Gordon Elizabeth, Pacheco Sergio
Instituto de Zoologia Tropical, Escuela de Biologia, Facultad de Ciencias, Universidad Central de Venezuela, A.P. 47058, Caracas 1041, Venezuela.
Rev Biol Trop. 2007 Sep-Dec;55(3-4):795-803. doi: 10.15517/rbt.v55i3-4.5956.
Carnivorous aquatic plants, genus Utricularia (Lentibulariaceae), capture small aquatic organisms, such as rotifers, copepods, and cladocerans, by means of anatomical structures named bladders. The present study aimed to determine prey size and composition in U. gibba and U inflata, which were collected from a small lake and an herbaceous wetland, respectively, located in Paria Peninsula (Sucre State, Venezuela). Water pH, conductivity, dissolved oxygen, and salinity were measured in situ at each sampling location, and water samples were collected to determine N-Kjeldahl, total-P, Na+, K+, Ca++, Mg++, and Cl-. Fifty bladders from each plant species were measured and their contents were analyzed. N-Kjeldahl and total-P values were similar in both sites, and were also similar to values reported for eutrophic ecosystems, although Na+, K+, Ca++, Mg++ concentrations and in situ water parameter values were higher in the herbaceous wetland. Bladder content showed the following zooplankton groups: rotifers, cladocerans, copepods, annelids, rhizopodeans, and insects; and the following phytoplankton divisions: Bacillariophyta, Chlorophyta, Cyanophyta, and Euglenophyta. U. inflata presented smaller and fewer bladders, but higher abundance and total algal and animal morphospecies richness than U. gibba. Prey composition similarity at the taxon level between the two carnivorous species was low.
狸藻属（狸藻科）的肉食性水生植物通过名为捕虫囊的解剖结构捕获小型水生生物，如轮虫、桡足类动物和枝角类动物。本研究旨在确定分别从位于帕里亚半岛（委内瑞拉苏克雷州）的一个小湖泊和一个草本湿地采集的圆叶狸藻和膨胀狸藻的猎物大小和组成。在每个采样地点现场测量水的pH值、电导率、溶解氧和盐度，并采集水样以测定凯氏氮、总磷、钠离子、钾离子、钙离子、镁离子和氯离子。对每个植物物种的50个捕虫囊进行测量并分析其内容物。两个地点的凯氏氮和总磷值相似，并且与富营养化生态系统报告的值也相似，尽管草本湿地中的钠离子、钾离子、钙离子、镁离子浓度和现场水参数值更高。捕虫囊内容物显示出以下浮游动物类群：轮虫、枝角类动物、桡足类动物、环节动物、根足类动物和昆虫；以及以下浮游植物门类：硅藻门、绿藻门、蓝藻门和裸藻门。膨胀狸藻的捕虫囊更小且数量更少，但比圆叶狸藻具有更高的丰度以及藻类和动物形态物种的总丰富度。这两种肉食性物种在分类水平上的猎物组成相似性较低。
