Feeding preference of the shredder Phylloicus sp. for plant leaves of Chrysophyllum oliviforme or Miconia chartacea after conditioning in streams from different biomes

Abstract Macroinvertebrate shredders consume preferably leaves conditioned by fungi and bacteria which offer greater palatability to them. Plant species in Cerrado present high concentration of chemical elements such as lignin and cellulose, phenols and tanins thus making them less attractive for shredders consumption and limiting the palatability. This study aimed to evaluate the feeding preference of a macroinvertebrate shredder of the genus Phylloicus for plant material from two different biomes (Cerrado and Mata Atlântica), after conditioning in a stream of Mata Atlântica and observing their physical and chemical characteristics. Senescent leaves were collected, monthly from the litterfall of riparian vegetation in a 500 m stretch of a stream in each biome from August 2014 to January 201. The most abundant species in each stream was selected for the experiment. The experimental design consisted in with two treatments. The first (T1) comprised leaf discs from Chrysophyllum oliviforme (Cerrado species) together with leaf discs of Miconia chartacea (Atlantic Forest species) which were conditioned in the Atlantic Forest stream. The second treatment (T2) involved leaf discs of Miconia chartacea conditioned in Mata Altlântica and Cerrado streams. Both tests had showed significant differences between the two treatments (T1 and T2). For T1, there was consumption of M. chartacea leaf discs by Phylloicus sp., but there was no consumption of C. oliviforme discs. For T2, there was preference for M. chartaceae leaves conditioned in a stream of Mata Atlântica than in Cerrado stream. The results showed that Phylloicus sp., had presented preference for food detritus of the Mata Antlântica biome and rejection to the one from Cerrado biome.

摘要：大型无脊椎动物撕食者（macroinvertebrate shredders）偏好取食经真菌与细菌定殖后的叶片，此类叶片具备更高的适口性。塞拉多（Cerrado）生态系统中的植物物种含有高浓度的木质素、纤维素、酚类与单宁等化学物质，因此对撕食者的吸引力较低，限制了其适口性。本研究旨在评估一种隶属于菲洛石蛾属（Phylloicus）的大型无脊椎动物撕食者，对来自塞拉多与大西洋森林（Mata Atlântica）两种不同生物群系的植物材料的取食偏好：实验前先将植物材料置于溪流中完成微生物预处理，并同步观测其物理与化学特性。2014年8月至201年1月期间，研究人员分别从两个生物群系中某溪流沿岸500米河段的河岸植被枯落物中，每月采集衰老叶片。选取各溪流中丰度最高的物种开展实验。实验设计包含两组处理：第一组（T1）为橄榄形金叶树（Chrysophyllum oliviforme，塞拉多物种）与密花野牡丹（Miconia chartacea，大西洋森林物种）的叶盘，将其置于大西洋森林溪流中进行预处理；第二组处理（T2）则将密花野牡丹的叶盘分别置于大西洋森林与塞拉多溪流中进行预处理。两组实验均显示两种处理间存在显著差异。在T1组中，菲洛石蛾属物种仅取食了密花野牡丹的叶盘，未取食橄榄形金叶树的叶盘。在T2组中，菲洛石蛾属生物更偏好取食经大西洋森林溪流预处理的密花野牡丹叶盘，而非经塞拉多溪流预处理的样本。研究结果表明，菲洛石蛾属物种更倾向于取食大西洋森林生物群系的食物碎屑，而对塞拉多生物群系的食物碎屑表现出拒食行为。