The blacklegged tick (Ixodes scapularis) and the European fire ant (Myrmica rubra) are notable invasive pests in Maine, especially across coastal and southern regions. I. scapularis is the primary vector of the bacterium Borrelia burgdorferi, which is the causative agent of Lyme disease, and Maine currently has one of the highest Lyme disease incidence rates in the U.S. Ticks have many natural predators, including ants. This study investigates the effects of M. rubra on I. scapularis abundance and pathogen infection prevalence in Acadia National Park (ANP). I collected ticks by drag-sampling at eight ant-infested sites and eight control sites in ANP. I hypothesized that I. scapularis abundance would be lower at treatment sites, due to predation by M. rubra, but found no significant difference. In addition, I conducted laboratory bioassays to measure M. rubra aggression against different life stages of I. scapularis. I found that M. rubra behaves more aggressively towards I. scapularis adults than towards nymphs and larvae. Finally, I extracted DNA from a subset of collected nymphs and tested the samples for B. burgdorferi to determine nymphal infection prevalence (NIP) at control and treatment sites. I hypothesized a decreased NIP at treatment sites due to reduced abundance and host-encounter frequency of the small mammal reservoir hosts of B. burgdorferi, and again found no significant difference between control and treatment sites.
Guarnieri, Lucy, "The Effects of European Fire Ants on Blacklegged Ticks in Acadia National Park" (2019). Honors College. 519.