Colony structure and caste distribution in living trees of the Ryukyu drywood termite,Neotermes sugioi (Blattodea: Kalotermitidae) in Okinawa Island

Termites are major pests of houses and buildings, and also living plants such as agricultural crops, trees in forests, urban areas and gardens. However, in Japan, the basic ecology of termites nesting in living trees is not fully understood. In this study, we observed 255 colonies (nests) of the drywood termite Neotermes sugioi, collected in the field on Okinawa Island, and reported the frequency composition of the reproductive castes, the size of wood with termite gallery, the population size of colonies, and the relative position of the reproductive and non-reproductive castes within nests. Most colonies were headed by a primary queen and a primary king. However, colonies headed only by primary queens, primary kings, or neotenic kings, each accounted for approximately 5% of the colonies. A colony size of 1,000– 4,000 individuals (2058.2 ± 1695.0 [mean ± SD]) was common and the average length of colony branches was less than 100 cm. Queens and kings were found in the same or nearby nest areas, and more predominantly in the central or root side of nest wood areas. The termites may experience colony fragmentation and reproductive loss as a consequence of typhoons. Incipient colonies (i.e., colonies at an early stage of development) were found on 11.3% of branches of Leucaena leucocephala that did not show any obvious signs of infestation. In future research, it will be necessary to update the list of trees damaged by this termite species, compare the damage by tree species, and evaluate the economic impact.     

Antennal cropping in the Asian dry-wood termite, Neotermes koshunensis

Antennal cropping, a behavior inferred to exist because queens and kings have shorter antennae than fresh alates, is widespread in termites. However, the proximate and ultimate mechanisms underlying this phenomenon remain unclear. We studied the occurrence of antennal cropping in queens and kings of the dry-wood termite Neotermes koshunensis (Kalotermitidae). Observation of the antennal tip structure with scanning electron microscopy and the occurrence of antennal cropping in new kings and queens reared in isolation indicated that self-cropping is an important proximate mechanism. Previous studies inferred that antennal cropping may play a key role in the life-history of alates at the colony-founding stage. However, we also found antennal cropping in adultoid reproductives (secondary reproductives) that had not experienced a colony founding. We propose a new hypothesis that antennal cropping is important for individuals in regulating their physiology when they change from the non-reproducing to the reproducing phase.     

Studies on the Natural Durability of Tropical Timbers to termite attack

Small samples of 28 tropical timbers were tested with the dry-wood termite Cryptotermes cynocephalus and the subterranean termite Coptotermes curvignathus using several methods of testing. The results revealed that four among 28 species of wood were completely durable to the two species of termite. They are Dalbergia latifolia, Eusideroxylon zwageri, Intsia bijuga and Tectona grandis. Agathis alba, Dipterocarpus spp. and Mangifera spp. were classified as the most susceptible wood species to termites.     

广西南宁市园林树木白蚁发生种类及危害情况

2009年311月对南宁市园林树木白蚁为害情况进行了调查。结果表明,台湾乳白蚁Coptotermes formosanus Shiraki是危害园林树木的优势种;调查的57种树木中,45种树木受到了白蚁的侵害,占总数的78.95%,树木受害株率达13.11%,严重受害株率为1.66%。银桦、侧柏和樟树等树种受白蚁危害最为严重。     

Economic and ecological importance of termites: A global review

In this review article, the positive and negative impacts of termites on ecosystems and human activities are examined. Various ecosystem services provided by termites – their importance as a food resource for humans, wildlife and domestic animals – are discussed, along with the use of these insects in scientific research and in folk and traditional medicine. Some insufficiently studied properties of termites (their ability to perceive the radiation of radioactive substances, electric fields and magnetic fields), as well as the use of termites in bionics, are described. Special attention is paid to the use of termite mounds for different purposes (e.g. in mineral deposit searches, in medical applications, as furnaces for copper smelting, for storage of some nuts, as burial sites, for gathering of edible mushrooms of the genus Termitomyces and as fertilizer). Examples of such use in different countries are given. This article reviews the activities of termites as pests of agriculture and forestry, including crops that are most affected, and termites as structural pests (e.g. wooden structures, household furniture, books and museum collections). Examples of termites’ malicious activities in different parts of the world are provided. Information on the invasions of termites is given, and the main areas of expansion of their habitat are described. The economic loss caused by termites in some countries and the world as a whole are presented. The article also lists the most economically important termite species in the world.     

Phylogenetic Position and In Situ Identification of Ectosymbiotic Spirochetes on Protists in the Termite Gut

Phylogenetic relationships, diversity, and in situ identification of spirochetes in the gut of the termite Neotermes koshunensis were examined without cultivation, with an emphasis on ectosymbionts attached to flagellated protists. Spirochetes in the gut microbial community investigated so far are related to the genus Treponema and divided into two phylogenetic clusters. In situ hybridizations with a 16S rRNA-targeting consensus oligonucleotide probe for one cluster (known as termite Treponema cluster I) detected both the ectosymbiotic spirochetes on gut protists and the free-swimming spirochetes in the gut fluid of N. koshunensis. The probe for the other cluster (cluster II), which has been identified as ectosymbionts on gut protists of two other termite species, Reticulitermes speratus and Hodotermopsis sjoestedti, failed to detect any spirochete population. The absence of cluster II spirochetes in N. koshunensis was confirmed by intensive 16S ribosomal DNA (rDNA) clone analysis, in which remarkably diverse spirochetes of 45 phylotypes were identified, almost all belonging to cluster I. Ectosymbiotic spirochetes of the three gut protist species Devescovina sp., Stephanonympha sp., and Oxymonas sp. in N. koshunensis were identified by their 16S rDNA and by in situ hybridizations using specific probes. The probes specific for these ectosymbionts did not receive a signal from the free-swimming spirochetes. The ectosymbionts were dispersed in cluster I of the phylogeny, and they formed distinct phylogenetic lineages, suggesting multiple origins of the spirochete attachment. Each single protist cell harbored multiple spirochete species, and some of the spirochetes were common among protist species. The results indicate complex relationships of the ectosymbiotic spirochetes with the gut protists.     

合肥环城公园林木白蚁的危害及防治

调查了合肥环城公园内 2 7种树木 ,其中 1 1种树木受到白蚁的侵害 ,占调查树种的 40 75 % ;树木侵害数为 82株 ,占总调查株数的 4 0 2 %。台湾乳白蚁CoptotermesformosanusShirak是危害林木的主要种类 ,在受害的 82株树木中 ,有 80株 (占受害株数的 97 5 6% )是受到台湾乳白蚁的危害 ,占调查株数的3 92 %。刺槐、榆树和构树受其危害最为严重。通过针对性防治 ,白蚁的发生情况明显减少     

The dynamics of hollowing in annually burnt savanna trees and its effect on adult tree mortality

Savanna trees often display significant hollows due to the combined action of fire and termites (N’Dri et al., J Trop Ecol 27:269–278, 2011). Observations have shown that internal cavities caused by termites in tree stems often result in external hollows under annual fire regimes, and it is quite possible that such hollows/fire interaction may increase the probability of trunk or big branch breakage and/or tree mortality. A study of individual tree and branch mortality as a function of prior termite and fire damage was undertaken in a West African savanna (Lamto, Côte d’Ivoire) where most of the trees naturally have hollows in their stems due to termite and fire interaction. Our goal was to examine the dynamics of hollowing and to determine whether hollowing significantly affected tree mortality. Branch and whole plant mortality were quantified for dominant tree species according to their initial hollow state and height. Four different responses were obtained depending on tree species: (1) mortality increased with cavity severity and tree size (Piliostigma thonningii), (2) mortality depended on tree size only (Bridelia ferruginea), (3) no mortality even after being hollowed by termites and externally damaged by fire (Crossopteryx febrifuga, the species with the highest proportion of individuals with hollows yet the greatest background survival time, 14 ± 2 years) and (4) high mortality, but few hollow trees suggesting a weak resistance to hollowing (Cussonia arborea which was insensitive to all the factors examined in this study). For species resistant to hollowing, tree mortality was rare; alternatively, for species prone to hollowing, whole trees died quickly and before the most severe hollow classes could be observed. Long-term demographic data yielded population-level mortality estimates of adult trees at least four times lower in fire-exclusion zones than that in fire-prone areas. Because hollow dynamics interact with fire in affecting adult mortality of some dominant tree species, fire management is important for a sustainable woody component of these savannas.     

Fungal nutrition allocation enhances mutualism with fungus-growing termite

Fungal nodules and aged fungus gardens are products of termite fungiculture systems, and are the diets of termites. To understand the nutrition flow in fungiculture, we quantified the number and mass of fungal nodules produced along with fungus garden maturation and analysed the α-amino acid and fatty acid compositions of fungal nodules, fungus gardens, and termite tissues of a fungus-growing termite, Odontotermes formosanus. 1 g of fungus garden produced 5,148 fungal nodules (∼68.0 mg). Approximately 7.0% of α-amino acids were allocated to the fungal nodules and the rest (∼93.0%) remained in the fungus gardens. The compositions of α-amino acids or fatty acids in aged fungus gardens and fungal nodules were more similar to that of termite tissues than fresh fungus gardens, which supports the idea that termites nutritionally depend on the fungal products. Among the 18 α-amino acids, tryptophan was an essential amino acid and was the only one missing from fresh and aged fungus gardens, but found in fungal nodules at significantly higher concentrations. Hence, termites must consume fungal nodules to obtain tryptophan for survival. Furthermore, the fungus spores incorporated in nodules, were transferred when nodules were ingested by termites. We propose that allocating tryptophan in fungal nodules is crucial to enhance the mutualism between the fungus and termite.     

Distribution pattern of Termitomyces types symbiotic with the fungus‐growing termite Odontotermes formosanus on Okinawa Island

Fungus‐growing termites (subfamily Macrotermitinae) cultivate the symbiotic basidiomycete fungus Termitomyces in their fungus comb to digest cellulosic materials and to supply nitrogen‐rich fungal diet. In Japan, the fungus‐growing termite Odontotermes formosanus is found on the Yaeyama Islands and Okinawa Island, Okinawa Prefecture. Odontotermes formosanus is thought to have been recently and artificially introduced to Okinawa Island as its distribution is discontinuous and restricted to small areas. Previous DNA analyses revealed that two types of Termitomyces, namely Termitomyces sp. Type A and Termitomyces sp. Type B, whose fruiting bodies correspond to Termitomyces microcarpus‐like pseudorhiza‐lacking small mushroom and Termitomyces intermedius, respectively, are cultivated by O. formosanus on the Yaeyama Islands. However, information about the Termitomyces types cultivated by O. formosanus on Okinawa Island is limited. To define the fungal types cultivated by O. formosanus on Okinawa Island, I developed a diagnostic polymerase chain reaction method using primer sets specific to the nuclear ribosomal DNA sequences consisting of the internal transcribed spacers (ITS1 and ITS2) and 5.8S rDNA of Termitomyces not using fungal mycelium, but using the termite gut metagenome including fungal DNA as a template. The results indicated that the same two Termitomyces types from Iriomote Island are cultivated by O. formosanus on Okinawa Island. The distribution pattern of Termitomyces types on Okinawa Island showed that Termitomyces sp. Type A is limited to the mountainous side of Sueyoshi Park, despite Termitomyces sp. Type B being widely distributed in the area in which O. formosanus is found. This finding implies that O. formosanus on Okinawa Island was recently introduced from Iriomote Island to Sueyoshi Park.     

Extended disease resistance emerging from the faecal nest of a subterranean termite

Social insects nesting in soil environments are in constant contact with entomopathogens but have evolved a range of defence mechanisms, resulting in both individual and social immunity that reduce the chance for epizootics in the colony, as in the case of subterranean termites. Coptotermes formosanus uses its faeces as building material for its nest structure that result into a ‘carton material’, and here, we report that the faecal nest supports the growth of Actinobacteria which provide another level of protection to the social group against entomopathogens. A Streptomyces species with in vivo antimicrobial activity against fungal entomopathogens was isolated from the nest material of multiple termite colonies. Termite groups were exposed to Metarhizium anisopliae, a fungal entomopathogen, during their foraging activity and the presence of Streptomyces within the nest structure provided a significant survival benefit to the termites. Therefore, this report describes a non-nutritional exosymbiosis in a termite, in the form of a defensive mutualism which has emerged from the use of faecal material in the nesting structure of Coptotermes. The association with an Actinobacteria community in the termite faecal material provides an extended disease resistance to the termite group as another level of defence, in addition to their individual and social immunity.     

Effect of fungi–termite interaction on the chlorophyll content of three rice varieties grown on ultisol soil of Ikenne,south-west Nigeria

The effect of fungi–termite interaction on three rice varieties was conducted in a screen house at the Africa Rice Center (AfricaRice) Ibadan, Nigeria. Of the 10 fungi species (Fusarium verticilloides, Trichoderma sp., Aspergillus niger, Aspergillus flavus, Macrophoma sp., Neurospora sp., Botryodiplodia theobromae, Penicillum sp., Rhizopus sp. and Sclerotium rolfsii) isolated from termites, soil and rice plants, F. verticilloides, Trichoderma sp. and B. theobromae were used for the interaction study. Each fungus was inoculated singly and in combinations with termite into the root of each rice variety in potted soil. Leaf samples were taken to measure the chlorophyll content which is a major parameter to estimate effect of termite–fungi interaction. The chlorophyll content of the inoculated rice plants was significantly reduced when compared with the control. Fungi interaction with termite had significant reduction on the chlorophyll content. The synergistic relationship between the fungi and the termite was discussed.     

Asexual queen succession in the higher termite Embiratermes neotenicus

Asexual queen succession (AQS), in which workers, soldiers and dispersing reproductives are produced sexually while numerous non-dispersing queens arise through thelytokous parthenogenesis, has recently been described in three species of lower termites of the genus Reticulitermes. Here, we show that AQS is not an oddity restricted to a single genus of lower termites, but a more widespread strategy occurring also in the most advanced termite group, the higher termites (Termitidae). We analysed the genetic structure in 10 colonies of the Neotropical higher termite Embiratermes neotenicus (Syntermitinae) using five newly developed polymorphic microsatellite loci. The colonies contained one primary king accompanied either by a single primary queen or by up to almost 200 neotenic queens. While the workers, the soldiers and most future dispersing reproductives were produced sexually, the non-dispersing neotenic queens originated through thelytokous parthenogenesis of the founding primary queen. Surprisingly, the mode of thelytoky observed in E. neotenicus is most probably automixis with central fusion, contrasting with the automixis with terminal fusion documented in Reticulitermes. The occurrence of AQS based on different mechanisms of ploidy restoration raises the hypothesis of an independent evolutionary origin of this unique reproductive strategy in individual lineages of lower and higher termites.     

Farmers’ perception of termites in agriculture production and their indigenous utilization in Northwest Benin

Background

Although termites are considered as agricultural pests, they play an important role in maintaining the ecosystem. Therefore, it matters to investigate the farmers’ perception of the impacts of the termites on the agriculture and their indigenous utilization.

Methods

A semi-structured questionnaire was used to interview 94 farmers through 10 villages of Atacora department, in the northwestern region of Benin, to obtain information for the development of successful strategies of termite management and conservation. Their perceptions on the importance and management of termites along with the indigenous nomenclature and utilization of termite mounds were assessed. Termite species identified by farmers were collected and preserved in 80% alcohol for identification.

Results

Eight crops were identified by farmers as susceptible to termites with maize, sorghum, and yam as being the most susceptible. According to farmers, the susceptibility to termites of these crops is due to their high-water content and sweet taste. A total of 27 vernacular names of termites were recorded corresponding to 10 species, Amitermes evuncifer, Macrotermes subhyalinus, and Trinervitermes oeconomus being the most damaging termite species. All the names given to termite species had a meaning. The drought was identified by farmers as the main factor favouring termite attacks. Demolition of termite mounds in the fields was the most commonly reported control method. Salt and other pesticides were commonly used by farmers to protect stored farm products. The lack of effective control methods is the main constraint for termite management. In northwestern Benin, farmers reported different purpose utilizations of termite mounds and termites.

Conclusions

The study has shown that farmers perceived termites as pests of several agricultural crops and apply various indigenous control practices whose efficiency need to be verified. Utilization of termites and termite mound soil as food and medicinal resources underlines the need for a more focused approach to termite control for the conservation of non-pest termite species. The sensitization of farmers on the importance of termites as well as the development of an integrated control method to combat termite pests proved necessary.

     

The spatial pattern of soil-dwelling termites in primary and logged forest in Sabah, Malaysia

Abstract.  1. Primary and logged lowland dipterocarp forest sites were sampled for subterranean termites using soil pits located on a grid system in order to detect any patchiness in their distribution.
2. A spatial pattern in termite distributions was observed in the primary and logged sites, but the response differed between soil-feeding and non-soil-feeding termites.
3. Spatial analysis showed that soil-feeding termites were homogeneously distributed in the primary forest but significantly aggregated in the logged forest. This pattern was reversed for non-soil-feeding termites and may result from differences in resource provisioning between the two sites.
4. Gaps in termite distribution comprised a greater area than patches for both feeding groups and sites, but gaps dominated the logged site.
5. A significant association between soil-feeding and non-soil-feeding termite distributions occurred at both sites. This arose from an association between patches in the primary forest and between gaps in the logged forest.
6. Termite spatial pattern was optimally observed at a minimum extent of 64 m and lag of 2 m.
7. The spatially explicit SADIE (Spatial Analysis by Distances IndicEs) analyses were more successful than (non-spatially explicit) multivariate analysis (Canonical Correspondence Analysis) at detecting associations between termite spatial distributions and that of other biotic and abiotic variables.     

Nitrogen Fixation by Termites in Tropical Forests, Thailand

Nitrogen (N) fixed by termites was evaluated as a N input to decomposition processes in two tropical forests, a dry deciduous forest (DDF) and the neighboring dry evergreen forest (DEF), Thailand. A diverse group of termite species were assayed by acetylene reduction method and only the wood/litter-feeding termites were found to fix N. More intensive samplings of two abundant species, Microcerotermes crassus and Globitermes sulphureus, were done across several seasons, suggesting N fixation rates of 0.21 and 0.28 kg ha⁻¹ y⁻¹ by termites in the DDF and DEF, respectively. Also, estimates of asymbiotic N fixation rates were 0.75 and 3.95 kg ha⁻¹ y⁻¹. N fixed by termites and by asymbiotic fixers is directly supplied to decomposers breaking down dead plant material and could be a major source of their N. N fixed by termites was 7–22% of that fixed by termites and asymbiotic fixers. Although N fixed by termites is a small input compared to other inputs, this N is likely important for decomposition processes.     

Termite diversity in Neotropical dry forests of Colombia and the potential role of rainfall in structuring termite diversity

Termites are ecosystem engineers that play an important role in the biotransformation and re‐distribution of nutrients in soil. The dry forests are endemic repositories, but at same time, they are most threatened by extensive livestock and crop farming, fires, and climate change. In Colombia, the best‐protected dry forests are located in the north. The termite fauna of dry forests are poorly known. The aim was to identify the termite species occurring in tropical dry forests of the Colombian Caribbean coast in relation to diet and precipitation, temperature, elevation, and soil properties. A total of 32 species in 1,103 occurrences were found. Termitidae accounted for 78% of the species richness with the Anoplotermes‐group, Microcerotermes, and Nasutitermes being the dominant genera. Differences in species composition and abundance were found across sites. These differences may be linked to anthropogenic disturbance and polygyny and polydomy. Strikingly, our highest elevation site (334 m) had the highest species richness much higher than the two lower elevation sites. This implies an inversion of the common elevation‐diversity gradient, also found for termites which can be explained by increasing precipitation with elevation in the dry forest. An analysis of termite species richness at the global scale confirms that termite species richness correlates positively with rainfall. Hence, rainfall seems to positively affect termite diversity. In line, the studied Colombian tropical dry forests had low diversity compared to rain forests. A decline of species‐rich soil‐feeding termites with increasing aridity may explain why the highest termite diversity occurs in humid tropical rain forests. Abstract in Spanish is available with online material.     

Fishes ofNeoclinus from Okinawa with notes on the traits of their habitats

All the fish specimens ofNeoclinus bryope species complex collected from Okinawa Island including the 2 specimens already reported asN. bryope are referable toN. okazakii. Neoclinus nudus, hitherto known only from Taiwan, is newly recorded from Okinawa Island. These two species are redescribed on the basis of the specimens from Okinawa Island. The specimens from Okinawa are compared with those from Shirahama in the case ofN. okazakii and with specimens from Taiwan as well asN. lacunicola andN. toshimaensis specimens from Shirahama in the case ofN. nudus. The habitats ofN. okazakii andN. nudus are clearly separated in the waters of Heshikiya, Okinawa Island and the habitat of either species is rather particular in that it is exceptionally unoccupied by blenniids which are flourishing in the coastal waters of the Okinawa Islands.     

Assessment of the contamination and genotoxicity of soil irrigated with wastewater

Soil structures built by litter-feeding termites are one of the main soil translocation processes in dry tropical savanna. Runways (soil sheeting) made of soil particles cemented with salivary secretions covering the dead plant pieces collected on the ground surface represent the main soil structures. The aim of this study was to determine the impact of this soil engineering activity on the microbially-mediated N transformations (nitrification and denitrification) associated with termite sheeting. We investigated the hypothesis that the physicochemical and microbial properties of termite soil sheeting depend on (i) the termite species and (ii) the type of organic substrate consumed. Soil sheeting built by two of the main savanna species, Macrotermes subhyalinus and Odontotermes nilensis, were sampled on field plots treated with three different types of litter (Acacia leaves, millet straw, both whole and ground (< 500 µm), and cattle manure). The soils organic C, total N, inorganic N, microbial biomass, potential CO₂ respiration, nitrification and denitrification were measured. For both termite species and all types of litter, the soil sheeting was enriched in organic C and inorganic N, resulting in an increase in soil respiration, whereas the microbial biomass was unchanged with respect to the reference soil. With the exception of the soil nitrification potential, the type of organic substrate did not significantly affect the properties of the soil sheeting measured. However, the nitrogen cycle was affected differently by the two termite species. In O. nilensis sheeting, the denitrification potential was reduced with respect to the reference soil, whereas the nitrification potential was inhibited in M. subhyalinus sheeting. The changes in the nitrogen cycle processes resulted in an increase in NH₄₊ and NO_3– in the termite soil sheeting, increasing the availability of nitrogen to plants. This study reinforces the importance of termites as a keystone savanna group whose building activities have an effect on tropical soil mineralization.