Mandibular glands

Much of the communication between insects involves chemical messengers called pheromones A species of cockroach secretes a substance from its mandibular glands that alerts other cockroaches to its presence and causes them to congregate One of the principal components of this aggregation pheromone is the alkane shown in the bond line formula that follows Give the molecular formula of this substance and represent it by a condensed formula... 

Terpenoid substances are of broad distribution and diverse function in insects. One set, elaborated by the mandibular glands of Acanthomyops claviger, acts both as a defensive secretion and as an alarm releaser. When fed Cu-labeled acetate or mevalonate, laboratory colonies of these ants produce radioactive citronellal and citral, providing unambiguous evidence for de novo synthesis of these terpenes by the ant. The incorporations of these precursors implicate the mevalonic acid pathway as the likely biosynthetic route. 

Nevertheless NGF from mouse mandibular gland has been infused into the right lateral ventricle of two patients (67 and 57 years) for three months at a rate of 75 pg/h. The younger showed no change in memory performance the older some improvement after one month, which ceased after the infusion was stopped. Both patients had various reversible side-effects such as back pain and weight loss. 

In recent years, there is only one example of a pheromone in solitary Apocrita being chemically identified. Chiral GC and chiral GC-EAD provided identification of (3S)-(+)-linalool 8 >99.9% e.e. as a mandibular gland mate attractant in both males and females of Colletes cunicularius. Male contact with a scented source could be initiated with 5 ng per lure (3S)-(+)-linalool, which may act as both a sex attractant and a food attractant [35]. 

Defensive substances are often general irritants that can be used in a variety of contexts. For example, the alloxystine wasps (Cynipoidea), all hyperpara-sitoids of other hymenopteran parasitoids, produce a large number of compounds in their cephalic (mainly mandibular) glands. These compounds include m/p-xylol, 6-methylhept-5-en-2-one 16, various iridoids 21 and frans-dihydro-nepetalactone 22 [46,73]. 

Akita and Ohta disclosed one of the earliest Sonogashira reactions of chloropyrazines and their A-oxides [24, 25]. The union of 2-chloro-3,6-dimethylpyrazine (23) and phenylacetylene led to 2,5-dimethyl-3-phenylethynylpyrazine (29). Subsequent Lindlar reduction of adduct 29 then delivered (Z)-2,5-dimethyl-3-styrylpyrazine (30), a natural product isolated from mandibular gland secretion of the Argentine ants, Iridomyrmex humilis. 

The cephalic extracts of the ants Anochetus kempfi and A. mayri were found to contain 2,5-dimethyl-3-isoamylpyrazine (121) and 3-methyl-4-phenylpyr-role (122) (Fig. 20). This is the first report of a phenylpyrrole in an insect [128]. These compounds are most likely mandibular gland products and have a pheromonal role. 

Among the social Hymenoptera, one of the best-understood examples is the sex pheromone used by the queen honeybee to attract drones for mating. This pheromone is produced in the mandibular gland that resides in the head capsule (Barbier and Lederer, 1960 Callow and Johnson, 1960 Callow et al., 1964). In... 

The best understood of the sexual pheromones of social insects is the queen substance of honeybees. Interestingly, the queen substance used for queen control inside the nest is also the substance used by virgin queens to attract drones for mating. Callow and Johnston (1960) and Barbier and Lederer (1960) identified 9-keto-2(E)-decenoic acid ([E]-9-oxodec-2-enoic acid) (9-ODA) as major components of the queen mandibular glands. 9-Hydroxy-2(E)-decenoic acid is also present (Callow et al., 1964) and together both attract drones. Additional components of the queen retinue pheromone have recently been identified (Keeling et al., 2003). 

There were at least two possibilities in the conversion of the stearic acid to the CIO hydroxyacids they could be first hydroxylated and then chain shortened, or they could be first chain shortened and then hydroxylated. That the former occurs was demonstrated by two lines of evidence (1) mandibular glands chain shortened 18-hydroxy and 17-hydroxy stearic acid to the CIO acids and (2) both n-1 and n-2 hydroxyacids with more than 10 carbons accumulated when... 

Figure 11.2 Biosynthetic pathways leading to honeybee worker and queen mandibular gland pheromones. Reprinted with permission from Plettner E., et al. (1966), 1966 American Association for the Advancement of Science.

Hughes W. O. H., Howse P. E. and Goulson D. (2001) Mandibular gland chemistry of grass-cutting ants species, caste and colony variation. J. Chem. Ecol. 27, 109-124. 

Moritz R. F. A., Crewe R. M. and Hepburn H. R. (2002) Queen avoidance and mandibular gland secretion of honeybee workers (Apis mellifera L.). Insectes Soc. 49 86-91. 

Simon U. E., Moritz R. F. A. and Crewe R. M. (2001) The ontogenetic pattern of mandibular gland components in queenless worker bees (Apis mellifera capensis Esch.). J. Insect Physiol. 47, 735-738. 

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