A Review of Termite Species and Their Distribution in Thailand.

Although 3105 termite species have been documented worldwide, little information is available on those in Thailand. In this review, the Google Scholar search platform and the Scopus and Science Direct databases were used to obtain information on termite species and for georeferencing. The QGIS software was used to create point localities that were overlaid on the Thailand administrative level 1 (province) to map the distribution of termite species in the country based on the World Geodetic System 1984. From the 19 reviewed sources, 44 defined coordinates were identified in 14 provinces across Thailand. Among these 44 coordinates, we found 75 termite species and 83 unknown species of termites; in total, 36 termite species were from the North (6 locations), 33 species were from the Northeast (10 locations), 34 species were from the West (4 locations), 29 species were from the Central region (3 locations), 44 species were from the East (8 locations), and 54 species were from the South (13 locations). The most predominant species in all regions were Globitermes sulphureus, Macrotermes gilvus, Microcerotermes crassus, and Microtermes obesi.

Ability of field populations of Coptotermes spp., Reticulitermes flavipes, and Mastotermes darwiniensis (Isoptera: Rhinotermitidae; Mastotermitidae) to damage plastic cable sheathings.

A comparative field study was conducted to evaluate the ability of subterranean termites to damage a set of four different plastic materials (cable sheathings) exposed below- and above-ground. Eight pest species from six countries were included, viz., Coptotermes formosanus (Shiraki) in China, Japan, and the United States; Coptotermes gestroi (Wasmann) in Thailand and Malaysia; Coptotermes curvignathus (Holmgren) and Coptotermes kalshoveni (Kemner) in Malaysia; Coptotermes acinaciformis (Froggatt) with two forms of the species complex and Mastotermes darwiniensis (Froggatt) in Australia; and Reticulitermes flavipes (Kollar) in the United States. Termite species were separated into four tiers relative to decreasing ability to damage plastics. The first tier, most damaging, included C. acinaciformis, mound-building form, and M. darwiniensis, both from tropical Australia. The second tier included C. acinaciformis, tree-nesting form, from temperate Australia and C. kalshoveni from Southeast Asia. The third tier included C. curcignathus and C. gestroi from Southeast Asia and C. formosanus from China, Japan, and the United States, whereas the fourth tier included only R. flavipes, which caused no damage. A consequence of these results is that plastics considered resistant to termite damage in some locations will not be so in others because of differences in the termite fauna, for example, resistant plastics from the United States and Japan will require further testing in Southeast Asia and Australia. However, plastics considered resistant in Australia will be resistant in all other locations.

Development of Silafluofen-Based Termiticides in Japan and Thailand.

With the advancement from natural pyrethrins to synthetic pyrethroids, their applications have expanded from household insecticides for indoor use against sanitary pests to outdoor use for agriculture, forestry, animal health, termite control, and many other pest situations. However, high fish toxicity and development of pyrethroid resistance in some pests have been cited as common shortcomings of pyrethroids. To overcome these pyrethroid problems such as high fish toxicity, Katsuda and fellow scientists invented silafluofen by introducing a silicone atom into the pyrethroidal chemical structure in 1984. In addition to the high insecticidal activity and low mammalian toxicity, this compound features low fish toxicity, chemical stability under sunlight, in the soil and under alkaline environments. These features make silafluofen unique among pyrethroids. In Japan, silafluofen has been used as an agricultural insecticide for 15 years since 1995 for various plants, especially useful for paddy rice protection because of its low fish toxicity. Over the last 20 years, silafluofen-based termiticides including emulsifiable concentrate (EC) and oil formulations have been widely used in Japan for soil treatment and timber treatments. Additional silafluofen product lines include anti-termitic plastic sheets which are laid under buildings. In this paper, literature on the development of silafluofen and its use in Japan are reviewed. On the other hand, in Thailand, we proceeded with development works of silafluofen-based termiticides from 2005 by starting laboratory efficacy tests and field efficacy tests in Phuket. Both laboratory and field tests showed good efficacy as a soil termiticide, suggesting that the material will perform well for commercial use in high biological hazard environments such as Thailand and can be used in environments close to water where fish toxicity might be a concern with other pyrethroids.

Identification and characterization of ectosymbionts of distinct lineages in Bacteroidales attached to flagellated protists in the gut of termites and a wood-feeding cockroach.

Bacterial attachments to nearly the entire surface of flagellated protists in the guts of termites and the wood-feeding cockroach Cryptocercus are often observed. Based on the polymerase chain reaction-amplified 16S rRNA gene sequences, we investigated the phylogenetic relationships of the rod-shaped, attached bacteria (ectosymbionts) of several protist species from five host taxa and confirmed their identity by fluorescence in situ hybridizations. These ectosymbionts are affiliated with the order Bacteroidales but formed three distinct lineages, each of which may represent novel bacterial genera. One lineage consisted of the closely related ectosymbionts of two species of the protist genus Devescovina (Cristamonadida). The second lineage comprised three phylotypes identified from the protist Streblomastix sp. (Oxymonadida). The third lineage included ectosymbionts of the three protist genera Hoplonympha, Barbulanympha and Urinympha in the family Hoplonymphidae (Trichonymphida). The ultrastructural observations indicated that these rod-shaped ectosymbionts share morphological similarities of their cell walls and their point of attachment with the protist but differ in shape. Elongated forms of the ectosymbionts appeared in all the three lineages. The protist cells Streblomastix sp. and Hoplonympha sp. display deep furrows and vane-like structures, but these impressive structures are probably evolutionarily convergent because both the host protists and their ectosymbionts are distantly related.

Intra- and interspecific comparisons of bacterial diversity and community structure support coevolution of gut microbiota and termite host.

We investigated the bacterial gut microbiota from 32 colonies of wood-feeding termites, comprising four Microcerotermes species (Termitidae) and four Reticulitermes species (Rhinotermitidae), using terminal restriction fragment length polymorphism analysis and clonal analysis of 16S rRNA. The obtained molecular community profiles were compared statistically between individuals, colonies, locations, and species of termites. Both analyses revealed that the bacterial community structure was remarkably similar within each termite genus, with small but significant differences between sampling sites and/or termite species. In contrast, considerable differences were found between the two termite genera. Only one bacterial phylotype (defined with 97% sequence identity) was shared between the two termite genera, while 18% and 50% of the phylotypes were shared between two congeneric species in the genera Microcerotermes and Reticulitermes, respectively. Nevertheless, a phylogenetic analysis of 228 phylotypes from Microcerotermes spp. and 367 phylotypes from Reticulitermes spp. with other termite gut clones available in public databases demonstrated the monophyly of many phylotypes from distantly related termites. The monophyletic "termite clusters" comprised of phylotypes from more than one termite species were distributed among 15 bacterial phyla, including the novel candidate phyla TG2 and TG3. These termite clusters accounted for 95% of the 960 clones analyzed in this study. Moreover, the clusters in 12 phyla comprised phylotypes from more than one termite (sub)family, accounting for 75% of the analyzed clones. Our results suggest that the majority of gut bacteria are not allochthonous but are specific symbionts that have coevolved with termites and that their community structure is basically consistent within a genus of termites.

Molecular phylogeny of Asian termites (Isoptera) of the families Termitidae and Rhinotermitidae based on mitochondrial COII sequences.

The families Termitidae and Rhinotermitidae are the most evolved and diverse groups of the social insects, termites (Order Isoptera), showing elaborated morphology and complex behavior. Molecular phylogeny of termites with the emphasis on these families was examined by Bayesian and maximum-likelihood analyses based on DNA sequence of mitochondrial cytochrome oxidase II (COII) gene of 31 genera sampled in Asia (mainly Thailand and Japan) along with those reported previously. Termitidae was monophyletic and originated from within polyphyletic Rhinotermitidae. Among the four subfamilies of Termitidae, Macrotermitinae was monophyletic suggesting a single common origin of fungus-growing habit characteristic for this subfamily, and was placed in the basal position in the family. A group consisting of other subfamilies Termitinae and Nasutitermitinae, though some important groups were still untouched, was the most apical but neither Termitinae nor Nasutitermitinae formed a monophyletic lineage. It was implied that, as defense systems of the soldier castes, the appearance of snapping mandibles has occurred at a single event, but the development of nasus for chemical secretion has probably not. Our tree provides some evidence concerning contradictions in the previously proposed phylogeny of termites.