Does experimental evolution produce better biological control agents? A critical review of the evidence

Abstract

Biological control of crop pests is considered a good alternative or complement to the use of pesticides. However, legislation restricts the importation of natural enemies of pests. A potential way to circumvent this limitation is by using experimental evolution and/or artificial selection to improve native biological control agents. Here, we review studies that have used these methodologies and evaluate their success. Experimental evolution or artificial selection has been used on a wide range of traits, with most focusing on improving the performance of natural enemies in ecologically relevant environments, such as in the presence of pesticides or at different temperatures. Although most studies were poorly replicated, the selected traits generally improved following the selection process. However, correlated responses (often in the form of trade-offs) with other traits of interest were common. We suggest that the selection procedure can be improved by increasing replication and performing experimental evolution under more semi-natural environments, to ensure that the most useful traits are being selected.

Next Generation Biological Control: The Need for Integrating Genetics and Evolution

“…Rather than performing individual crosses with individuals of desired traits, experimental evolution exposes populations to specific environmental conditions for several generations and determines the effect on the trait of interest. Although generally successful (Lirakis & Magalhaes, 2019), selective breeding results have not been used in commercial biocontrol practice to an extent that might be expected, and artificial selection remains underutilised (Wajnberg, 2004;Lommen et al, 2017;Kruitwagen et al, 2018). There are several reasons for this.…”

“…This may be reflected in selection persistence being documented in insect lines even after many generations of no active maintenance on the trait (e.g. (White et al, 1970;Croft & Meyer, 1973;Roush & Hoy, 1980; see Lirakis & Magalhaes, 2019). It is also standard industrial practice to conduct quality control of biocontrol agent products (van Lenteren, 2003), which effectively screens against lines that have lost desirable traits.…”

“…For decades, it has been advocated to use genetic means to improve the efficacy of biocontrol programs (White, Debach, & Garber, 1970;Hoy, 1986;Hopper et al, 1993;Narang, Bartlett, & Faust, 1993;Nunney, 2003;Routray et al, 2017, Kruitwagen, Beukeboom, & Wertheim, 2018Lirakis & Magalhaes, 2019). Significant genetic variation has been demonstrated in several key life-history and behavioural traits of potential biocontrol agents (Hoy, 1985;Rousch, 1990;Hopper et al, 1993;Wajnberg, 2004, Ferguson et al, inpreparation a).…”

“…However, despite its proven application in, for example, crop and livestock breeding, there have been few attempts made to improve biocontrol agents through genetic means. We currently witness a revival of the idea to apply genetics to improve biocontrol programs, in terms of exploiting intra-and interspecific variation (Lommen, de Jong, & Pannebakker, 2017;Kruitwagen et al, 2018), performing experimental evolution (Lirakis & Magalhaes, 2019), adapting the microbiome for improving rearing methods (Ras et al, 2017), and population monitoring of released agents (Roderick & Navajas, 2003;Stouthamer & Nunney, 2014;Coelho et al, 2016). Notably, these methods all employ classic genetics principles within a species' existing gene pool, distinguishing them from Genetically Modified Organisms (GMOs) that have DNA from foreign organisms introduced into their genomes.…”

Classical biological control: should we stop or continue?

“…Narrow-directed genetic changes in population driven by artificial selection can be a cause of evolutionary trade-offs when adaptation to adverse conditions leads to a decrease in fitness for other conditions [8]. Natural selection targeting all traits shouldn't have such disadvantages or even induce some positive changes in several traits simultaneosly.…”