Termite Assemblage and Damage on Tree Trunks in Fast-Growing Teak Plantations of Different Age: A Case Study in West Java, Indonesia.

We conducted surveys of termite assemblages and tree trunks damaged by termites in teakwood (Tectona grandis L.f.) plantations. The surveys were conducted in five-, six-, and nine-year-old plantations. We used a standardized belt-transect to collect termites and build tree inventories. Data of collected termites at the genus and functional-group levels and termites' diversity between plantations were compared with their attack rate. The results showed that four genera of soil recycler termites belonging to groups IIf and III were present across the plantations. Distribution analysis suggested that termite communities might develop from a stochastic distribution to a nonrandom co-occurrence distribution over time. Diversity analysis showed an increased nestedness-resultant diversity contribution to the total dissimilarity over time. Observed attacks on tree trunks were superficial and limited to the outer bark, with group IIf as the main contributor. Furthermore, the level of damage done by termites to tree trunks was positively correlated with increases in the group IIf occupancy area and overgrown understory vegetation. Plantation management by maintaining an adequate understory might suppress termite attacks on fast-growing teakwood, although in the case of our study, termite attacks are inevitable when termites from group IIf were already present.

Influence of Age and Mating Status on Pheromone Production in a Powderpost Beetle Lyctus africanus (Coleoptera: Lyctinae).

Powderpost beetles such as Lyctus africanus are a common pest group for dried cured wood, causing significant harm to wood and wood products. We examined the life span and effects of aging and mating status on pheromone production in the powderpost beetle L. africanus (Coleoptera: Lyctinae). Experiments compared starved and unstarved male groups, and chemical analysis was used to determine factors affecting pheromone production. Regarding lifespan, male beetles provided food survived up to 14 weeks, while starved beetles died before the fifth week. Thus, an adult L. africanus male may require food throughout its lifespan, and food availability may affect pheromone production. There was no significant difference in the quantity of two major pheromone compounds, compound 2 (3-pentyl dodecanoate) and 3 (3-pentyl tetradecanoate) between mated and un-mated males. On the other hand, a minor compound, compound 1 (2-propyl dodecanoate) showed increased quantity after mating. The two major compounds were produced in low amounts by young L. africanus beetles, increasing until the fifth week, and beginning to decrease at the ninth week. The minor compound was produced steadily without significant change up to 9 weeks. Our results represent a step forward in the knowledge of the chemical communication of this important pest.

Identification of Esters as Novel Aggregation Pheromone Components Produced by the Male Powder-Post Beetle, Lyctus africanus Lesne (Coleoptera: Lyctinae).

Lyctus africanus is a cosmopolitan powder-post beetle that is considered one of the major pests threatening timber and timber products. Because infestations of this beetle are inconspicuous, damage is difficult to detect and identification is often delayed. We identified the chemical compounds involved in the aggregation behavior of L. africanus using preparations of crude hexanic extracts from male and female beetles (ME and FE, respectively). Both male and female beetles showed significant preferences for ME, which was found to contain three esters. FE was ignored by both the sexes. Further bioassay confirmed the role of esters in the aggregation behavior of L. africanus. Three esters were identified as 2-propyl dodecanoate, 3-pentyl dodecanoate, and 3-pentyl tetradecanoate. Further behavioral bioassays revealed 3-pentyl dodecanoate to play the main role in the aggregation behavior of female L. africanus beetles. However, significantly more beetles aggregated on a paper disk treated with a blend of the three esters than on a paper disk treated with a single ester. This is the first report on pheromone identification in L. africanus; in addition, the study for the first time presents 3-pentyl dodecanoate as an insect pheromone.

Evaluation of Wood and Cellulosic Materials as Fillers in Artificial Diets for Lyctus africanus Lesne (Coleoptera: Bostrichidae).

We studied the usefulness of wood- and cellulose-based diets for L. africanus Lesne. Three diets were prepared which differed on the base ingredients; wood particles (Diet 1), cellulose powder (Diet 2), and alpha-cellulose (Diet 3). The diets were provided to adult L. africanus and the number of larvae, as well as the number of adults that emerged sex ratio, and body weight of the progeny was determined. Findings indicated similar results for the number of larvae, sex ratio and body weight of the emerged L. africanus fed on each diet. However, the number of adult produced by L. africanus on Diet 3 was significantly lower. The results indicate that the amount of vital nutrients is not the only important factor in selecting a suitable diet for L. africanus because the filler used in artificial diets influences the beetles overall population growth. For the population upon which the diets were tested, Diet 1 and Diet 2 could be utilized to rear beetles in the laboratory.