The long needle-like extension on the tip of the abdomen is the ovipositor, or egg-laying structure of this female parasitoid wasp. I watched her thrust the ovipositor down into the centre of the native daisy multiple times. This type of behaviour suggests she was laying eggs inside a host, probably some type of arthropod living concealed inside the disc florets. It serves as a reminder that in gardens and habitats with a diversity of native plants, tri-trophic interactions are more likely to occur because most native insects depend on native plants for survival (plant is native oxeye sunflower: "Heliopsis helianthoides", family Asteraceae).
parasitoidichneumonichneumonoideahymenopteraovipositorinsectwaspdaisyheliopsisasteraceaenative plantflowerbiodiversityontariocanadaunited states of Americanorth america