Pale brown chafer

Fig. 4 Gas chromatographic traces of extracts from females of the pale brown chafer Phyl-lopertha diversa monitored by a conventional detector, flame-ionization detector (FID), and a biosensor, electroantennographic detector (EAD), using a male antenna as the sensing element. Although the peak of the sex pheromone (arrow) is hardly seen in the FID trace, its pheromonal activity was initially indicated by the strong EAD peak. Structural elucidation, followed by synthesis and behavioral studies lead to the identification of an unusual sex pheromone, l,3-dimethyl-2,4-(lff,3ff)-quinazolinedione [124]. It is unlikely that this minor compound would be fished out by a bioassay-oriented isolation procedure...

Wojtasek H. and Leal W. S. (1999a) Degradation of an alkaloid pheromone from the pale-brown chafer, Phyllopertha diversa (Coleoptera carabaeidae), by an insect olfactory cytochrome P450. FEBS Letters 458, 333-336. 

A unique pheromone structure is represented by the alkaloid l,3-dimethyl-2,4-(17/,3 /)-quinazolinedione (Ar56), which is the sex pheromone of the pale-brown chafer Phyllopertha diversa260 Its degradation with special enzymes on the antennae leading to signal inactivation has been described 261... 

After the olfactory receptor is activated, the semiochemical signal must be destroyed to prevent continued stimulation. Esterase, dehydrogenase, aldehyde oxidase, epoxidase, and glutathione-S-transferase activities have all been detected in the sensillum and could degrade the signal. A further example is found in the pale-brown chafer. Phyllopertha diversa. which uses 1,3-dimethyl-2,4-( liT,3//)-quinazolinedione 10 as its sex pheromone. 

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