sawfly larvae on the edge of a hazelnut leave in a defensive s pose

leaf green insect invertebrate nature animal plant branch tree arthropod produce wildlife shrub animals arch birch sawfly black spots caterpillar closeup craesus septentrionalis creepy curl damage deciduous defense defensive posture defoliation disturbed dusky eating edge entomology feeding flat-legged tenthred foliage grey hazel hazelnut hungry larvae leaves macro margin nematus outdoors parasite pest prolegs raised body shape scare shiny head small wasp leave pose