Ubiquinone-O in defensive spray of African millipede

Buzonamine, a new alkaloid from the defensive secretion of the millipede, Buzonium crassipes

GC-MS analysis of the defensive secretion from the millipede Buzonium crassipes showed three volatile components, beta-pinene (35%), limonene (6%) and a new alkaloid, buzonamine (59%). Buzonamine had an HRMS molecular ion at m/z=221.1785 (calculated for C(14)H(23)NO, 221.1781), 14 carbons in the 13C-NMR and 23 hydrogens by SFORD, DEPT and APT experiments. All distinct 1H nuclei were assigned to 13C resonances with 2D 1H-13C COSY data, and the final structure was determined by 1H-1H COSY, 1H-13C HMBC and nOe experiments. Buzonamine contains four rings including an epoxy group and a tertiary nitrogen. beta-Pinene, limonene or buzonamine, kept the mound nesting ant, Formica obscuripes, from eating mealworms (Tenebrio molitor) treated with 1mg of the chemical. A 150mg millipede expels 4mg of secretion.

Materia melanica: further dark thoughts

The view is advanced that melanogenesis arose evolutionarily as a detoxification pathway for intrinsically-generated orthoquinones. The primary impetus for the production of orthoquinones may have been their general antibiotic properties and the utility of these chemical species in forming covalent cross-links between proteins, as illustrated by cuticular sclerotization in insects. It is argued that polymerization to give rise to visible pigments may have originated as a pathway for the inactivation of orthoquinones. The possible evolutionary advantages accruing from the generation of melanin are discussed with special reference to acuity of photoreceptors and the physico-chemical properties of melanin, as well as the contribution of melanin to protective colouration or display.

Mahogany discoloration of the skin due to the defensive secretion of a millipede

An 8-year-old boy developed a sudden mahogany discoloration of his skin after exposure to defensive secretions of a millipede. The mechanisms and the composition of the secretion and other clinical features are briefly reviewed.

Chemical Ecology: Studies from East Africa

The International Centre of Insect Physiology and Ecology (ICIPE), in Nairobi, provides a laboratory at which a multinational group of scientists pursues interdisciplinary research. In collaboration with their colleagues in biology, ICIPE chemists have characterized the sex pheromones of the tick which serves as a vector of East Coast fever and have identified a termite queen-cell-building pheromone. The structure of many anthropod defensive chemicals have been determined; most interesting of these are the trinervitenes, structurally novel diterpenoids from nasute termites. Several highly active insect antifeedants were discovered using a simple bioassay to screen selected East African plants. These antifeedants may provide leads for the development of new insect-control techniques.