Gammans Nicola, Bullock James M, Gibbons Hannah, Schönrogge Karsten
Centre for Ecology and Hydrology, CEH Dorset, Winfrith Technology Centre, Dorchester, DT2 8ZD, UK.
J Chem Ecol. 2006 Sep;32(9):1935-47. doi: 10.1007/s10886-006-9119-7.
It has been proposed that chemicals on plant elaiosomes aid seed detection by seed-dispersing ants. We hypothesized that the chemical interaction between ants and elaiosomes is more intimate than a generic attraction, and that elaiosome chemicals will attract mutualistic but not granivorous ant species. We investigated this by using two gorse species, Ulex minor and U. europaeus, and two associated ant species from European heathlands, the mutualist Myrmica ruginodis and the granivore Tetramorium caespitum. Behavioral studies were conducted with laboratory nests and foraging arenas. Both ants will take Ulex seeds, but while M. ruginodis showed increased antennation toward ether extracts of elaiosome surface chemicals compared with controls, T. caespitum showed no response. Elaiosome extracts were separated into seven lipid fractions. M. ruginodis showed increased antennation only toward the diglyceride fractions of both Ulex species, whereas T. caespitum showed no consistent reaction. This indicates that M. ruginodis can detect the elaiosome by responding to its surface chemicals, but T. caespitum is unresponsive to these chemicals. Responses to surface chemicals could increase the rate of seed detection in the field, and so these results suggest that Ulex elaiosomes produce chemicals that facilitate attraction of mutualistic rather than granivorous ant species. This could reduce seed predation and increase Ulex fitness.
有人提出，植物油质体上的化学物质有助于种子传播蚂蚁检测种子。我们假设，蚂蚁与油质体之间的化学相互作用比一般的吸引更为密切，并且油质体化学物质会吸引共生蚂蚁物种而非食谷蚂蚁物种。我们通过使用两种金雀花物种，即小叶金雀花（Ulex minor）和欧洲金雀花（U. europaeus），以及来自欧洲石南荒原的两种相关蚂蚁物种，即共生的皱红蚁（Myrmica ruginodis）和食谷的铺道蚁（Tetramorium caespitum）来对此进行研究。利用实验室蚁巢和觅食区域进行了行为研究。两种蚂蚁都会取食金雀花种子，但与对照组相比，皱红蚁对油质体表面化学物质的乙醚提取物表现出更多的触角探索行为，而铺道蚁则没有反应。油质体提取物被分离成七个脂质部分。皱红蚁仅对两种金雀花物种的甘油二酯部分表现出更多的触角探索行为，而铺道蚁则没有一致的反应。这表明皱红蚁可以通过对油质体表面化学物质做出反应来检测油质体，但铺道蚁对这些化学物质没有反应。对表面化学物质的反应可能会提高野外种子检测的速率，因此这些结果表明，金雀花油质体产生的化学物质有助于吸引共生蚂蚁物种而非食谷蚂蚁物种。这可以减少种子捕食并提高金雀花的适合度。
