Moorehead Jeff R, Taper Mark L, Case Ted J
Department of Biology, C-0116, University of CA, San Diego, 92093, La Jolla, CA, USA.
Oecologia. 1993 Sep;95(3):385-392. doi: 10.1007/BF00320993.
We examined the utilization by the cynipid gall former, Andricus californicus, of oak trees ranging across a hybrid continuum from pure Quercus dumosa to pure Q. engelmannii. Two components of utilization were considered, the proportion of trees parasitized and the density of galls on parasitized trees. Although the wasp normally only parasitizes Q. dumosa, galls were found on trees with up to 85% of the genetic character of the non-host, as determined by a hybrid index. The proportion of hybrids utilized did not differ statistically from the proportion of pure Q. dumosa utilized. We consider competing hypotheses about the genetic mechanism behind host choice in the light of our results. The model that is most consistent with the observed incidence pattern is based on a "cluster concept": A number of independent genetic factors in the host determine its acceptability, however, these factors are substitutable, such that no single factor is critical, but some threshold number of factors must be exceeded.
我们研究了瘿蜂形成者——加利福尼亚安德茧蜂（Andricus californicus）对橡树的利用情况，这些橡树分布在一个从纯毛果栎（Quercus dumosa）到纯恩氏栎（Q. engelmannii）的杂交连续体中。我们考虑了利用的两个组成部分，即被寄生树木的比例和被寄生树上瘿的密度。尽管这种黄蜂通常只寄生毛果栎，但根据杂交指数测定，在具有高达85%非寄主遗传特征的树上也发现了瘿。被利用的杂交种比例与被利用的纯毛果栎比例在统计学上没有差异。我们根据研究结果考虑了关于寄主选择背后遗传机制的相互竞争的假说。与观察到的发生模式最一致的模型基于“聚类概念”：寄主中的许多独立遗传因素决定了它的可接受性，然而，这些因素是可替代的，因此没有单一因素是关键的，但必须超过一定数量的因素阈值。
