Measuring wood preference in termites

Feeding preferences of xylophagous termites have been determined by comparing differences in wood biomass removed, percentage of wood consumed or degree of damage rated in arbitrary categories. When test woods differ in physical characteristics such as density, these measures are not comparable. We examined the response of the Formosan termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) to wood that differed in physical characteristics by compressing blocks to 40% greater than the natural density. Termites ate significantly greater percentages, but similar amounts of biomass, of uncompressed over compressed natural pine. In contrast, they ate significantly greater amounts of biomass, but similar percentages, of compressed over uncompressed mahogany. Whether percentage or amount of biomass removed should be used as a measure of preference depends on what regulates insect meal size. If termites consume meals of fixed biomass, then biomass consumed is the correct measure; percentage removed is appropriate if they consume meals of fixed volume.Deceased, July 25, 1989     

Characterization of a laccase from a wood‐feeding termite,Coptotermes formosanus

Coptotermes formosanus Shiraki is a wood‐feeding termite which secretes a series of lignolytic and cellulolytic enzymes for woody biomass degradation. However, the lignin modification mechanism in the termite is largely elusive, and the characteristics of most lignolytic enzymes in termites remain unknown. In this study, a laccase gene lac1 from C. formosanus was heterogeneously expressed in insect Sf9 cells. The purified Lac1 showed strong activities toward hydroquinone (305 mU/mg) and 2,6‐dimethoxyphenol (2.9 mU/mg) with low K_m values, but not veratryl alcohol or 2,2’‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid). Lac1 could function well from pH 4.5 to 7.5, and its activity was significantly inhibited by H₂O₂ at above 4.85 mmol/L (P < 0.01). In addition, the lac1 gene was found to be mainly expressed in the salivary glands and foregut of C. formosanus, and seldom in the midgut or hindgut. These findings suggested that Lac1 is a phenol‐oxidizing laccase like RflacA and RflacB from termite Reticulitermes flavipes, except that Lac1 was found to be more efficient in phenol oxidation, and it did not require H₂O₂ for its function. It is suspected that this kind of termite laccase might only be able to directly oxidize low redox‐potential substrates, and the high redox‐potential groups in lignin might be oxidized by other enzymes in the termite or by using the Fenton reaction.     

台湾金线兰组织培养及营养成分分析

用台湾金线兰（ＡｎｏｅｃｔｏｃｈｉｌｕｓｆｏｒｍｏｓａｎｕｓＨａｙ．）的茎段作外植体,比较不同的培养基、蔗糖浓度、有机添加物、ｐＨ值、激素等因素对丛生芽生成的影响,实验证明Ｂ５及ＭＳ较好,蔗糖浓度为２％～３％,在细胞分裂素试验中发现ＢＡ作用优于ＫＴ和ＺＴ,最适浓度为４ｍｇ／ｌ,还证明４Ｐｕ－３０在０．５ｍｇ／ｌ浓度下即有很好的作用。台湾金线兰组织培养苗及与同属植物花叶开唇兰（Ａ．ｒｏｘ－ｂｕｒｇｈｉ（Ｗａｌ．）Ｌｉｎｄｌ．）组培苗和野生药材的氨基酸、维生素的含量测定,结果表明台湾金线兰的氨基酸含量较高,并有丰富的ＶＣ,ＶＢ１,ＶＢ２,ＶＥ,尼克酸及胡罗卜素,对进一步直接开发利用金线连组织培养苗提供了依据     

台湾乳白蚁与赭黄乳白蚁的异名关系---基于形态与分子特征的分析(等翅目：鼻白蚁科）

乳白蚁属Coptotermes是鼻白蚁科Rhinotermitidae最具经济意义的属之一,其中的台湾乳白蚁Coptotermes formosanus Shriaki分布广、适应性强,个体在不同种群以及不同巢龄间外部形态存在明显变异,已报道多个同物异名。本研究发现在模式产地重新采集到经形态学鉴定为赭黄乳白蚁Coptotermes ochraceus Ping et Xu的标本,其形态特征与台湾乳白蚁相似度较高,又以线粒体16S rRNA和CO II基因作为分子标记,将两者进行了序列比对,并与美国国立生物技术信息中心(NCBI)中台湾乳白蚁以及其他一些乳白蚁种类的相应序列一起进行了遗传差异比较和同源性分析。结果表明,台湾乳白蚁与赭黄乳白蚁16S rRNA和CO II序列的遗传差异均明显小于台湾乳白蚁与属内其它种之间的差异;在基于两种分子标记构建的支序图中,台湾乳白蚁和赭黄乳白蚁均聚为一支,并得到了很高的自展支持率。综合分子和形态两方面的证据,本研究建议赭黄乳白蚁为台湾乳白蚁的次异名。     

Evaluation of an entomopathogenic fungus, Paecilomyces fumosoroseus (Wize) Brown and Smith (Deuteromycota: Hyphomycetes) obtained from Formosan subterranean termites (Isop., Rhinotermitidae)

Abstract:  An isolate of Paecilomyces fumosoroseus was obtained from Coptotermes formosanus collected in Hong Kong, and a commercially available isolate of Metarhizium anisopliae , were both tested against C. formosanus shipped live from China. Survivorship of termites treated with a suspension of 5 × 10⁵ M. anisopliae conidia/ml and kept alone declined more rapidly than for those treated at the same concentration of P. fumosoroseus conidia. At a 5 × 10⁶ conidia/ml concentration, no significant differences in terms of termite survivorship were observed between the two fungal species. However, among termites kept in groups of 10 after treatment, those sprayed with P. fumosoroseus conidia at either 5 × 10⁵ or 5 × 10⁶ conidia/ml had significantly lower survivorship than those sprayed with M. anisopliae conidia. All the cadavers of termites treated with P. fumosoroseus and kept alone sporulated and among grouped termites 29% of the cadavers sporulated. By comparison, 53% of the cadavers of termites treated with M. anisopliae and kept alone sporulated, and only 4% of the cadavers of treated termites kept in groups sporulated.     

Formosan subterranean termite swarming behavior and alate sex-ratio (Isoptera: Rhinotermitidae)

Summary The Formosan subterranean termite (Coptotermes formosanus Shiraki) was first sighted in the cities of New Orleans and Lake Charles, Louisiana, in 1966. Its distribution in the historic French Quarter of New Orleans 23 years later (1989) and in 1991 and 1992 is reported here using counts of alates from light-traps. Light-trappings revealed a Quarter-wide distribution of the termite.C. formosanus shows an extended pause in flight behavior in the middle of the two-month flight season that is predictable and independent of weather. A colony-level mechanism, namely, developmental inhibition of nymphs by alates, may regulate this intermission in flight. The sex-ratio of light-trapped alates varies over time, but is generally female-biased, especially at the height of the flight season.     

A Novel Strain of Steinernema riobrave (Rhabditida: Steinernematidae) Possesses Superior Virulence to Subterranean Termites (Isoptera: Rhinotermitidae)

Subterranean termites are major global pests of wood structures and wood products. Among the most economically important subterranean termite species in the US are Heterotermes aureus, Reticulitermes flavipes, and Coptotermes formosanus. In prior studies, the entomopathogenic nematode, Steinernema riobrave strain 355, exhibited a high level of virulence to H. aureus compared with other nematode species. However, S. riobrave 355 was reported to be poorly or only moderately virulent to R. flavipes and C. formosanus, respectively. We hypothesized that other strains of S. riobrave may possess a high level of virulence to all three termite species. Under laboratory conditions we compared three novel strains of S. riobrave (3-8b, 7-12, and TP) with the 355 strain for virulence to H. aureus, R. flavipes, and C. formosanus workers. H. aureus was very susceptible to all the S. riobrave strains, and termites in all nematode treatments were dead after 4 d. The TP strain of S. riobrave caused greater mortality in R. flavipes and C. formosanus compared to the other nematode strains. Specifically, the TP strain caused 75% and 91% mortality in R. flavipes and C. formosanus, respectively, which was more than 300% and 70% higher than the mortality caused by other strains. Additional studies are warranted to determine the ability of S. riobrave (TP) to control the targeted termite species under field conditions.     

黑翅土白蚁踪迹信息素组分数量的柱层析分离和活性测定分析

本文分析了在活性限浓度进行生物活性测定时,黑翅土白蚁Odontotermes formosanu Shiraki对踪迹信息素的行为反应特点以及使用不同踪迹线载体对踪迹信息素活性的影响。并设计标准生物活性测试方法,测定了采用柱层析方法分离的黑翅土白蚁踪迹信息素各分离馏分的活性,发现黑翅土白蚁踪迹信息素用22%乙酸乙酯/正己烷洗脱液等度洗脱分离后的各馏分中包含两个强活性区段,推测黑翅土白蚁踪迹信息素至少包含2个有轻微极性差异的组分。     

Distribution and Properties of Endo-β-1,4-glucanase from a Lower Termite,Coptotermes formosanus (Shiraki)

A multi-enzyme distribution of endo-β-1,4-glucanase activity was found in the digestive system of a worker caste of the lower termite Coptotermes formosanus (Shiraki) by zymogram analysis. Its distribution analysis demonstrated that about 80% of this activity was localized in salivary glands from where only one component (EG-E) was secreted into the digestive tract.

EG-E was isolated by a combination of chromatographic and electrophoretic techniques. Its molecular mass, optimal pH and temperature, isoelectric point, and K _m were 48 kDa, 6.0, 50°C, 4.2, and 3.8 (mg/ml on carboxymethylcellulose), respectively. EG-E hydrolyzed cellooligosaccharides with a degree of polymerization of 4 and larger, and had low activity on crystalline cellulose. Main reaction products from low molecular weight cellulose were cellobiose and cellotriose. The N-terminal amino acid sequence of EG-E has similarity with fungal endo-β-1,4-glucanases and cellobiohydrolases of the glycosyl hydrolase family 7 rather than the other insect endo-β-1,4-glucanases of family 9.     

扩头蔡白蚁消化与生殖系统解剖及其与黑翅土白蚁的比较研究

扩头蔡白蚁Tsaitermes ampliceps(Wang&Li)和黑翅土白蚁Odotoermes formosanus(Shiraki)是分布广泛的食木性昆虫,群居生活,具有复杂的品级分化.本试验研究了低等白蚁扩头蔡白蚁不同品级的消化和生殖系统结构,并与高等白蚁黑翅土白蚁进行了比较.结果显示扩头蔡白蚁的消化、生殖系...