Selecting biological control agents

Predicting direct non-target impacts

Selecting agents for safety

Comparisons of associations in native and receiving range

Apart from the records of host associations in the native range of the natural enemy, other records essential to the assessment of both the efficacy and risk of a biological control agent are:

other hosts of the proposed control agent in the native range;
other hosts of the control agent where it has established outside its native range;
other natural enemies of the host in the native range;
other natural enemies of the host where it has established outside its native range;
natural enemies of hosts in the native range that are related to the target (Hoddle 2004);
natural enemies of hosts in the exotic range that are related to the target;
natural enemies of hosts related to the target in the receiving range (Hill and Hulley 1995).

For all the wealth of information now available, it is almost certain that there will be insufficient recorded information to adequately define the risks posed by the proposed natural enemy to non-target species and ecosystems. The non-target fauna in the receiving region may be under-studied or the agents may even be new to science. Gaps in the identification of fauna at risk in the receiving range can be filled by developing a list of species at risk based on critically examining the phylogeny, morphology, physiology, behaviour, geography, phenology, vagility, climatic requirements and habitat preferences or requirements of both agents and potential hosts (Hoddle 2004).

Lack of host records where they might be otherwise expected may be useful in identifying primary host range or ecological limits to host use (Sands and Van Driesche 2004).

Sources of information about host associations for natural enemies in New Zealand include:

the plant and insect databases at Landcare Research [http://www.landcareresearch.co.nz/databases];
- Te Papa Tongarewa and other museums and institutions;
- the BUGS database;
PlantSyNZ database [http://dataversity.org.nz/guide/systems/plant_synz/];
PIPN database (MPI Biosecurity);
Forest Research Institute collection

References

Hill M.P. and Hulley P.E. (1995). Host-range extension by native parasitoids to weed biocontrol agents introduced to South Africa. Biological Control 5: 297-302.

Hoddle M. (2004). Restoring balance using exotic species to control invasive exotic species. Conservation Biology 18: 38-49

Sands D.P.A. and Van Driesche R.G. (2004). Using the scientific literature to estimate the host range of a biological control agent. Pp. 15-23 In: Assessing host ranges for parasitoids and predators used for classical biological control: a guide to best practice, R.G. Van Driesche and R. Reardon (Ed.) USDA Forest Service, Morgantown, West Virginia.