Numerous biological control introductions have adversely affected non-target native species. While many of these problems occurred in the early days of biological control, some are recent. Because there is little monitoring of species, communities and ecosystems that could be affected by biological control agents, it is quite possible that the known problems are the tip of an iceberg. Regulations for officially approved biological control releases are insufficient, and there are also unregulated independent releases made by private citizens.
Cost-benefit analyses for conservation problems, including those associated with biological control, are extremely difficult because it is difficult to assign values to loss of species or ecosystem functions. Risk assessment for biological control is difficult because of how difficult it is to predict the impacts of introduced species across the community and ecosystem and because introduced species disperse and evolve. However, cost-benefit analyses and risk assessments for the introduction of biological control would have the healthy effect of forcing consideration of myriad factors that now often receive superficial attention and of expanding public understanding of the problems. Classic biological control (biocontrol) is the selection and introduction of a natural enemy of an invasive plant or insect pest that suppresses that pest in its area of origin, and the “meeting of this natural enemy with the invasive pest” to provide sustainable, cost-effective and long-term pest management.
Other forms of biocontrol exist, including augmentative and conservation biocontrol (learn more about them here), but this site does not focus on those types. Since many of the main crop pests are insects, many of the predators used in biological control are insectivorous species. Conservation biological control, which focuses primarily on supporting native enemy populations, uses biotic resistance with greater force, although any natural enemy with sufficient density prior to pest establishment can help prevent establishment. We conducted a systematic review of empirical studies on enemy risk effects on biocontrol systems using combinations of the search terms “biological control”, “biocontrol” and “pest” with the terms “non-consumptive”, “non-consumptive”, “non-lethal”, “sublethal”, “risk effect*”, “anti-predatory” or “anti-predatory”, or “anti-predatory” predator.
A potential obstacle to biological pest control measures is that producers may prefer to stick to family use of pesticides. Community ecologists can also find, in biological control systems, abundant examples where the consequences of risk effects manifest themselves in well-characterized systems between predators and prey, including coevolved and new associations between predators and prey. The term biological control was first used by Harry Scott Smith at the 1919 meeting of the Pacific Slope branch of the American Association of Economic Entomologists, in Riverside, California. This means that many studies focusing on EC lack the scale necessary to capture enemy risk effects, a topic that has been reviewed elsewhere (Hermann and Landis, 201) and covered with respect to biological control in Table 2.
Compensatory mortality can also occur in biological control systems, such as when density-dependent mortality is replaced by enemy-induced mortality, leading to no general difference in mortality (Cloutier and Bauduin, 1995; Suh et al. Focusing on preventing unwanted and harmful pest behavior, whether by eliminating pests or changing their behavior, expands the scope of interactions that can be used in biological control. After the failure of a massive and controversial insecticide-based eradication effort, the focus was on classical biological control. Natural enemies of insect pests, also known as biological control agents, include predators, parasitoids, pathogens, and competitors.
However, in the native ranges of red ants, they concluded that they were poor candidates for effective biological control, because they achieved very low rates of parasitism (Jouvenaz et al. . .