Bark beetles species

Although a number of spedes utilize complex chemicals containing chiral centers and may, in fact, produce only one stereoisomer, the behavior of the responding male in some species is not affected by the presence of the other isomers and a racemic blend is as active as the pure isomer. However, other cases have been found in which a distinct chemical is found to be used by an insect species, but it is also part of the mating communication system of other related species. Species specificity then can be effected by utilizing a specific blend of the enantiomers (10). An example of this is with the two bark beetle species that utilize... 

Oxygenated monoterpenes which are found in almost every bark beetle species attacking coniferous trees, include czs-verbenol 246, frans-verbenol 247, and myrtenol 248, representing primary products of allylic oxidation of the host terpene a-pinene 45. Further oxidation of 247 or 248 leads to the... 

Separation of terpinen-4-ol enantiomers performed by a chiral GC columnand a chiral lanthanide shift reagent Eu(hfc)3, showed that the enantiomeric composition of an isolated compound from sweet marjoram oil was 73% (5)(- -) 27% R) —). The (4f )(—)-enantiomer was found in the oil of Eucalyptus dives Terpinen-4-ol was also found in several bark beetle species and is the main component in the aggregation pheromone of Polygraphuspoligraphus ... 

The trap-out treatment generally utilizes the aggregation pheromone of the target bark beetle species in association with a trap that kills the adults, i.e. sticky traps or containers that prevent the escape of species coming in contact with them. These techniques are not species specific per se because of the attraction of the natural enemies to the aggregation pheromones, i.e. kairomonal activity. Hence, the natural enemies are also trapped resulting in mortality to the adults. 

Historically, the first bark sprays to be used widely were fumigants (18, 41). Called penetrating sprays, they are applied in high volumes (2 to 6 gal./100 sq. ft. of bark surface) to penetrate the bark and kill the bark beetles in their galleries. Through the years the fumigant ethylene dibromide in oil or water emulsion was developed and adopted for suppression of several bark beetle species as a penetrating spray (15, 19, 29, 30, 42, 45, 47). 

At a given spray concentration and application rate, solutions are more reliable. Emulsions of lindane usually work well enough, however, if applied in larger volume or at higher concentration. Elimination of the oil carrier reduces the cost and also the hazard of phytotoxic reactions where living trees are sprayed for protection. Several early studies report the excellent control afforded by lindane emulsions (4, 5,12,14, 20, 23), and reports on the excellent performance of lindane emulsions on a wide assortment of bark beetle species have recently grown (6, 7, 8, 9, 10, 17, 37, 40, 44). Massey (28) has reported on the successful use of an emulsion of DDT to protect living trees. 

Examples include the alkylated 2,8-dioxabicyclo[3.2.1]octane (aro-brevicomin, 54), 6,8-dioxabicyclo[3.2.1]-octanes (frontalin, 55, and multistriatin, 56), and the 2,9-dioxabicyclo[3.3.1]nonane (57). Brevicomin, frontalin, and multistriatin are important components of the male or female pheromones of several bark beetle species. More recently, several hydroxylated 6,8-dioxabicyclo[3.2.1]octanes, including 58-60, have been identified from the mountain pine beetle, Dendroctonusponderosae Interestingly, frontalin (55) also represents an important component of the Asian elephant s male pheromone (Figure 20). ... 

KROKENE, P., SOLHEIM, H., Fungal associates of five bark beetle species colonizing Norway spruce. Can. J. For. Res., 1996, 26, 2115-2122. 

Mice and some bark beetle species also share some terpene compounds as pheromones. There are a number of reasons why these overlaps occur. The first is that all animals share a common heritage and so have basically the same metabolic... 

In the present chapter we want to demonstrate in the form of chemo-ecological/analytical study the applicability of the GCxGC-TOFMS for achiral and chiral insect semiochemicals analysis together with another key instrumental technique in this research - the gas chromatography with electroantennographic detection (GC-EAD). The insects we described in the study were the two above mentioned Chinese bark beetle species - Ips nitidus and Ips shangrila. 

For physiological experiments sex determination of tiving specimens was necessary since males and females often produce different sets of semiochemicals. In general, sex determination of living individuals of some bark beetles species is morphologically quite... 

Many compounds have been isolated and identified from various bark beetle species and claims made as to their effects on behavior. A few of the claims are conflicting and some others are not well proved. It is therefore difficult to state categorically exactly which compounds do what and to whom. Also, the behavioral chemicals to which most bark beetles respond appear to be a complex blend of components and the actual behavioral contribution and meaning of each component part remain essentially unknown. However, it is known that the pheromonal blends, so far identified, to which beetles in the genera Ips, Dendroctonus and Scolytus respond, have a number of similarities. 

In the case of bark beetles invading a host tree, one would expect from the preceding that the ability to produce enzymes capable of oxidizing the monoterpenes would be rapidly induced. If this were the case then many experiments exposing various bark beetle species to a-pinene and myrcene are more understandable. 

---