J Plant Ecol ›› 2020, Vol. 13 ›› Issue (4): 405-412.DOI: 10.1093/jpe/rtaa027

• Research Articles • Previous Articles     Next Articles

Aboveground herbivory increases soil nematode abundance of an invasive plant

Jia Liu1,2, Susu Dai1,2, Wei Huang1,3, * and Jianqing Ding4, *   

  1. 1CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, Hubei, China, 2 University of Chinese Academy of Sciences, Beijing 100049, China, 3 Core Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, Hubei, China, 4 School of Life Sciences, Henan University, Kaifeng 475004, Henan, China

    *Corresponding author. E-mail: huangwei0519@wbgcas.cn (W.H.); jding@henu.edu.cn (J.D.)
  • Received:2019-12-16 Revised:2020-04-20 Accepted:2020-05-21 Online:2020-05-26 Published:2020-08-01

Abstract:

Aims

Plant invasions have the potential to affect the community structure of soil nematodes, but little is known about whether such effects are mediated by aboveground herbivores since invasive plants are not completely released from herbivores in the introduced range. In this study, we explored how aboveground insect herbivores mediated the effect of invasive plant Alternanthera philoxeroides on soil nematodes and examined the temporal variations of such an herbivory-elicited effect.

Methods

We conducted a greenhouse experiment by applying different herbivory treatments (no insect herbivores, specialist Agasicles hygrophila and generalist Cassida piperata) to potted A. philoxeroides, and then measured the community compositions of soil nematodes in corresponding pots on the 1st, 10th and 20th day after removal of all herbivores. In addition, the carbon content of roots and root exudate of A. philoxeroides were also measured.

Important Findings

Our results showed that aboveground herbivory significantly increased the abundance of soil nematodes of A. philoxeroides, likely plant feeder nematodes, after insect herbivores were removed immediately (1st day). However, such impacts waned with time and there was no significant difference at later stages (10th and 20th days). Furthermore, the effects of specialist A. hygrophila and generalist C. piperata herbivory were consistent on the abundance of soil nematodes. Overall, our results suggest that aboveground insect herbivores have the potential to alter the effects of plant invasions on soil nematodes, but such impacts are transient. Furthermore, our study highlighted the importance of integrating the effects of above- and belowground organisms when evaluating the impacts of plant invasions.

Key words: aboveground insect herbivores, soil nematodes, trophic groups, plant invasions, temporal change

摘要:
入侵植物往往可以影响土壤线虫的群落结构。然而,入侵植物在入侵地并未完全逃逸地上植食性昆虫的取食危害,而我们对昆虫取食是否会调节入侵植物对土壤线虫群落的影响还知之甚少。在本研究中,我们探讨了地上植食性昆虫取食危害如何调节入侵植物空心莲子草(Alternanthera philoxeroides)对土壤线虫群落的影响,并研究了昆虫调节作用的时间效应。我们开展温室实验,对盆栽的空心莲子草施加三种不同的昆虫取食处理[无昆虫取食、专食性昆虫莲草直胸跳甲(Agasicles hygrophila)取食、广食性昆虫虾钳菜披龟甲(Cassida piperata)取食],并在移除所有植食性昆虫后的第1、10和20天测定土壤线虫的群落结构。此外,我们还测定了空心莲子草根系及根系分泌物的碳含量。研究发现,在植食性昆虫被移除的第1天,昆虫取食处理显著提高了空心莲子草根围土壤线虫的丰度,特别是植食性线虫。然而,随着时间推移,这种影响逐渐减退,并在后期(第10和20天)完全消失。此外,专食性昆虫莲草直胸跳甲和广食性昆虫虾钳菜披龟甲的取食危害对土壤线虫丰度的影响并无显著性差异。综上所述,本研究表明地上植食性昆虫的取食危害可以改变入侵植物对土壤线虫群落的影响,但昆虫的调节作用是短暂的。此外,我们的研究强调了在评估入侵植物的影响时,需要同时考虑地上和地下生物群落。

关键词: 地上植食性昆虫, 土壤线虫, 功能群, 植物入侵, 时间效应