An application to release the white admiral butterfly (Limenitis glorifica) was approved by the EPA in August 2013. This is the first of several proposed biocontrol agents that will work together to help control Japanese honeysuckle in New Zealand.
This application was submitted by Greater Wellington Regional Council, acting on behalf of the National Biocontrol Collective, a consortium of regional councils and the Department of Conservation. The Collective funds the development of weed biocontrol programmes in New Zealand. Landcare Research was the science provider for this research. Landcare Research has looked for natural enemies for honeysuckle in Japan for 3 years, and along with Japanese colleagues has conducted research to show that the butterfly would be suitable for release in New Zealand. Richard Hill & Associates prepared the application and managed the application process on behalf of Greater Wellington Regional Council and Landcare Research, including widespread consultation with EPA and other stakeholders.
Japanese honeysuckle vines grow rapidly, creating dense tangled curtains. Honeysuckle can form a complete blanket, shading out small trees and shrubs. It can cause canopy collapse. Stems produce roots where they touch the ground, helping the vine to clamber across the ground. It also provides support for faster-growing weedy vines such as morning glory and moth plant. It overtakes native forest remnants, wetlands, pine plantations, shrubland and transit corridors throughout New Zealand, and is regarded as a serious threat to the native flora. Fruit eating birds spread the seeds, but many new infestations originate from material from home gardens dumped on bushland and roadside edges
The biological control programme aims to gain control over this weed by establishing several natural enemies that damage it in a variety of ways. Together, the damage caused by control agents is expected to benefit the environment by reducing the growth rate and bulk of Japanese honeysuckle blankets to allow native vegetation to persist beneath it, and by reducing the rate at which the weed is spreading in new sites of invasion.
This application seeks approval to release the first of several control agents, the white admiral butterfly. The larvae of this butterfly feed on the foliage of Japanese honeysuckle, and will be introduced from Japan itself.
The potential risks, costs and benefits of biological control of Japanese honeysuckle and of the introduction of the insect itself have been formally identified
The key possible adverse effects of introducingLimenitis glorificawill be addressed fully in the application:
the risk of direct damage to valued garden ornamentals
the risk of direct damage to native plants
indirect effects on flora and fauna as a result of disruption of ecological relationships
the removal of Japanese honeysuckle as a food source for as a food source for native birds
White admiral butterflies can only survive on very narrow range of host plants. Research shows that no native plants will be at risk. However, larvae placed on several ornamental honeysuckles in the laboratory were able to feed on ornamental honeysuckles. Whether this could happen in the field is not certain, so we must assume that some damage to ornamentals could result from the introduction of this butterfly. This possibility will be discussed fully in the application, and taken into account when EPA makes its decision.
The agent is specific to honeysuckles, and butterfly populations will only build up where those host plants are abundant. Butterflies are very mobile. They may well be seen far from their host, but population densities capable of interacting significantly with other plants or animals will only be found in close proximity to large areas of honeysuckle. As a result, no significant disturbance of ecological relationships is expected in New Zealand. The presence of Japanese honeysuckle itself massively modifies natural interactions between species, and any reduction in the weed will help reverse those impacts. SomeLoniceraspecies recorded medicinal uses overseas, but biocontrol will not limit the supply of plants for any future use in New Zealand. Honeysuckles are important ornamental species, but outslde of ornamental use,Loniceraspecies have no significant value in New Zealand
Consultation with Māori
The EPA Māori National Network will be contacted and members will be asked to contribute their views for inclusion in the application. As applicant, Greater Wellington Regional Council will use its own networks to consult in more depth with iwi , hapū and organisations within that takiwā.
Consultations on previous applications to introduce biological control agents identified a range of generic views about the beneficial and adverse effects relevant to this technique. These views will be captured in the application. The Network will be informed when the application has been submitted and is opened for public submissions.
Safety issues are paramount in the minds of biocontrol of weeds researchers. Researchers rigorously test all proposed agents to assess the risk of damage to non-target plants. A set of procedures was developed to help researchers choose a suitable shortlist of test plants, and this methodology is now well-accepted internationally (Wapshere, 1974). The technique is under constant review to update best practice (e.g. Sheppard et al., 2005; Briese, 2005).
The results of host range testing conducted in Japan will be summarised in the application. The original data is contained in the following unpublished report. Interpretation of these reports will be peer reviewed, and the review will be included in the application.
A survey of the invertebrate fauna and fungi associated with Japanese honeysuckle,Lonicera japonica, in New Zealand was carried out between November 2004 and April 2005 by Landcare Research for regional councils and the Department of Conservation.