Many insects have a close association with one or a few species of plant that they use for food. For these insects that “specialize” on a single plant, the fate of the insect is tied to the fate of the plant. Changes in environment that decrease the host plant population decrease the population of the insect.
The Tansy Beetle, Chrysolina graminis, is a beautiful metallic green beetle that feeds on Tansy, Tanacetum vulgare. Tansy is native to Europe and Asia, but can be invasive in other parts of the world. In England, the tansy population is declining due to shading by willow and livestock grazing. The decline in the Tansy population has fragmented the population of Tansy Beetles and caused a decline in beetle populations.
The Tansy Beetle is currently confined to a 30 km stretch of the River Ouse. Nearby Askham Bryan College has adopted the Beetle and is planting an “Ark” (As in Noah’s Ark) for the beetle. Currently the beetle populations are maintained by captive breeding. However, the planting and maintenance of refuges can save the beetle from extinction. The key to saving endangered species is protection of the habitat and resources that are required by the endangered species.
For students at the college, the Beetle “Ark” provides a hands on introduction to the problems of endangered species and the need for habitat preservation and in some cases creation and management of additional protected habitat.
Tansy Beetle
Photo: Geoff Oxford
Living With Insects Blog 
Beautiful beetle. I’ve heard that God is inordinately fond of them, beetles in general.
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Hi I found one of these yesterday in our Granny’s garden. We’ve been gardening therefor 50 years it’s a type of allotment and we’ve never seen one before. Today I’ve ordered some Tansy seed in order to give them what they want. Do I need to record it anywhere that we have them in the garden?