Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales-Consejo Superior de Investigaciones Científicas, Madrid, Spain.
PLoS One. 2013 Jul 24;8(7):e70529. doi: 10.1371/journal.pone.0070529. Print 2013.
The cuticle of certain insect body parts can be hardened by the addition of metals, and because niche separation may require morphological adaptations, inclusion of such metals may be linked to life history traits. Here, we analysed the distribution and enrichment of metals in the mandibles and ovipositors of a large family of gall-inducing wasps (Cynipidae, or Gall-Wasps) (plus one gall-inducing Chalcidoidea), and their associated wasps (gall-parasitoids and gall-inquilines) (Cynipidae, Chalcidoidea and Ichneumonoidea). Both plant types/organs where galls are induced, as well as galls themselves, vary considerably in hardness, thus making this group of wasps an ideal model to test if substrate hardness can predict metal enrichment. Non-galler, parasitic Cynipoidea attacking unconcealed hosts were used as ecological "outgroup". With varying occurrence and concentration, Zn, Mn and Cu were detected in mandibles and ovipositors of the studied species. Zn tends be exclusively concentrated at the distal parts of the organs, while Mn and Cu showed a linear increase from the proximal to the distal parts of the organs. In general, we found that most of species having metal-enriched ovipositors (independently of metal type and concentration) were gall-invaders. Among gall-inducers, metals in the ovipositors were more likely to be found in species inducing galls in woody plants. Overall, a clear positive effect of substrate hardness on metal concentration was detected for all the three metals. Phylogenetic relationships among species, as suggested by the most recent estimates, seemed to have a weak role in explaining metal variation. On the other hand, no relationships were found between substrate hardness or gall-association type and concentration of metals in mandibles. We suggest that ecological pressures related to oviposition were sufficiently strong to drive changes in ovipositor elemental structure in these gall-associated Hymenoptera.
某些昆虫身体部位的角质层可以通过添加金属来硬化，由于生态位分离可能需要形态适应，因此包含这些金属可能与生活史特征有关。在这里，我们分析了一大类诱导瘿蜂（瘿蜂科，或瘿蜂）（外加一种诱导瘿蜂的 Chalcidoidea）的下颚和产卵器，以及它们相关的蜂（瘿寄生蜂和瘿寄居蜂）（瘿蜂科、 Chalcidoidea 和膜翅目）中金属的分布和富集。诱导瘿的植物类型/器官以及瘿本身的硬度差异很大，因此，这组蜂是测试基质硬度是否可以预测金属富集的理想模型。非瘿寄生的寄生性 Cynipoidea 攻击无保护宿主被用作生态“外群”。在所研究的物种的下颚和产卵器中，检测到 Zn、Mn 和 Cu 的含量不同且浓度不同。Zn 往往专门集中在器官的远端部分，而 Mn 和 Cu 则显示出从器官的近端到远端的线性增加。一般来说，我们发现大多数具有富含金属的产卵器的物种（独立于金属类型和浓度）都是瘿入侵者。在诱导瘿的物种中，木质植物中诱导瘿的物种的产卵器中更容易发现金属。总体而言，所有三种金属的浓度都明显受到基质硬度的正向影响。物种之间的系统发育关系，如最近的估计所表明的那样，似乎在解释金属变异方面作用微弱。另一方面，在颚骨中，没有发现基质硬度或瘿关联类型与金属浓度之间的关系。我们认为，与产卵有关的生态压力足以促使这些与瘿相关的膜翅目昆虫的产卵器元素结构发生变化。
