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A detailed comparative analysis of the exocrine chemistry of nine Bruneian Camponotus species in the cylindricus complex is reported. Workers of these species are known to have hypertrophied mandibular glands and release their glandular contents suicidally from the head by rupturing the intersegmental membrane of the gaster. All of the species produce mixtures of polyacetate-derived aromatics, including hydroxyacetophenones, which display pH-dependent color changes, and aliphatic hydrocarbons and alcohols. In addition, three species contained (6R)-2,6-dimethyl-(2E)-octen-1,8-dioic acid (9) or (3S)-8-hydroxycitro-nellic acid (10a), previously unreported from insects. These compounds were characterized from their spectral data, and confirmed by comparison with synthetic samples. The allomonal role of these compounds is based on numerous field observations, and their chemotaxonomic value is presented.

Summary• The giant flowers of the parasitic Rafflesia occur in the shade of the forest understorey. They present several characteristics in common with the related species, Rhizanthes lowii , which is a strongly endothermic flower . The possible existence of endothermy in Rafflesia tuan-mudae was investigated here.• The internal and surface temperature of the flowers were continuously monitored with fine thermocouples while radiation fluxes and microclimatic variables were recorded. A computational fluid dynamic model was used to predict the concentrations of CO 2 inside the diaphragm of the flower.• It was found that the internal parts of the flower were maintained a few degrees (1-6 K) above air temperature. It was not possible to account for this temperature rise without postulating a significant internal source of heat. It was concluded that R. tuan-mudae is an endothermic flower that generates a maximum of 50 -60 W m − 2 of heat in the centre of the column.• The possible role of endothermy, CO 2 and volatiles as elements in the mimicry of the flower to attract pollinating blowflies is discussed and compared with the related species Rhizanthes lowii .

The defensive chemistry of two species of ants from Brunei in the genus Crematogaster (Physocrema group) has been investigated. Ants in this group release a white secretion from hypertrophied metapleural glands on their thorax when they are disturbed. Previously, one species in this group has been shown to produce alkylphenols and alkylresorcinols. In the present investigation, similar compounds along with salicylic acids and resorcylic acids that are anacardic acid and olivetolic acid homologs, respectively, are described from two species. The structures of these compounds were suggested by their spectroscopic data and confirmed by direct comparison with synthetic samples. Some of these compounds occur in lichens and have well documented physiological activities.

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