Volatiles from Merino fleece evoke antennal and behavioural responses in the Australian sheep blow fly Lucilia cuprina

To identify flystrike‐related volatile compounds in wool from Merino sheep, the attractiveness of wool to Lucilia cuprina Wiedmann (Diptera: Calliphoridae) was examined. First, a selection of wool samples guided by previous knowledge of sheep lines, predicted to be more susceptible or more resistant to flystrike, was tested. The attractiveness of the 10 samples selected was not associated with field susceptibility: two samples from the more resistant line were identified as most attractive and two samples from the more susceptible line were identified as least attractive, based on the behavioural assays with gravid flies. Comparison of the headspace volatiles of these samples, using solid phase microextraction and gas chromatography‐mass spectrometry‐electroantennographic detection, revealed octanal and nonanal to be present in the attractive wool samples that elicited responses from the fly antenna. Furthermore, the two compounds were not present in wool that was least attractive to L. cuprina. In laboratory bioassays, octanal and nonanal evoked antennal and behavioural responses in gravid L. cuprina, thus confirming their potential role as semiochemicals responsible for attracting L. cuprina to Merino sheep.     

Evaluation of semiochemicals potentially synergistic to α-pinene for trapping the larger European pine shoot beetle, Tomicus piniperda (Col., Scolytidae)

Abstract:  The pine shoot beetle, Tomicus piniperda (L.) (Col., Scolytidae) is an exotic pest of pine, Pinus spp., in North America. It is attracted strongly to host volatiles (±)- α -pinene, (+)-3-carene, and α -terpinolene. Attraction to insect-produced compounds is less clear. Other potential attractants include trans -verbenol, myrtenol, myrtenal, nonanal and α -pinene oxide. We conducted a series of field experiments to determine if any of these compounds would increase attraction of T. piniperda to α -pinene, either individually or in various combinations. None of the individual compounds increased attraction. Although several combinations that included trans -verbenol, nonanal, myrtenol, or myrtenal increased attraction, results were variable between experiments.     

黄曲条跳甲成虫挥发物成分及其活性研究

应用固相微萃取方法分别收集黄曲条跳甲Phyllotreta striolata Fabricius雌雄成虫的虫体挥发物,用GC-MS(气相色谱-质谱)技术对挥发物进行分析和比较。结果显示,雌虫和雄虫挥发性化学物质含有烷烃类、烯烃类、醇类,主要组分以烷烃类和烯烃类物质为主,其中两者共同含有且含量较大的为2-异丙基-5-甲基-1-庚醇和2,4-二甲基-1-癸烯。雌、雄成虫释放的挥发性物质种类差异较大,有12种仅存在于雌虫中,25种仅存在于雄虫中。同时,两者都释放的挥发物含量差异也比较明显。选取了雄虫挥发物中特有的化合物异胡薄荷醇和壬醛,应用四臂嗅觉仪测定黄曲条跳甲成虫对其嗅觉反应。结果表明:两种物质在不同浓度、流速下对黄曲条跳甲的作用不同,雌雄虫对两种物质的反应也不同。异胡薄荷醇在流速150 m L/min、浓度10 u L/m L时对雌虫具有显著的吸引作用,而对雄虫没有显著效果;壬醛在流速100 m L/min、浓度10μL/m L时对雌虫具有显著的驱避作用,而在流速200 m L/min、浓度0.1和1μL/m L时对雄虫具有一定的吸引作用。     

Occurrence of a New Lipoxygenase Isoenzyme in Germinating Barley Embryos

Partially purified preparations of lipoxygenase from the germinating barley embryos converted linoleic acid to 9- and 13-hydroperoxy linoleic acids in the ratio of approximately 3:1, while the similar preparations from the ungerminated embryos converted linoleic acid mainly to 9-hydroperoxy linoleic acid.

Isoelectric focusing of the partially purified preparations of the germinating embryos revealed the presence of the two lipoxygenase active peaks, having isoelectric point at pH 4.9 and 6.6, respectively. The former peak (barley lipoxygenase-1) was identical to lipoxygenase of the ungerminated embryos, but the latter peak (barley lipoxygenase-2) was found only in the germinating embryos. The newly found isoenzyme, barley lipoxygenase-2, converted linoleic acid mainly to 13-hydroperoxy linoleic acid, and could oxidize esterified derivatives of linoleic acid (methyl linoleate and trilinolein) much strongly than barley lipoxygenase-1.     

Nonanal in epicuticular wax of golden egg plums (Prunus domestica)

Nonanal was identified, as a major component, in the aldehyde fraction of the cuticular wax of the plum cultivar, Golden Egg. This compound was found to play an important role in the overall aroma of the plum.