de Araújol Walter Santos, Julião Genimar Rebouças, Ribeiro Bárbara Araújo, Silva Isadora Portes Abraham, dos Santos Benedito Baptista
Pós-Graduação em Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus Samambaia, 74001-970 Goiânia, Goiás, CP 131, Brazil.
Rev Biol Trop. 2011 Dec;59(4):1589-97. doi: 10.15517/rbt.v59i4.3422.
Impacts of forest fragmentation and edge effect on plant-herbivores interactions are relatively unknown, and the relationships between galling insects and their host plants are very susceptible to environmental variations. The goal of our study was to test the edge effect hypothesis for galling insects associated with Styrax pohlii (Styracaceae) host plant. Samplings were conducted at a fragment of semi-deciduous forest in Goiânia, Goiás, Brazil. Thirty host plant individuals (15 at fragment edge and 15 in its interior) were sampled in July of 2007; in each plant, 10 apical branches were collected at the top, middle and bottom crown levels. Our results supported the prediction of greater richness of gall morphotypes in the edge habitat compared with remnant interior. In a similar way, gall abundance and frequency of attacked leaves were also greater in the fragment edge. These findings consequently suggest a positive response of galling insect diversity to edge effect; in the Saint-Hilaire forest, this effect probably operates through the changes in microclimatic conditions of edge habitats, which results in an increased hygrothermal stress, a determinant factor to distribution patterns of galling insects. We also concluded that these organisms could be employed as biological indicators (i) because of their host-specificity, (ii) they are sensitive to changes in plant quality, and (iii) present dissimilar and specific responses to local variation in habitat conditions.
森林破碎化和边缘效应 对植物 - 食草动物相互作用的影响相对未知，而且瘿蜂及其寄主植物之间的关系非常容易受到环境变化的影响。我们研究的目的是检验与皱叶安息香（安息香科）寄主植物相关的瘿蜂的边缘效应假说。采样在巴西戈亚斯州戈亚尼亚市的一片半落叶林片段中进行。2007年7月对30株寄主植物个体（15株在片段边缘，15株在其内部）进行了采样；在每株植物上，从树冠的顶部、中部和底部水平采集10个顶端枝条。我们的结果支持了以下预测：与残余内部相比，边缘栖息地的瘿形态类型更丰富。同样，片段边缘的瘿丰度和叶片受攻击频率也更高。这些发现因此表明瘿蜂多样性对边缘效应有积极反应；在圣伊莱尔森林中，这种效应可能通过边缘栖息地微气候条件的变化起作用，这导致湿热胁迫增加，而湿热胁迫是瘿蜂分布模式的一个决定性因素。我们还得出结论，这些生物可以用作生物指标，（i）因为它们具有寄主特异性，（ii）它们对植物质量的变化敏感，以及（iii）对栖息地条件的局部变化呈现不同且特定的反应。
