Love them or hate them, this year the east coast is going to encounter a phenomenon that only happens once every 17 years. We will see billions of insects – more specifically, cicadas – crowding our region for a four-to-six-week period in the late spring through early summer. Smithsonian Gardens Plant Health Specialist Holly Walker will answer the pertinent questions – Where have they been? What’s the difference between Annual vs. Periodical Cicadas? What’s all that noise? What do they do? What are they good for? – and maybe convince us to respect their role in the environment.