Weevil (Buddleja leaf) Cleopus japonicus
Species: C. japonicus
Scientific name: Cleopus japonicus
Common name: Buddleja leaf weevil, Buddleja weevil
Cleopus japonicus is a small weevil (about 4 mm long) from China and was introduced to New Zealand in 2006 as a weed biocontrol agent of Buddleja davidii. It has been released at over 30 sites in the North and South Islands and it has established readily. The buddleia leaf weevil is the first biological control agent to be released for buddleia anywhere in the world.
Buddleja davidii is a native plant from the Sichuan and Hubei provinces in central China and is now a major invasive weed and is now common throughout New Zealand. Buddleia is extremely ecologically versatile, tolerating a wide range of soils, especially poor soils. It can tolerate frost and a wide range of conditions. Thickets establish and grow quickly, and are self-replacing. It invades river beds, stream sides, disturbed forest, shrubland margins and bare land. In riverbeds, it can alter water flow, causing silt to build up and flooding problems. It is spread by fine seeds which are windblown and cut stumps will also resprout.
The female Buddleja weevil (Cleopus japonicus) lays a single egg (0.5mm in diameter) just under the surface of the leaves of buddleia bushes. A female can lay up to 20 eggs per day. The eggs hatch and grow into a soft-bodied, yellow to greenish larvae that are up to 5mm in length. They are covered with a shiny mucous that is sticky and adheres to animals and humans enabling them to be transferred to new plants. The larvae are usually present from around September to May. They eat away at both the upper and lower surfaces of leaves. They can completely defoliate a plant and will eventually kill it. The adults who can live up to a year also feed on the upper surface of the leaves. When mature the larvae spin oval brown cocoons where they pupate attached to the plant or in the leaf litter below.
Although the nectar of buddleja flowers is food for butterflies, the plant's potential impact on our native ecosystems far outweighs its food value for butterflies. For more details on the weed plant Buddleja http://www.terrain.net.nz/friends-of-te-henui-group/weeds-by-scientific-names/summer-lilac.html
Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/