Bugs scaring bugs: enemy‐risk effects in biological control systems

Abstract

Enemy‐risk effects, often referred to as non‐consumptive effects (NCEs), are an important feature of predator–prey ecology, but their significance has had little impact on the conceptual underpinning or practice of biological control. We provide an overview of enemy‐risk effects in predator–prey interactions, discuss ways in which risk effects may impact biocontrol programs and suggest avenues for further integration of natural enemy ecology and integrated pest management. Enemy‐risk effects can have important influences on different stages of biological control programs, including natural enemy selection, efficacy testing and quantification of non‐target impacts. Enemy‐risk effects can also shape the interactions of biological control with other pest management practices. Biocontrol systems also provide community ecologists with some of the richest examples of behaviourally mediated trophic cascades and demonstrations of how enemy‐risk effects play out among species with no shared evolutionary history, important topics for invasion biology and conservation. We conclude that the longstanding use of ecological theory by biocontrol practitioners should be expanded to incorporate enemy‐risk effects, and that community ecologists will find many opportunities to study enemy‐risk effects in biocontrol settings.

Predator complementarity dampens variability of phytoplankton biomass in a diversity-stability trophic cascade

“…This scenario aligns with our experiment. It is also possible that the predators facilitated each other, for example if the behavior of one predator disturbed the other predator's prey from a refuge, thereby increasing its vulnerability to the second predator (Culshaw-Maurer et al 2020). The lack of refuges in the tanks makes this scenario less likely, however.…”

Risk-Induced Trait Responses and Non-consumptive Effects in Plants and Animals in Response to Their Invertebrate Herbivore and Parasite Natural Enemies

“…When it comes to TMIEs broadly involving plant-herbivore interactions, most work has considered reductions in plant damage owing to altered herbivore behaviors when the natural enemies of these herbivores (predators and parasitoids) are recruited (e.g., Culshaw-Maurer et al, 2020). But enemy RITRs in plants themselves could also result in TMIEs.…”

“…Costly pre-emptive defenses by prey, and consumption-based defensive responses of plants and animal hosts to herbivores and parasites, respectively, are well-documented in comparison. Future work should thus consider the interplay between pre-emptive (risk-induced) and consumption-induced trait changes in the two victim systems, particularly as it relates to applying NCE knowledge for natural enemy control (e.g., Culshaw-Maurer et al, 2020), and the population viability of focal organisms in habitats where herbivore or parasite threat may be either diminished or heightened (e.g., Rusch et al, 2013;Gottdenker et al, 2014).…”

Controlling invasive species with biologically-inspired robots

“…We believe that state-of-the-art robots inspired by live predators offer an extraordinary opportunity to alter the behavior of invasive species and study the detrimental consequences of fear and anxiety on their survival and reproduction. World-leading experts in ecology and evolution indeed advocate for expanding the conceptual underpinning and practice of biological control (Culshaw-Maurer et al, 2020). In this vein, cutting-edge technologies can play a key role in revealing the evolutionary vulnerabilities of invasive and pest species, and transfer the fundamental knowledge from predator-prey ecology to inform a new generation of biocontrol practices.…”