Franceschini María Celeste, De Wysiecki María Laura, Poi de Neiff Alicia, Galassi María Eugenia, Martínez Fedra Solange
Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Ecología Aplicada del Litoral, Ruta 5, km 2,5 -3400- Corrientes, Argentina.
Rev Biol Trop. 2011 Sep;59(3):1407-18.
Cornops aquaticum is a widely distributed semiaquatic grasshopper in the Neotropics. The development, feeding and oviposition of C. aquaticum take place on Pontederiaceae, especially on species of Eichhornia. Several aspects of the feeding of C. aquaticum are studied because is one of the most important herbivores of the highly invasive floating Eichhornia crassipes in native areas. The aims of this paper were: (1) to quantify the amount of E. crassipes consumed by C. aquaticum, (2) to determine the growth rate and the conversion efficiency of food ingested by this grasshopper, and (3) to determine the possible effect of consumption on E. crassipes productivity. Thirty individuals from each specific age class were used in the experiment: nymphs A, nymphs B, adult males and adult females. Insects were individually confined in plastic pots with a leaf of E. crassipes. We estimated feeding by individual, consumption index (CI), relative growth rate (GR) and efficiency of conversion of ingested food to body substance (ECI). The impact of C. aquaticum consumption on E. crassipes floating meadows was assessed with the abundance of the grasshopper, and the available data on primary production of the host plant at the study site. Food intake of C. aquaticum was 11.23% of plant productivity. Food consumption, growth rate and food conversion efficiency of this grasshopper varied according to the specific age classes. Damage caused by C. aquaticum is high in comparison with the damage caused by other semiaquatic and grassland grasshoppers, however it is not enough to prevent the growth and coverage of native E. crassipes floating meadows because abundance of grasshoppers are realtively low and the growth rate and productivity of the host plant is high.
水玉蝗是一种广泛分布于新热带地区的半水生蝗虫。水玉蝗的发育、取食和产卵都发生在雨久花科植物上，尤其是凤眼蓝属的物种。对水玉蝗的取食进行了多方面研究，因为它是原生地区极具入侵性的漂浮植物凤眼莲的最重要食草动物之一。本文的目的是：（1）量化水玉蝗消耗的凤眼莲数量；（2）确定这种蝗虫的生长速率和摄入食物的转化效率；（3）确定取食对凤眼莲生产力的可能影响。实验使用了每个特定年龄组的30只个体：A龄若虫、B龄若虫、成年雄性和成年雌性。将昆虫单独饲养在装有一片凤眼莲叶的塑料盆中。我们估计了个体的取食量、消耗指数（CI）、相对生长速率（GR）以及摄入食物转化为身体物质的效率（ECI）。通过蝗虫的数量以及研究地点寄主植物初级生产的现有数据，评估了水玉蝗取食对凤眼莲漂浮草甸的影响。水玉蝗的食物摄入量占植物生产力的11.23%。这种蝗虫的食物消耗量、生长速率和食物转化效率因特定年龄组而异。与其他半水生和草原蝗虫造成的损害相比，水玉蝗造成的损害较高，然而，这并不足以阻止原生凤眼莲漂浮草甸的生长和覆盖，因为蝗虫数量相对较少，且寄主植物的生长速率和生产力较高。
