Oecophylla longinoda

A trisubstituted alkene moiety, widely found in various natural bioactive molecules including several important pheromones and antibiotics, often has certain biological activities. For example, the following methodology has been employed to synthesize (2 )-2-butyloct-2-enal (62), an alarm pheromone component of the African weaver ant, Oecophylla longinoda (Scheme 5.11). 

Duffield et al. (200) found that Dufour s gland secretion of Svastra obliqua contains a series of 32 aliphatic esters, while according to Bradshaw the mandibular gland secretion of the weaver ant Oecophylla longinoda consists of 33 chemical entities (201, 202),... 

Workers of the African Weaver Ant, Oecophylla longinoda. Physiol. Entomol. 4, 15-25 (1979). 

HOlldobler, B. K. and Wilson, E. O. (1978) The multiple recruitment systems of the African weaver ant Oecophylla longinoda. Behav. Ecol. SociobioL, 3, 19-60. 

The most complex alarm communication system to be investigated to date is that of the African weaver ant Oecophylla longinoda (Formicinae), where no less than four glands are employed. One, the sternal gland, is used for short-range recruitment of nestmates to disturbances or prey items, and will be... 

Fig. 15.6 Active spaces of four components of the mandibular gland secretion of major workers of Oecophylla longinoda, 20 s after deposition, at the point arrowed, on a flat surface.

Fig. 15.7 Four major workers of Oecophylla longinoda, responding to the excised leg of a locust which has been contaminated with mandibular gland secretion at the cut end (arrowed). The worker on the left is being attracted by 1-hexanol (compare with Fig. 15.6), the one in the centre is about to attack near to the source, where the two workers on the right are already biting (drawn from a photograph).

The various worker castes frequently carry out different roles in defence. In many species there is a specialized soldier caste, whose behavior and exocrine chemistry may differ markedly from those of other workers (e.g.. Law et aL, 1965). Workers of the African weaver ant Oecophylla longinoda are dimorphic the major workers forage and defend the nests and territory, while the minor workers serve as nurses to the brood, and are rarely seen outside the nests (Weber, 1949). The blend of compounds in the mandibular glands differs markedly between the two castes (Bradshaw et aL, 1979b) all the compounds present in minor workers are alcohols, and three of the four compounds most important in alarm communication between majors are absent, namely hexanal, 3-undecanone and 2-butyl-2-octenal. The only abundant compound held in common is 1-hexanol, and the secretion in minor workers is largely made up of the monoterpene nerol. Both nerol and 1-hexanol are highly repellent to minor workers, and they are thus displaced from sources of both minor and major worker secretions. Nerol is a powerful attractant and arrestant for major workers. 

Aggressive behavior is released by the territorial pheromone of Oecophylla longinoda, however. This pheromone is located in the drops of brown rectal sac fluid which the workers deposit over the territorial surface. They are particularly active in marking any fresh areas which they may encounter, but established territory is also marked constantly, albeit at a greatly reduced rate. Workers which encounter spots of rectal sac fluid produced by members of another colony inspect them frequently with their antennae, and often adopt threat postures in the complete absence of any foreign ants. Moreover, the presence of their own territorial marks enables workers to recruit faster than workers on alien territory (Hdlldobler and Wilson, 1977a). 

Bradshaw, J. W. S. (1981) The physicochemical transmission of two components of a multiple chemical signal in the African weaver ant, (Oecophylla longinoda), Anim, Behav, 29, 581-5. 

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. 

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