Predation: The Role of Generalist Predators in Biodiversity and Biological Control

Classic biological control of pest non-marine mollusks has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting mollusks are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusk pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusk biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusk biocontrol programs to date.

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Assessing the role of generalist predators in the biological control of alfalfa weevil (Coleoptera: Curculionidae)

The Canadian Entomologist ◽

10.4039/tce.2017.9 ◽

2017 ◽

Vol 149 (4) ◽

pp. 525-533 ◽

Cited By ~ 1

Author(s):

Tatyana A. Rand

Keyword(s):

United States ◽

Biological Control ◽

Experimental Work ◽

United States Of America ◽

Acyrthosiphon Pisum ◽

The United States ◽

Generalist Predators ◽

Alfalfa Weevil ◽

Exclusion Experiment ◽

Predator Exclusion

AbstractAlfalfa weevil (Coleoptera:Curculionidae) is a major pest of alfalfa throughout the United States of America. Biological control research has disproportionately focussed on introduced parasitoids. Generalist predators may also be important, but experimental work evaluating their impacts is lacking. I combined a cross-site survey with a predator exclusion experiment to identify key predators, and test for impacts on weevil survival and plant defoliation levels in Montana and North Dakota, United States of America. Spiders (Araneae) dominated the complex, followed by Nabidae (Hemiptera) and Coccinellidae (Coleoptera). None of the dominant predators showed aggregative responses to weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) or pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) densities across 10 sites surveyed. However, weevil densities were positively correlated with both coccinellid and nabid densities across transects at the experimental site. Thus, predator groups traditionally associated with aphids can show strong aggregative numerical responses to alfalfa weevil larvae at smaller scales. Predator exclusion revealed no significant predator effects on larval survival or alfalfa damage. However, final densities of pea aphids were significantly higher in exclusion treatments relative to controls. The results suggest that even under conditions where predators exert significant pressure on aphids, they may still have minimal impacts on weevils. Additional experimental work is necessary to determine the broader potential of generalist predators as alfalfa weevil control agents.

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Biological Control and Mitigation of Aflatoxin Contamination in Commodities

Toxins ◽

10.3390/toxins13020104 ◽

2021 ◽

Vol 13 (2) ◽

pp. 104

Author(s):

Ferenc Peles ◽

Péter Sipos ◽

Szilvia Kovács ◽

Zoltán Győri ◽

István Pócsi ◽

...

Keyword(s):

Biological Control ◽

Secondary Metabolites ◽

Competitive Exclusion ◽

Aflatoxin Contamination ◽

Post Harvest ◽

Physical Chemical ◽

Synthetic Chemicals ◽

Ruminal Degradation

Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.

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PREY PREFERENCES OF ADULT AND IMMATURE ZETZELLIA MALI EWING (ACARI: STIGMAEIDAE) AND TYPHLODROMUS CAUDIGLANS SCHUSTER (ACARI: PHYTOSEIIDAE)

The Canadian Entomologist ◽

10.4039/ent125967-5 ◽

1993 ◽

Vol 125 (5) ◽

pp. 967-969 ◽

Cited By ~ 14

Author(s):

David R. Clements ◽

Rudolf Harmsen

Keyword(s):

Biological Control ◽

Potential Role ◽

Panonychus Ulmi ◽

Economic Damage ◽

Apple Orchards ◽

Effective Management ◽

Phytoseiid Mites ◽

Prey Preferences ◽

Eriophyid Mites

Effective management of the interactions within the mite community is critical to biological control of economically damaging phytophagous mites such as Panonychus ulmi Koch (Tetranychidae) (Clements and Harmsen 1990). Although much is known about the potential role of phytoseiid mites in controlling P. ulmi (Dover et al. 1979), mites from at least seven other families may be present in apple orchards (Thistlewood 1991). Stigmaeid mites are predators which may play a beneficial role in biological control in conjunction with phytoseiids (Clements and Harmsen 1992). Eriophyid mites are phytophagous but seldom cause economic damage, and may compete with tetranychids and provide alternative food for predators of tetranychids (Croft and Hoying 1977).

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