Black-margined Loosestrife Beetle - Galerucella calmariensis

"Galerucella calmariensis" is a species of leaf beetle in the family Chrysomelidae. It is commonly known as the black-margined loosestrife beetle and is native to Europe and Asia where both adults and larvae feed on purple loosestrife. It has been introduced in North America as a biological control agent for purple loosestrife.