A Keystone Ant Species Provides Robust Biological Control of the Coffee Berry Borer Under Varying Pest Densities

ants;bioloigical controls;coffee berry borer;agroecology;Natural Resources and Environment

Morris, JonathanVanderneer, John ;

University of Michigan

关键词: ants;    bioloigical controls;    coffee berry borer;    agroecology;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/117665/Morris%20Thesis%202016.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Species’ functional traits are an important part of the ecological complexity thatdetermines the provisioning of ecosystem services. In biological pest control, predator responseto pest density variation is a dynamic trait that impacts the provision of this service inagroecosystems. When pest populations fluctuate, farmers relying on biocontrol services need toknow how natural enemies respond to these changes. Here we test the effect of variation incoffee berry borer (CBB) density on the biocontrol efficiency of a keystone ant species (Aztecasericeasur) in a coffee agroecosystem. We performed exclosure experiments to measure theinfestation rate of CBB released on coffee branches in the presence and absence of ants at four different CBB density levels. We measured infestation rate as the number of CBB bored intofruits after 24 hours, quantified biocontrol efficiency (BCE) as the proportion of infesting CBBremoved by ants, and estimated functional response from ant attack rates, measured as thedifference in CBB infestation between branches.Infestation rates of CBB on branches with ants were significantly lower (71%-82%) thanon those without ants across all density levels. Additionally, biocontrol efficiency was generallyhigh and did not significantly vary across pest density treatments. Furthermore, ant attack rates increased linearly with increasing CBB density, suggesting a Type I functional response. Theseresults demonstrate that ants can provide robust biological control of CBB, despite variation inpest density, and that the response of predators to pest density variation is an important factor inthe provision of biocontrol services. Considering how natural enemies respond to changes in pest densities will allow for more accurate biocontrol predictions and better-informed management ofthis ecosystem service in agroecosystems.