Ginzel Matthew D, Moreira Jardel A, Ray Ann M, Millar Jocelyn G, Hanks Lawrence M
Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
J Chem Ecol. 2006 Feb;32(2):435-51. doi: 10.1007/s10886-005-9010-y. Epub 2006 Apr 6.
Male Megacyllene caryae (Gahan) (Coleoptera: Cerambycidae) respond to females only after touching them with their antennae, indicating that mate recognition is mediated by a contact sex pheromone. Gas chromatography-mass spectrometry analyses of whole-body solvent extracts of male and female M. caryae revealed substantial differences in hydrocarbon profiles, with nearly half of the compounds in the extracts from females being absent from those of males. Biological activities of fractions of crude extracts of females, and reconstructed blends of the most abundant straight-chain (nC(27), nC(28), nC(29)), methyl-branched (2Me-C(26), 9Me-C(29), 11, 13, 15Me-C(29)), and unsaturated (Z9:C(29), Z13:C(29), Z14:C(29), Z13:C(31), Z14:C(31), Z15:C(31)) compounds in extracts of females were tested in arena bioassays, assessing four steps in the mating behavior sequence of males (orientation, arrestment, body alignment, mounting and attempting to couple the genitalia). Males showed limited response to dead females treated with fractions of the crude extract or blends of synthetic straight-chain and methyl-branched alkanes, but responded strongly to the blend of synthetic monoenes. Further trials determined that the complete sequence of mating behaviors, up to and including coupling the genitalia, was elicited by Z9:C(29) alone. Z9:C(29) is a homolog of the contact pheromone (Z9:C(25)) of the congener M. robiniae (Förster). Previous work with M. robiniae suggested that wipe sampling of cuticular hydrocarbons of females by solid phase microextraction yielded a more representative profile of components actually encountered by a male's antennae, and so provided a more readily interpretable profile of potential semiochemicals present in the wax layer than does solvent extraction. We tested this hypothesis by comparing hydrocarbon profiles of female M. caryae by the two sampling methods. Z9:C(29) was the only compound among the dominant hydrocarbons that was present in higher abundance in SPME than in solvent extracts ( approximately 12% vs. approximately 8%, respectively), supporting this hypothesis.
雄性胡桃大吉丁虫（Megacyllene caryae (Gahan)，鞘翅目：天牛科）只有在用触角触碰雌性后才会对其做出反应，这表明配偶识别是由接触性信息素介导的。对雄性和雌性胡桃大吉丁虫全身溶剂提取物进行气相色谱 - 质谱分析，结果显示烃类谱存在显著差异，雌性提取物中的化合物有近一半在雄性提取物中不存在。对雌性粗提物各组分以及雌性提取物中最丰富的直链（nC(27)、nC(28)、nC(29)）、甲基支链（2Me - C(26)、9Me - C(29)、11, 13, 15Me - C(29)）和不饱和（Z9:C(29)、Z13:C(29)、Z14:C(29)、Z13:C(31)、Z14:C(31)、Z15:C(31)）化合物的重构混合物进行生物活性测试，在 arena 生物测定中评估雄性交配行为序列的四个步骤（定向、停滞、身体对齐、挂载并试图连接生殖器）。雄性对用粗提物组分或合成直链和甲基支链烷烃混合物处理过的死雌性反应有限，但对合成单烯混合物反应强烈。进一步试验确定，仅 Z9:C(29)就能引发完整的交配行为序列，直至包括连接生殖器。Z9:C(29)是同属的罗宾氏大吉丁虫（Megacyllene robiniae (Förster)）接触性信息素（Z9:C(25)）的同系物。先前对罗宾氏大吉丁虫的研究表明，通过固相微萃取对雌性表皮碳氢化合物进行擦拭采样，能得到雄性触角实际接触到的成分更具代表性的图谱，因此与溶剂萃取相比，能提供蜡层中潜在信息化学物质更易于解释的图谱。我们通过比较两种采样方法得到的雌性胡桃大吉丁虫的烃类图谱来检验这一假设。Z9:C(29)是主要碳氢化合物中唯一在固相微萃取中比在溶剂提取物中丰度更高的化合物（分别约为 12%和 8%），支持了这一假设。
