Supplemental data for: Friend or foe? Investigating Lasius neoniger (Hymenoptera: Formicidae) and Myzus persicae (Hemiptera: Aphididae) interspecies dynamics in a greenhouse agroecosystem

Ant–aphid interactions are common in agroecosystems, yet the species-specific ecological and agronomic interactions remain understudied in North America, particularly in an agricultural hotspot like Ontario. This study investigates the relationship between a common ant, Lasius neoniger, and the green peach aphid, Myzus persicae. This study explores how these interactions affect aphid population dynamics and the growth of greenhouse-grown bell pepper, Capsicum annuum plants.

Using a controlled laboratory experiment with four treatment groups (control, ants only, aphids only, ants + aphids), we measured aphid density, ant colony development, and pepper plant leaf number, stem length, and root density. Aphid densities were significantly lower in the presence of ants, suggesting that L. neoniger may suppress M. persicae populations, likely through predation rather than mutualistic tending. This challenges the common assumption of obligate mutualism in ant–aphid relationships and suggests that ant-aphid interactions are species-specific.

Despite reduced aphid numbers, plant growth metrics did not differ significantly across treatments. These findings offer new insight into the context-dependent nature of ant–aphid interactions, suggesting that under certain conditions, ants could suppress aphids. This research contributes to a growing body of literature on multi-trophic interactions.

It highlights the potential for native ants like L. neoniger to play a role in sustainable greenhouse agriculture. Future studies should incorporate behavioural observations, longer observation timelines, and multi-species comparisons to further clarify the ecological mechanisms and practical applications of these interactions. The manuscript associated with this study will be published in the journal of the Entomological Society of Ontario.