Exploring agent and host traits in successful classical biological control programmes
Classical biological control of invasive alien plants has shown some excellent results worldwide, decreasing populations of some pests to below an economic and ecological threshold. Taxonomy and feeding characteristics of a biological control agent, and the life history of an invasive alien plant have been described as traits that can predict success. Global biological control programmes against invasive alien plants were evaluated for correlations between the biological control agent and target species traits. Data from the 5th edition of ‘Biological Control of Weeds: A World Catalogue of Agents and Their Target Weeds’ were used as the basis of the analysis. Analyses of biocontrol agents’ establishment, reveal that the following traits were correlated with a greater probability of establishment: being an internal feeder, feeding on above-ground plant tissues, multivoltine agents and agents that feed during both their adult and immature life stages. The study did not find an correlation with insect taxon and establishment, except for Lepidopteran biocontrol agents, which had the lowest establishment probability. For invasive plant traits, species occurring in aquatic or riparian habitats were associated with a higher probability of biocontrol agent establishment. The study also looked at impact of biological control agents. Those which had the greatest impact were agents feeding externally and on vegetative plant tissues, multivoltine agents and those with both adult and immature stages feeding on the host. Greater biocontrol impact was associated with perennials, plants reproducing only vegetatively and those invading aquatic or riparian habitats. These correlations, could be used when prioritizing invasive alien plants for biocontrol, and the selection of suitable biocontrol agents.
Sources
Panta S, Schwarzländer M, Weyl PSR, Hinz HL, Winston RL, Eigenbrode SD, Harmon BL, Bacher S, Paynter Q (2024) Traits of insect herbivores and target weeds associated with greater biological weed control establishment and impact. BioControl. https://doi.org/10.1007/s10526-024-10245-6