Plant–herbivore–parasitoid interactions in an experimental freshwater tritrophic system: higher trophic levels modify competitive interactions between invasive macrophytes

Martin, Grant D; Coetzee, Julie A; Compton, Stephen

Title: Plant–herbivore–parasitoid interactions in an experimental freshwater tritrophic system: higher trophic levels modify competitive interactions between invasive macrophytes
Creator: Martin, Grant D
Creator: Coetzee, Julie A
Creator: Compton, Stephen
Date Issued: 2018
Date: 2018
Type: text
Type: article
Identifier: http://hdl.handle.net/10962/103892
Identifier: vital:32321
Identifier: https://doi.org/10.1007/s10750-017-3417-7
Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwater systems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and re-established the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
Format: 12 pages
Format: pdf
Language: English
Relation: Hydrobiologia
Relation: Martin, G.D., Coetzee, J.A. and Compton, S., 2018. Plant–herbivore–parasitoid interactions in an experimental freshwater tritrophic system: higher trophic levels modify competitive interactions between invasive macrophytes. Hydrobiologia, pp.1-12.
Relation: Hydrobiologia volume 817 number 1 307 318 July 2018 1573-5117
Rights: Authors
Rights: Use of this resource is governed by the terms and conditions of the SpringerLink Terms of Use Statement (https://link.springer.com/termsandconditions)

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Martin, Grant D (Dr)

Coetzee, Julie A (Prof)

RU Department of Botany

RU Department of Zoology and Entomology

RU DST/NRF SARChI for Insects in Sustainable Agricultural Ecosystems

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