Glands frontal

In addition to their mandibles, which are used to bite, pierce, shear, and cut intruders, soldiers of Coptotermes formosanus, a Formosan subterranean termite, are also armed with chemical weaponry. When disturbed, the soldiers secrete a gluelike white fluid from the frontal gland, which often form a drop between the open mandibles. Lignoceric and hexacosanoic acids were the two major components identified in this secretion [183]. 

In European Reticulitermes termites however, 16 known terpene compounds were isolated from the soldier frontal gland secretion, including monoterpenes, sesquiterpenes, diterpenes, and one sesterterpene [184]. 

A group of novel diterpenoids has been isolated from the sticky secretions of the frontal glands of nasute termite soldiers. The structure of trinervi-2, 3a,9a-triol... 

Gustafsson, M. K. S. Vaihela, B. (1981). Two types of frontal glands in Diphyllobothrium dendriticum (Cestoda, Pseudophyllidea) and their fate during the maturation of the worm. Zeitschrift fur Parasitenkunde, 66 145-54. 

The fine structure of frontal glands in adult cestodes. International Journal for Parasitology, 12 285-93. 

A curious diterpenoid isocyanide (174) has been obtained from the marine sponge Hymeniacidon amphilecta and its structure established by X-ray analysis. Divarol acetate (175), which is related to the dolatriols, has been obtained from some marine Dolabella species. Two further trinervitene diterpenoids (176), the 2a,3a- and 2a,3/8-diols, have been isolated from the frontal glands of the termite Nasutitermes costalis. The verrucosane skeleton has been assigned to some further diterpenoids from the liverwort Mylia verrucosa. Three more... 

A further group of trinervitene (126) diterpenoids have been isolated from the frontal glands of a termite soldier, Nasutitermes rippertii. These include the 9/8-mono-ol, the 2/8,3a-diol and its acetates, the 2/3,3a,9o -triol and its triacetate, the 2j8,3a,13a-triol and its triacetate, and the 13-oxotrinervi-j8,3a-diol and its diacetate. Isotrinervi-2jS-ol has been obtained from the defensive secretions of T. gratiosus. Kempene-1 (127) and kempene-2 (128) are tetracyclic diterpenoids of a related type which were obtained from another Nasutitermes species. The structure (128) was established by A-ray analysis. 

Scent-marking in marsupials. In addition to using specific anal-cloacal, and sternal glands, marsupials use saliva, urine and feces in chemical communication (Eisenberg and Golani, 1977). Other specific glands, such as frontal glands and parts of the body (such as the flank), are also used (Schultze-Westrum, 1965, 1969 Fadem and Cole, 1985). 

Daubing which involves application of a secretion from the frontal gland through an elongated labrum Schedorhinotermes). 

Biting with simultaneous addition of a toxic substance from the frontal gland Amitermes, Cubitermes, Macrotermes, Odontotermes and Noditermes). 

Fig. 1. The drawings show three aspects of the chemical defenses that can be found in termites. In Cubitermes, the secretion from the frontal gland penetrates the wound made by the jaws. For Schedorhinotermes, the action of the jaws becomes secondary, since the secretion is directly applied against the adversary like a brush. In the case of Trinervitermes, the secretion is ejected from a distance, the nasute has no contact with the antagonist and the mandibles are withdrawn.

Wadhan, L.J., R. Baker, and P.E. Howse 4,11-Epoxy-cis-eudesmane, a Novel Oxygenated Sesquiterpene in the Frontal Gland Secretion of the Termite Amitermes evuncifer (Silvestri). Tetrahedron Lett. 1697-1700 (1974). 

Prestwich, G.D., S.P. Tanis, J.P. Springer, and J. Clardy Nasute Termite Soldier Frontal Gland Secretions. 1. Structure of Trinervi-2-p-3-a-9a-triol-9-0-acetate, a Novel Diterpene from Trinervitermes Soldiers. J. Amer. Chem. Soc. 98, 6061-6062... 

B.A. Bierl, E.D. Devilbiss, and M.P.B. Chaudhury Soldier Frontal Glands of the Termite Macrotermes subhyalinus Morphology, Chemical Composition and Use in Defense. J. Chem. Ecol. 3, 579-590 (1977). 

Baker, R., H.R. Coles, M. Edwards, D.A. Evans, P.E. Howse, and S. Walmsley Chemical Composition of the Frontal Gland Secretion of Syntermes Soldiers. (Isoptera, Termitidae). J. Chem. Ecol. 7,135-145 (1981). 

Parton, A.H., P.E. Howse, R. Baker, and J.L. Clement Variation in the Chemistry of the Frontal Gland Secretion of European Reticulitermes Species. In P.E. Howse and J.L. Clement eds., Biosystematic of Social Insects, p. 193-209. New York Academic Press 1981. 

Valterova, I., M. BuofeSiNSKt, F. Turecek, and J. VrkoC Minor Diterpene Components of the Defense Secretion from the Frontal Gland of Soldiers of the Species Nasutitermes costalis (Holmgren). Collect. Czech. Chem. Comm. 49, 2024-2039 (1984). 

J. KreCek, and J. VroC Frontal Gland Secretion and Ecology of the Greater Antillean Termite Nasutitermes hubbardii (Isoptera Termitidae). Acta Entomol. Bo-hemoslov 81, 416-425 (1984). 

The Rhinotermitidae are small subterranean wood-eating termites. In this family, and in the Termitidae, the winged adults and the soldiers possess an unpaired cephalic gland known as the frontal gland, which opens through a frontal pore, or fontanelle, situated on the dorsal surface of the head. 

Reticulitermes is a genus with a small frontal gland, which has a biology similar to the Termopsidae. These small termites are destructive to timber used in construction of buildings in many parts of the world, including the USA, Southern Europe, emd the Feu East. 

Fig. 16.6 Plan view of soldier head and sagittal section of Coptotermes ceylonicus showing the frontal pore (f) and the extent of the frontal gland (after Bugnion, 1927).

Although it is known that the Rhinotermitidae with a labral brush use this for smearing or daubing their adversaries with the frontal gland secretion, remarkably little is known of the efficiency of this method of defence in natural... 

A more common method of chemical defense in the Termitinae is the use of biting or cutting mandibles which are contaminated with a frontal gland secretion, such as occurs in Cubitermes and Amitermes species. 

African species of Amitermes build hard small mound nests of wood carton and earthen material, often based on a rotting tree stump. The frontal gland secretions of the Amitermes species are, however, totally different from those of Cubitermes. The West African species A. evt/nci/cr contains a sesquiterpene ether, 4,11-epoxy-cis-eudesmane (>90%) (Wadhams et al., 1974) with 10-epi-endesma-3,11-diene, 8-epi-cararrapi oxide, cararrapi oxide, and c/5-/3-ocimene as minor components (Fig. 16.11) (Baker et al., 1978). The secretion is toxic to some ants on topical application, causing motor ataxia, frequently followed by death. Two potential predators, the ants Odontomachus haematodus and Oecophylla longinoda are affected in this way. 

The diversity of frontal gland secretions in members of the genus Amitermes so far explored hardly suggests that chemotaxonomy has a promising future in termites, although, in the Nasutitermitinae, which we will now consider, there have been attempts to discern evolutionary trends on the basis of frontal gland chemistry. 

Fig. 16.12 Soldier heads of (a) Syntermes molestus, (b) S. dims and (c) S. grandis showing the position and relative size of the frontal gland (from Coles, 1980).

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