Floating pennywort: Biological control using co-evolved, host specific herbivores

How is the evidence assessed?
  • Effectiveness
    20%
  • Certainty
    50%
  • Harms
    not assessed

Source countries

Key messages

  • A replicated laboratory and field study in South America found that the South American weevil caused more feeding lesions on floating pennywort than on any other plant species, but field results found that the weevil did not reduce floating pennywort biomass.

 

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated laboratory and field study in 2011 in South America (Walsh & Maestro 2011) found that the South American weevil Listronotus elongatus, was the most common herbivore on floating pennywort and caused more feeding lesions on floating pennywort than on any other plant species, but field results found that the weevil did not reduce floating pennywort biomass.  Other species found to feed on floating pennywort included mining flies of genus Monochaetoscinella and Hydrellia, and the larvae of the moth Paracles quadrata. When the weevils were allowed to invade a mixed patch containing floating pennywort in the field, the highest numbers of larvae and adult weevils were found on patches of floating pennywort with the highest biomass, indicating that weevils perhaps move away from damaged plant sections and concentrate in the denser sections of the plant patch.  Studies of adult weevil plant choice involved  a three-stage process, beginning with a simple no-choice, cut-leaf feeding test on many plant species, followed by a whole-plant against cut-leaf no-choice test on selected species.   Finally, South American weevils were allowed to invade a mixed patch containing floating pennywort, where after two months, damage was evaluated in 30 randomly selected 10 x 10 cm squares.

    Study and other actions tested
Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Some Aspects of Control of Freshwater Invasive Species. Pages 555-87 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Control of Freshwater Invasive Species

This Action forms part of the Action Synopsis:

Control of Freshwater Invasive Species
Control of Freshwater Invasive Species

Control of Freshwater Invasive Species - Published 2017

Control of Freshwater Invasive Species Synopsis

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust