Heterotermes indicola

Choice and no-choice tests were run to evaluate natural resistance of the woods of two Morus species (Morus alba and Morus nigra) against the subterranean, Heterotermes indicola, under field conditions. Toxicity, antifeedant and repellency potential of the heartwood extractives was also investigated under laboratory conditions. Heartwood extractives were removed from wood shavings by using methanol or an ethanol: toluene (2:1) mixture. Results of choice and no-choice tests with sap and heartwood blocks exposed to termites, showed that both mulberry species were resistant to termites but in comparison, Morus alba wood was more resistant than Morus nigra to termite feeding as it showed <5 % weight loss after 90 days. Termites exhibited a concentration dependent mortality after exposure to either mulberry species’ heartwood extractives. The highest termite mortality occurred after termites were exposed to filter paper treated with Morus alba extractives at a concentration of 5 %. At this concentration, antifeedancy and repellency were calculated to be 91,67 and 84 % respectively. . Our results also showed that extractives from either mulberry species imparted resistance to vacuum-pressure treated non-durable Populus deltoides wood. Termite mortality was greater than 75 % after feeding on Populus deltoides wood treated with extractives from Morus alba. Solvent only (methanol) treated Populus deltoides controls, showed a minimum weight loss of 2,69 % after 28 days. These results suggest that Morus alba extractives have antitermitic properties and may be potentially useful in the development of environment friendly termiticides.

Consequences of shade management on the taxonomic patterns and functional diversity of termites (Blattodea: Termitidae) in cocoa agroforestry systems.

Termites have gained importance as major pests in cocoa agroforests. Proper identification of termite species and knowledge on their functional diversity are the first steps in developing environmentally compatible management strategies. We tested the hypothesis that patterns of termite species richness in different cocoa agroforests is related to responses by termite functional groups to changes in shade management. We compared termite assemblages under five cocoa agroforestry systems in Cameroon to assess the impact of shade on termite taxonomic and functional group diversity. Sampling was done using a modified standardized transect method. Two 30 × 30 m quadrates each divided into three transects were laid in four farms at each site. Termites sampled were identified and grouped according to habitats, functional groups, and feeding habits. Sixty‐nine termite species in 33 genera and five subfamilies under two families were sampled. Termitidae was the most dominant family and Rhinotermitidae the least dominant with few species. Termite species richness decreased significantly from the heavy shaded cocoa agroforests (44 species) to the full sun (11 species). Functional group pattern differed significantly in all the cocoa agroforests and within each agroforestry system and dominated by wood and litter feeder species. Many species belonging to this group were responsible to most damages on cocoa trees. Both the richness of termite pests and marketable yield followed a quadratic curve and were found to be lowest and highest in plots with shade cover above 40%. The simulated optimal shade levels for low termite infestations and marketable yield overlapped between 45% and 65% indicating that cocoa agroforestry systems with around 55% shade cover may be optimal to balance termite infestations and marketable yield. Shade maintenance in cocoa agroforests is valuable in reducing termite pest species and conserving soil feeding termites which provide beneficial ecosystem services.

Feeding rate of subterranean termites in wood treated with smoke wood and borax

This study aimed to analyze the feeding preference of subterranean termites (Coptotermes curvignathus) against 3 Indonesian native woods such as Jabon (Anthocephalus cadamba), Jati (Tectona grandis) and Ulin (Eusideroxylon zwageri) treated with borax and bamboo smoke wood. The method was conducted and evaluated according to Japanese Industrial Standards (JIS 2004) and Indoneisan National Standard (SNI 2014) with Pinus mercusii as the control. The results showed that Jabon (A. cadamba), Jati (T. grandis) and Ulin (E. zwageri) woods treated using smoke and borax were not significantly different. All treatments have effectively increased the resistance to subterranean termite attacks. The treated wood samples have less weight loss, higher termite mortality, and lower termite feeding rate compared to the untreated wood. Daily termite feeding rate of untreated P. mercusii was 1.63 mg/termite/day, smoke wood treated was 1.5 mg/termite/day and borax treated wood was 1.4 mg/termite/day. In conclusion, the smoke wood treatments effectively decreased the daily feeding rate of the termites.

Biodelignification and hydrolysis of rice straw by novel bacteria isolated from wood feeding termite.

In this study, two bacterial strains capable of degrading lignin, cellulose, and hemicellulose were isolated from wood feeding termite. The isolates were identified by 16S rRNA gene sequencing. A bacterium Ochrobactrum oryzae BMP03 capable of degrading lignin was isolated on alkali lignin medium and Bacillus sp. BMP01 strain capable of degrading cellulose and hemicellulose were isolated on carboxymethyl cellulose and xylan media. The efficiency of bacterial degradation was studied by evaluating the composition of rice straw both before and after degradation. The appearance of new cellulose bands at 1382, 1276, 1200, and 871cm-1, and the absence of former lignin bands at 1726, 1307, and 1246cm-1 was observed after biodelignification. This was further confirmed by the formation of channeling and layering of the microstructure of biodelignified rice straw observed under electron microscope. Maximum lignin removal was achieved in separate biodelignification and hydrolysis process after the 14th day of treatment by Ochrobactrum oryzae BMP03 (53.74% lignin removal). Hydrolysis of the biodelignified rice straw released 69.96% of total reducing sugars after the 14th day hydrolysis by Bacillus sp. BMP01. In simultaneous delignification and hydrolysis process, about 58.67% of total reducing sugars were obtained after the 13th day of biotreatment. Separate delignification and hydrolysis process were found to be effective in lignin removal and sugar released than the simultaneous process. The bacteria, Bacillus sp. BMP01, has the ability to degrade hemicellulose and cellulose simultaneously. Overall, these results demonstrate that the possibility of rice straw bioconversion into reducing sugars by bacteria from termite gut.

Structure, soil properties and spatial patterning of mounds built by a soil feeding termite across a rainfall gradient in a savanna ecosystem

Although the ecosystem engineering role of termites has long been recognized, understanding the distribution and properties of their nests that affect ecosystem heterogeneity continues to be a priority. Studies have investigated soil properties like clay and organic matter (OM) composition of mounds belonging to fungus growing termites, however, little is known for southern African savanna soil feeding termites. Indeed, studies on the spatial distribution of termite mounds in savannas have been carried out with a focus mainly on the genus Macrotermes in savanna woodlands, leaving us with little information on other species that often occur on grasslands, for example soil feeding Cubitermes. Therefore, in this study we aimed to understand the effect of rainfall on Cubitermes breviceps mounds structure, soil properties and spatial point patterning at three sites. At each site two 25 m × 25 m plots were marked for spatial analysis. Mound height and basal diameter were recorded. Two soil properties (clay and OM) from mound and savanna matrix soil were investigated. A decreasing trend in mound height and diameter was observed from the more arid to the wettest site. Mound height was positively influenced by the amount of both clay and OM. However, both clay and OM had a negative relationship with numerical density of mounds, and we suggest other factors such as grass cover and the prevailing conditions such as moisture and competition at early colony establishment also influence mound density. Cubitermes breviceps mounds were generally completely spatially random across sites, except for Ripley’s L summary function that showed clustering, which we attribute to its cumulative nature. In conclusion, soil feeding C. breviceps incorporate more OM in their mounds and do not show competition between colonies probably due to them not feeding on limited food resources in the savanna such as grass and wood.

Population structure of Guyanagaster necrorhizus supports termite dispersal for this enigmatic fungus.

Understanding how species accomplish dispersal of their propagules can shed light on how they are adapted for their ecosystem. Guyanagaster necrorhizus is a sequestrate fungus, meaning its dispersal propagules, or spores, are entirely enclosed within a fruiting body, termed a sporocarp. This fungus is most closely related to Armillaria and its allies. While Armillaria species form mushrooms and have forcibly discharged spores, G.necrorhizus spores have lost this ability, and by necessity, must be passively dispersed. However, G.necrorhizus does not possess characteristics of other sequestrate fungi with known dispersal mechanisms. Repeated observations of termites feeding on G.necrorhizus sporocarps, and spores subsequently adhering to their exoskeletons, led to the hypothesis that termites disperse G.necrorhizus spores. To test this hypothesis, we used microsatellite markers and population genetics analyses to understand patterns of clonality and population structure of G.necrorhizus. While Armillaria individuals can spread vegetatively over large areas, high genotypic diversity in G.necrorhizus populations suggests spores are the primary mode of dispersal. Spatial genetic structure analyses show that G.necrorhizus sporocarps within 238m of each other are more closely related than would be expected by chance and conservative estimates from population assignment tests suggest gene flow no longer occurs between sporocarps separated by 2km. These distances are consistent with previous studies analysing foraging distances of the termites found associated with G.necrorhizus sporocarps. Termites have rarely been recorded to specifically target fungal sporocarps, making this a potentially novel fungal-insect interaction.

Effects of White Mulberry (Morus alba) Heartwood Extract Against Reticulitermes flavipes (Blattodea: Rhinotermitidae).

Heartwood extract from white mulberry (Morus alba L.) (Rosales: Moraceae) were investigated for antitermitic activity against Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae) in laboratory experiments. An ethanol:toluene (2:1) solvent system was used to remove extract from heartwood shavings. A concentration-dependent feeding response and mortality were observed for termites exposed to a concentration series range of 1.25 to 10 mg/ml of extract based on their dry weight. Results showed that maximum termite mortality occurred at 10 mg/ml. Based on the concentration series data, LC50 was calculated at 1.71 mg/ml. In filter paper feeding and repellency assays, extract significantly decreased the total number of gut protozoa compared with untreated and solvent controls. After feeding on filter paper treated at 10 mg/ml for 2 wk, protozoan populations were reduced by >55%. In choice and no-choice tests with mulberry heartwood, greater wood loss from termite feeding was found on solvent extracted blocks compared with nonextracted. Complete (100%) mortality was observed after feeding on nonextracted blocks compared with extracted blocks. Heartwood extract from white mulberry imparted resistance to vacuum pressure treated, nondurable southern pine and cottonwood. At every concentration tested, 100% mortality was observed after feeding on extract-treated southern pine or cottonwood. GC-MS analysis of extract showed high levels of the phenol compound, resorcinol. Results indicated that heartwood extract from white mulberry have antitermitic properties and might be potentially valuable in the development of environmentally benign termiticides.

Changes in the Contribution of Termites to Mass Loss of Dead Wood among Three Tree Species during 23 Months in a Lowland Tropical Rainforest

This study investigated the contribution of termites to mass loss of dead wood (Macaranga bancana, Elateriospermum tapos, and Dillenia beccariana) in a lowland tropical rainforest, Brunei Darussalam. Mesh bag method was used to exclude termites, and the mass remaining was monitored after 3, 7, 13, and 23 months. C/N ratio of the samples was analyzed after 13 and 23 months. Initial wood density was 0.63, 0.92, and 1.02 g/cm3 for M. bancana, E. tapos, and D. beccariana, respectively, and the termite contribution to mass loss was an average (range) of 13.05±5.68 (4.17-29.59%), 3.48±1.13 (2.20-6.49), and 3.40±1.92% (0.74-10.78), respectively. Until 7 months, termites contributed highly to mass loss, given the low initial wood density, and interaction effect of species and treatment was significant. After 7 months, the contribution decreased in M. bancana and E. tapos, whereas it increased consistently in D. beccariana. The interaction effect was not significant, whereas differences in C/N ratio among the species were significant, with a lower C/N ratio in M. bancana and E. tapos than in D. beccariana. After 23 months, the differences in C/N ratio were not significant, and ants were present at 40% of control samples in M. bancana and E. tapos. Our results suggest that the contribution of termites to mass loss varies by dead wood species and is temporally variable. Initial wood traits could affect the termite feeding in the beginning, however, termites thereafter could forage in response to the varying C/N ratio among species and predators.