Abdominal glands, moths

Like many other insects, moths attract mates by long-distance pheromones. Females produce these pheromones in specialized abdominal glands. Chemically, they are acetates, often active in precise mixtures of geometric isomers. Males fly upwind, following the females pheromone plume to the somce, and mating ensues. In a typical experiment, a female moth, or just the pheromone, serves as odor source. An air current from that source helps to attract males who fly upwind to the pheromone source and attempt to mate. With this technique, we can compare the effects of known pheromones from different, related species on one species (species specificity). We can also test the attractiveness of different compounds that are stracturally similar to a known pheromone. In the laboratory, a wind tunnel, where available, is ideal, for this experience. 

Bombykol, 10-trans-12-cis-hexodecadienol-(I) a pheromone exuded by female silk moths (Bombyx mori) to attract males. B. is an oil, n 1.4835. The first structural determination (by Adolf Butenendt) was performed on 15 mg B. isolated from the abdominal glands of 500,000 female moths. The configuration was established by comparison of the biological activities of synthetic compounds with the natural product. 

Fractions obtained from abdominal tips, excised glands or trapped air volatiles obtained from virgin females were tested by electroantennography and a behavioural bioassay (Van der Kraan, publication in preparation). The latter used wind tunnels with funnels upwind and a common chamber downwind. Test samples were placed in the funnels, and the behaviour of male moths, released in the middle of the tunnels, as well as the numbers trapped in the funnels, were examined. 

Sexual communication between sexes in Lepidopteran species is mediated mainly by sex pheromones, which are volatile compounds used by the female to attract potential mates from a distance [18]. In moths, sex pheromones play an important role in the elicitation of mating behaviour, and are, therefore, crucial for successful mating. They are synthesised by females in a specialised gland, which is a modification of the inter-segmental membrane located between the eighth and ninth abdominal segments [19, 20]. The pheromone is produced within the epithelial cells, transported through the cuticle via special porous cuticular spines and disseminated from the surface [19, 20]. 

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