Preferences of the common garden ant (Lasius niger) in choice of aphid mutualist : Possibilities to increase biological control of the rosy apple aphid (Dysaphis plantaginea)

Abstract: The aim of this study is to acquire knowledge about the preferences regarding aphids of the ant Lasius niger (common garden ant), commonly found attending aphids and protecting them agains their natural enemies in apple orchards around the world. By knowing this, it is hypothesized that another plant can be brought into an orchard carrying another aphid, more suitable as an ant-mutualist, to compete with the pest aphid present on site. The aphid Dysaphis plantaginea (rosy apple aphid), one of the key pests in apple orchards, was compared with Aphis fabae (black bean aphid), a common aphid that has been widely studied. This was done in an experiment involving multiple elements, including three arthropod organisms, apple trees and bean plants, in a semi-lab environment, to mimic real orchardconditions. The result of the experiment was in undisputed favour of Aphis fabae, showing a significantly higher attention-rate by ants, and also a growing attention over time in comparison with the attention of D. plantaginea that did not increase. In conclusion, it can be stated that A. fabae is a better ant-mutualist and that the addition of this aphid could very well amplify the effects of biological control of D. plantaginea by natural enemies in orchards.